L,d-polylactide copolymers with controlled morphology

• US 5,346,966 A
• Filed: 10/26/1993
• Issued: 09/13/1994
• Est. Priority Date: 12/31/1991
• Status: Expired due to Fees

• Current Assignee: Ecological Chemical Products Company
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Spinu, Maria
• Primary Examiner(s): Seidleck, James J.
• Assistant Examiner(s): Hamilton, III, Thomas
• Application Number:
  US08/141,183
• Time in Patent Office: 322 Days
• Field of Search: 325/411, 325/413, 325/415, 528/354, 528/357
• US Class Current: 525/411
• CPC Class Codes: C08G 63/08 Lactones or lactides
• CPC Class Codes: C08G 63/664 derived from hydroxy carboxylic acids

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.

Claims

1. A copolymer of the formula R'"'"'O--(BAIABL)_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.

2. The copolymer of claim 1 wherein --L-- is the residue of a diisocyanate.

3. The copolymer of claim 1 wherein copolymer segments A have a number average molecular weight of 500 to 20,000.

4. The copolymer of claim 3 wherein polymer segments B have a number average molecular weight of 1,000 to 40,000.

5. The copolymer of claim 4 wherein the copolymer segments A are 15 to 85 weight percent L-lactide and 85 to 15 weight percent D-lactide.

6. The copolymer of claim 5 wherein --I-- has the formula --(OR)_n O-- wherein --R-- is an alkylene group containing 2 to 6 carbon atoms and n is 2 to 20.

7. The copolymer of claim 6 wherein --L-- is the residue of a diisocyanate.

8. The copolymer of claim 5 wherein --R-- is an alkylene group containing 4 carbon atoms.

9. The copolymer of claim 8 wherein --L-- is the residue of toluene diisocyanate.