reacted with an amine terminal group on a precursor polyalkylene oxide pao polymer chain to form the graft copolymer for example in fig1 the carboxyl groups of the pan pvc backbone are formed by acid hydrolysis they are then reacted with polyethylene glycol amine to produce a graft copolymer fig1 depicts the acid hydrolysis of a pan pvc copolymer wherein the ratio of acrylonitrile to vinyl chloride is 45 55 however other ratios of acrylonitrile to vinyl chloride may also be used the graft copolymers of the present invention can also be formed by reduction of pan pvc the reactive sites are formed by reduction of the cyano groups into amine groups the applicants have found that sodium borohydride reduction of the copolymer produces amino groups that can be used to bind an activated pao such as a succinimidyl carbonate derivatized pao this is shown in fig2 where the amine groups are then reacted with polyethylene glycol succinimide activated paos can be commercially obtained for example from polysciences inc warrington pa and shearwater polymers huntsville ala another method for producing the graft copolymers of the present invention involves reacting the chloride groups of pvc with thiol urea to produce thiol groups on pvc pvc sh and then reacting epoxide terminated pao with pvc sh to produce grafted pao units on the pvc portion of pan pvc.