| abstract |
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 ΔHA and ΔHB of the two polyesters in the mixture is greater than the normalized sum of the fusion entalpies Δ1 and ΔH2 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. |