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 (L LA) with aminohydroxymethylpropanediol (AHPD) or aminopropanediol (APD ) using stannous octoate as catalyst. Nuclear magnetic resonance, Four ier-transform infra-red spectroscopy, gel permeation chromatography (g .p.c.), differential scanning calorimetry (d.s.c.) and thermogravimetr ic 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 temper ature T-g, melting temperature T-m, enthalpy of melting Delta H-m and number-average molecular weight M(n). The potential biodegradability o f these polymers was tested with the aid of enzymatic and alkali hydro lysis. Total organic carbon and g.p.c. measurements showed that high A HPD or APD contents impart to polymers a higher susceptibility to degr adation.