Séparation d'un copolymère greffé de l'homopolymère correspondant par formation de gels réversibles perfectionnements et applications aux résines abs

Abstract

From a mixture containing a graft copolymer A-B in the presence of homopolymers A and B, it is possible to separate for instance the homopolymer B, corresponding to the grafts, by the reversible gel technique. The reversible crosslinking is achieved by fixing selectively COONa groups on polymer A. Improvements of this separation method are proposed in the case of ABS resins, obtained by grafting styrene-acrylonitrile (SAN) copolymers on polybutadiene. Carboxylation of the polybutadiene part can be achieved, after grafting, by treatment with thioglycolic acid. The separation is performed for two different carboxy contents of the polybutadiene. The high efficiency of the separation is shown. It is also confirmed that there is no fractionation in composition of the graft copolymer during this separation.