Assignment of ~(13)C NMR chemical shift and microstructure of copolymers of 2-chloroethyl vinyl ether-maleic anhydride and n-butyl vinyl ether-maleic anhydride

摘要

The chemical shift in the ~(13)C NMR spectral of copolymers of 2-chloroethyl vinyl ether (CEVE) and maleic anhydride (MA), and of n-butyl vinyl ether (BVE) and MA is assigned. It is found that both copolymers are made of completely alternating monomer unit sequences and that the proportion of cis linkage configuration at the cyclic MA units is 45% and 47% in the CEVE-MA copolymer and in the BVE-MA copolymer respectively. Depending on the relative orientation of the cyclic anhydride group, quasi "isotactic" and quasi "syndiotactic" tacticity are considered, with quasi "syndiotactic" diads shielding the vinyl ether carbons more effectively.