Alternating (ABA)N polylactide block copolymers
AssigneeE. I. Du Pont de Nemours and Company
InventorMaria Spinu
Life of this patent
Estimating the term…
Abstract
Polymers of the general formula R--(A-B-A-I)-.sub.x A-B-A-R and their preparation are disclosed. In the general formula, -A- is a polyhydroxy acid residue preferably a polymer of either 98 to 100% L-lactide or 98 to 100% D-lactide having a molecular weight of 500 to 40,000 and preferably 2,000 to 20,000, -B- is an oligomeric diol or diamine residue, having a number average molecular weight of 500 to 20,000 and preferably 2,000 to 8,000. The polymers are prepared by polymerizing a lactone onto the diol or diamine followed by reacting the resulting polymeric H-A-B-A-H with an diisocyanate or diacyl chloride to form the -L- chain extending units in the general formula.
Claims25
A block copolymer of the formula R--A--B--A--L).sub.x A--B--A--R where -B- is an oligomeric diol residue or an oligomeric diamine residue having a having a number average molecular weight of 500 to 20,000, -A- is a polylhydroxy acid block comprising either a polylactide, polyglycolide, or copolymer thereof having a number average molecular weight 500 to 40,000, x is 1 to 100, and -L- is a diacyl residue derived from an aromatic diacyl halide or diisocyanate containing 8 to 20 carbon atoms, and -R is hydrogen or an end-capping group, wherein said block copolymer has a number average molecular weight of greater than 10,000.
A process for preparing a block copolymer comprising reacting an oligomeric diol or oligomeric diamine, H-B-H, having a number average molecular weight of 500 to 20,000 with a lactone of a hydroxycarboxylic acid of the formula:
- ##STR13## where R.sup.5 and R.sup.6 are H, aliphatic group of 1 to 10 carbon atoms or aromatic groups of 6 to 12 carbon atoms and m is 2 to 10, or ##STR14## where -R.sup.7, -R.sup.8, -R.sup.9, and -R.sup.10 are the same or different and are an aliphatic group of 1 to 10 carbon atoms or an aromatic group of 6 to 12 carbon atoms, to form a polymer H-A-B-A-H where the -A- blocks have a number average molecular weight of 500 to 40,000, reacting polymer H-A-B-A-H with an diisocyanate or diacyl halide containing 8 to 20 carbon atoms, to form a polymer of the formula R--A--B--A--L).sub.X A--B--A--R having a number average molecular weight of 500 to 20,000 where -L- is the residue from the diisocyanate or diacyl halide and -R is hydrogen, a residue from an diacyl halide or diisocyanate or an end-capping agent.
Dependencies are inferred from the claim text.