Process for the preparation of polymers of dimeric cyclic esters
AssigneeBoard of Trustees operating Michigan State University
InventorsGregory L. Baker, Milton R. Smith III
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Abstract
The present invention provides a process for the direct synthesis of high melting polymers made from dimeric cyclic esters. In particular, the present invention provides a process for synthesis of polylactic acid (PLA) from racemic materials such as racemic lactide and polymandelide from mandelide. The process further provides racemic metal organic ligand catalysts such as racemic salbinap that catalyzes the polymerization of racemic dimeric cyclic ester monomers to a polylactide stereocomplex. Polymandelide and mixed dimeric cyclic esters are also prepared in the presence of low amounts of water.
Claims31
A process for the preparation of a polymer which comprises:
- (a) providing an anhydrous dimeric cyclic ester of the formula:
- 14
- wherein R1 and R3 are selected from the group consisting of linear, branched and unsaturated alkyl containing 1 to 24 carbon atoms, aryl, and aromatic, and wherein R1 and R4 are selected from the group consisting of hydrogen and methyl;
- (b) mixing an anhydrous metal organic ligand with the anhydrous dimeric cyclic ester under anhydrous conditions to provide a reaction mixture;
- (c) heating the reaction mixture to polymerize the dimeric cyclic ester to form the polymer in the reaction mixture;
- and
- (d) removing the polymer from the reaction mixture, wherein the steps (a) to (d) are conducted in the presence of less than 2 mole percent water based upon the ester.
A process for the preparation of a crystalline polymer of a dimeric cyclic ester which comprises reacting a racemic mixture of a dimeric cyclic ester with a metal organic ligand catalyst which is racemic so that the crystalline polymer is produced.
A process for the preparation of a crystalline polylactic acid (PLA) which includes poly(L-lactide) and poly(D-lactide) polymer domains which comprises reacting a racemic mixture of a lactide with a metal organic ligand catalyst which is racemic so that the crystalline PLA is produced.
A process for the preparation of a polymandelide which comprises:
- (a) providing anhydrous mandelide;
- (b) mixing the mandelide with a metal organic ligand catalyst for the mandelide under anhydrous conditions to provide a reaction mixture;
- (c) heating the reaction mixture to polymerize the mandelide in the reaction mixture to form the polymandelide;
- and
- (d) separating the polymandelide from the reaction mixture, wherein the steps (a) to (d) are conducted in the presence of less than 2 mole percent water based upon the mandelide monomer.
A polymandelide polymer having a molecular weight distribution of above about 50,000 and a Polymer Dispersity Index (PDI) of between 1 and 2.
Dependencies are inferred from the claim text.