Stereo-regularity increase of syndiotactic or isotactic polymer mixts. - by extraction using selective solvents which remove low average stereo-regular components

摘要

The stereoregularity of a syndiotactic or isotactic polymer mixt. of linear alternating copolymers derived from carbon monoxide and a monomer CH2=CH-R can be increased by treating the polymer mixt. with a selective solvent in which the copolymers show a higher degree of solubility with lower stereoregularity. R is an opt. polarly substd. hydrocarbyl gp. The process can be carried out by either extracting the polymer mixt. with the selective solvent whereby the remaining polymer shows higher averagew stereoregularity or the polymer mixt. can be completely dissolved in one solvent and then adding the selective solvent which pptes. the polymer mixt. with higher stereoregularity.