Damping materials are used to control mechanical vibrations, and piezoelectric damping composite is a very promising material due to its unique mechanism. In this study, a potential piezoelectric damping composite was developed by simply melt mixing poly(vinylidene fluoride) (PVDF) with small amounts of organic modified montmorillonite (OMMT) and multi-walled carbon nanotubes (MWCNTs). The piezoelectric, mechanical and electrical properties were investigated using a dynamic mechanical analyser, direct current electrical resistivity measurements, X-ray diffraction, Fourier transform infrared spectroscopy and the direct quasi-static d₃₃ piezoelectric coefficient method. It was found that the damping property of PVDF can be greatly improved by adding both MWCNTs and OMMT, and the composite containing 1.9 wt% of MWCNTs and 3 wt% of OMMT showed the best damping property. A model and an approximate calculation were applied to explain the improved damping property. Moreover, similar mechanical properties of PVDF composites were observed in the tensile testing and dynamic mechanical analyser measurements. Copyright © 2012 Society of Chemical Industry

The damping property of PVDF piezoelectric damping composite which containing 1.9 wt% MWCNTs and 3 wt% OMMT was greatly improved. A model and an approximate calculation were applied to explain the reason

Novel inner asymmetric composite microspheres were prepared by encapsulating surface-modified magnetic particles via mini-emulsion polymerization. Most of the surface-modified magnetic particles encapsulated into the polymer matrix aggregate in one side of each microsphere, while only a few particles randomly disperse in the remaining part. The magnetic content of these novel asymmetric composite microspheres is 46.7% and the saturation magnetization is 23.8 emu g⁻¹. Copyright © 2012 Society of Chemical Industry

Novel inner asymmetric composite microspheres were prepared by encapsulating surface-modified magnetic particles via mini-emulsion polymerization. The possible mechanism of formation of the inner asymmetric composite microspheres is discussed.

In this study, novel nitrile functionalized graphene (GN-nitrile)/poly(arylene ether nitrile) (PEN) nanocomposites were prepared by an easy solution-casting method and investigated for the effect of surface modification on the dielectric, mechanical and thermal properties. Graphene (GN) was first functionalized by introduction of nitrile groups onto the GN plane, which was confirmed by scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, thermogravimetric analysis and dispersibility research. Compared with pure GN, the grafted nitrile groups on the GN-nitrile can interact with nitrile groups in PEN and lead to flat but better dispersion and stronger adhesion in/to the PEN matrix. Consequently, GN-nitrile had a more significant enhancement effect on the properties of PEN. The dielectric constant of the PEN/GN-nitrile nanocomposite with 5 wt% GN-nitrile reaches 11.5 at 100 Hz, which is much larger than that of the pure PEN matrix (3.1). Meanwhile, dielectric loss is quite small and stable and the dielectric properties showed little frequency dependence. For 5 wt% GN-nitrile reinforced PEN composites, increases of 17.6% in tensile strength, 26.4% in tensile modulus and 21 °C in T_d5% were obtained. All PEN/GN-nitrile nanocomposite films can stand high temperature, up to 480 °C. Hence, novel dielectric PEN/GN-nitrile nanocomposite films with excellent mechanical and thermal properties can be used as dielectric materials under some critical circumstances such as high wear and temperature. Copyright © 2012 Society of Chemical Industry

The effect of nitrile functionalized graphene on the properties of poly (arylene ether nitrile) nanocomposite films was investigated in terms of morphological, dielectric, mechanical and thermal properties.

The dependence of hierarchy in crystalline structures and molecular orientations of high density polyethylene parts with different molecular weights molded by gas-assisted injection molding (GAIM) was intensively examined by scanning electron microscopy, two-dimensional wide-angle X-ray scattering as well as dynamic rheological measurements. The non-isothermal crystallization kinetics of the samples were also analyzed with a differential scanning calorimeter at various scanning rates. It was found that oriented lamellar structure, shish-kebab and common spherulites were formed in different regions of the GAIM samples. The scanning electron microscope observations were consistent with the two-dimensional wide-angle X-ray scattering results and showed that the molecular chains near the mold wall had strong orientation behavior, revealing the distribution of the shear rate of the GAIM process. The differences in crystal morphologies can be attributed to molecular weight differences as well as their responses to the external fields during the GAIM process. The formation mechanism of the shish-kebab structure under the flow field of GAIM was also explored. Copyright © 2012 Society of Chemical Industry

The differences in crystal morphologies of GAIM HDPE parts with different molecular weights can be attributed to the Mw differences and their responses to the external fields during GAIM.

The surface structure and nanomechanical properties of solution-cast nylon 6 (NY6)/feather keratin (FK) blend films were investigated using a combination of tapping-mode atomic force microscopy (AFM) phase imaging and nanoscale indentation. A tendency for a nanoscale phase separation between NY6 and FK in their various blends was judged based on the blend phase images. The surface topography and roughness analysis of the AFM height images revealed that FK-rich blends had coarser surfaces than NY6-rich ones, possibly due to the heterogeneous nature of the FK chemical structure. Amplitude–phase–distance measurements involving the assignment of the darker and brighter regions of the phase images to NY6-rich and FK-rich, respectively, or vice versa led to the recognition of a phase inversion in the blend containing 40 wt% FK. The occurrence of the phase inversion phenomenon was related to the significant difference between the molecular weights of the blend constituents. Analysis of nanoindentation data showed that blending FK and NY6 at various ratios resulted in mixtures with modified mechanical and adhesion features. On the one hand, the NY6 component was responsible for an enhanced elastic modulus and stiffness of the blends, and on the other hand, the FK component provided higher pull-off force and work of adhesion for the samples. A new approach is also proposed to directly determine the surface energy (γ) values of samples from the nanoindentation data. The excellent consistency between the calculated γ values and the results obtained from contact angle measurements lends credence to the proposed approach. Copyright © 2012 Society of Chemical Industry

A new approach is proposed to directly determine the surface energy values of nylon 6 (NY6)/feather keratin (FK) blend films through a combination of tapping-mode AFM and nanoindentation data.

The microwave-assisted polycondensation of maleic anhydride and 1,6-hexanediol was carried out using p-toluenesulfonic acid as catalyst. The resulting unsaturated polyester was characterized using Fourier transform infrared (FTIR) and ¹H NMR spectroscopy, and the molecular weight determined using gel permeation chromatography. 4,4′-Decanediyldioxydi(N-methyl-p-phenylenenitrone) was chosen as a model compound for the crosslinking of the unsaturated polyester. The crosslinking, which is known to proceed via 1,3-dipolaric cycloaddition, was followed using differential scanning calorimetry. Additionally, the kinetics of the cycloaddition was evaluated at 120 °C using FTIR spectroscopy. Copyright © 2012 Society of Chemical Industry

Using bis(nitrone)s as curing agents enables the crosslinking of unsaturated polyesters at low temperatures without the need for a catalyst.

In order to improve the photostability of polyoxymethylene (POM), a core-shell acrylate elastomer with UV stabilization, i.e. poly[(methyl methacrylate)-(butyl acrylate)-2-hydroxy-4-(3-methacryloxy-2-hydroxypropoxy)benzophenone] (core-shell poly(MMA-BA-BPMA)), was added into the POM matrix using a melt-mixing method. The effect of the modification with core-shell poly(MMA-BA-BPMA) on POM was compared with that of poly(MMA-co-BA-co-BPMA) copolymer. Scanning electron microscopy, metallographic microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and X-ray photoelectron spectroscopy were employed to characterize POM blends before and after UV irradiation, and the mechanical properties of the POM blends were investigated. The results showed that core-shell poly(MMA-BA-BPMA) improved well the compatibility with and toughness of the POM matrix, and its light-stable functional groups could increase the UV resistance of POM blends. During UV aging, the impact strength and elongation at break of POM/core-shell poly(MMA-BA-BPMA) blends were retained, the growth rate of surface cracks of POM was inhibited effectively by core-shell poly(MMA-BA-BPMA) and the degree of photo-oxidation of POM blend surfaces was improved to a certain extent. Compared with poly(MMA-co-BA-co-BPMA), core-shell poly(MMA-BA-BPMA) had a better UV stabilization effect on the POM matrix. Our results indicate that the core-shell acrylate elastomer with toughening and UV stabilization functions can significantly improve the long-term UV stability of POM. Copyright © 2012 Society of Chemical Industry

Compared with poly(MMA-co-BA-co-BPMA), core-shell poly(MMA-BA-BPMA) has a better UV-resistance effect on polyoxymethylene; the mechanical properties are better retained and the surface protected significantly in a UV aging process.

Polyhydroxyurethanes (PHUs) produced by the reaction between dicyclocarbonate and diamine groups are often presented as possible candidates to substitute for classical polyurethanes based on isocyanate precursors. In the literature, the synthesis of this class of polymers is often performed according to arbitrary conditions of time and temperature without any scientific justification. As such, the real potential of PHUs is probably not fully known. Numerous contradictions in previously published results seem to support this hypothesis. Our paper proposes two methodologies based on dynamic rheometry to determine optimized conditions for the synthesis of PHUs. The case of a PHU formed by the reaction between 1,10-diaminodecane and a dicyclocarbonate bearing a central aromatic group is described more precisely. The first approach consists of conducting various rheological experiments (kinetics, thermomechanical analyses) in situ on the reaction mixture. The second one retains the same technique to qualify the viscoelastic properties of PHUs synthesized according to various conditions. In this latter case, all samples show thermomechanical behaviour of amorphous thermoplastic polymers. But discrepancies are observed with regard to the value of the glass transition temperature and the existence or not of a rubbery zone. Comparison of these data with size exclusion chromatography results shows that these differences are direct consequences of the polymer molecular weight that can be predicted using macromolecular theory. The properties of the PHUs obtained after optimization of the polymerization reaction were compared with literature data in order to complete the evaluation of the efficiency of the rheological methodology. Copyright © 2012 Society of Chemical Industry

The temperature and time of polymerization reactions that lead to polyhydroxyurethanes with optimal properties have been determined according to rheological methods.

The radical polymerization of N-isopropylacrylamide was carried out in toluene at low temperatures in the presence of silyl alcohols, such as triethylsilanol. Poly(N-isopropylacrylamide) with a racemo dyad content of 75% was obtained at − 80 °C with a 4:1 triethylsilanol to monomer ratio loading. NMR analysis suggests that the mechanism for syndiotactic induction, in the presence of silyl alcohols, may be similar to that observed with alkyl alcohols. In this case, a 1:2 complex formation, via hydrogen bonding interactions, leads to the induction of syndiotactic specificity. Copyright © 2012 Society of Chemical Industry

The radical polymerization of N-isopropylacrylamide in toluene at −80 °C in the presence of triethylsilanol was found to give a syndiotactic polymer with a racemo dyad content of 75%.

Low-molecular-weight (M_n) polytetrafluoroethylene (PTFE) homopolymers were successfully prepared using a perfluorodiacyl initiator, bis(perfluoro-2-n-propoxypropionyl) peroxide, in supercritical carbon dioxide. Solid-state ¹⁹F NMR and Fourier transform infrared spectral analyses show that perfluoroalkyl end-groups are present in the resultant PTFEs. Thermogravimetric analysis suggests all polymers with various M_n have outstanding thermal stability. Differential scanning calorimetry measurements indicate that both melting and crystallization transitions of PTFE shift to lower temperatures when M_n decreases, because shorter polymer chains can move more easily at lower temperatures. Investigation of polymerization kinetics suggests that the rate law for the polymerization has kinetic orders of 0.5 and 1.0 with respect to initiator and monomer concentrations, indicating that termination occurs through coupling of propagating chains. Melt fusion crystallinity of as-polymerized PTFE can be as high as 86%, and the polymerization rate does not seem to be obviously affected by the total interphase area of the polymer phase, implying polymerization mainly occurs in the carbon dioxide-rich fluid phase; meanwhile, the low viscosity and high diffusivity of supercritical carbon dioxide mean that propagating chains have more opportunities to meet, thus yielding low-M_n PTFEs. Copyright © 2012 Society of Chemical Industry

Low-molecular-weight polytetrafluoroethylenes with perfluoroalkyl end-groups were prepared. Homopolymers have excellent thermal stability, which should be ascribed to the stable perfluoroalkyl end-groups arising from the perfluorodiacyl initiator.

Thiol-ene/clay (TE/clay) nanocomposite thin films were prepared by a simple photocuring process for use as transparent barrier films. In this work, tetrafunctional thiol and triene monomer were employed and organic clay surface modified with octadecylamine was mixed by sonication and a mechanical method as a reinforcing filler. The successful formation of the TE structure was confirmed by differential scanning calorimetry and X-ray diffraction. The homogeneous dispersion (intercalation and exfoliation) of clay into the TE polymer matrix was observed with transmission electron microscopy. Atomic force microscopy images displayed the surface properties of the TE/clay nanocomposite thin films. The thermal expansion behavior of the resulting hybrid film was monitored by thermomechanical analysis. In addition, gas permeation properties as well as light transmittance of the TE/clay films were measured for potential applications in various fields as dimensionally stable films under heating and as a transparent barrier. Copyright © 2012 Society of Chemical Industry

The preparation of TE/Clay nanocomposite thin films showing optical transparency, thermal stability, and enhanced gas barrier properties has been reported.

This study describes the preparation of polystyrene–clay nanocomposite (PS-nanocomposite) colloidal particles via free-radical polymerization in dispersion. Montmorillonite clay (MMT) was pre-modified using different concentrations of cationic styrene oligomeric (‘PS-cationic’), and the subsequent modified PS-MMT was used as stabilizer in the dispersion polymerization of styrene. The main objective of this study was to use the clay platelets as fillers to improve the thermal and mechanical properties of the final PS-nanocomposites and as steric stabilizers in dispersion polymerization after modification with PS-cationic. The correlation between the degree of clay modification and the morphology of the colloidal PS particles was investigated. The clay platelets were found to be encapsulated inside PS latex only when the clay surface was rendered highly hydrophobic, and stable polymer latex was obtained. The morphology of PS-nanocomposite material (after film formation) was found to range from partially exfoliated to intercalated structure depending on the percentage of PS-MMT loading. The impact of the modified clay loading on the monomer conversion, the polymer molecular weight, the thermal stability and the thermomechanical properties of the final PS-nanocomposites was determined. Copyright © 2012 Society of Chemical Industry

Polystyrene-clay nanocomposites colloidal particles were prepared using dispersion polymerization. Clay was pre-modified using PS-cationic, and then used as stabilizer in dispersion polymerization of styrene. The morphology of and colloidal stability of PS-nanocomposites latexes was strongly affected by the degree of clay modification.

Polyurethanes cover a large range of materials exhibiting various physical and mechanical properties making them useful in different applications such as elastomers or biomaterials, for instance. The introduction of ionic groups in the polyurethane backbone opens the way to new applications where the ionic groups can act as physical crosslinkers that greatly modify the final mechanical and thermal properties of the materials. Furthermore, the hydrophilicity of the chains can be enhanced by the presence of the ionic species, and so the materials can be processed as conventional dispersions even in a polar solvent such as water. As a consequence the applications are numerous; the main commercial outlets are focused on coatings and textiles industries where they can be used as waterproof coatings or substitutes for leather. But these materials can also be used in high-tech industries for shape memory materials, biomedical devices and biocompatible materials. This review summarizes the latest developments of this class of promising materials and provides the reader with the potentialities of these polymers in various areas.

This review gives an overview of the new trends in the area of the synthesis of polyurethane ionomers. Some applications of this interesting class of materials are detailed and comparisons of properties of various structures are given.

The time- and temperature-related crystallization process for the structure transitions of asymmetric crystalline-crystalline diblock copolymers from the melt to crystallites was investigated with synchrotron simultaneous small-angle/wide-angle X-ray scattering. Two asymmetric poly(ethylene oxide)-poly(ε-caprolactone) diblock copolymers were chosen. It is found in the course of the copolymer crystallization that the shorter blocks are uncrystallizable in both of the asymmetric diblock copolymers and final lamellar structures are formed in both of them. The final lamellar structure was confirmed from atomic force microscopy observations. The small-angle X-ray scattering data collected were analyzed with different methods for the early stage of crystallization. Guinier and Debye-Bueche plots indicate that there are neither isolated domains nor correlated domains formed before the formation of lamellae in the asymmetric diblock copolymers during the crystallization process. The structure evolution was calculated according to the correlation function, and the soft nanoconfined crystallization behavior is discussed. Copyright © 2012 Society of Chemical Industry

The shorter blocks in the nanoconfined environments are uncrystallizable in both poly(ethylene oxide)–poly(ε-caprolactone) asymmetric diblock copolymers (PEO_5k–PCL_1k and PEO_5k–PCL_30k) and the final lamellar structure is formed in both of the asymmetric diblock copolymers.

The preparation of 5-fluorouracil (5-FU) loaded poly(lactic-co-glycolic acid) (PLGA) biodegradable nanocapsules containing magnetite nanoparticles was studied through the modified multiple emulsion solvent evaporation method for magnetically controlled delivery of anticancer drugs. The morphology and size distribution of the prepared magnetite/PLGA nanocapsules were investigated by transmission and scanning electron microscopy. The micrographs showed that the magnetic nanocapsules were almost spherical in shape and their mean diameter was in the nanometer range with a narrow size distribution. Fourier transform infrared and ultraviolet–visible spectroscopy confirmed incorporation of 5-FU molecules into the PLGA matrix. The magnetite content was assessed by thermogravimetric and magnetometry analysis and the results showed a magnetite content of 35 wt% with high magnetic responsivity. Magnetometry measurements showed superparamagnetic properties of the magnetic nanocapsules with a saturation magnetization of 13.7 emu g⁻¹. Such biodegradable magnetic nanocapsules could be considered as an appropriate choice for drug targeting. Furthermore, the influence of some important processing parameters such as PLGA concentration, initial loading of 5-FU and poly(vinyl alcohol) concentration on drug content, encapsulation efficiency and in vitro drug release kinetics was investigated and optimized. The drug content and encapsulation efficiency of the magnetic nanocapsules were 4–7 wt% and 60%–80%, respectively, and the nanocapsules demonstrated controlled release of 5-FU at 37 °C in a buffer solution. All samples exhibited a burst release at the initial stage and this burst release showed its close dependence on the formulation parameters. Copyright © 2012 Society of Chemical Industry

A novel approach for preparation of 5-fluorouracil loaded poly (lactic-co-glycolic acid) biodegradable nanocapsules containing magnetite nanoparticles was investigated through modified multiple emulsion- solvent evaporation method for magnetically controlled delivery of anticancer drugs.

Nanowire-polypyrrole/gelatin hydrogels were fabricated by dispersion of nanowire-polypyrrole into a gelatin aqueous solution followed by solvent casting. The electromechanical properties, thermal properties and deflection of pure gelatin hydrogel and nanowire-polypyrrole/gelatin hydrogels were studied as functions of temperature, frequency and electric field strength. The 0.01%, 0.1%, 0.5%, 1% v/v nanowire-polypyrrole/gelatin hydrogels and pure gelatin hydrogel possess storage modulus sensitivity values of 0.75, 1.04, 0.88, 0.99 and 0.46, respectively, at an electric field strength of 800 V mm⁻¹. The effect of temperature on the electromechanical properties of the pure gelatin hydrogel and nanowire-polypyrrole/gelatin hydrogels was investigated between 30 and 80 °C; there are three regimes for the storage modulus behaviour. In deflection testing in a cantilever fixture, the dielectrophoresis force was determined and found to increase monotonically with electric field strength. The pure gelatin hydrogel shows the highest deflection angle and dielectrophoresis force at an electric field strength of 800 V mm⁻¹ relative to those of the nanowire-polypyrrole/gelatin hydrogels. Copyright © 2012 Society of Chemical Industry

Nanowire-Ppy/gelatin hydrogels were studied for the bending behavior as a function of electric field strength. The deflection distances of the hydrogels increase monotonically with increasing electric field strength.

Temperature and pH responsive poly(N-isopropylacrylamide-co-methacrylic acid) (P(NIPAAm-co-MAA)) microcontainers with encapsulated magnetic nanoparticles in the shell were prepared by a two-stage distillation precipitation polymerization. PMAA@Fe₃O₄/P(NIPAAm-co-MAA) core–shell nanoparticles were synthesized by the second-stage polymerization of NIPAAm, MAA and N, N′-methylenebisacrylamide as crosslinker in the presence of magnetic nanoparticles and PMAA as core. These novel triple-functional microcontainers were prepared by selective removal of the PMAA core in water. Daunorubicin hydrochloride (DNR) was loaded into the microcontainers and the release profile was studied by UV–visible spectroscopy. The synthesized nanostructures were characterized with transmission and scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The magnetic properties were evaluated by vibrating sample magnetometry. The shrink and swelling behavior was studied by dynamic light scattering. Copyright © 2012 Society of Chemical Industry

Temperature and pH sensitive microcontainers with Fe₃O₄ nanoparticles encapsulated in the shell were synthesized by distillation precipitation polymerization. Thermal, pH, magnetic properties, drug loading and release were investigated.

In the present study, the effect of adhesive on the morphology of different electrospun polymeric mats was investigated. The modification of two polymers, poly(methyl methacrylate) and poly(vinyl chloride), was carried out by blending the polymers with different amounts of poly(butyl acrylate) (PBA) adhesive to investigate the effect of different amounts of adhesive with heat hardener in hybrid mats. The introduction of various concentrations of PBA into different polymer solutions led to the formation of point-bonded electrospun fibrous mats. Scanning electron microscopy images indicated that point-bonded polymer/adhesive fibers were uniformly distributed throughout the mats. Fourier transform infrared spectrometry, contact angle measurements and thermogravimetric analysis were used to study the different properties of the hybrid mats. The tensile strength of the blended fibrous electrospun mats was increased effectively. This enhancement of the mechanical properties of the mats due to the presence of adhesive increases the number of potential applications of the electrospun mats, especially for mechanically weak polymers. Copyright © 2012 Society of Chemical Industry

Point-bonded electrospun mats of PMMA and PVC with excellent mechanical properties were successfully fabricated by the addition of PBA adhesive and subsequent heat treatments.

Modified eucalyptus kraft lignin doped with multiwall carbon nanotubes (MWCNTs) was used as a macromonomer in step-growth polymerization with tolylene 2,4-diisocyanate terminated poly(propylene glycol) with the aim of producing a conductive copolymer for all-solid-state potentiometric chemical sensor applications. The crosslinked elastomeric polyurethane obtained was characterized by Fourier transform infrared attenuated total reflection spectroscopy, scanning electron microscopy, tunnelling electron microscopy and atomic force microscopy. Doping of lignin-based polyurethane with MWCNTs produced a significant enhancement of its electrical conductivity without deterioration of thermal and viscoelastic properties. The polymer composite displayed a low percolation threshold at an MWCNT concentration of 0.18% (w/w), which was explained by the oriented distribution of MWCNTs along lignin clusters. All lignin-based polyurethanes doped with MWCNTs at concentrations above the percolation threshold are suitable for sensor applications. Copyright © 2012 Society of Chemical Industry

Copolymer of modified kraft lignin and tolylene 2,4-diisocyanate terminated poly(propylene glycol) doped with carbon nanotubes is a conductive elastomer promising for sensorial applications.

4,4′-Bis(4-chloroformylphenylthio)benzene was synthesized in two steps and was reacted with diamine-containing thioether and amide units to prepare a polyamide containing high contents of thioether groups. The intrinsic viscosities of the polyamides were 0.76–0.87 dL g⁻¹. These polyamides had excellent thermal properties, with glass transition temperatures of 234.8–269 °C and initial degradation temperatures of 461–469.7 °C. They showed improved solubility in polar aprotic solvents and could form moderate strength films with a tensile strength of 75.2–111.6 MPa and storage modulus of 1.0–1.3 GPa (at 220 °C). These polymer films also had good optical properties, including an optical transmittance of the aromatic polyamide film at 450 nm that was higher than 90%. Additionally, the high quantity of thioether units provided the polymers with high refractive indices of 1.700–1.704 and low birefringences of 0.007–0.008. Copyright © 2012 Society of Chemical Industry

Optical films were prepared by introducing the amide group, sulfone group and thioether groups to the polyamide backbone.

The readily available mixed-valent iron trifluoroacetate complex [Fe₂^IIIFe^II(µ₃-O)(O₂CCF₃)₆(H₂O)₃] is an effective catalyst for the polymerization of epoxides. A very small amount of the catalyst (1.0–0.01 mol%) could initiate the polymerization of cyclohexene oxide, cyclopentene oxide and epichlorohydrin. Based on quantitative end-group analysis by ¹⁹F NMR spectroscopy, a Lewis acid (LA^⊕) catalyzed anionic reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry

It is presented that the readily-available mixed-valent iron trifluoroacetate complex [Fe₂^IIIFe^II(µ₃-O)(O₂CCF₃)₆(H₂O)₃] (1) is an effective catalyst for the polymerization of epoxides.

The ring-opening polymerization of γ-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) was initiated by n-hexylamine in N,N-dimethyformamide under normal pressure at 0 °C. The products were characterizated by gel permeation chromatography, matrix-assisted laser desorption/ionization time of flight mass spectroscopy (MALDI-TOF MS), nuclear magnetic resonance etc. MALDI-TOF MS gave direct evidence that the side reactions during the polymerization of BLG-NCA could be greatly reduced by decreasing the reaction temperature, e.g. from room temperature to 0 °C. As a result, over 90% of the products were amino-terminated poly(γ-benzyl-L-glutamate) (PBLG) with low polydispersity index when the polymerization was carried out at 0 °C, which could be used to re-initiate the polymerization of other NCAs. Then several well-defined PBLG-containing block copolypeptides were successfully synthesized in a convenient way. Copyright © 2012 Society of Chemical Industry

Amino-terminated poly (γ-benzyl-L-glutamate) (PBLG) was synthesized at 0 °C and well-defined PBLG-based block co-polypeptides with low PDI were obtained in such a convenient way.

To investigate the nucleation of metal pimelate for isotactic polypropylene (iPP) crystallization, iPP filled with a series of metal oxides with and without metal pimelate on their surface was prepared. There was a chemical reaction between pimelic acid (PA) and metal oxides MgO, CaO, BaO or ZnO, but not TiO₂. The corresponding metal pimelate formed by the chemical reaction between PA and MgO, CaO, BaO or ZnO had a different influence on the crystallization behavior and melting characteristics of iPP. Addition of metal oxides increased the crystallization temperature of iPP and mainly formed α-phase due to the heterogeneous α-nucleation of metal oxides. The α-nucleation of CaO could be easily changed into β-nucleation using CaO-supported PA, and 90.1% β-phase was obtained. The β-nucleation of BaO could be markedly enhanced by barium pimelate formed using supported PA. However, no β-phase was observed for iPP filled with MgO- or ZnO-supported PA. The various metal oxides with supported PA had a different influence on the crystallization behavior and melting characteristics of iPP due to the different structure of metal pimelate formed by chemical reaction between PA and the metal oxides. Copyright © 2012 Society of Chemical Industry

Various metal oxides supporting pimelic acid showed different β-nucleation for isotactic polypropylene crystallization due to the different structures of metal pimelate supported on the surface of the metal oxides.

Polyesters were synthesized by direct polycondensation of thiophene-2,5-dicarboxylic acid and five different silarylene-containing diphenols using a tosyl chloride/pyridine/N,N-dimethylformamide system as a condensing agent. Polymers were obtained in good yields and were characterized using Fourier transform infrared and NMR (¹H, ¹³C, 135-DEPT and ²⁹Si) spectroscopy and elemental analysis. All polymers were completely soluble in aprotic organic polar solvents such as dimethylformamide, dimethylsulfoxide and N-methyl-2-pyrrolidone. The range of effective mass of the polymers (m/z) was 1 × 10⁵–2 × 10⁵, determined using electrospray ionization mass spectrometry. Asymmetry and steric hindrance prevented dense packing of the polymeric chains, showing glass transition temperatures between − 78 and − 51 °C and loss of thermal stability at 177–199 °C (10% weight loss). Additionally, the melting points of the polyesters were found to be in the range 62–67 °C. Because of this, the samples were semi-solid at room temperature. The optical band gaps of the polymers were observed between 4.54 and 4.48 eV, corresponding in all cases to insulator behavior. The molecular structure of the samples was studied using X-ray diffraction, showing a degree of order that was associated with two monoclinic lattices. Additionally, the conductivity was studied using a two-point method with contacts on top of polymer films. Prior to the electrical measurement, the samples were polarized in an external electric field of 0.8 to 6.4 V cm⁻¹, and the alignment of the dipoles increased the electrical conductivity. Copyright © 2012 Society of Chemical Industry

Polyesters containing silarylene and thiophene units were synthesized. The resonance effect on conductivity after polarization by application of an external electric field was studied. According to the results, the polymers are dielectric insulators, where the chains can be broken above a threshold field, properties that are associated with a high band gap.

The advent of the so-called ‘click chemistry’ a decade ago has significantly improved the chemical toolbox for producing novel biomaterials. This review focuses primarily on the application of Cu(I)-catalysed azide–alkyne 1,3-cycloadditon in the preparation of numerous, diverse biomaterials and biomedical materials and concepts. In addition, the thiol–ene ‘click’ reaction is addressed in the same manner, and the possibility of using both click reactions orthogonally is highlighted. A strategy for the preparation of novel intriguing poly(ε-caprolactone)-based nanobiomaterials by orthogonal click chemistry is elaborated. The present state of creating functional and biologically active surfaces by click chemistry is presented. Finally, conducting surfaces based on an azide-functionalized polymer with prospective biological sensor potential are introduced. Copyright © 2012 Society of Chemical Industry

Syntheses of various biomaterials by azide-alkyne 1,3-cycloaddition and/or thiol-ene ‘click’ chemistry are reviewed. Routes for the preparation of functional, biological and conducting surfaces are discussed.

The conformational changes, crystal structure and melting behavior of poly(ethylene/trimethylene terephthalate) (ET) copolyesters were investigated using in situ Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) under isothermal crystallization conditions. The results show that the minimum melting temperature was observed in ET53, in which the relative amount of ethylene glycol (EG) to 1,3-propanediol (PDO) was 52.68/47.32 and the PDO-dimethyl terephthalate (DMT)-PDO segments in the molecular chain dominated the crystal formation. The minimum crystallinity of ET copolyesters was found in ET66, in which the relative amount of EG/PDO was 65.91/34.09 and the EG-DMT-EG segments in the molecular chain dominated the crystal formation. A rapid and continuous conformational transition in ET copolyesters was observed using in situ FTIR in the first 10 min under isothermal crystallization conditions. The continuously adjusting conformation in the molecules reflects the crystallization of ET copolyesters. Based on the DSC and the X-ray analyses of the crystallization behavior in the ET copolyesters, crystalline conformation transitions of molecules in ET copolyesters take place rapidly and early. Copyright © 2012 Society of Chemical Industry

The methylene groups of the synthesized poly(ethylene/trimethylene terephthalate) random copolyesters arranged to fold into a crystal lattice by all-trans conformation and double gauche conformation, respectively.

Flake-like polyaniline with various thicknesses was prepared by cationic emulsion polymerization of aniline monomer in the presence of cetyltrimethylammonium bromide (CTAB). The morphology of polyaniline with uniform and smooth flake-like structure was observed using field-emission scanning electron microscopy and transmission electron microscopy. The lamellar complex of (CTA)₂S₂O₈, acting as a reactive soft template for the formation of polyaniline, was investigated using low-angle X-ray diffraction. The soft template provides an expanding space for the growth of polyaniline, in which the oxidization of aniline monomers can construct effectively a flake-like structure. The concentration of CTAB plays an important role in adjusting the d-spacing of the soft template. Crystallization and composition of polyaniline were characterized using X-ray diffraction and Fourier transform infrared spectroscopy. The X-ray diffraction pattern has a sharp peak at 2θ = 6.4° (d-spacing = 13.7 Å), showing that polyaniline has a solid-state ordering structure and high degree of crystallization. Doping and dispersive experiments were also included in the study. Copyright © 2012 Society of Chemical Industry

Flake-like polyaniline with various thicknesses was prepared by cationic emulsion polymerization of aniline monomer in the presence of cetyltrimethylammonium bromide without any acid using a falling-pH dopant-free method.

Dendrimer-like polystyrenes (PSs) containing azobenzene moieties/core were prepared by one-pot copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) and atom transfer radical polymerization (ATRP) in the presence of PS with terminal azide groups, styrene monomers, 2,4-dibromoisobutyrate-4′-propynyloxyazobenzene, copper(I) bromide and ligand. The successful preparation of the dendrimer-like PSs was confirmed using gel permeation chromatography and ¹H NMR and Fourier transform infrared spectroscopy. The dendrimer-like PSs prepared from one-pot CuAAC and ATRP exhibit a well-defined and controlled molecular structure in both whole macromolecules and the branches, which is attributed to the controlled character of ATRP and the quantitative yield of click chemistry. The dendrimer-like PSs prepared also exhibit good photo-isomerization properties due to the incorporation of azobenzene units within the dendrimers. Copyright © 2012 Society of Chemical Industry

Well-defined dendrimer-like polystyrenes were prepared by one-pot atom transfer radical polymerization (ATRP) and copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC).

Crystalline silk fibroin nanoparticles (CSFs), a kind of natural protein nanocrystal, were prepared by treatment of silk fibroin (SF) powders with 64 wt% aqueous sulfuric acid. Various treatment periods were tested, and optimal conditions corresponded to 2 h at 45 °C. Transmission electron microscopy observation showed that the CSFs existed as short rod-like fragments and spherical particles. The content ratio of β-sheet structure to α-form/random coil and the percentage crystallinity (χ_c) increased, but the weight-average molecular weight of CSFs decreased with prolonged degradation time. Compared with native SF, these CSFs of nanometer size and relatively high χ_c showed an upward shift of the glass transition temperature and thermal degradation temperature. Furthermore, high-strength elastic nanocomposite materials were successfully prepared from the CSFs and waterborne polyurethane (WPU). One of the WPU/CSF films produced exhibited significant increases from 1070 to 2370% for elongation at break, 0.6 to 2.2 MPa for tensile strength and 0.3 to 4.0 MPa for Young's modulus. This work provides a new pathway for the preparation of natural nanocrystals and WPU-based elastomers with high strength and toughness. Copyright © 2012 Society of Chemical Industry

Short rod-like crystalline silk fibroin nanoparticles (CSFs) were prepared by sulfuric acid hydrolysis of silk fibroin powders, and the CSFs were dispersed in waterborne polyurethane with shapes of rods and hexagons.

The network structure of styrene–butadiene rubber (SBR) in the presence of carbon black (CB) with two different structures and multi-walled carbon nanotubes (MWCNTs) was investigated. Swelling behaviour, tensile properties at various strain rates and cure kinetics were characterized. Experimental data were analysed using the Flory–Rehner model as well as the tube model theory. It is found that the network structure of CB-filled SBR follows a three-phase composite model including rigid particles, semi-rigid bound rubber and matrix rubber. This bound rubber is postulated to be critical for the mechanical and deformational properties, development of crosslinking density in matrix rubber and polymer–filler interaction. For MWCNT-filled SBR, the bound rubber does not show a substantial contribution to the network structure and mechanical performance, and these properties are greatly dominated by the higher aspect ratio and polymer–filler interaction. Additionally it is deduced that the crosslinking density of matrix rubber increases on incorporation of the fillers compared to unfilled matrix rubber. Copyright © 2012 Society of Chemical Industry

A series of styrene–butadiene rubber vulcanizates filled with multi–walled carbon nanotubes and carbon black with different microstructures were analysed to clarify the network structure of the filled composites.

The mechanical and damping properties as well as the shape memory behavior of copolymers obtained by cationic copolymerization of tung oil with styrene with different stoichiometric ratios are presented and analyzed in this work. The glass transition temperatures are close to room temperature for all the copolymers, and generally increase with the content of styrene. A similar trend is observed for the modulus, which exhibits values from 4.89 MPa for the copolymer with 30 wt% styrene to 13.92 MPa for the copolymer with 70 wt% styrene. These hard elastomers present shape memory behavior with high recovery and fixity ratios, as well as high damping quality (damping factors 0.4 and 1.38 at 28.9 and 43.3 °C, for the tung oil homopolymer and the copolymer with 70 wt% styrene, respectively), opening possibilities for practical applications that require material response close to room temperature. Copyright © 2012 Society of Chemical Industry

Copolymers obtained by cationic copolymerization of tung oil with styrene can present shape memory behavior and/or damping properties depending of chemical stoichiometry with possibilities for significant practical applications.

Highly crystalline camphor sulfonic acid (CSA)-doped polyaniline (PANI) thin films cast from m-cresol and N-methylpyrrolidone (NMP) were investigated. PANI powder prepared by chemical oxidative polymerization subjected to doping–de-doping–re-doping procedures was cast into thin films using NMP and m-cresol as solvents. X-ray diffraction (XRD) reveals the presence of exceptionally highly crystalline or rather ordered regions in the PANI film samples prepared from m-cresol. Atomic force microscopy (AFM) images also support the presence of crystalline regions on the surface of these films. The DC electrical conductivity of m-cresol-cast PANI is found to be quite high, and much higher than that of NMP-cast PANI. The free-carrier absorption tail extending to the near-infrared region observed in the optical absorption spectrum of the m-cresol-cast PANI films suggests a metallic nature and regular structural arrangement in these films. Both inter-chain and intra-chain ordering brought about as a result of CSA doping, secondary doping effect of m-cresol and ultrasonication are suggested to be the prime factors contributing towards the observed excellent crystallinity of these PANI films as evident from the XRD and AFM studies. The marked thermal stability of the m-cresol-cast PANI films is also established based on the variation of DC electrical conductivity with temperature and on thermogravimetric analysis. Copyright © 2012 Society of Chemical Industry

Ultrasonication and secondary doping with m-cresol can produce camphor sulfonic acid-doped polyaniline thin films with excellent crystallinity and very high conductivity.

The anionic curing initiated by 1-methyl imidazole of diglycidyl ether of bisphenol A with a hyperbranched polymer (HBP) containing long aliphatic chains in the structure were studied. The hydroxyl groups present as chain ends in the HBP structure played an important role in the curing kinetics, as demonstrated by differential scanning calorimetry, Fourier transform infrared spectroscopy and rheological studies. Properties such as shrinkage on curing and thermomechanical characteristics were also investigated. The structure of the HBP, which contains long aliphatic chains and reactive hydroxyl groups as chain ends, flexibilizes the network significantly, improving the impact resistance without notably affecting either the glass transition temperature or the microhardness of the modified thermosets. Copyright © 2012 Society of Chemical Industry

The anionic curing of DGEBA/ hyperbranched polyester (HBP) mixtures was studied. Shrinkage on curing and thermomechanical characteristics were investigated. HBP flexibilizes the network improving impact resistance without affecting T_g or microhardness.

A series of novel photo-crosslinkable fluorinated poly(phthalazinone ether)s containing 1,1-diphenylethylene segments in the polymer main chain, used for optical waveguide materials, were synthesized by polycondensation reaction of decafluorobiphenyl with a mixture of 4-(4-hydroxylphenyl)(2H)-phthalazin-1-one (DHPZ), 4,4-(hexafluoroisopropylidene)diphenol and 1,1-bis(4-hydroxyphenyl)ethylene (BHPE) as co-reactant. The feed ratio of DHPZ to total bisphenols varied from 0 to 80 mol%, while that of BHPE remained at 20 mol% for all polymers. The obtained copolymers show good solubility in some common polar organic solvents. The resulting polymers were photo-crosslinked after UV irradiation for 10 min in the presence of a photoinitiator. The cured polymers show good chemical resistance, high thermal stability (temperatures of 1% mass loss after curing of 472–496 °C under nitrogen) and high glass transition temperatures (160–249 °C) which could be further increased by about 10 °C after photochemical crosslinking. By adjusting the copolymerizing bisphenol content, the refractive indices of transverse electric and transverse magnetic modes (at 1550 nm) of films of the polymers were exactly tuned in the range 1.5029–1.5661 and 1.4950–1.5502, respectively. The propagation losses of the cured films were measured and found to be less than 0.3 dB cm⁻¹ at 1550 nm, indicating the promise of these materials for passive optical waveguide devices. Copyright © 2011 Society of Chemical Industry

Photo-crosslinkable fluorinated poly(phthalazinone ether)s containing 1,1-diphenylethylene segments, having low optical loss and low birefringence, were synthesized as promising materials for passive optical waveguide devices.

Temperature-dependent values of dielectric permittivity ε′ and dielectric loss ε″ of polyvinylpyrrolidone (PVP, commercialized as PVP K-60) solution of average molecular weight 160 000 g mol⁻¹ were measured. The measurements were carried out in the frequency range 10 MHz to 20 GHz using time domain reflectometry at temperatures from 25 to 0 °C. The dielectric spectra can be described by the Davidson-Cole model. Dielectric parameters such as the static dielectric constant ε₀, the high frequency limiting dielectric constant ε_∞, the relaxation time τ₀ and the distribution parameter β and thermodynamic parameters such as the free energy of activation ΔF_τ, the enthalpy of activation ΔH_τ and the entropy of activation ΔS_τ were determined. The average free energy of activation was found to be in the range 12.55–14.65 KJ mol⁻¹ and the enthalpy of activation was found to be 6.86 KJ mol⁻¹. Entropies of activation were found to be positive at all the measured temperature values and these large positive values of entropies reveal a less ordered structure of the PVP solution. The Kirkwood correlation factor g and the dipole moment µ were also determined for PVP solution. The results were compared with the results of the PVP-water system studied previously. Copyright © 2011 Society of Chemical Industry

Dielectric permittivity ε′ and loss ε″ of Polyvinylpyrrolidone (PVP K-60) solution in the temperature region 25-0° C and in the frequency range of 10 MHz to 20 GHz have been measured. The dielectric loss spectra were found to shift towards low frequency as the temperature of the system changes from 25 °C to 0 °C.

New functionalized poly(2,6-dimethyl-1,4-phenylene oxide)s (PPOs) containing ethylenic, aldehydic, hydroxyl and acrylate pendant groups were synthesized and their structure, properties and curing kinetics were investigated. The incorporation of polar functional groups resulted in an improvement in the glass transition temperature in the order aldehydic PPO > acrylate PPO > hydroxyl PPO > vinyl PPO > brominated PPO > pristine PPO. Upon thermal curing, the electron-donating substituent in the vinyl PPO resulted in an increase in the activation energy in the order –Pr, –Bu > –Ph > –H, whereas the electron-withdrawing substituent in the acrylate PPO caused a slight decrease in the activation energy. Copyright © 2011 Society of Chemical Industry

The synthesis and properties of functionalized poly(phenylene oxide)s (PPOs) are investigated. The glass transition temperature is in the order aldehydic PPO > acrylate PPO > hydroxyl PPO > vinyl PPO > brominated PPO > pristine PPO.

A novel charring agent poly(1,3-propylene terephthalamide) (PPTA) was synthesized and characterized by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance. This novel charring agent combined with ammonium polyphosphate (APP) was adopted as an intumescent flame retardant (IFR) to impart flame retardance and dripping resistance to acrylonitrile-butadiene-styrene copolymer (ABS). Flammability and thermal behaviors of the treated ABS were investigated by limiting oxygen index, vertical burning test and thermogravimetric analysis. The results showed that the IFR with the novel charring agent had both excellent flame retardant and anti-dripping abilities for ABS. The thermogravimetric analysis curves indicated that there was a synergistic effect between PPTA and APP, which greatly promoted the char formation of IFR-ABS composites. Meanwhile, the thermal degradation mechanism of PPTA and APP/PPTA was characterized using thermogravimetric analysis/infrared spectrometry. The results demonstrated that APP changed the thermal degradation behavior of PPTA and reacted with PPTA to form a crosslinked structure. Additionally, the structure and morphology of char residues were studied by Fourier transform infrared spectroscopy and scanning electron microscopy. Copyright © 2011 Society of Chemical Industry

The synergistic effect between novel charring agent poly(p-propane terephthalamide) (PPTA) and ammonium polyphosphate (APP) improved the flame retardancy and anti-dripping effects of ABS.

Poly(ethylene terephthalate) (PET) fibers are very hydrophobic and are therefore treated by alkaline hydrolysis to reduce their hydrophobicity, which not only reduces their weight but also enhances their softness, flexibility and drapability. In addition, if alcohol is used as a pretreatment agent, the form of the fibers can be changed and more benefits can be obtained from the subsequent alkaline hydrolysis treatment. Therefore various alcohols were used as pretreatment agents and their effect was investigated. Treatment with 1-decanol leads to more weight loss of the PET fibers than treatment with the other alcohols investigated. Treatment with sodium hydroxide leads to weight loss in PET fabrics because terephthalic acid and ethylene glycol are separated by the hydrolysis of the ester group in the PET chains. Weight loss increases with increasing hydrolysis time and the reaction does not immediately reach equilibrium. The microvoids of the PET surface hold water molecules. The surface morphology of PET shows that the pretreatment reagent attacks almost the entire surface of a fiber, causing surface etching. As the surface etching progresses, it propagates inside the fiber, resulting in the formation of elongated cavities on the surface. Copyright © 2011 Society of Chemical Industry

A polyester fabric treated with various alcohols showed higher water absorption. Hydroxyl groups were crowded at the parts with craters made by the alcohol pretreatment, and this increased the water absorption.

Eight molecularly imprinted polymers (MIP1–MIP8) were synthesized with different functional monomers and porogens using 3,4-dihydroxyphenylacetic acid (DOPAC) as a template. Thermal, radical bulk polymerization was employed in the presence of ethylene glycol dimethacrylate as a cross-linker. A computational analysis indicated that complexes with four molecules of 4-vinylpyridine, 1-vinylimidazole and acrylonitrile had high positive enthalpies of formation. The polymers synthesized with these monomers showed an imprinting factor below 1. Polymer MIP8 synthesized with allylamine as the functional monomer, with the highest energy of interaction with DOPAC, was characterized by the highest imprinting factor equal to 1.91. Examination of the binding ability of DOPAC and a group of structurally related compounds showed that the strong interactions between amine groups in the polymer and carboxylic groups in the analyte governed the recognition mechanism. The Langmuir adsorption model and the pseudo-second-order mechanism properly evaluated the MIP8 and non-imprinted polymer 8 adsorption characteristics. Scatchard analysis revealed that MIP8 had two classes of heterogeneous binding sites with K_d(1) = 0.12 µmol L⁻¹ and K_d(2) = 1.46 µmol L⁻¹. Finally, the potential application of MIP8 for separation of DOPAC was demonstrated. Copyright © 2011 Society of Chemical Industry

3,4-Dihydroxyphenylacetic acid (DOPAC) imprinted polymer system built up from allylamine-EGDMA could be used to effective enrichment and analysis of DOPAC samples.

Silicon carbide was incorporated in poly(dimethyl siloxane) (PDMS) in combination with multiwall carbon nanotubes (MWCNTs) to improve the thermal conduction behavior. The amount of silicon carbide was increased from 0 to 150 phr and the amount of MWCNTs was increased from 0 to 8 phr at a fixed amount of silicon carbide (150 phr). The thermal conductivity of the PDMS composite was increased with increasing amount of the MWCNTs and fine dispersibility of the incorporated MWCNTs was achieved without pretreatment. The rheological properties of the PDMS composites incorporating silicon carbide and MWCNTs were investigated and the activation energy of the composites was calculated during thermal decomposition using the Horowitz-Metzger method. Importantly, unexpected thermal decomposition behavior as indicated by the reduction in activation energy from 361.63 to 194.18 kJ mol⁻¹, namely acceleration of decomposition of the PDMS matrix caused by MWCNTs, was observed for the first time. Copyright © 2011 Society of Chemical Industry

SiC/MWCNTs filled PDMS nanocomposites were prepared and their properties were investigated. Thermal conductivity was improved with the addition of fillers, however, the acceleration of decomposition of PDMS by MWCNTs was observed.

Biofouling that involves protein adsorption, cell and bacteria adhesion, and biofilm formation between a surface and biological entities is a great challenge for biomedical and industry applications. In this work, L-tyrosine-derived polyurethanes (L-polyurethane) with different molecular weights of poly(ethylene glycol) (PEG) were synthesized, characterized and coated on gold surfaces using spin-coating. The non-fouling activity of different L-polyurethane films was evaluated by protein adsorption and cell adhesion. Surface plasmon resonance and cell assay results demonstrate that the PEG content in these L-polyurethanes contributes excellent resistance to protein adsorption and cell attachments. This work provides alternative and effective biomaterials for potential applications in blood-contacting devices. Copyright © 2011 Society of Chemical Industry

We synthesize and characterize a series of PEG-based L-tyrosine polyurethanes for effectively resisting nonspecific protein adsorption and cell adhesion.

Three bio-based thiols were synthesized via the thermal thiol-ene reactions between sucrose soya ester (SSE) and multifunctional thiols; then, thiourethane coatings were produced from these thiols and their coating properties were studied. A series of high bio-renewable content thiol oligomers were synthesized according to the previously reported thermal thiol-ene reaction. Fourier transform infrared spectra (FTIR) confirmed the complete consumption of the double bonds in SSE, and gel permeation chromatography confirmed the formation of high-molecular-weight oligomers. The viscosity of these oligomers remained low due to their compact and branched structures. Thermoset thiourethane coatings were prepared from these thiol oligomers and polyisocyanate trimer resins with dibutyltin diacetate as the catalyst. FTIR spectra confirmed the formation of the thiourethane group. However, coatings based on isophorone diisocyanate (IPDI) polyisocyanate resin showed a lower degree of cure because of the decreased resin mobility due to the rigid cyclohexane ring. Generally, all the coatings showed good adhesion to aluminum panels, and had high gloss. However, they exhibited low tensile strength, modulus and chemical resistance due to the flexibility of the fatty acid chain. Coatings based on more rigid IPDI-based polyisocyanate showed higher T_g, hardness and direct impact resistance compared with the hexamethylene-diisocyanate (HDI) based polyisocyanate counterparts. Thermogravimetric analysis results showed that coatings based on mercaptanized soybean oil have better thermal stability than those from di-pentene dimercaptan or glycol di-3-mercaptopropionate. Two T_g values were found by both differential scanning calorimetry and dynamic mechanical thermal analysis of thiourethanes from HDI-based polyisocyanate and di-pentene dimercaptan or glycol di-3-mercaptopropionate based oligomers due to phase separation resulting from the poor compatibility between HDI-based polyisocyanate and the respective oligomers. Copyright © 2011 Society of Chemical Industry

Three bio-based thiols were synthesized based on the thermal thiol-ene reactions between sucrose soya ester (SSE) and multifunctional thiols; then, thiourethane coatings were produced from these bio-based thiols and their coating properties were studied.

An interpenetrating polymer network hydrogel composed of 2-hydroxypropyltrimethyl ammonium chloride chitosan and poly(vinyl alcohol) was prepared. Its swelling properties and electroresponsive behavior in aqueous NaCl solutions were studied. The results indicated that the water uptake ability of the hydrogel decreased with increasing ionic strength of aqueous NaCl solution. The Young's modulus, elongation at break and tensile strength of the hydrogel swollen in deionized water were 4.29 MPa, 76.5% and 3.26 MPa, respectively. The hydrogel swollen in the NaCl solution bent toward the anode under non-contact direct current electric fields, and its bending speed and equilibrium strain increased with increasing applied voltage. The electroresponsive behavior of the hydrogel was also affected by the electrolyte concentration of external NaCl solution, and there was a critical ionic strength of 0.10 where the maximum equilibrium strain of the hydrogel occurred. By changing the direction of the applied potential cyclically, the hydrogel exhibited good reversible bending behavior. Copyright © 2011 Society of Chemical Industry

When a DC electric field was applied, the strip of hydrogel bent toward the positive electrode. Under a cyclically varying electric field, the hydrogel exhibited a good reversible bending behavior without hysteresis.

It is well known that bicyclic compounds like spiro-orthocarbonates (SOCs) have the ability to reduce or eliminate the shrinkage produced during polymerization. In the work reported, four different SOCs were prepared, two of them with one and two hydroxyl groups, respectively, another with two alkoxy groups and one reference compound without substituents. It was found that the SOCs with hydroxyl groups increased the photopolymerization rate and conversion of an epoxycycloaliphatic monomer, while the compound with butoxy groups had an antagonistic effect, reducing both photopolymerization rate and conversion, due to the basic character of the ether groups. The reference compound did not display accelerating effects but it did increase slightly the conversion. Dynamic mechanical analysis revealed that the SOC with two hydroxyl groups increased the values of storage modulus of the obtained polymer in comparison with the polymer from pristine monomer. This may be due to the multifunctionality of this compound that induced a higher level of crosslinking, while the SOC with one hydroxyl group had the opposite effect, decreasing the viscoelastic property values of the polymer due to chain-transfer reactions originated by the hydroxyl groups. The SOC with two hydroxyl groups was the more efficient of the studied compounds in reducing the shrinkage of the cured polyether. Copyright © 2011 Society of Chemical Industry

Four spiro-orthocarbonates(SOCs) were synthesized and their ability to reduce the shrinkage of an epoxy resin was evaluated. The SOC with two hydroxyl groups proved to be the most efficient as a volume control agent, reducing shrinkage by 88%.

A new class of derivatives of poly(vinyl alcohol) (PVA) was prepared through hydrophobic cationic modification. The structure and composition of PVA grafted with glycidyl-N-alkyl-N,N-dimethyl-ammonium chloride (DA) (PVA-graft-DA) was confirmed with Fourier transform infrared spectral analysis and ¹H NMR spectral analysis. The stress-strain curves of PVA-graft-DA samples all exhibited an elastic deformation stress plateau, and strain hardening behavior can be observed, indicating the transition of PVA from brittle fracture to ductile fracture. Compared with virgin PVA, the relaxation peak (T_g) of PVA-graft-DA shifted to a lower temperature. With increasing alkyl chain length and grafting ratio of DA, T_g decreased, and PVA-graft-DA exhibited a gradually decreasing storage modulus over the whole temperature range of testing due to the relatively weak intermolecular hydrogen bonding and increasing flexibility of molecular chains by introduction of long alkyl chains. PVA crystallites were not affected by grafting with DA, while the crystallization temperature and crystallinity of PVA were improved and the grain size decreased. On grafting with DA, the fracture surface of PVA changed from a smooth surface to regularly distanced striations, displaying much obvious character of tough fracture, indicating that appropriate intermolecular association of the hydrophobic groups facilitated the formation of physical entanglement of molecular chains to strengthen and toughen the PVA matrix. PVA-graft-DA showed a significant decreasing surface tension with polymer concentration, while the surface tension of PVA-graft-DA12 dropped most dramatically and declined with increasing grafting ratio of DA12, indicating improvement of the surface activity of PVA by introduction of hydrophobic alkyl chains and hydrophilic cationic groups. Copyright © 2011 Society of Chemical Industry

A new class of derivatives of PVA was prepared. After introduction of hydrophobic cationic group, the fracture surface changed from smoothness to regularly distant striations, displaying character of tough fracture.

Isotactic polypropylene filled with various contents of multi-walled carbon nanotubes (MWCNTs) were fabricated by the injection molding technique and then rolled at room temperature. The unrolled samples (URS) and rolled samples (RS) were characterized by X-ray diffraction studies, scanning electron microscopy, mechanical and micromechanical tests and differential thermal analyses. Although the URS exhibit the lamellar α-crystal with a*-axis orientation, the RS show the same crystals with both a*- and c-axis orientation, which is explained by interlamellar and intralamellar slips and lamellar destruction. Scanning electron micrographs display distinct surface morphological features for both URS and RS. While the tensile strength of RS is higher than that of URS, the Young's modulus (Y) is found to be lower than that of URS. Anisotropy in microharness (H) parallel and perpendicular to the rolled direction has been detected, although H for both samples increases with increasing MWCNT contents. The average relationship H/Y ≈ 0.18 as estimated for URS is closer to the predicted value of 0.10 for polymers than the H/Y ≈ 0.22 obtained for RS. The lamellar thickness for URS increases with increase of MWCNT content and that for RS decreases, as evaluated from both differential thermal analyses and X-ray diffraction data. Copyright © 2011 Society of Chemical Industry

Multi-walled carbon nanotubes (MWCNTs) reinforced isotactic polypropylene with various contents of MWCNTs were cold-rolled and then studied in order to determine the structural changes and properties in the samples.

To introduce an ultrahydrophobic polymeric phase onto a silicon wafer, an initiator-modified silicon wafer was prepared with 2-bromopropionyl bromide and then surface-initiated atom transfer radical polymerization of octadecyl acrylate was carried out from the initiator-grafted silicon wafer using CuBr and N,N,N′,N″-pentamethyldiethylenetriamine as catalyst precursors. The resultant poly(octadecyl acrylate) [poly(ODA)] brushes were characterized by ellipsometry, X-ray photoelectron spectroscopy, grazing angle Fourier transform infrared spectroscopy, atomic force microscopy, gel permeation chromatography and water contact angle measurements. Wettability of the poly(ODA) brushes was found to depend on the surface coverage (Γ) and the root mean square roughness. The most hydrophobic surface (Γ = 25.35 mg m⁻² and root mean square roughness 11.9 nm) exhibited a water contact angle of 171.1 ± 0.2°. Copyright © 2011 Society of Chemical Industry

Ultrahydrophobic poly(octadecyl acrylate) [poly(ODA)] brushes were synthesized on silicon wafer. The most hydrophobic surface (Γ = 25.35 mg/m² and rms roughness = 11.9 nm) exhibited water contact-angle of 171.1 ± 0.2°.

Tetramethylbisphenol F epoxy resin (TMBPFE) was successfully synthesized based on tetramethylbisphenol F (TMBPF) and epichlorohydrin with tetrabutylammonium bromide as the catalyst. The structure of TMBPFE was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance and elemental analysis. Then, a mixed system composed of TMBPFE and 4,4′-diglycidyl (3,3′,5,5′-tetramethylbiphenyl) epoxy (TMBP) was prepared by a melting method, i.e. without any solvent. Both the TMBPFE and the mixed system were cured using 4,4′-diaminodiphenyl methane (DDM) as the curing agent. The thermal properties of TMBPFE and the mixed system were studied using differential scanning calorimetry, dynamic mechanical analysis and thermogravimetric analysis (TGA). The results showed that the TMBP mixed in the TMBPFE matrix had little effect on the thermal properties of TMBPFE. However, the glass transition temperature improved markedly with increasing content of TMBP. Moreover, the TGA results showed that the degradation characteristics of TMBPFE resins did not seriously decrease when TMBP was incorporated into the TMBPFE matrix, although there are large steric hindrance biphenyl groups in TMBP. Both TMBPFE and the TMBPFE/TMBP system have potential applications in electrical and electronic fields. Copyright © 2011 Society of Chemical Industry

A composite system composed of TMBPFE and TMBP was prepared. Tg improved a lot with increasing the content of TMBP. The composite systems exhibited excellent thermal property.

Poly(4-aminodiphenylamine)-silver nanocomposites were synthesized by an easy one-step aqueous chemical oxidative polymerization of 4-aminodiphenylamine (4ADPA) using silver nitrate (AgNO₃) as the oxidant. Two different structure directing surfactants, p-toluene sulfonic acid (p-TSA) and cetyl trimethyl ammonium bromide/hydrochloric acid (CTAB/HCl), were independently used for the nanocomposite (NC) preparation. The NCs prepared in p-TSA and CTAB/HCl medium were designated as P4ADPA/AgNC_(p−TSA) and P4ADPA/AgNC_(CTAB/HCl), respectively. We investigated the morphological variations in the NCs based on the medium. P4ADPA/AgNC_(p−TSA) and P4ADPA/AgNC_(CTAB/HCl) were characterized by field emission scanning electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis and UV-visible spectroscopy. Copyright © 2011 Society of Chemical Industry

Spherical and rod nanostructure of poly(4-aminodiphenylamine)-silver composite is produced from p-toluene sulfonic acid and cetyltrimethyl ammoniumbromide, respectively. The thermal and electronic properties of the nanocomposites are compared.

A novel series of biodegradable shape memory polyurethane ureas (SMPUUs) were designed and synthesized based on poly(D,L-lactic acid) diol, hexamethylene diisocyanate and piperazine. Their structure, degree of crosslinking, thermal properties, shape memory behaviors and mechanical properties were characterized using Fourier transform infrared and ¹H NMR spectroscopy, weight analysis, differential scanning calorimetry and tensile testing. The results reveal that successfully introducing the piperazine into the backbone of the SMPUUs gives them excellent shape memory behaviors and good mechanical properties. This, in combination with the ideal shape recovery temperature, which can be designed near human body temperature, could make these biodegradable polyurethanes of great interest as potential biomaterials for medical implantations. On increasing the percentage of hard content of the SMPUUs from 9.00 to 12.12 wt%, the shape fixation rate increases from 95.3 to 98.2%, but the shape recovery ratio decreases from 98.6 to 93.2%; also, both the tensile modulus and tensile strength increase, but elongation at break decreases. To profile the advantages of our SMPUUs, a polyurethane based on poly(D,L-lactic acid) diol, hexamethylene diisocyanate and 1,4-butanediamine was chosen as control. Copyright © 2011 Society of Chemical Industry

Novel shape memory polyurethane ureas (SMPUUs) were designed and synthesized. Successfully introducing piperazine into the backbone of the SMPUUs gave them excellent shape memory behaviors and good mechanical properties.

The change of morphology of poly(3-hexylthiophene) (P3HT) film as a result of blending with [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) was studied using a freeze-dry method. A porous structure was observed as the P3HT/PCBM solution was freeze-dried. The pore size decreased as the proportion of PCBM increased in the P3HT/PCBM blended film. Additionally, the freeze-dried P3HT/PCBM film was more resistant to the formation of PCBM crystals than that prepared by a spin-coating method during the thermal annealing process. Homogeneous distribution of PCBM in the freeze-dried P3HT/PCBM film was the main reason for the reduction of large PCBM crystal formation. Copyright © 2011 Society of Chemical Industry

Addition of [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) to poly(3-hexylthiophene) (P3HT) solution induced local aggregation of P3HT and resulted in a pore structure with smaller pore size than that without PCBM.

The dispersion of three kinds of acid-treated carbon nanotubes (CNTs) in poly(acrylic acid) (PAA) aqueous solution of different pH and ionic strengths (varied by NaCl, KCl and ZnCl₂) was investigated by visual observation, zeta potential, particle size analysis, transmission electron microscopy and scanning electron microscopy. Visual observation revealed that the dispersion of CNTs acid treated at 60 °C for 3 h and at 80 °C for 2 h was poor in aqueous solutions with pH < 2 or pH > 12. The poor dispersion of acid-treated CNTs may be improved by adding PAA. In particular, PAA improved the dispersion of CNTs with greater COOH content. In a low pH solution (pH 1.5), a higher PAA content resulted in poorer CNT dispersion while in a high pH solution (pH 12.5), a higher PAA content led to better CNT dispersion. For superior dispersion in a basic aqueous solution (pH 12.5), experimental data showed that a greater atomic radius or a higher cationic charge of the added salt may result in faster aggregation and thus precipitation of CNTs. Copyright © 2011 Society of Chemical Industry

A higher PAA content resulted in poorer CNT dispersion in the solution with pH 1.5, whereas a higher PAA content led to better CNT dispersion in the solution with pH 12.5.

The effect of liquid isoprene rubber (LIR) on the dynamic mechanical properties of emulsion-polymerized styrene/butadiene rubber (ESBR) vulcanizates was investigated by temperature sweep using dynamic mechanical analysis. The introduction of LIR led to ESBR vulcanizates having higher loss factor (tan δ) in the temperature range − 30 to 0 °C, and lower tan δ in the range 60 to 80 °C. A small amount of LIR-403 (LIR with carboxyl groups) led to a significant change in tan δ: the addition of LIR-403 (3 phr) led to a 7.5% increase in tan δ from − 30 to 0 °C, and a 24.9% decrease in tan δ from 60 to 80 °C. It was found that the introduction of LIR increased the bound rubber content in the ESBR compound. Equilibrium swelling experiments showed that the crosslink density of the vulcanizates increased after the introduction of LIR-403 or LIR-50 (general purpose LIR). The change in tan δ from 60 to 80 °C was related to polymer–filler interactions. The characteristic constant of filler–ESBR matrix interaction (m) was calculated. At a given filler volume fraction, the increase in m in the presence of LIR could be well related to the decrease in tan δ from 60 to 80 °C. The influence of LIR on filler network in the ESBR compound was also investigated by strain and temperature sweeps using a rubber processing analyzer. Copyright © 2011 Society of Chemical Industry

The addition of LIR-403 (3 phr) led to a 7.5% increase in tan δ from −30 to 0°C, and a 24.9% decrease from 60 to 80°C.

A series of functional polyhedral oligomeric silsesquioxane (POSS)/polyimide (PI) nanocomposites were prepared using a two-step approach. First, octa(aminophenyl)silsesquioxane (OAPS) was mixed with poly(amic acid) (PAA) prepared by reacting bis(4-amino-3,5-dimethylphenyl)-3-quinolylmethane and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride. Second, the resulting solution was subjected to thermal imidization. The well-defined ‘hard particles’ (POSS) and the strong covalent bonds in the amide linkage between the carbon atom of the carboxyl side group in PAA and the nitrogen atom of the amino group in POSS lead to a significant improvement in the thermal and mechanical properties. Homogeneous dispersion of POSS cages in the PI is evident from scanning electron microscopy, which further confirms that the POSS molecule becomes an integral part of the organic-inorganic inter-crosslinked network system. Differential scanning calorimetry and dynamic mechanical analysis show that the glass transition temperatures of the POSS-containing nanocomposites are higher than that of the corresponding neat PI system, owing to the significant increase of the crosslinking density in the PI/POSS nanocomposites. Increasing the concentration of OAPS in the PI networks decreases the dielectric constant. Pure PI and PI/POSS systems have good antimicrobial activity. Copyright © 2011 Society of Chemical Industry

The incorporation of polyhedral oligomeric silsesquioxane in a polyimide matrix reinforces the latter as a result of the formation of an organic–inorganic hybrid network. The new material has high glass transition temperature, crosslinking density and storage modulus, and low thermal expansion and dielectric constant.

A series of uncontrolled molecular weight homopolyimides and copolyimides based on 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA)/4,4′-oxydianiline (4,4′-ODA)/1,3-bis(4-aminophenoxy)benzene (TPER) were synthesized. All the polyimides displayed excellent thermal stability and mechanical properties, as evidenced by dynamic thermogravimetric analysis and tensile properties testing. A singular glass transition temperature (T_g) was found for each composite from either differential scanning calorimetry (DSC) or dynamic mechanical analysis (DMA), but the values determined from tan δ of DMA were much different from those determined from DSC and storage modulus (E′) of DMA. The Fox equation was used to estimate the random T_g values. Some composites exhibited re-crystallization after quenching from the melt; upon heating, multi-melting behavior was observed after isothermal crystallization at different temperatures. The equilibrium melting temperature was estimated using the Hoffman-Weeks method. Additionally, DMA was conducted to obtain E′ and tan δ. Optical properties were strongly dependent on the monomer composition as evidenced by UV-visible spectra. X-ray diffraction was used to interpret the crystal structure. All the results indicated that composites with TPER composition ≥ 70% were dominated by the TPER/s-BPDA polyimide phase, and ≤40% by the 4,4′-ODA/s-BPDA polyimide phase. When the ratio between the two diamines was close to 1:1, the properties of the copolyimides were very irregular, which means a complicated internal structure. Copyright © 2011 Society of Chemical Industry

Some composites exhibited recrystallization with an increase of 4,4′-oxydianiline content and multi-melting behavior was seen after isothermal crystallization at various temperatures.

Ternary composites of glass fiber-reinforced poly(p-phenylene sulfide) (PPS/GF) filled with nanometric calcium carbonate (nano-CaCO₃) were prepared by means of a twin-screw extruder. The nano-CaCO₃ surface was treated with stearate and treated with titanate, the composites being called SI composite system and SII composite system, respectively. The crystallization and heatproof properties of the PPS/GF/nano-CaCO₃ composites were measured using a differential scanning calorimeter, to investigate the influence of the nanometric filler content on the crystallinity. The results show that the variation of the starting crystallization temperature, crystallization temperature and crystallinity with an increase of the particle weigh fraction (ϕ_f) of SI composite system is different from that of SII composite system. When ϕ_f is less than 4 wt%, the crystallinity of the two composite systems increases and then decreases slightly with increasing ϕ_f. Moreover, the crystallization behavior and mechanisms are discussed. Copyright © 2011 Society of Chemical Industry

The crystallization of poly(p-phenylene sulfide)/glass fiber/nano-CaCO₃ composites was measured using a differential scanning calorimeter. The results showed that the crystallinity increased and then decreased slightly with increasing nano-CaCO₃ content.

Organic solar cells offer an opportunity to diversify renewable energy sources owing to their low technological cost. They are amenable to large surfaces and can easily be integrated into buildings. It is necessary, however, to improve their energy efficiency and durability for the development of a sustainable technology. In these devices, photovoltaic conversion is based on the separation of photogenerated charges at an interface between electron donor and acceptor materials, which imposes some constraints on the photoactive layer of the cells. In this paper, which includes some of our studies, we address optimization of the active layer: absorption and exciton dissociation steps, the open-circuit voltage and the active layer morphology. A promising direction proposed to improve the active layer morphology and cell efficiency is the incorporation of highly anisotropic nanoparticles such as carbon nanotubes, which may facilitate charge transport to the electrodes. Dispersion and orientation of the nanotubes in the organic matrix are discussed and we suggest an ideal model polymer solar cell which will maximize performance of the cells by using carbon nanotubes in the active layer. Copyright © 2012 Society of Chemical Industry

The active layer optimization of polymer solar cells, materials and cells design, incorporation of carbon nanotubes, are reviewed. Dispersion and orientation of the nanotubes in the organic matrix are discussed to propose an ideal model polymer solar cell.

In the field of photovoltaic energy conversion, hybrid inorganic/organic devices represent promising alternatives to standard photovoltaic systems in terms of exploiting the specific features of both organic semiconductors and inorganic nanomaterials. Two main categories of hybrid solar cells coexist today, both of which make much use of metal oxide nanostructures based on titanium dioxide (TiO₂) and zinc oxide (ZnO) as electron transporters. These metal oxides are cheap to synthesise, are non-toxic, are biocompatible and have suitable charge transport properties, all these features being necessary to demonstrate highly efficient solar cells at low cost. Historically, the first hybrid approach developed was the dye-sensitized solar cell (DSSC) concept based on a nanostructured porous metal oxide electrode sensitized by a molecular dye. In particular, solid-state hybrid DSSCs, which reduce the complexity of cell assembly, demonstrate very promising performance today. The second hybrid approach exploits the bulk heterojunction (BHJ) concept, where conjugated polymer/metal oxide interfaces are used to generate photocurrent. In this context, we review the recent progress and new concepts in the field of hybrid solid-state DSSC and BHJ solar cells based on TiO₂ and ZnO nanostructures, incorporating dyes and conjugated polymers. We point out the specificities in common hybrid device structures and give an overview on new concepts, which couple and exploit the main advantages of both DSSC and BHJ approaches. In particular, we show that there is a trend of convergence between both DSSC and BHJ approaches into mixed concepts at the borderline which may allow in the near future the development of hybrid devices for competitive photovoltaic energy conversion. Copyright © 2011 Society of Chemical Industry

We review the recent progress in the field of hybrid solar cells based on metal oxide nanostructures and organic dyes or conjugated polymers. The discussion focuses specifically on TiO₂ and ZnO metal oxides, and both solid-state dye-sensitized solar cells and hybrid polymer/metal oxide heterojunctions. Finally, novel mixed device concepts at the borderline are reviewed.

Significant advances have been made recently in the area of organic electronics and optoelectronics based on small molecules as a result of the synthesis of new soluble and air-stable molecules. First reported 20 years ago, organic transistors quickly became a focus of intense research and development in academic and industrial laboratories. The great progress achieved thus far offers an opportunity for the production of new small electro-active molecules and the implementation of low-cost device fabrication technologies. This review focuses on recently synthesized p- or n-type organic semiconductors, particularly those suitable for fabrication of solution-processed and/or air-stable field effect transistors with an emphasis on low-cost wet processes. The numerous recent efforts realized in optoelectronics, particularly on phototransistors based on small molecules, offer various opportunities in applications for such organic compounds. Copyright © 2011 Society of Chemical Industry

This review focuses on recently synthesized p- or n-type organic semiconductors suitable for solution-processed and/or air-stable transistors. The recent results offer to such organic compounds various opportunities in applications.

Organic solid-state lasers are reviewed, with a special emphasis on works published during the last decade. Referring originally to dyes in solid-state polymeric matrices, organic lasers also include the rich family of organic semiconductors, paced by the rapid development of organic light-emitting diodes. Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low cost. In this review, we describe the basic photophysics of the materials used as gain media in organic lasers with a specific look at the distinctive features of dyes and semiconductors. We also outline the laser architectures used in state-of-the-art organic lasers and the performances of these devices with regard to output power, lifetime and beam quality. A survey of the recent trends in the field is given, highlighting the latest developments in terms of wavelength coverage, wavelength agility, efficiency and compactness, and towards integrated low-cost sources, with a special focus on the great challenges remaining for achieving direct electrical pumping. Finally, we discuss the very recent demonstration of new kinds of organic lasers based on polaritons or surface plasmons, which open new and very promising routes in the field of organic nanophotonics. Copyright © 2011 Society of Chemical Industry

This review of organic solid-state lasers draws a picture of the field as it appears to the authors at the beginning of 2011, emphasizing the latest advances and trends, particularly in the field of device physics.

Calix[4]arenes were double alkylated with various alkylhalogenides and the residual OH functions were subsequently dimethacrylated with methacryloyl chloride. The successful synthesis of polymerizable calixarenes was proved using ¹H NMR spectroscopy, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and differential scanning calorimetry. The polymerization behaviour was confirmed by copolymerization with methacrylic acid methyl ester. Furthermore, the flexural strength, the flexural modulus of elasticity, the exothermic course of the photo-curing reaction and the polymerization shrinkage of experimental dental filling composites containing the modified calixarenes were evaluated. Copyright © 2012 Society of Chemical Industry

Calix[4]arenedimethacrylates act as crosslinking agents for dental composite materials. The mechanical and thermal properties and the shrinkage behaviour of these dental composites are analysed.

Hydrolyzed cyclocopolymer prepared from divinyl ether and maleic anhydride, poly[(divinyl ether)-co-(maleic anhydride)] (DIVEMA), was functionalized with aminoadamantane and subsequently compared with the hydrolyzed DIVEMA with respect to physicochemical properties. The complexation behavior of adamantyl modified DIVEMA with cyclodextrin derivatives was examined by dynamic light scattering, nuclear magnetic resonance spectroscopy and zeta potential. The scattering studies indicated the formation of well-defined aggregated structures with an average diameter of 120 nm. These aggregated structures collapsed on addition of randomly methylated β-cyclodextrin to give 4.2 nm in hydrodynamic diameter. Interactions with crosslinked β-cyclodextrins indicated gel formation which was analyzed by means of rheology and temperature-dependent viscosity showing disaggregation of the host-guest system at 42 °C. This novel physical hydrogel is very interesting for medical applications as a drug delivery system with included anti-tumor activity. Copyright © 2012 Society of Chemical Industry

Hydrophobically modified DIVEMA and its physicochemical properties are described and analyzed. In combination with polymeric CD novel hydrogels via host-guest assembly were achieved.

Poly(L-lactic acid) (PLLA) films containing various concentrations of two natural antioxidants, α-tocopherol and resveratrol, were fabricated by a melt compounding and compression molding process. The influence of the antioxidants on the optical properties such as color and UV-visible light transmission was analyzed. The thermal, mechanical, rheological and physical properties of PLLA films with added antioxidants were assessed. PLLA films with added α-tocopherol and resveratrol showed a yellowish brown color and the lightness was influenced by the presence of the antioxidants. The glass transition and melting temperatures were significantly reduced with the addition of antioxidants while enhanced thermal stability was observed, which could be a benefit and important for processing and production. PLLA films with added antioxidants were slightly more hydrophobic than neat PLLA. The combination effect of plasticizing and enhancement of the elastic modulus with differing concentrations of two antioxidants played a critical role in the mechanical and thermomechanical properties of PLLA films. The melt viscosity of the PLLA films with added antioxidants was substantially higher than that of neat PLLA. The higher melt viscosity and G′(ω) could be an indication of formation of entanglement between PLLA and the two antioxidants. Copyright © 2012 Society of Chemical Industry

The presence of α-tocopherol and resveratrol into poly(L-lactic acid) (PLLA) films plasticized the PLLA matrix and enhanced the mechanical properties and the melt viscosity of the PLLA/antioxidant films.

Polymerizable ionic liquids (ILs) 1-methyl-3-(4-vinylbenzyl)imidazolium chloride, 1-hexyl-3-(4-vinylbenzyl)imidazolium chloride and 1-dodecyl-3-(4-vinylbenzyl)imidazolium chloride were prepared and used as new surfactants for the modification of montmorillonite (MMT). Functionalized MMTs were prepared by cationic exchange between sodium MMT and each of the ILs. Polystyrene (PS)/MMT composites were subsequently prepared by in situ intercalative free radical polymerization of styrene containing dispersed organophilic MMT. Exfoliation of MMT in the PS matrix was achieved only for MMT functionalized with the 1-dodecyl-3-(4-vinylbenzyl)imidazolium-based IL as revealed by X-ray diffraction and electron microscopy. The exfoliated composites showed good transparency and higher decomposition temperature than virgin polymer matrix, particularly pronounced under air atmosphere (ΔT_max = 66 °C), data comparable to or even greater than those reported in the literature for exfoliated PS nanocomposites. Copyright © 2012 Society of Chemical Industry

Thermally stable and transparent exfoliated polystyrene (PS) composites were prepared by in situ intercalative polymerization of styrene containing suspended montmorillonite (MMT) functionalized with polymerizable imidazolium-based ionic liquids.

In this work poly(hydroxybutyrate/poly(vinyl butyral)- co-(vinyl alcohol)-co(vinyl acetate) (or ethylene propylene diene monomer rubber) blends were prepared by conventional processing techniques (extrusion and injection moulding). A droplet type morphology was obtained for P(3HB)/PVB blends whereas P(3HB)/EPDM blends presented some extent of co-continuous morphology. In addition, rubbery domains were much smaller in the case of PVB. These differences in morphology are discussed taking into account solubility parameters and rheological behaviours of each component. For both blends, the increase of elastomer ratio led to a decrease of Young's modulus but an increase in elongation at break and impact strength. The latter increased more in the case of P(3HB)/EPDM blends although the rubbery domains were larger. These results are explained in the light of the glass transition of the rubber and the presence of plasticizer in the case of PVB. The addition of elastomer also resulted in an increase of P(3HB) biodegradation rate, especially in the case of EPDM. It is assumed that, in this case, the size and morphology of the rubbery domains induce a geometrical modification of the ‘erosion front’ which leads to an increase of the interface between P(3HB) phase and the degradation medium and consequently to an apparently faster biodegradation kinetics of PHB/rubber blends. Copyright © 2011 Society of Chemical Industry

A droplet type morphology was obtained for P(3HB)/PVB blends whereas P(3HB)/EPDM blends presented some extent of co-continuous morphology. The addition of elastomer increased the biodegradation rate of P(3HB), especially in the case of EPDM. It is assumed that the size and morphology of the rubbery domains induces a geometrical modification of the “erosion front”. That leads to an increase of the interface between P(3HB) phase and the degradation medium and consequently to an apparent faster biodegradation kinetic of PHB/rubber blends.

Poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) with very different weight-average molecular weights (M_w) of 4.0 × 10³ and 7.0 × 10⁵ g mol⁻¹ (M_w(PDLA)/M_w(PLLA) = 175) were blended at different PDLA weight ratios (X_D = PDLA weight/blend weight) and their crystallization from the melt was investigated. The presence of low molecular weight PLLA facilitated the stereocomplexation and thereby lowered the cold crystallization temperature (T_cc) for non-isothermal crystallization during heating and elevated the radial growth rate of spherulites (G) for isothermal crystallization, irrespective of X_D. The orientation of lamellae in the spherulites was higher for the neat PLLA, PDLA and an equimolar blend than for the non-equimolar blends. It was found that the orientation of lamellae in the blends was maintained by the stereocomplex (SC) crystallites. Although the G values are expected to decrease with an increase in X_D or the content of high-molecular-weight PDLA with lower chain mobility compared with that of low-molecular-weight PLLA, G was highest at X_D = 0.5 where the maximum amount of SC crystallites was formed and the G values were very similar for X_D = 0.4 and X_D = 0.6 with the same enantiomeric excess. This means that the effect of SC crystallites overwhelmed that of chain mobility. The nucleating mechanisms of SC crystallites were identical for X_D = 0.1–0.5 in the T_c range 130–180 °C. Copyright © 2011 Society of Chemical Industry

The presence of low-molecular-weight poly(L-lactic acid) facilitates stereocomplexation, which dominates and accelerates crystallization. The nucleating mechanisms were identical for poly(D-lactic acid) fractions of 10–50%.

Side-chain polyesters were synthesized from N-octyl-, N-dodecyl- or N-hexadecyl-diethanolamine and succinic acid anhydride. These polyesters were then transformed into polyester hydrochlorides by protonation of the amino groups using different amounts of HCl (20–100 mol%). Above 60 mol% the reaction is not quantitative and a degree of protonation of up to 88% is obtained. The structures of the synthesized polyesters and their hydrochlorides were determined by ¹H nuclear magnetic resonance spectroscopy. The thermal properties of the synthesized polyesters and their hydrochlorides were also studied using differential scanning calorimetry in relation to the side-chain length and the degree of polyester protonation. The polyester with octyl side chains and its hydrochlorides were amorphous liquids at room temperature, while the polyester and polyester hydrochlorides with hexadecyl side chains formed a smectic crystalline phase, S_mB, or its tilted analogues. The polyester with a dodecyl side chain was also an amorphous liquid at room temperature, while its hydrochlorides with various degrees of protonation were smectic liquid crystals, as determined by X-ray diffraction. By simply varying the degree of protonation the liquid crystal isotropization temperature was increased from 32 °C to 82 °C. Copyright © 2011 Society of Chemical Industry

Side-chain polyesters were synthesized from various N-alkyldiethanolamines and transformed into polyester hydrochlorides using different amounts of HCl (20–100 mol%). By simply varying the degree of protonation we were able to tune the LC-isotropization temperature.

The homogeneous dispersion of nanofillers in polymer matrices to form polymer nanocomposites remains a challenge in the development of high-performance polymer materials for various applications. In the work reported, a stearate ion-modified MgAl layered double hydroxide (St-LDH) as nanofiller was incorporated in a silicone rubber (SR) matrix by solution intercalation and subsequently characterized. X-ray diffraction and transmission electron microscopy studies confirm the formation of a predominantly exfoliated dispersion of St-LDH layers of 75–100 nm in width and about 1–2 nm in thickness in the SR. Thermogravimetric analysis shows that the thermal degradation temperature of the exfoliated SR/St-LDH (1 wt%) nanocomposites is about 80 °C higher than that of pure SR. Differential scanning calorimetric studies indicate that the melting and crystallization temperatures are higher by 4 and 10 °C for 5 and 8 wt% St-LDH-loaded SR nanocomposites compared to neat SR. A significant improvement of 97% in tensile strength and 714% in storage modulus and a reduction of 82% in oxygen permeability have been achieved at 3 wt% St-LDH loading in SR. Copyright © 2011 Society of Chemical Industry

A significant improvement in mechanical and thermal properties has been achieved in stearate ion-modified Mg-Al layered double hydroxide-reinforced silicone rubber nanocomposites prepared by solution intercalation.

γ-Butyrolactone (GBL)-processable high modulus heat-resistant materials were developed in this work. The polyaddition of an ester-containing tetracarboxylic dianhydride, i.e. hydroquinone bis(trimellitate anhydride) (TAHQ), and 2,2′-bis(trifluoromethyl)benzidine (TFMB) in GBL resulted in gelation in the initial reaction stage. The incorporation of a methyl group to TAHQ (M-TAHQ) allowed polymerization with TFMB in GBL and led to a homogeneous poly(ester imide) (PEsI) precursor solution with a short pot life of 3 days, whereas a simple copolymerization approach using bulky/flexible comonomers to TAHQ/TFMB was less effective. PEsI precursors (PEsAAs) were prepared from TFMB, M-TAHQ and a minor fraction of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) or a fluorene-containing tetracarboxylic dianhydride. These PEsAA systems showed drastically improved GBL solution stability. In particular, the M-TAHQ(80);6FDA(20)/TFMB copolymer system provided a PEsAA film with a very high light transmittance at 365 nm (>70%). A photosensitive film composed of this matrix resin and diazonaphthoquinone provided a clear positive-tone pattern by development in a 2.38 wt% tetramethylammonium hydroxide aqueous solution at room temperature with a high dissolution contrast. The thermally cured PEsI film achieved a very high tensile modulus (>5 GPa) as the present target with other desirable properties, i.e. sufficient film flexibility, a relatively low coefficient of thermal expansion, a high T_g and low water absorption. The present materials can be promising candidates as novel buffer coat films in semiconductor applications. Copyright © 2011 Society of Chemical Industry

A poly(ester imide) precursor with high transparency at 365 nm was polymerized in γ-butyrolactone. The diazonaphthoquinone-dispersed film provided a clear positive-tone pattern on development in an aqueous tetramethylammonium hydroxide solution. The cured film showed a very high modulus.

Ternary blends composed of matrix polymer poly(vinylidene fluoride) (PVDF) with different proportions of poly(methyl methacrylate) (PMMA)/poly(vinyl pyrrolidone) (PVP) blends were prepared by melt mixing. The miscibility, crystallization behavior, mechanical properties and hydrophilicity of the ternary blends have been investigated. The high compatibility of PVDF/PMMA/PVP ternary blends is induced by strong interactions between the carbonyl groups of the PMMA/PVP blend and the CF₂ or CH₂ group of PVDF. According to the Fourier transform infrared and wide-angle X-ray difffraction analyses, the introduction of PMMA does not change the crystalline state (i.e. α phase) of PVDF. By contrast, the addition of PVP in the blends favors the transformation of the crystalline state of PVDF from non-polar α to polar β phase. Moreover, the crystallinity of the PVDF/PMMA/PVP ternary blends also decreases compared with neat PVDF. Through mechanical analysis, the elongation at break of the blends significantly increases to more than six times that of neat PVDF. This confirms that the addition of the PMMA/PVP blend enhances the toughness of PVDF. Besides, the hydrophilicity of PVDF is remarkably improved by blending with PMMA/PVP; in particular when the content of PVP reaches 30 wt%, the water contact angle displays its lowest value which decreased from 91.4° to 51.0°. Copyright © 2011 Society of Chemical Industry

Significant changes of the crystallinity, crystallization rate, crystal size, and homogeneity of PVDF are determined by the hydrogen bonding and dipole-dipole interactions of the ternary blend.