NOVEL POLYLACTIDES WITH AMINOPROPANEDIOL OR AMINOHYDROXYMETHYLPROPANEDIOL USING STANNOUS OCTOATE AS CATALYST - SYNTHESIS, CHARACTERIZATION AND STUDY OF THEIR BIODEGRADABILITY .2.

Two series of novel polymers were synthesized by reacting L-lactide (LLA) with aminohydroxymethylpropanediol (AHPD) or aminopropanediol (APD) using stannous octoate as catalyst. Nuclear magnetic resonance, Fourier-transform infra-red spectroscopy, gel permeation chromatography (g.p.c.), differential scanning calorimetry (d.s.c.) and thermogravimetric analysis were employed for the characterization of these polymers. The above-mentioned polymers were semicrystalline (d.s.c. traces) when the molar ratio LLA/AHPD or LLA/APD was higher than 32/1. However, at molar ratios LLA/AHPD or LLA/APD below 32/1, the synthesized polymers were amorphous. D.s.c. and g.p.c. measurements show that, the higher the LLA content in the polymer, the higher the glass transition temperature T-g, melting temperature T-m, enthalpy of melting Delta H-m and number-average molecular weight M(n). The potential biodegradability of these polymers was tested with the aid of enzymatic and alkali hydrolysis. Total organic carbon and g.p.c. measurements showed that high AHPD or APD contents impart to polymers a higher susceptibility to degradation.