Structural analysis of alkene/maleic anhydride copolymers

Abstract

Abstract Structural investigations on maleic anhydride (MAn) copolymers with ethene, propene and styrene, their products of hydrolysis, and their methyl half‐esters by means of 13 C NMR spectroscopy are presented. The spectra of 2,3‐diethylsuccinic acid and its anhydrides in the erythro ‐ and threo ‐configuration and of butylsuccinic acid and its anhydride were obtained and compared with the spectra of the copolymers. In each case the results show the formation of both threo(trans) ‐ and erythro(cis) ‐structures. At a polymerization temperature of 60°C the proportions were 88% threo to 12% erythro for ethene/MAn copolymers and 80% threo to 20% erythro for propene/MAn copolymers, a ratio which was confirmed also by the hydrolyzed forms. Copolymerization at 150°C leads, in the case of propene/MAn, to 67% threo and 33% erythro . The production of ethene/MA copolymer via the copolymerization of ethene and fumaric acid half‐ester and its saponification to ethene/fumaric acid leads to a ratio of 38% threo to 62% erythro . These results are in accordance with the thermal stabilities of the configurations. In the case of styrene/MAn copolymer it is not possible to obtain a unique interpretation of the configurations from the spectra. For the conversion of propene/MAn and styrene/MAn copolymers by means of methanol to half‐esters it can be derived from the 13 C NMR spectra how many of the half‐ester moieties are obtained in the neighbourhood of the methyl and phenyl groups, respectively, of the olefin.