Haloaldehyde polymers, 15. Stabilization of polychloral by posttreatment

Abstract

AbstractPolychloral prepared by anionic polymerization has primarily alkoxide endgroups as the living terminal ends. The initial endgroups depend on the type of nucleophile used for the initiation. Alkoxide‐terminated polychloral degrades to monomer on heating to slightly above 100°C or on extraction with methanol or acetone. Programmed DTG shows a degradation rate maximum (MDT) near 150°C. Terminations of the polymer endgroups were observed when the polymer was allowed to stand for long periods of time before workup. The type and amount of stabilization depends on the cation and residual monomer. With HCI the alkoxide ends can be protonated to give hydroxyl terminated polychloral, which is stable to extraction and has an MDT of 220°C. Acylation or alkylation as posttreatments could not be shown to produce the expected acyl‐ or alkyl endcapped polychloral, but posttreatment with acetyl chloride produced partially stable polymer (one MDT higher than 300°C) without detectable acetyl endgroups. The most effective posttreatment is with PCl5/CCl4 which gives highly stabilized polychloral with an MDT near 350°C. The treatment was only effective in thin sections of polymer and appeared to have introduced a chlorine endgroup.