Enzymatic ring-opening polymerization of trimethylene carbonate with macrodiol: Synthesis of block poly(ester-co-carbonate) for biomaterial preparation

Abstract

Novozym 435-catalyzed ring-opening polymerization (ROP) of trimethylene carbonate (TMC) with telechelic hydroxylated poly[(R)-3-hydroxybutyrate] [PHB-diol; Mn = 3000 g/mol (GPC)] as initiator gave di-block poly(HB-co-TMC) with different weight percents of the blocks and Mn of 4400-8700 g/mol (GPC) in 54-89% yield, being the first enzymatic preparation of block poly(ester-co-carbonate). The generality of the novel enzymatic method was demonstrated by the enzymatic ROP of TMC with poly(ε-caprolactone)-diol [PCL-diol; Mn of 4200 g/mol (GPC)] to give A-B-A tri-block-poly(TMC-co-CL-co-TMC) with different weight percents of the blocks and Mn of 7700-10600 g/mol (GPC) in 54-67% yield. The prepared block poly(ester-co-carbonate) with two terminal hydroxyl groups was proven to be a useful starting material for the further preparation of thermoplastic block copolymers. Polymerization of di-block poly(24 wt % HB-co-76 wt % TMC) with methylene diphenyl-4,4′-diisocyanate (MDI) afforded the corresponding polyurethane with Mn of 53 800 g/mol (GPC) in 94% yield. The polymer showed excellent thermoplastic properties (Tm of 144 and 152 °C, Tg of -9 °C, εb of 252%, σmax of 6.37 MPa, and E of 23 MPa), being potentially useful for soft tissue engineering. © 2011 American Chemical Society.