Abstract: This invention relates to materials medical or veterinary use that possess considerably improved properties with regard to friction. The invention also relates to the production of such materials from existing materials that possess suitable bulk properties, but inappropriate frictional properties. This invention also relates to a hydrophilic coating material that provides improved frictional properties.

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: A lactide polymer composition combining compositional and purity limitations and catalyst optimization or addition of stabilizing agents resulting in a melt-stable polymer is disclosed. The melt-stable lactide polymer comprises a plurality of polylactide polymer chains, residual lactide in concentration of less than 2 percent and water in concentration of less than 1000 parts-per-million. A stabilizing agent in an amount sufficient to reduce depolymerization of the lactide polymer during melt-processing or alternatively, control of catalyst level at a molar ratio of monomer to catalyst greater than 3000:1 is also included in the melt-stable composition. A process for manufacture of a melt-stable lactide polymer composition includes polymerizing a lactide mixture and adding stabilizing agents sufficient to reduce depolymerization of the polylactide during melt-processing, followed by devolatilizing the polylactide to remove monomer and water.

Abstract: Disclosed are polyurethane base resins, and polyurethane composites and adhesive compositions formed using the base resins. The polyurethane base resins are formed by reacting a polycarbodiimide-modified 4, 4'-diphenylmethane diisocyanate with a mixture of the following polyols: (a) a hydroxyl-terminated, linear, saturated liquid copolyester diol having a glass transition temperature of at most -10.degree. C. and at least -60.degree. C.; and (b) a homopolyester polyol that is a ring-opened polymer of a cyclic ester. The polyurethane composites include typical active hydrogen-containing species that will react with isocyanates and promote curing, in addition to the polyurethane base resin. The polyurethane adhesive compositions, which are thermosetting, include the cured polyurethane base resin, cured by exposure to moisture or any other applicable curing mechanism. The adhesive compositions have improved performance (e.g.

Abstract: A one piece surgical repair device consists essentially of a polymeric wire. The polymeric wire is comprised of an oriented, semicrystalline polymer. The surgical repair device can be a staple and is capable of permanent flexural deformation at ambient temperature.

Abstract: Block copolymers have a first copolymer block wherein lactide is the predominant component and a second copolymer block wherein trimethylene carbonate is the predominant component. The copolymers are useful in forming surgical devices, including monofilament sutures.

Abstract: Polymer blends of glycolide and/or lactide homopolymer and/or glycolide/lactide copolymer and polycaprolactone and/or polytrimethylene carbonate homopolymer or copolymers thereof and absorbable surgical devices manufactured therefrom having improved mechanical properties, such as improved impact resistance and improved cyclic flex, are disclosed.

Abstract: A process of purifying and stabilizing a high molecular weight polylactide polymer by contacting solid polymer particles with methyl alcohol and subsequently acetone.

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: A block copolymer for use in the fabrication of bioabsorbable articles such as monofilament surgical sutures is prepared by copolymerizing one or more hard phase forming monomers and 1,4-dioxan-2-one, and then polymerizing one or more hard phase forming monomers with the dioxanone-containing copolymer.

Abstract: A method providing a catalyzed ring opening polyester polymerization at a high reaction rate wherein the amount of organic acid in the reaction medium is maintained at an acid: catalyst ratio below 6:1.

Abstract: The invention relates to a process for preparing poly-D,L-lactide and its use as a carrier for active substances.

Abstract: A process for polymerizing lactide and up to 20 mole percent of another lactone is disclosed. The cayalysts used have the formula MZ.sub.3 wherein M is scandium, yttrium, bismuth, a lanthanide series rare earth metal or a mixture thereof and the Zs are independently the same or different highly coordinating ligands. The preferred metals M are lanthanum, cerium, praseodymium and neodymium with lanthanum being especially preferred. The preferred ligands are betadiketones, betaketoesters and malonate anions with the betadiketones such as 2,2,6,6-tetramethyl-3,5-heptanedionates being especially preferred.

Abstract: A polysiloxane-modified epoxy-based encapsulation composition comprising an epoxy resin, a curing agent for the epoxy resin, a polylactone-polysiloxane block copolymer, and a filler is described. The powder molding compositions provide a low internal stress epoxy composition without significantly sacrificing T.sub.g.

Abstract: A biodegradable polymer is provided for use in providing syringeable, in-situ forming, solid biodegradable implants for animals. The polymer is placed into the animal in liquid form and cures to form the implant in-situ. A thermoplastic system to form said implant comprises the steps of dissolving a non-reactive polymer in biocompatible solvent to form a liquid, placing the liquid within the animal, and allowing the solvent to dissipate to produce the implant. An alternative, thermosetting system comprises mixing together effective amounts of a liquid acrylic ester terminated, biodegradable prepolymer and a curing agent, placing the liquid mixture within an animal and allowing the prepolymer to cure to form the implant. Both systems provide a syringeable, solid biodegradable delivery system by the addition of an effective level of biologically active agent to the liquid before injection into the body.

Abstract: A process for the continuous conversion of crude lactic acid to a substantially purified lactide or polylactide including the steps of polymerizing the lactic acid to form a prepolymer with subsequent depolymerization to form a crude lactide in the presence of a catalyst. The crude lactide is purified in an improved distillation system in which at least three fractions are formed with the substantially purified lactide removed as an intermediate boiling sidedraw stream. The substantially purified lactide may then be polymerized.

Abstract: Compatibilizing agents suitable for blending otherwise immiscible polymers comprise a block or graft copolymer in which at least one of the block segments is formed by a living anionic polymerization and thereafter chemically converted to provide a polymer having at least one functional end group. The functional groups of the polymer blocks thus formed are reacted with a functionalized monomer, or an oligomer to provide a second block polymer segment. Compatibilizing agents containing more than two blocks may be formed in similar fashion. The compatibilizing agents are used to provide uniform blends of polar and non-polar polymers having superior uniformity and other physical properties.

Abstract: An optically active 7-substituted-1,4-dioxepan-5-one derivative represented by the general formula (I): ##STR1## wherein R represents an alkyl group having from 1 to 5 carbon atoms; and * means an asymmetric carbon atom, is disclosed. An optically active polymer represented by formula (II): ##STR2## wherein R and * are as defined above; and n is an integer of 25 or more, obtained by ring opening polymerization of the optically active 7-substituted-1,4-dioxepan-5-one derivative represented by formula (I) is also disclosed. A process for producing the optically active polymer represented by formula (II) is further disclosed, comprising subjecting an optically active 7-substituted-1,4-dioxepan-5-one derivative represented by formula (I) to ring opening polymerization in the presence of at least one catalyst selected from the group consisting of (i) an organotin compound, (ii) an organoaluminum compound and water, and (iii) an organozinc compound and water.

Abstract: Siloxane-modified polyester resins are disclosed. These resins comprise a copolymer of a siloxane compound, which contains at least one active hydrogen atom, and a lactone compound. The copolymer is substantially free of unreacted siloxane compound. The siloxane-modified polyester resins are useful for the production of heat-sensitive recording material, magnetic recording media and release agents. Processes for the production of the siloxane-modified polyester resins are also disclosed.

Abstract: A process for the continuous production of polylactide polymers from lactic acid which incorporates removal of water or a solvent carrier to concentrate the lactic acid feed followed by polymerization to a low-molecular-weight prepolymer. This prepolymer is fed to a reactor in which a catalyst is added to facilitate generation of lactide, the depolymerization product of polylactic acid. The lactide generated is continuously fed to a distillation system as a liquid or vapor wherein water and other impurities are removed. The resultant purified liquid lactide is fed directly to a polymerization process.

Abstract: Graft copolymers containing a vinyl polymer as a trunk polymer component, and both organopolysiloxane and polylactone as a branch polymer component, and methods of producing them. Covering compositions containing said graft copolymers as a major component can form coats excellent in not only heat resistance and hardness, but also flexibility, weather resistance, water repellability, stain resistance, mold releasability, lubricity and so on.

Abstract: An environmentally degradable composition comprises blends of a physical mixture of a poly(lactic acid), comprising about 1 to 99 weight percent of the composition, and an elastomeric blend compatible polymer, such as a segmented polyester, that provides improved impact resistance to the poly(lactic acid) and is discrete and intimately bound; plasticizer is added to the blend that is selected from the group consisting of lactide monomer, lactic acid oligomer, lactic acid, and mixtures thereof. Other plasticizer that may be added includes one or more derivatives of an oligomer of lactic acid, its esters and copolymer.

Abstract: A copolymer comprising a bioabsorbable, segmented molecular architecture has been invented. The copolymer has at least two different ester linkages. The segmented molecular architecture comprises a plurality of fast transesterifying linkages. The fast transesterifying linkages have a segment length distribution of greater than 1.3. The segmented molecular architecture also comprises a plurality of slow transesterifying linkages. The following proviso is a material limitation to this invention: for the fast transesterifying linkages consisting essentially of glycolate linkages and the slow transesterifying linkages selected from the group consisting of trimethylene carbonate and caproate linkages, the segment length distribution of the fast transesterifying linkages is up to 2.0 and the number average segment length of the slow transesterifying linkages is greater than 2.5 linkages per segment.

Abstract: A process for the continuous production of substantially purified lactide and lactide polymers from an ester of lactic acid including the steps of forming crude lactide in the presence of a catalyst means to form a condensation reaction by-product and polylactic acid and depolymerizing the polylactic acid molecules followed by subsequent purification of the crude lactide in a distillation system. A purified lactide is then polymerized.

Abstract: A process for the continuous production of polylactide polymers from lactic acid which incorporates removal of water or a solvent carrier to concentrate the lactic acid feed followed by polymerization to a low-molecular-weight prepolymer. This prepolymer is fed to a reactor in which a catalyst is added to facilitate generation of lactide, the depolymerization product of polylactic acid. The lactide generated is continuously fed to a distillation system as a liquid or vapor wherein water and other impurities are removed. The resultant purified liquid lactide is fed directly to a polymerization process.

Abstract: The curable resin having a number average molecular weight of 600 to 6000 and at least two hydrolyzable silyl groups which is prepared by reacting an aliphatic polyester resin having acryloyl group and alcoholic hydroxyl group with an isocyanate silane compound: ##STR1## reacting the obtained reaction product with an aminosilane compound: ##STR2## and reacting the obtained reaction product with a monofunctional isocyanate: OCN-R.sup.5 and/or a polyfunctional isocyanate; and the composition containing the resin. The curable resin and the composition are excellent in acid resistance such as acid resin resistance, scratch resistance, solvent resistance, flexibility, and the like.

Abstract: A masterbatch composition is provided, comprising greater than about 10% to about 70% by weight of organic peroxide homogeneously dispersed in a polycaprolactone carrier. The peroxide masterbatches are safer and easier to store, ship, handle and use than the peroxides from which they are made. The use of the masterbatch compositions to modify a host polymer or resin to which the masterbatch is added is also disclosed.

Abstract: Block copolymers have a first polymer block wherein glycolide is the predominant component and a second block having glycolide, lactide and trimethylene carbonate linkages. The copolymers are useful in forming surgical devices, including monofilament sutures.

Abstract: A process for polymerizing lactide and up to 20 mole percent of another lactone in the absence of solvent at 100.degree. to 220.degree. C. using an yttrium or lanthanide series rare earth metal catalyst.

Abstract: Mixture containing at least 70% by weight of polyhydroxyalkanoate and one or more compounds which contain reactive alcohol and/or acid groups, mixtures of poly-D (-)-3-hydroxybutyric acid with a polyether being excluded, process for the preparation of a polymer by melting the above mixture and a polymer in which at least some of the acid and/or alcohol groups of the polyhydroxyalkanoate are bonded via ester bonds to alcohol and/or acid groups of the admixed compound.

Abstract: Biodegradable and resorbable surgical materials of molded articles of poly(lactic acid) or copolymers of lactic acid and glycolic acid, characterized in that the articles are molecular-orientated, and having a bending strength of 1.6.times.10.sup.33 to 2.5.times.10.sup.3 kg/cm.sup.2, a bending modulus of 5.5.times.10.sup.2 to 24.0.times.10.sup.2 kg/cm.sup.2, a crystallinity, determined by density measurement, of 10 to 60%, and a viscosity average molecular weight measured after melt processing of not less than 200,000, and in that at least 80% of initial strength of the articles is maintained after dipping in a saline at 37.degree. C. for three months.

Abstract: This invention relates to mixtures of short fibers of varying lengths, diameters and aspect ratios composed of an anisotropic polymer, to compositions containing said fibers and one or more thermoplastic or thermoset resins, and to a process for forming said mixtures.

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: A block copolymer for use in the fabrication of bioabsorbable articles such as monofilament surgical sutures is prepared by copolymerizing lactide and 1,4-dioxanone, and then polymerizing glycolide with the lactide/1,4-dioxanone copolymer.

Abstract: A process for polymerizing lactide and up to 20 mole percent of another lactone is disclosed. The cayalysts used have the formula MZ.sub.3 wherein M is scandium, yttrium, bismuth, a lanthanide series rare earth metal or a mixture thereof and the Zs are independantly the same or different highly coordinating ligands. The preferred metals M are lanthanum, cerium, praseodymium and neodymium with lanthanum being especially preferred. The preferred ligands are betadiketones, betaketoesters and malonate anions with the beta diketones such as 2,2,6,6-tetramethyl-3,5-heptanedionates being especially preferred.

Abstract: Novel oxymethylene graft polymers are obtained by grafting, via Michael addition, an amine functional polymer onto an oxymethylene backbone having pendant acrylate or substituted acrylate ester groups serving as reactive sites for the graft reaction.

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.

Abstract: Disclosed is an improved process of the post-emulsion method capable of forming crosslinked resin particles which do not have fusion bonds between particles and which have good storage stability and good redispersibility in an aqueous medium. The process comprises (a) dispersing in an aqueous medium a resinous component comprising (I) a base resin having a glass transition temperature (Tg) of 0.degree. C. or less and a polymerizable double bond, (II) a monomer which, when polymerized, provides a resin of which Tg is 20.degree. C. higher than that of said base resin, or a resin of which Tg is 20.degree. C. higher than that of the base resin, and (III) a polyvinyl compound; (b) crosslinking inside the dispersed resin particles and; (c) removing the aqueous medium therefrom.

Abstract: A heterofunctional macromer represented by the formula: ##STR1## in which R.sub.1 is H or C.sub.1 -C.sub.4 alkyl; R.sub.2 is a (poly) lactone or (poly) ether chain;X.sub.1 is --COO--, --COOCH.sub.2 CH.sub.2 OCO--, --CONHCOO--, --COOCH.sub.2 CH.sub.2 NH--COO-- or ##STR2## X.sub.2 is --O--, --COO-- or --OCO--NH--R.sub.3 --NHCOO-- group; R.sub.3 is C.sub.1 -C.sub.6 alkylene, aromatic or alicyclic group;A is --CH.sub.2 --, --C(CH.sub.3).sub.2 -- or ##STR3## group; and reactive polymers derived from said macromer.

Abstract: This invention relates to novel copolymers containing carbonate repeat units and ester repeat units.

Abstract: Disclosed are fluorinated macromonomers containing one or more hydroxy groups, which are useful as monomers in other polymerization. Also disclosed are processes and an intermediate for making such macromonomers, and condensation and free radically made polymers which contain the macromonomers. The macromonomers are useful for modifying the properties of the polymers into which they are incorporated.

Abstract: Block copolymers of polyoxazoline and polylactone moieties can be used as polymeric compatibilizers for polyamides and polyolefins.

Abstract: This invention relates to binary thermoplastic polyblend that comprises a thermoplastic aromatic polycarbonate and a polycaprolactone polyol-based thermoplastic polyurethane (TPU). The polyblends exhibit improved hydrocarbon solvent resistance and melt flow properties.

Abstract: Block copolymers can be formed from heterocyclic polymers such as PBO and thermoplastic polymers such as polyamide or poly(aromatic ether ketone). The block copolymer compositions are thermoplastic and do not experiSTATEMENT OF GOVERNMENT INTERESTThis invention was made with Government support under contract F33615-86-C-5068 awarded by the Department of the Air Force. The Government has certain rights in this invention.

Abstract: A process for the continuous production of polylactide polymers from lactic acid which incorporates removal of water or a solvent carrier to concentrate the lactic acid feed followed by polymerization to a low-molecular-weight prepolymer. This prepolymer is fed to a reactor in which a catalyst is added to facilitate generation of lactide, the depolymerization product of polylactic acid. The lactide generated is continuously fed to a distillation system as a liquid or vapor wherein water and other impurities are removed. The resultant purified liquid lactide is fed directly to a polymerization process.

Abstract: A mixture of hydroxy functional polymers which can be used to form isocyanate prepolymers which are non-hairing at application temperature are disclosed. Examples of suitable mixtures of hydroxy functional polymers that can be used to form the prepolymers are:(1) linear polyester blends, comprising a first and second polyester wherein each polyester is the reaction product of a polyol and a polyacid, whereina+b<or=4, c+d>or=6a+b>4 or .ltoreq.6, c+d>or=10a+b>6 or .ltoreq.

Abstract: Copolymers of lactic acid, from 0.5 to 20 weight % of 4-valerolactone and from 0 to 20 weight % of a C.sub.6-8 lactone form polymers having a higher intrinsic viscosity than homopolymers of lactic acid per se. The polymers also have an increased heat stability over the homopolymer of lactic acid.

Abstract: Adducts of the formula I ##STR1## are described in which R.sup.1 is an e-valent aliphatic radical after the removal of the functional groups, X is --O--or --NH--, R.sup.2 is a d+l-valent carbocyclic-aromatic radical, R.sup.3 is hydrogen or methyl, R.sup.4 is an aliphatic, aromatic, or araliphatic c+l-valent radical, Y is --O--, --S--or --NR.sup.5 --, R.sup.5 is hydrogen or ##STR2## b is an integer from 2 to 15, b is an integer from 1 to 25, c is 1, 2 or 3, d is 1, 2 or 3 and e is 2, 3 or 4.The adducts can be combined with latent curing agents and, if appropriate, other epoxy resins to give adhesives having good stability on storage and high flexibility.

Abstract: A biodegradable plastic composition is disclosed which includes a polycaprolactone and a poly-.beta.-hydroxybutyrate. Disclosed also is a biodegradable plastic shaped body formed of such a composition. The shaped body may be produced by melt-mixing a blend of a polycaprolactone, a poly-.beta.-hydroxybutyrate and a copolymerization catalyst to copolymerize a portion of the polycaprolactone with a portion of the poly-.beta.-hydroxybutyrate, thereby to obtain a caprolactone/.beta.-hydroxybutyric acid copolymer-containing melt, which is subsequently shaped into a desired form.

Abstract: This invention relates to a novel polycarbonate-based block polymer, and to fibers and bioresorbable implantable medical devices fabricated from said fibers.