BINARY MIXTURES OF BIODEGRADABLE ALIPHATIC POLYESTERS AND PRODUCTS OBTAINED FROM THESE

摘要

A biodegradable mixture obtained by melt mixing polyesters comprising: (A) an aliphatic polyesters of the kind polyhydroxyacid or diaic/diol and their copolymer; (B) a polymer of lactic acid comprising L or D polylactic acid, L, D-polylactic, meso polylactic acid and lactic acid copolymers with hydroxyacids or lactones thereof containing at least 75% of L-lactic or D-lactic acid in which the concentration by weight of A with respect to (A+B) is in the range 30-60% and in which the sum of the fusion entalpies DELTA H>A< and DELTA H>B< of the two polyesters in the mixture is greater than the normalized sum of the fusion entalpies DELTA >1< and DELTA H>2< of the aliphatic polyesters prior to melt mixing, the fusion entalpy converted to the polylactic acid-family polymer when the temperature of the film is raised being greater than 35 J/g.