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