Synthesis and microstructure of organotin polymers

Abstract

IR spectroscopy and derivatography have been used to analyze the intramolecular conversions of the bis-tri- n-butylstanny esters of maleic and fumaric acids and also their copolymers. Thermal isomerization of the maleates to fumarates does not occur up to temperatures of the onset of decomposition of the substances. On free-radical copolymerization of the maleates with styrene there is partial isomerezation and in the structure of the chain, units of the diesters of maleic (85–90%) and fumaric (10–15) acids are found. In the alternating styrene-maleic anhydride copolymers after esterification by organotin oxides the number of isotactic diads may be 10%. Change in the microtacticity is explained by the formation of polycarbanions. Heating of the copolymers to 500 K leads to exothermal change in the configuration of the maleate units and then to their cyclization with the formation of maleic anhydride units.