MACROMOLECULAR ENGINEERING OF POLYLACTONES AND POLYLACTIDES .15. POLY(D,L)-LACTIDE MACROMONOMERS AS PRECURSORS OF BIOCOMPATIBLE GRAFT-COPOLYMERS AND BIOERODIBLE GELS
I. Barakat et al., MACROMOLECULAR ENGINEERING OF POLYLACTONES AND POLYLACTIDES .15. POLY(D,L)-LACTIDE MACROMONOMERS AS PRECURSORS OF BIOCOMPATIBLE GRAFT-COPOLYMERS AND BIOERODIBLE GELS, Journal of polymer science. Part A, Polymer chemistry, 32(11), 1994, pp. 2099-2110
The functional aluminum alkoxide, Et2Al-O-(CH2)2-O-C(O)-C(CH3)=CH2, is
a very effective initiator for the (D,L)-lactide (LA) polymerization
in toluene at 70-degrees-C. The coordination-insertion type of polymer
ization is living and exclusively yields linear P (D,L)lactide macromo
nomers of a predictable molecular weight and a narrow molecular weight
distribution. IR and H-1-NMR studies show that the methacryloyl group
of the initiator is selectively and quantitatively attached to one ch
ain end, whereas the second extremity is systematically a hydroxyl fun
ction resulting from the hydrolysis of the living growing site. alpha,
omega-Dimethacryloyl-P(D,L)-lactides, i.e., alpha,omega-macromonomers,
have also been successfully synthesized by the additional control of
the termination step, i.e., by reaction of Al alkoxide end groups with
methacryloyl chloride. Alpha-Macromonomer and alpha,omega-macromonome
r P(D,L)-lactides are easily free-radical copolymerized with 2-hydroxy
ethyl methacrylate (HEMA), resulting in a hydrophilic poly (HEMA) back
bone grafted with hydrophobic P(D,L)-lactide subchains and a biodegrad
able amphiphilic network, respectively. (C) 1994 John Wiley