Journal of Polymer Science Part A: Polymer Chemistry

Calcium-containing poly(urethane-urea)s (PUUs) were synthesized by reacting hexamethylene diisocyanate (HMDI) or tolylene 2,4-diisocyanate (TDI) with 1:1 mixtures of calcium salt of mono(hydroxypentyl)phthalate [Ca(HPP)₂] and each of the bisureas like hexamethylene bis(ω,N-hydroxyethylurea) (HBHEU), tolylene 2,4-bis(ω,N-hydroxyethylurea) (TBHEU), hexamethylene bis(ω,N-hydroxypropylurea) (HBHPU), and tolylene 2,4-bis(ω,N-hydroxypropylurea) (TBHPU) using di-n-butyltin dilaurate (DBTDL) as catalyst. The PUUs were well characterized by FT-IR, ¹H & ¹³C-NMR, solid-state ¹³C-CP-MAS NMR, viscosity, solubility, elemental analysis, and X-ray diffraction studies. Thermal properties of the polymers were also studied using thermogravimetric analysis and differential scanning calorimetry.

Presence of substitution on both m- and p-phenylene rings (polymer 6) improves solution fluorescence quantum efficiency of the polymer. As anticipated, the alkoxy substitution on the phenyl rings leads to fine tune of emission color [from 489 nm (film 2) to 529 nm (film 6)]. Unexpectedly, the alkoxy substitution on an m- or p-phenylene shows significant effect on the EL properties.

The utilization of an automated synthesizer for the systematical kinetic screening of all combinations of four 2-oxazoline monomers with four initiators at two temperatures and four monomer/initiator ratios is described. Samples were taken automatically from the reaction mixtures to determine the livingness and the polymerization rates for the different polymerizations. The gained kinetic insights into the polymerizations were applied for the directed synthesis of random copolymers with and without composition drift.

A catalyst system composed of η⁵-C₅H₄(tert-Bu)TiCl₃ and MAO proceeded the polymerization of isoprene to yield highly cis-configurated polyisoprene with narrow MWD.

A series of new polybenzimidazopyrrolones (polypyrrolone, PPy) were synthesized by polycondensation of pyridine-bridged aromatic tetraamines, including 2,6-bis (3′,4′-diaminophenyl)-4-phenylpyridine (PTPA) and 2,6-bis(3′,4′- diaminophenyl)-4-(3″-trifluoromethyl)phenyl pyridine (3FPA), with various aromatic dianhydrides. Experimental results indicated that the PPys, multiaromatic conjugated and semiladder polymers, showed good thermal stabilities with thermal-decomposition temperatures of about 500 °C and residual weight retention at 750 °C as high as 84%. Moreover, the PPy films exhibited excellent alkaline hydrolysis resistance, which retained their original shapes and toughness after boiling 7 days in 10% sodium hydroxide solution.

The nucleophilic substitution reaction of poly(vinyl chloride) with potassium 4-acetamidothiophenolate was shown to proceed through the local configuration-driven mechanism found in a previous work for other nucleophiles. However, the evolution of the glass-transition temperature (T_g) with the degree of conversion was found to change, similarly to the ratio of the extents to which mmr and rrmr structures intervened in the substitution reaction. From these studies, it followed that the specific molecular interactions due to the polar nature of the nucleophile enhanced the molecular-microstructure-based mechanisms, which were responsible for T_g.

Epoxy/amine hybrid resins with various contents of amine resins were obtained through the in situ curing of bisphenol A epoxy and hexakis(methoxymethyl)melamine with 2 wt % (3-glycidoxypropyl)trimethoxysilane as a facial coupling agent. The hybrid resins showed good miscibility, high transparency, high glass-transition temperatures, good thermooxidative stability, and good flame retardance. The outstanding properties of the hybrid resins may lead to their use in high-performance green electronic products.

A high-throughput approach was developed for the rapid screening and optimization of the reaction conditions for atom transfer radical polymerization (ATRP). The optimal reaction conditions for Cu(I) halide, CuSCN, and Fe(II) halide-mediated ATRP systems were effectively determined.

The lactide polymerization mechanism using zirconium(IV) acetylacetonate [Zr(acac)₄] as an initiator was investigated. In the reaction between Zr(acac)₄ and the monomer molecule, lactide deprotonation and the release of acetylacetone occurred. The polymer chain grew on one ligand, which was formed in advance from a deprotonated lactide.

A series of tetrakis Sn(IV) alkoxides was studied for the ring-opening polymerization (ROP) of D,L-lactide. The complexes bearing bulky alkoxide ligands acted as highly active ROP catalysts producing poly(D,L-lactide) with a very narrow molar-mass distribution. Because of the living ROP, the preparation of block L-lactide-co-ϵ-caprolactone also was demonstrated. The clear advantage of these tetrakis Sn(IV) alkoxide catalysts over the frequently used Sn(II) alkanoates and their derivatives is a significantly higher polymerization activity.

Microparticles of poly(methacrylic acid)–gadolinium(III) (Gd³⁺) ion complex were prepared in 100 nm. Potentiometric titration of the complexation of the particle with Gd³⁺ ions indicated the formation of a very stable tris-carboxylate coordinate complex with the Gd³⁺ ion. The particle gave strong magnetic responses in the magnetic force microscopy measurement, of which the images were dependent on the Gd³⁺ ion content in the particle.

Poly(aryl-ethynylene) polymers of tuned rigidity/flexibility were synthesized by a palladium-catalyzed polycondensation of 2,5-diethynyl-4-dodecyltoluene with 2,5- and/or 3,5-dibromopyridine. The shape of the new poly(pyridyl/phenyl-ethynylenes) (PPyPEs) was altered from a rigid rod to a random coil by varying the 2,5-/3,5-linkage ratio of the pyridyl moities in the polymer backbone. The glass-transition and melting temperatures varied systematically with the degree of rigidity/flexibility and could be directly related to the conformational changes as reflected from the small-angle X-ray scattering data.

This article describes the synthesis and characterization of 1-methoxypoly(oxyethylene)benzocyclobutene (1). The Diels–Alder reactions of 1 with maleic anhydride (MA) and N-phenylmaleimide (NPHMI) were also studied and the resulting adducts (2 and 3) were characterized. The usefulness of the MA adduct, 2, is demonstrated by its reaction with o-toluidine.

Segmented terpolymers, poly(alkyl methacrylate)-g-poly(D-lactide)/poly(dimethylsiloxane) (PLA/PDMS), were prepared with a combination of the “grafting through” technique (macromonomer method) and controlled/living radical polymerization (atom transfer radical polymerization or reversible addition–fragmentation transfer polymerization). Two synthetic pathways were used. The first was a single-step approach in which a low-molecular-weight methacrylate monomer (methyl methacrylate or butyl methacrylate) was copolymerized with a PLA macromonomer and a PDMS macromonomer. The second strategy was a two-step approach in which a graft copolymer containing one macromonomer was chain-extended by a copolymerization of the second macromonomer and the low-molecular-weight methacrylate. The kinetics of both synthetic approaches were investigated, showing that the polymerizations exhibited a controlled/living behavior. Furthermore, the molecular structure of the terpolymers (composition, molecular weight distribution, and microstructure) was investigated by two-dimensional liquid chromatography. Well-defined terpolymers with controlled branch distribution, composition (F_w,PMMA/F_w,PLA/F_w,PDMS ∼ 50/30/20) molecular weight (M_n ∼ 50,000 g · mol⁻¹), and a narrow molecular weight distribution (M_w/M_n ∼ 1.3) were prepared via both pathways.

Photografting of maleic anhydride onto polypropylene using benzophenone as the photoinitiator was studied and compared with peroxide initiated grafting. A high grafting efficiency for the photografting was determined and attributed to triplet sensitization of maleic anhydride by benzophenone, which generates the excited triplet state of maleic anhydride as the primary initiating species. Studies using laser flash photolysis and a model compound 2,4-dimethylpentane confirmed the proposed mechanism.

A novel ligand, N,N,N′,N′,N″-penta (methyl acrylate) diethylenetriamine (MA₅-DETA), was synthesized by the reaction of diethylenetriamine with methyl acrylate in almost quantitive yield. The polymerizations of methyl methacrylate with MA₅-DETA as the ligand and α,α-dichlorotoluene (DCT) and ethyl 2-bromoisobutyrate (2-EBiB) as the initiators, respectively, under different conditions were examined. The polymerization with CuCl/MA₅-DETA/DCT was closely controlled in bulk and gave polymers with quite narrow molecular weight distributions (M_w/M_n's) of 1.16–1.29. The polymerization with the system CuBr/MA₅-DETA/EBiB in bulk gave high activity. However, the system was not well controlled and gave the polymers with M_w/M_n = 1.35–1.53. The solution polymerization in anisole with CuBr/MA₅-DETA/EBiB showed a better-controlled nature. Moreover, the addition of CuBr₂ into the aforementioned system can further improve its controllability. The M_w/M_n's of the resulting polymers ranged from 1.11 to 1.21.

We have measured the time evolution of the structure of perpendicular-oriented cylindrical-phase diblock copolymer films using statistical analysis of high-resolution scanning electron microscope (SEM) images.

Nanocomposites made of silica particles coated with poly(ε-caprolactone) and poly(L-lactide) were synthesized with anionic-coordinated ring-opening polymerization of the corresponding cyclic monomers initiated by hydroxyl groups introduced on the inorganic surface. A systematic study of the influence of the nature of the metal and the metal concentration on the grafting efficiency enabled us to improve the composite polymer content. Nanocomposites containing up to 96% of polymer were obtained by this method.

Real-time Fourier transform near-infrared spectroscopy has been used to monitor monomer and water concentrations simultaneously during cationic vinyl ether photopolymerization. This approach provides a highly informative, dynamic technique for examining the influence of moisture on polymerization reactions. Significant differences have been observed in the effects of absorbed water on the cationic photopolymerization kinetics of vinyl ether monomers with or without a hydrophilic OH group.

We describe the synthesis of several different polycarbonate particles by mini-emulsion polymerization. The monomers employed were allylmethyl carbonate (AlMeC), di(ethylene glycol)-bisallylcarbonate (DBAC) and 4-vinyl-1,3-dioxan-2-one (vinyl ethylene carbonate VEC). The choice of monomer was the major determinant of particle size. In polymerization reactions carried out at 85 °C with benzoyl peroxide as the initiator and with otherwise identical recipes, we obtained particle sizes of 181 nm with AlMeC, 296 nm with VEC, and 203 nm with DBAC. Fluorescent particles were synthesized with co-monomers based on the benzothioxanthene nucleus.

Poly(acrylo-amidino diethylenediamine) was synthesized to study the effects of hydrogen bonds at different pHs during the formation of ionic bonds between the polymer and anions. The supramolecular architecture of the bonds between poly(acrylo-amidino diethylenediamine) and cromate or phosphate ions depended on the pH. This was confirmed with Fourier transform infrared spectra. However, when poly(acrylo-amidino diethylenediamine) and metal ions (Cu²⁺, Ni²⁺, Fe²⁺, and Ag⁺) formed complexes, a hydrogen-bonding effect was not observed with Fourier transform infrared.

Several N-vinylimidazole/divinylbenzene resins were synthesized by suspension polymerization to achieve a quantitative incorporation of the N-vinylimidazole monomer into the final polymer while a high specific surface area was maintained. The retention properties of copolymers with different nitrogen contents were evaluated with the solid-phase extraction of polar compounds from water samples, and the best results were obtained for a polymer containing 6.3% N with a surface area of 627 m² g⁻¹. The sorption properties of the resins were compared to those of styrene–divinylbenzene and other copolymers containing nitrogen, and the results were best for the new sorbents with N-vinylimidazole as the polar monomer.

This article involves the synthesis and properties of novel poly(ether amide)s containing phthalazinone units in polymer's backbone. The scheme of Graphical Abstract shows us the polymerization reaction of three novel substituted-diamines with different aromatic diacids. The poly(phthalazinone ether amide)s obtained here have attractive properties such as high T_g above 300 °C and good solubility in polar solvents.

Divinyl ether monomers containing phosphoric residue were synthesized by the addition reaction of glycidyl vinyl ether (GVE) with various phosphonic dichlorides or dichlorophosphates with quaternary onium salts as catalysts. The reaction of GVE with phenylphosphonic dichloride gave bis[1-(chloromethyl)-2-(vinyloxy)ethyl]phenylphosphonate (1a) in a 77% yield. The polycondensation of 1a with terephthalic acid was also carried out with 1,8-diazabicyclo[5.4.0]undecene-7 (DBU) as a condensing agent to afford the corresponding phosphorus-containing polyester. A multifunctional monomer containing both vinyl ether groups and methacrylate groups was prepared by the reaction of 1a with methacrylic acid with DBU. The photoinitiated cationic of these vinyl ether compounds proceeded rapidly with bis[4-(diphenylsulfonio)phenyl]sulfide-bishexafluorophosphate as the cationic photoinitiator without a solvent upon ultraviolet irradiation.

Chemical oxidative polymerization of aniline is carried out using different organic acids (acetic, citric, oxalic, and tartaric acid) as protonation media. From the UV–visible spectroscopy it is observed that, among all the acids used for doping purposes, oxalic acid doped polyaniline shows the greatest extent of selective formation of a conducting emeraldine salt phase. This is further supported by conductivity measurements in which the conductivity of oxalic acid doped polyaniline is very high.