Alternating copolymerization of β-methylstyrene and maleic anhydride

Alternating copolymers of β-methylstyrene and maleic anhydride were prepared by free-radical-initiated polymerization in bulk and in toluene as a solvent. The reactivity ratios k1c/k12 and k2c/k21 were calculated from the change of copolymerization rate with a monomer feed at a constant total monomer concentration according to the generalized model of Shirota and coworkers. From the equation Rp = Rp(f) + Rp(CT) were calculated Rp(f) and Rp(CT), and it was found that in toluene the copolymerization proceeds predominantly by the addition of CT-complex monomers. Termination occurs predominantly by homotermination of β-methyl-styrene macro free radicals, kt22, but the cross termination kt21 is also operative.