COPOLYMERIZATION OF T-BUTOXYCARBONYLOXYSTYRENE AND SULFUR-DIOXIDE

The reaction kinetics of radical chain copolymerization of t-butoxycar bonyloxystyrene (TBS) and sulfur dioxide have been studied using a rea ction/sampling apparatus that permits accurate determination of the re action mixture concentrations during polymerization. The results are c ompared with the styrene-sulfur dioxide copolymerization kinetics. The influence of temperature and reactant concentrations on the polymeriz ation rate and copolymer composition are reported. With increasing rea ction temperature, the amount of SO2 incorporated and the molecular we ight of the copolymer are found to decrease. For a constant TBS concen tration in the reaction solution, raising the SO2 concentration causes an increase of SO2 incorporation in the copolymer, up to a maximum SO 2 content corresponding to a TBS:SO2 mole ratio of 2:1. However, for a constant SO2 concentration, the amount of TBS incorporated in the cop olymer increases with decreasing TBS concentration in the reaction sol ution. The polymerization rate and copolymer molecular weight increase proportionally with monomer concentration as expected for a normal ra dical chain polymerization mechanism. Comparison of these findings wit h various kinetic models for styrene-SO2 copolymerization indicates go od agreement with models proposed by Barb (1-3) and Walling (4); howev er, the data do not agree with the predictions of Matsuda et al (5) Th e understanding of the kinetics and reaction mechanism provided in thi s study will aid in the manufacture of this lithographically important copolymer.