Abstract: Polymers more suitable for use in organ transplantation are formed by coupling biologically active moieties to the free amino groups of polymers formed by incorporation of .alpha. amino acids into polymers formed of alpha hydroxy acids such as lactic acids. In the preferred embodiment, the peptides are coupled to the free amino groups.

Abstract: A purification process of a polyhydroxycarboxylic acid for efficiently removing a catalyst with a simple method from solid polyhydroxycarboxylic acid by bringing the solid polyhydroxycarboxylic acid which is obtained by a catalytic reaction and has an inherent viscosity of 0.1.about.5.0 dl/g into contact with an acid substance in the presence of a hydrophilic organic solvent. Also disclosed is a polyhydroxycarboxylic acid prepared by direct dehydration polymerization having an extremely reduced content of residual catalyst.

Abstract: The invention relates to a continuous process for the preparation of resorbable polyesters.

Abstract: Polymers and copolymers of L(+) and D(-) lactic acid, with high molecular weight and in the absence of catalysts, are prepared by upgrading low molecular weight polymers in the solid state.

Abstract: A copolymerized poly(lactide) polymer. A lactide is copolymerized with an epoxidized fat, oil, or mixture thereof thereby resulting in poly(lactide) copolymers having improved processing properties over prior poly(lactide)s.

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: High molecular weight polylactic acid is generally produced by the polymerization of lactide. Lactide is prepared by the depolymerization of low molecular weight polylactic acid. There are difficulties in the preparation of high molecular weight polylactic acid and high purity lactide isomers due to the equilibrium between lactic acid, low molecular weight polylactic acid, high molecular weight polylactic acid, lactide and water. Further it has never been proposed to provide a continuous process to produce high molecular weight polylactic acid from lactic acid. The present invention overcomes the equilibrium problem and provides a continuous process.

Abstract: A method is disclosed for making a molded article of manufacture of polymerized .beta.-lactone which method involves injecting into a mold at least one .beta.-lactone monomer and at least one nucleophilic initiator, substantially polymerizing the .beta.-lactone in the mold and removing the resultant polymerized article from the mold.

Abstract: Polyesters having predetermined monomeric sequence are produced by stepwise addition of monomeric hydroxyacids to a growing polymeric chain. Included herein are various polyesters having predetermined primary sequence, various methods of producing polyesters having predetermined primary sequence, various articles formed from polyesters having predetermined primary sequence and various methods of using such articles.

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: 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: A process for preparing polyhydroxycarboxylic acid by conducting a dehydration condensation of a hydroxycarboxylic acid or an oligomer thereof in a reaction mixture containing an organic solvent substantially in the absence of water and the polyhydroxycarboxylic acid thus obtained. The process provides polyhydroxycarboxylic acid having excellent properties and processability.

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 present document describes the use of an inhibitor for cationic polymerization as an additive to a thermocurable composition based on at least one cationically polymerizable organic material and an initiator for cationic polymerization in the form of an onium compound or a compound of the formula (I)[M.sup.+n (L).sub.x ].sup.n+ nX.sup.- (I),in which n is 2 or 3, M is a metal cation selected from the group comprising Zn.sup.2+, Mg.sup.2+, Fe.sup.2+, Co.sup.2+, Ni.sup.2+, Cr.sup.2+, Ru.sup.2+, Mn.sup.2+, Sn.sup.2+, VO.sup.2+, Fe.sup.3+, Al.sup.3+ and Co.sup.3+, X.sup.- is an anion selected from the group comprising PF.sub.6.sup.-, AsF.sub.6.sup.-, SbF.sub.6.sup.-, BiF.sub.6.sup.-, derivatives of these anions in which at least one fluorine atom has been replaced by a hydroxyl group, and CF.sub.3 SO.sub.3.sup.-, or in which up to 50% of the anions X.sup.-, based on the total amount of anions, may be any desired anions, L is water or an organic .sigma.

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: An improved process for the ring-opening polymerization of ring-opening polymerizable cyclic compounds using a fluidized bed.

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: 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: 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: 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: Compositions comprising polyesters having predetermined monomeric sequence are produced by stepwise addition of monomeric hydroxyacids to a growing polymeric chain. Included herein are various polyesters having predetermined monomeric sequence, methods of their production use as well as articles formed from said compositions.

Abstract: Compositions comprising amino acid terminated polyesters having predetermined monomeric sequence are produced by stepwise addition of monomeric hydroxyacids to an amine to form a growing polymeric chain. Included herein are various amino acid terminated polyesters having predetermined monomeric sequence, methods for their production and use as well as articles formed from said compositions.

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: 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: A method for the manufacture of polymer products from cyclic esters, according to which a catalyst and cyclic monomers are mixed in a mixing chamber and are optionally brought to a higher temperature, after which the mixture is injected, under pressure, into a cavity of a mold consisting of at least two parts and the mold is heated for some time at a temperature above the melting temperature of the monomers, after which the mold is opened and the product is removed from the mold. Polymer products manufactured by this method can be used in medical fields and particularly in reconstructive orthopedics.

Abstract: Disclosed is a method for modifying a medical material of lactic acid polymer, the method comprising heat-treating the material at a temperature which is not lower than 100.degree. C. and is lower than the melting point of the polymer for at least 10 minutes while continuously releasing the gas from the system.

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: Initiator compositions for materials which can be polymerized cationically are described, these containingi) an anhydride of a polycarboxylic acid, a polyisocyanate, a cyclic carbonate, a lactone or a mixture of such compounds, and dissolved thereinii) at least one compound of the formula I[M.sup.+n (L).sub.x ].sup.n+ nX.sup.- (I)in which n is 2 or 3, M is a metal cation selected from the group consisting of Zn.sup.2+, Mg.sup.2+, Fe.sup.2+, Co.sup.2+, Ni.sup.2+, Cr.sup.2+, Ru.sup.2+, Mn.sup.2+, Sn.sup.2+, VO.sup.2+, Fe.sup.3+, Al.sup.3+ and Co.sup.3+, X.sup.- is an anion which is selected from the group consisting of AsF.sub.6.sup.-, SbF.sub.6.sup.-, BiF.sub.6.sup.- and derivatives derived from these anions in which a fluorine atom is replaced by hydroxyl groups, or in which up to 50% of the anions X.sup.-, based on the total amount of anions, can also be any desired anions, L is water or an organic .sigma.

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: Macrocyclic polyarylate oligomers containing a mixture of isophthalate and terephthalate moieties are prepared by reaction of a mixture of isophthaloyl and terephthaloyl chloride with one or more bisphenols under specific reaction conditions. They are characterized by a reduced degree of crystallinity and therefore lower processing temperatures than the corresponding isophthalate oligomers.

Abstract: Crystalline copolymer comprising the reaction product of: a) a predominant amount of a high molecular weight prepolymer of .epsilon.-caprolactone and glycolide, and b) the balance glycolide. A surgical device such as a surgical filament, in particular a surgical suture, prepared by injection molding or melt spinning the crystalline copolymer.

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: Initiator compositions for materials which can be polymerized cationically are described, these containingi) an anhydride of a polycarboxylic acid, a polyisocyanate, a cyclic carbonate, a lactone or a mixture of such compounds, and dissolved thereinii) at least one compoumd of the formula I[M.sup.+n (L).sub.x ].sup.n+ nX.sup.- (I)in which n is 2 or 3, M is a metal cation selected from the group consisting of Zn.sup.2+, Mg.sup.2+, Fe.sup.2+, Co.sup.2+, Ni.sup.2+, Cr.sup.2+, Ru.sup.2+, Mn.sup.2+, Sn.sup.2+, VO.sup.2+, Fe.sup.3+, Al.sup.3+ and Co.sup.3+, X.sup.- is an anion which is selected from the group consisting of AsF.sub.6.sup.-, SbF.sub.6.sup.-, BiF.sub.6.sup.- and derivatives derived from these anions in which a fluorine atom is replaced by hydroxyl groups, or in which up to 50% of the anions X.sup.-, based on the total amount of anions, can also be any desired anions, L is water or an organic .sigma.

Abstract: Polyurethane resins having excellent hydrolysis resistance are prepared from copolymerized caprolactone polyol obtained by the copolymerization of .epsilon.-caprolactone with trimethylcaprolactone having side chains as a diol component. The polyurethane resins so-obtained have excellent hydrolysis resistance, and retain high levels of mechanical strength, more excellent resistance under high heat and moisture conditions, etc., thereby maintaining a good balance of properties and are useful in a very wide variety of forms including spandex, rigid or flexible urethane foams, thermoplastic urethane elastomers, thermosetting urethane elastomers, adhesives, synthetic leather, and paints, etc.

Abstract: A method is provided for producing a modified addition polymer from an ethylenically unsaturated monomer composition that includes at least one monomer having hydroxyl or carboxyl functionality. The ethylenically unsaturated monomer composition, and a free radical initiator therefor, is dissolved in a solvent-free molten composition maintained at an addition polymerization temperature, the molten composition comprising a cyclic compound reactive via ring-opening with the hydroxyl or carboxyl functionality. The resulting material is useful in the manufacture of paints in liquid or powder form.

Abstract: A polymer lactide is prepared by the polymerization of meso-3,6-dimethyl-1,4-dioxane-2,5-dione or mesodilactide and, if desired, other monomers. The mesolactide monomer has preferably a free acid content of less than 1 meq/kg dilactide and is then polymerized in a manner known per se. The compositions containing polymesolactide obtained according to this process do not posess the typical characteristics of poly-DL-lactide, poly-D-lactide or poly-L-lactide. A shorter degradation time of a substrate based on the present polymer is unofficial for several purposes. The present polymers have a good biocompatibility and are thus suited for bone plates, clamps and sutures and controlled release of biologically active compounds. The present polylactides and/or copolymers thereof have the benefit of a good biodegradability, biocompatibility, non-toxicity and non-mutagenicity.

Abstract: Lactone monomers are polymerized using double metal cyanide compounds as catalysts to yield useful lactone polymers. Block or random copolymers of lactones and epoxides may also be prepared.

Abstract: Process for yttrium and rare earth compound catalyzed polymerization of lactones and the living polymer compositions of such polymerizations, novel polyester products of such polymerizations and novel yttrium and rare earth metal compounds useful as catalysts in the polymerization of biodegradable polymers for medical uses and flexible films for packaging.

Abstract: A method of polymerizing at least one .beta.-substituted-.beta.-propiolactone in the presence of a catalytic amount of isobutylaluminoxane in a solvent for the .beta.-propiolactone(s) and isobutylaluminoxane for a time and at a temperature to produce a poly(.beta.-substituted-.beta.-propiolactone) polyester and the polyesters produced thereby are disclosed.

Abstract: Copolyestercarbonates are prepared by the reaction of at least one cyclic polycarbonate oligomer with at least one cyclic polyester oligomer in the presence of a cyclic polycarbonate polymerization catalyst at temperatures in the range of about 280.degree.-375.degree. C. Mixtures of bisphenol A polycarbonate and bisphenol A isophthalate or terephthalate oligomers are preferably employed, and the preferred catalysts are tetraarylborate salts such as tetra-n-butylammonium tetraphenylborate.

Abstract: In a first stage, a lactone is polymerized by an ionic route in vinyl chloride with the aid of a catalyst consisting of the product, optionally complexed with tetrahydrofuran, of the reaction of an alkylmetal with ethylenically unsaturated alcohol, optionally in the presence of water and, in a second stage, the said vinyl chloride is polymerized by a radical route in an aqueous suspension and in the presence of the polymerization medium originating from the first stage, to which other unsaturated monomers are optionally added.The invention also relates to new modified vinyl chloride polymers consisting of lactone polymers whose number-average molecular weight is less than 5,000, grafted with vinyl chloride polymers.

Abstract: Novel, semi-crystalline depsipeptide polymers and copolymers particularly suitable for use in fabricating bioabsorbable medical implant devices such as sutures or clips and obtained through ring-opening polymerization of certain 3-substituted-2,5-morpholinediones prepared by reacting a naturally occurring alpha-amino acid with an alpha-halo acid chloride in inert solvent in the presence of an acid acceptor.

Abstract: Preparation of a macromolecular monomer of a lactone having an alpha-beta monoolefinically unsaturated "head" is effected at low temperature with a strong oxonium salt, such as a trialkyloxonium (TAO) hexafluorophosphate catalyst, with essentially no formation of cyclic oligomers and an insignificant amount of diacrylate. Cationic ring-opening polymerization of lactone monomer in conjunction with an unsaturated alcohol (propagator) having an acryloyl or methacryloyl double bond, produces a polylactone macromer having an ethylenic double bond at one end and a hydroxyl group at the other. The polymerization proceeds by polyaddition of the lactone to the OH group which is the propagating species. The macromer so formed allows the preparation of a macromer of block copolymer of the polylactone with a polyether such as epichlorohydrin, using the same TAO catalyst. In such a macromer of block copolymer, the polylactone ester block is next to the double bond, followed by the polyether block.

Abstract: A process for copolymerizing lactide and glycolide by using a specific amount of stannous octoate as a catalyst in the presence of a polymerization regulator at temperature of 200.degree.-230.degree. C. to prepare dl-lactic acid-glycolic acid-copolymers which contain 50-60 mol % of a dl-lactic acid unit and 40-50 mol % of a glycolic acid unit and have inherent viscosity of 0.4-0.6 in chloroform.

Abstract: Block copolymers of glycolide and p-dioxanone are produced by reacting poly(p-dioxanone) that is substantially free of p-dioxanone monomer with glycolide.

Abstract: Cyclic polyester and especially polyarylate oligomers, typically having degrees of polymerization from 2 to about 7, are prepared by reacting a bisphenol such as bisphenol A or 6,6'-dihydroxy-3,3,3',3'-tetramethylspiro(bis)indane with a dicarboxylic acid chloride such as isophthaloyl or terephthaloyl chloride in the presence of a catalyst, under conditions of low concentration. The cyclic oligomers may be polymerized to linear polyesters by contact with a transesterification catalyst at a temperature in the range of about 200.degree.-300.degree. C.

Abstract: Cyclic polycarbonate oligomer compositions are polymerized with lactones in the presence of a catalyst for the polymerization of either. Usually, the lactone is first polymerized at a lower temperature, followed by the cyclic polycarbonate at a higher temperature.