Biodegradable polymeric compositions based on starch and thermoplastic polymers

Claim 1

A polymeric composition obtainable from a melt comprising a starch component, a plasticizer and a synthetic thermoplastic polymer component, wherein the synthetic component comprises at least one polymer or mixture of polymers selected from the group consisting of: (a) homopolymers of aliphatic hydroxyacids having from 2 to 24 carbon atoms, the corresponding lactones or lactides; (b) copolymers of a first monomer selected from the group consisting of aliphatic hydroxyacids having from 2 to 24 carbon atoms, the corresponding lactones or lactides with a second monomer selected from the group consisting of aliphatic hydroxyacids having from 2 to 24 carbon atoms other than that constituting the first monomer, corresponding lactones or lactides, aromatic hydroxyacids, aliphatic or aromatic isocyanates; (c) block or graft copolymers between the homopolymers and copolymers (a) or (b) with one or more of the following components: (i) cellulose or modified cellulose; (ii) amylose, amylopectin, natural or modified starches; (iii) polymers deriving from reaction of diols, polyester prepolymers or polymers having diol terminal groups with: aromatic or aliphatic bifunctional isocyanates, aromatic or aliphatic bifunctional epoxydes, aliphatic bicarboxylic acids, bicarboxylic cycloaliphatic acids, aromatic acids or anhydrides, (iv) polyurethanes, polyamide-urethanes from diisocyanates and aminoalcohols, polyamides, polyesteramides from bicarboxylic acids and aminoalcohols, polyester-urea from aminoacids and diesters of glycols, (v) polyhydroxylated polymers selected from the group consisting of polyvinylalcohol, ethylenevinylalcohol copolymers, totally or partially hydrolyzed, and polysaccharides up to dextrins, (vi) polyvinylpyrrolidone, polyvinylpyrrolidonevinylacetate copolymers, polyethyloxazolines; (vii) ionomeric polymers selected from polyacrylates and polymetacrylates; (d) polyesters obtained from monomers or comonomers as defined above at (a) and (b) upgraded with chain extenders selected from the group consisting of isocyanates, epoxides, phenylesters and aliphatic carbonates; (e) polyesters obtained from monomers and comonomers defined at (a) and (b) above partially crosslinked by means of polyfunctional acids selected from the group consisting of trimellitic acid, pyromellitic acid, polyisocyanates and polyepoxides, said starch component and said synthetic polymer component being present in a ratio of from 1:9 to 9:1.