Journal of Polymer Science Part A: Polymer Chemistry

The polyaddition reactions of 5-(4-methoxyphenyl)-1,4,6,7,7-pentamethyl-2,5-norbornadiene-2,3-dicarboxylic acid diglycidyl esters with certain dicarboxylic acids were carried out, producing corresponding polyesters containing donor–acceptor norbornadiene residues in the main chain. The photochemical reactions of the resulting polymers were also examined.

N-Chloro,N-propyl-p-toluenesulfonamide is demonstrated as initiating atom transfer radical polymerization of methyl methacrylate and styrene monomers when used in combination with an organic soluble cuprous bromide/hexahexyl triethylenetetramine (CuBr/HTETA) complex.

An investigation was performed on the polymerization kinetics of butyl acrylate/[2-(methacryloyoxy)ethyl]trimethyl ammonium chloride (BA/MAETAC) macroemulsion and miniemulsion copolymerizations with cumene hydroperoxide/tetraethylenepentamine (CHP/TEPA) as a redox initiator system. The postulate of interfacial copolymerization with a two-component redox initiator system, one hydrophobic and the other hydrophilic (as shown in the graphic), was confirmed. Adding MAETAC had a complex effect on the polymerization kinetics of BA. The influence was ascribed to varying the nucleation mechanism dependent on the feeding ratio of MAETAC and the polymerization method.

Two poly(pyridinium salt)s containing tosylate as a counterion were synthesized by the ring-transmutation polymerization reaction of bis(pyrylium tosylate) with the corresponding aromatic diamines and characterized for their lyotropic liquid-crystalline as well as fluorescence properties in both polar protic and aprotic solvents.

Novel polynorbornenes containing cationic cyclopentadienyliron moieties pendent to the polymer side chains were prepared via polymerization of metallated norbornene monomers using Grubbs' catalyst. Thermogravimetric analysis of the organometallic polymers showed two weight loss steps: the first at 200–230 °C represented loss of the metallic moieties, followed by decomposition of the polymer backbone between 400 and 450 °C. Cyclic voltammetric studies of the organometallic polymers showed one reversible reduction process.

Well-defined multicyclic polystyrenes are prepared in two steps. The first step is the preparation of a cyclic difunctional polystyrene by the reaction of α,ω-dilithiopolystyrene chains with 1,3-bis(phenylethenyl)benzene. Then, this product is covalently grafted to poly(chloromethylstyrene) chains leading to the formation of a high molar mass product containing linear and cyclic parts. As a model reaction and to optimize the previous reaction, a study of coupling of the linear difunctional model polystyrene with poly(chloromethylstyrene) is performed leading to grafted polystyrene. The grafted products are analyzed by size-exclusion chromatography, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and liquid chromatography at the exclusion-adsorption transition point.

α-Cyclodextrin threads onto amphiphilic, multiblock copolymers to give supramolecular inclusion complexes with physical properties that are different from those of the individual components. The stoichiometry of the inclusion complexes is controlled by a decrease in the polymer solubility that occurs as the polymer/α-cyclodextrin complex is formed.

A kinetic study of the dead-end polymerization of styrene initiated by azobiscyanovaleric acid (ACVA) is investigated. The kinetic relationships allowed us to show the importance of the primary radical termination (PRT) and find the rate constant of PRT to be about 1.10¹⁰ L · mol⁻¹ · s⁻¹. Finally, with a simulation program we evaluated the rate constant of primary radical deactivation, which represents the reaction between two ACVA radicals.

A highly alternative copolymer of carbon dioxide and propylene oxide was obtained using a lanthanide trichloroacetates-based ternary catalyst. The rare-earth compound in the ternary catalyst was critical to dramatically raise the yield and molecular weight of the copolymer in addition to maintaining a high alternating ratio of the copolymer.

A model polyethylene-poly(L-lactide) diblock copolymer (PE-b-PLLA) was synthesized using hydroxyl-terminated PE (PE-OH) as a macroinitiator for the ring-opening polymerization of L-lactide. Binary blends containing poly(L-lactide) (PLLA) and very low-density PE (LDPE) and ternary blends containing PLLA, LDPE, and PE-b-PLLA were prepared by solution blending followed by precipitation and compression molding. Particle size analysis and scanning electron microscopy results showed that both the particle size and distribution of the LDPE dispersed in the PLLA matrix sharply decreased upon addition of PE-b-PLLA. The tensile and Izod impact testing results on the ternary blends showed significantly improved toughness as compared to the PLLA homopolymer or the corresponding PLLA/LDPE binary blends.

Macromonomers were synthesized by anionic “living” polymerization. They comprised a poly(ethylene oxide) hydrophilic block and a hydrophobic block or sequence terminated with an unsaturation. The surface activity properties of these materials (critical micelle concentration and parking area) were determined, and the values were compared and discussed in terms of the molecular structure of these new surfactants. Some of the macromonomers were employed as emulsifiers in two-step emulsion polymerizations. The data obtained were discussed while taking into account the different chemical structures of the macromonomers and the efficiency of these species as emulsifiers in the polymerization recipes.

Polystyrene stars were made using reversible addition–fragmentation chain-transfer (RAFT) polymerization. The molecular weight distributions revealed the presence of star-polymer formation together with linear polymer. Evidence for radical–radical termination by combination is also presented.

A series of random copolymers of N-isopropylacrylamide (NIPAM) and sodium 2-acrylamido-2-methyl-1-propanesulphonate (AMPS) were synthesized. The content of AMPS in the copolymers ranged from 1.1 to 9.6 mol %. The reactivity ratios of both comonomers were calculated. The lower critical-solution temperature of the copolymers depends on the copolymer composition, concentration, and the ionic strength of the solution.

The polymerization of butadiene (Bd) with Co(acac)₃ in combination with methylaluminoxane (MAO) was investigated. High cis-1,4 selectivity and molecular weight-controlled polymerization of Bd were achieved in the polymerization of Bd with the Co(acac)₃-MAO catalyst, although the molecular weight distribution was not narrow. The polymer yields and molecular weight polymers depended on reaction temperature, the Bd concentration, and the MAO/Co(acac)₃ ratio. The high cis-1,4 content of the polymer was not influenced significantly by the polymerization conditions examined.

An ester-free, cycloaliphatic, liquid, trifunctional epoxide containing epoxycyclohexyl moiety linked via ether bonds was synthesized. Compared with the commercial diepoxide ERL-4221 under the same curing conditions, the cured product based on the new material showed a much higher glass-transition temperature (198 °C), a higher crosslinking density (2.08 × 10⁻³ mol/cm³), and a lower coefficient of thermal expansion [6.2 × 10⁵(/°C)]. It may become a promising candidate material for modern microelectronic packaging.

Benzyl cyclopentadienyl titanium trichloride was synthesized from benzyl bromide, cyclopentadienyl lithium, and titanium tetrachloride and used in combination with methylaluminoxane (MAO) for the syndiospecific polymerization of styrene. By analyzing the polymerization runs and the physical properties of the polymers with differential scanning calorimetry, ¹³C NMR spectroscopy, wide-angle X-ray scattering measurements, and gel permeation chromatography, we found that the phenyl ring coordinates to the titanium atom during polymerization.

Reactive surfactants allow the surfactant molecules to become covalently bound to the particles and thus provide added stability to the colloid particles, longer shelf life, better shear resistance, and polymer particles that can be redispersed. This article reports for the first time the use of a novel addition–fragmenation chain-transfer reactive surfactant (transurf) in ab initio emulsion polymerizations of methyl methacrylate at 70 °C.

The initiating behavior of the functional tosylates 1–4 and triflates 5 and 6 for the cationic ring-opening polymerization of 2-methyl-1,3-oxazoline was investigated. The emphasis was directed at tosylates and triflates with 2,2-dimethyl-1,3-dioxolane-, 2,3-epoxypropyl-, 2,3-didodecanoyl-glycerol-, and cholest-5-en-moieties that allow the construction of amphiphilic polyoxazoline conjugates. 2,2-Dimethyl-(4-trifluoromethanesulfonyloxymethyl)-1,3-dioxolane 6 gave the best results in respect to molecular weight and polydispersity. Starting from functional oxazoline polymers obtained with 6 as an initiator, amphiphilic lipid-polyoxazoline conjugates with a diacylglycerol backbone could be prepared.

Emulsion homopolymerizations and copolymerizations of butyl acrylate (BuA) and methyl methacrylate (MMA) were carried out with different types and concentrations of surfactants to determine the influence of these parameters on the particle size and particle size distribution and to elucidate the mechanism of particle formation. As expected, the mechanisms of nucleation above and below the critical micelle concentration were very different. In addition, the presence of partially soluble monomers such as MMA in the water phase changed the critical micelle concentration of Triton by more than 50%.

Liquid-crystalline epoxy resins were synthesized from 6-hydroxy-2-naphthoic acid, which was used as a mesogenic component, with phenylhydroquinone or isosorbide and via a further reaction with (6-bromo-1-hexyl)glycidylether, which was used as a flexible spacer. In this way, phenylhydroquinone-bis-6-[6-(glycidyloxy)hexyloxy]2-naphthoate (Gly A) and isosorbide-bis-6-[6-(glycidyloxy)hexyloxy]2-naphthoate (Gly B) were obtained. Nematic elastomers were obtained by the crosslinking of Gly A with 2,4-diaminotoluene (DAT) and 1,10-decanedicarboxylic acid (SA). The liquid-crystalline behavior was investigated with differential scanning calorimetry, polarizing light microscopy, and X-ray diffractometry. Cholesteric mesophases were produced by the blending of different ratios of Gly A and Gly B, and these blends were then crosslinked with SA to produce nematic mesophases.

For methoxy phenylacetylene dendrimers in dilute solutions in poly(tert-butyl methacrylate), there is an intramolecular charge-transfer (CT) state that lies at an increasing energy location with respect to the π* state with increasing dendrimer size. It stabilizes rapidly with increasing pressure, so that above about 40 kbar, it is the emitting state for all dendrimers. For the neat dendrimer, above the pressure at which the CT state is occupied by excitation transfer from the π* state, intermolecular CT occurs with a resultant complex formation.