Bis-HPMA Poly(1,4-Butanediol Adipate)/IPDI Copolymer is a urethane polymer formed by a multi-step process. First, a prepolymer is made by reacting 1,4-Butanediol and Adipic Acid, which is subsequently reacted with Isophorone Diisocyanate (IPDI). The resulting polymer is end-capped with Hydroxypropyl Methacrylate (HPMA).