Copolymerization of 4-acetyl phenylacrylate with methyl methacrylate and butyl methacrylate: Synthesis, characterization and reactivity ratios

Abstract

Several copolymers of methyl methacrylate (MMA) and butyl methacrylate (BMA) with 4-acetyl phenylacrylate (APA) having different copolymer compositions were synthesized in 2-butanone using benzoyl peroxide as a free radical initiator at 65 ± 0.5 °C. The composition of monomeric units in the copolymer system was calculated using 1H NMR spectroscopy by comparing the integral values of well separated aromatic and aliphatic proton peaks. The reactivity ratios were calculated by employing Fineman-Ross, Kelen-Tudos and extended Kelen-Tudos methods. The values of r 1, and r 2 obtained by the Kelen-Tudos and the Extended Kelen-Tudos methods appear to be in close agreement with each other i.e r 1 (APA) = 0.78 and r 2 (MMA): 0.575 for the copoly(APA-MMA) system; r 1(APA) = 1.465 and r 2(BMA) = 0.685 for the copoly(APA-BMA) system. The copolymers were characterized by IR, 1H and 13C NMR spectroscopic techniques. By using gel permeation chromatography, weight average ( M ̄ w ) and number average ( M ̄ n ) molecular weights and polydispersity indices of the copolymers were determined. Thermal stabilities of the homo- and co-polymers were calculated using thermogravimetric analysis, while differential scanning calorimetry was used to determine the glass transition temperature. Thermally stable copolymers were obtained by the incorporation of APA units as the initial decomposition temperature of the copolymers increased with increase in concentration of APA units.