Abstract: This invention relates to ultramicrocellular structures that incorporate fillers such as functional fillers.

Abstract: This invention relates to ultramicrocellular structures that incorporate fillers such as functional fillers.

Abstract: Blends of two or more polyethylenes are made by reacting ethylene with an oligomerization catalyst that forms ?-olefins, and two polymerization catalysts, one of which under the process conditions copolymerizes ethylene and ?-olefins, and the other of which under process conditions does not readily copolymerize ethylene and ?-olefins. The blends may have improved physical properties and/or processing characteristics.

Abstract: Blends of two or more polyethylenes are made by reacting ethylene with an oligomerization catalyst that forms &agr;-olefins, and two polymerization catalysts, one of which under the process conditions copolymerizes ethylene and &agr;-olefins, and the other of which under process conditions does not readily copolymerize ethylene and &agr;-olefins. The blends may have improved physical properties and/or processing characteristics.

Abstract: Blends of two or more polyethylenes are made by reacting ethylene with an oligomerization catalyst that forms &agr;-olefins, and two polymerization catalysts, one of which under the process conditions copolymerizes ethylene and &agr;-olefins, and the other of which under process conditions does not readily copolymerize ethylene and &agr;-olefins. The blends may have improved physical properties and/or processing characteristics.

Abstract: Blends of two or more polyethylenes are made by reacting ethylene with an oligomerization catalyst that forms &agr;-olefins, and two polymerization catalysts, one of which under the process conditions copolymerizes ethylene and &agr;-olefins, and the other of which under process conditions does not readily copolymerize ethylene and &agr;-olefins. The blends may have improved physical properties and/or processing characteristics.

Abstract: This invention concerns a process for polymerizing cyclic oligomers to homopolymers or copolymers, conducted in the presence of one or more linear polymers.

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.

Abstract: Polyvinyl alcohol esterified by lactic is produced by dissolving polyvinyl alcohol and lactic acid in water, and removing the water by volatilization at a temperature of 75.degree. C. to 175.degree. C. The lactic acid esterified polyvinyl alcohol is useful as a molding resin, and in films, fibers and adhesives.

Abstract: Polylactide stereocomplex is formed by mixing poly-D-lactide and L-lactide or poly-L-lactide and D-lactide and a lactide polymerization catalyst, and heating to polymerize the monomeric lactide, preferably under pressure. The parts are useful in medical devices such as bone screws.

Abstract: Linear 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 onto the original alternating block copolymers.

Abstract: Star-shaped poly (hydroxyacid) chains and the process for preparing them are disclosed. The star shaped polymers have the residue of a central polyfunctional compound having at least 5 hydroxyl or amino groups and 5 to 100 carbon atoms with polymeric arms attached to the functional groups. The polymeric arms are formed from lactide, glycolide or caprolactone. In a preferred aspect the inner segment of the arms are an amorphous copolymer of D-lactide and L-lactide and the outer segment of the arms are a semicrystalline polymer of one of L-lactide or D-lactide.

Abstract: Environmentally benign closed cell compositions made by foaming star-shaped polymers with a plurality of poly(hydroxy acid) chains attached to a central polyfunctional compound having a plurality of hydroxyl and/or amino groups.

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.