New isomers of polyvinyl fluoride with controlled regiosequence microstructure.

The addition polymer of vinyl fluoride, PVF, contains head- to-head and tail-to-tail structural irregularities (regiosequence defects) caused by monomer reversals during chain propagation. Heretofore, there has been no method for significantly altering the level of regiosequence defects, which typically amounts to 11% reverse addition and changes little with polymerization temperature. We report here a novel synthetic procedure which enables us to adjust this defect level by reductive dechlorination of precursor copolymers of VF with suitable chlorofluoroethylenes, using tributyltin hydride to quantitatively replace chlorine with hydrogen.