The influence of the microstructure of some chlorine containing polymers on their miscibility with poly(butadiene-stat-acrylonitrile)

A range of poly(butadiene-stat-acrylonitrile), BAN, copolymers with compositions ranging between 17.8 wt% and 66.9 wt% acrylonitrile, have been mixed with three chlorine containing (~ 56 wt% Cl) polymers: conventional poly(vinyl chloride), PVC, chlorinated poly(1,4-butadiene) and chlorinated polyethylene, CPE. The polybutadiene which has been chlorinated at the double bonds can be regarded as head-to-head PVC, (H-H) PVC, whereas the CPE is a random copolymer of head-to-tail PVC, (H-T) PVC, and (H-H) PVC. Thus the samples which contain the same amount of chlorine will vary only in its sequence distribution along the chain. When these were blended with BAN samples, the extent of the miscibility ranges established were found to increase in the order: (H-T) PVC < CPE < (H-H) PVC. This gives a qualitative demonstration of the influence of sequence distribution on the miscibility of some polymer blends. Substitution of bromine for chlorine in the halogenated poly(1,4-butadiene) resulted in immiscible blends and highlighted the sensitivity of many polymer blend systems to small changes in the chemical structure of the polymers. © 1992.