L,d-polylactide copolymers with controlled morphology
AssigneeE. I. Du Pont de Nemours and Company
InventorMaria Spinu
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Abstract
Linear stereo block copolymers are disclosed. The polymers comprise a plurality of alternating polymeric blocks of amorphous copolymers of L-lactide and D-lactide with semicrystalline blocks of either L-lactide homopolymer or D-lactide homopolymer. The molecular weight can be built up by either of two techniques. The first technique is to use a chain extending agent such as a diacyl chloride or a diisocyanate to link a plurality of the preformed block copolymers. The second technique is to polymerize additional alternating amorphous and semicrystalline segments or blocks onto the original alternating block copolymers.
Claims9
A copolymer of the formula R'O--(BAIABL).sub.y --BAIABOR' wherein L is the residue of a diacyl chloride or diisocyanate containing 8 to 20 carbon atoms, A is a copolymer of 10 to 90 weight percent L-lactide and 90 to 10 weight percent D-lactide, B is a polylactide formed from 98 to 100 weight percent L-lactide or 98 to 100 weight percent D-lactide, R' is H, a chain extender residue or a capping agent, and --I-- is the residue of a diamine or diol containing 2 to 100 carbon atoms, and y is 0 to 100.
Dependencies are inferred from the claim text.