The influence of steric factors on the mechanism of copolymerization of phenylvinyl alkyl ethers and maleic anhydride

By assuming that the initial rate of copolymerization (R_p) of phenylvinyl alkyl ether (I) and maleic anhydride (MAn) equals the sum of the rate of polymerization of free monomers R_p(f) and CT complex monomers R_p(CT) the reactivity ratios k_1c/k₁₂ and k_2c/k₂₁ were calculated for copolymerization of I(R = Me, n-Pr, iso-Pr, and sec-Bu) and MAn from the change of copolymerization rate with monomer feed at a constant total monomer concentration. From the equation R_p = R_p(f) + R_p(CT) were calculated R_p(f) and R_p(CT) by applying the generalized model described by Shirota and coworkers and it was found that the participation of CT complex monomers increases with an increase in total monomer concentration in the feed. It was also found that the degree of CT complex monomer participation depends largely on the steric factors. In the copolymerization of I which contains bulky isopropyl or sec-butyl group even in the dilute solutions, copolymerization proceeds by the addition of CT complex monomers.