INFLUENCE OF TEMPERATURE ON BUTYL ACRYLATE STYRENE COPOLYMERIZATION PARAMETERS

Butyl acrylate (BA) - styrene (ST) copolymerization was carried out in bulk without any free-radical initiator at 110, 150 and 170-degrees-C. The Kelen-Tudos (K-T) transformation of comonomers-copolymer composition data shows that the copolymerization can be sufficiently described by a terminal copolymerization model. Reactivity ratios for BA (r1) and ST (r2) were estimated by the K-T method as well as by the error-in-variables method. Together with previous reports on BA-ST copolymerization at 50 and 60-degrees-C, these values of r2 and r2 served to find the Arrhenius relationships: ln r1 = 1.3510- 1034.1/T, and ln r2 = 0.05919 - 131.6/T, where T is absolute temperature. Thus, although r1 can be strongly affected by temperature, r2 is practically temperature insensitive. This can be explained by the activation energy differences between homo- and cross-propagations (8.6 and 1.1 kJ mol-1, respectively). Effect of conversion on copolymer and comonomers composition is also discussed.