Complex-radical copolymerization of 2,4,4-trimethylpentene-1 with maleic anhydride

Abstract

The mechanism of radical copolymerization of 2,4,4-trimethylpentene-1 (TMP) as donor monomer with maleic anhydride (MA) as acceptor monomer in the presence of benzoyl peroxide is discussed. The constant of charge transfer complex ( K c) and copolymerization parameters ( r 1, r 2, r 1c, r 1c1, r 1c2, Q 1 and e 1) have been determined; their values are as follows: K c=0.27±0.1 L/mol and 0.16±0.07 L/mol at 35°C in CH 3COCH 3-d 6 for TMP–TMA and n-octene–MA (model system) complexes; r 1=0.12±0.005, r 2=0.38±0.02, r 1c=0.0068, r 1c1=0.127 and r 1c2=0.0072; Q 1=0.0012 and e 1=0.49. Some kinetic parameters of the reaction and quantitative contributions of TMP–MA complex to reactivity ratios of the monomers have been studied and their contribution to chain growth are estimated as: k 12/ k 21=3.51, k 1c/ k 12=0.98 and k 2c/ k 21=1.03. The copolymerization is found to proceed predominantly by the “mixed” mechanism with equal participation of complex-bound and free monomers in propagation. A solvent effect in radical copolymerization of TMP with MA is observed. The higher rate of copolymerization in the TMP–MA–dimethylformamide system is explained by the effect of the MA–solvent complex increasing the acceptor properties of the MA molecule.