Biodegradable polymeric compositions comprising starch and a thermoplastic polymer

摘要

Biodegradable heterophase polymeric compositions having good resistance to ageing and to low humidity conditions, comprising thermoplastic starch and a thermoplastic polymer incompatible with starch, in which starch constitutes the dispersed phase and the thermoplastic polymer constitutes the continuous phase, containing an interfacial agent selected from: esters of polyols with C12-C22 fatty acids having HLB indices lower than 5.5, the esters being used in quantities of from 10 to 40% by weight of the starch; non-ionic, water-soluble surfactants which, when added to the starch/thermoplastic polymer compositions indicated above, migrate in water by no more than 30% wt of their concentration after the material containing them has been immersed in water for 100 hours at ambient temperature; reaction products of an aliphatic or aromatic diisocyanate with a polymer containing terminal groups reactive with the diisocyanates.