COPOLYMERIZATION OF 4-ACETYL PHENYLACRYLATE WITH METHYL-METHACRYLATE AND BUTYL METHACRYLATE - SYNTHESIS, CHARACTERIZATION AND REACTIVITY RATIOS

Several copolymers of methyl methacrylate (MMA) and butyl methacrylate (BMA) with 4-acetyl phenylacrylate (APA) having different copolymer c ompositions were synthesized in 2-butanone using benzoyl peroxide as a free radical initiator at 65 +/- 0.5 degrees C. The composition of mo nomeric units in the copolymer system was calculated using H-1 NMR spe ctroscopy by comparing the integral values of well separated aromatic and aliphatic proton peaks. The reactivity ratios were calculated by e mploying Fineman-Ross, Kelen-Tudos and extended Kelen-Tudos methods. T he values of r(1), and r(2) obtained by the Kelen-Tudos and the Extend ed 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, H-1 and C-13 NMR sp ectroscopic techniques. By using gel permeation chromatography, weight average (<(M)over bar (n)>) and number average (<(M)over bar (n)>) mo lecular weights and polydispersity indices of the copolymers were dete rmined. Thermal stabilities of the home-and co-polymers were calculate d using thermogravimetric analysis, while differential scanning calori metry was used to determine the glass transition temperature. Thermall y stable copolymers were obtained by the incorporation of APA units as the initial decomposition temperature of the copolymers increased wit h increase in concentration of APA units. (C) 1997 Elsevier Science Lt d.