Multiphase block and graft copolymers comprising a hydrophilic continuous phase and hydrophobic domains

Abstract

This invention relates to thermoplastic, multiphase copolymers selected from the group consisting of copolymers represented by graft copolymers having the general formula ##STR1## AND BLOCK COPOLYMERS HAVING THE GENERAL FORMULA XB--[AB].sub.n --yA wherein n is an integer .gtoreq.1, m is >1, x and y are 0 or 1, and y is 1 when n is 1, A is a thermoplastic, hydrophobic polymer block having a softening point (i.e., a glass transition or crystalline melting point) of at least 35.degree. C and a molecular weight of at least 2,000, and B is a thermoplastic, hydrophilic polymer block having a softening point of at least about 35.degree. C and a molecular weight of at least about 6,000, which comprises from about 30-97 wt % of said copolymer. The novel polymers of this invention are useful for making water containing gels. Preferably, the thermoplastic multiphase copolymer is a styrene-ethylene oxide copolymer. The novel polymers are made by a process which allows one to prepare a copolymer which is substantially free of homopolymeric impurities. The compositions of the instant invention are melt processable by conventional thermoplastic techniques.

Dependencies are inferred from the claim text.