Synthesis of poly(vinyl acetate) by degenerative transfer polymerization in the presence of iodine

A new curing agent containing maleimide and biphenyl moieties (MIBP) was synthesized by the condensation polymerization of 4,4′-bismethoxymethylbiphenyl and N-(4-hydroxyphenyl)maleimide (HPM). The chemical structure was characterized with Fourier transform infrared (FTIR) spectroscopy, and the molecular weight of the new curing agent was determined by gel permeation chromatography. Curing reactions of O-cresol formaldehyde epoxy (CNE) resin with MIBP were investigated under nonisothermal differential scanning calorimetry, and the exotherm exhibited two overlapping exothermic peaks during the curing process; this was demonstrated by FTIR traces. The Flynn–Wall–Ozawa and Friedman methods were used to examine the kinetic parameters and the kinetic models of the curing processes of the CNE/MIBP mixtures. Both reactions turned out to be nth-order curing mechanisms. Values of the reaction order (n) = 1.42 and activation energy (E_a) = 91.2 kJ/mol were obtained for the first reaction of the curing of the CNE/MIBP system, and values of n = 1.11 and E_a = 78.7 kJ/mol were obtained for the second reaction. The thermal properties of the cured resin were measured with thermogravimetric analysis, and the results show a high glass-transition temperature (T_g = 155°C), good thermal stability (temperature at 10% weight loss, under nitrogen and in air, ≈ 400 and 408°C, respectively), and high char yield (temperature = 800°C, char residue = 44.5% under nitrogen). These excellent thermal properties were due to the introduction of the maleimide and biphenyl groups of MIBP into the polymer structure. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012