a method of preparing a mixed - phase thermoplastic biomaterial comprises contacting and reacting a diol and a graft pre - polymer comprising a diol and at least one covalently bonded unsaturated monomer with an organic diisocyanate compound . the reaction is conducted within an aprotic solvent and for a period of time and at a temperature sufficient to produce the mixed - phase thermoplastic biomaterial . the diol may be selected from the group consisting of siloxane diols , polyether diols , polyester diols and polycarbonate diols while the at least one covalently bonded unsaturated monomer may be selected from the group consisting of a fluorinated monomer , a siloxane monomer , an aliphatic ester of methacrylic acid , a cyclic ester of methacrylic acid , a charged monomer , a sulfonium salt , a vinyl monomer with phenol or benzoic acid , n - vinyl pyrrolidone , an aminoglucoside , and a therapeutic agent . the mixed - phase thermoplastic biomaterial may further include an anti - microbial , a therapeutic agent or both .