Abstract: Provided is a method for producing polylactic acid comprising the step of a ring-opening polymerization of lactide in the presence of an alkylaluminum compound represented by the following formula (1): R1nAlX3-n??Formula (1) (wherein n represents an integer of 1 to 3; R1 may be the same or different and independently represents a linear or branched alkyl group having 1 to 10 carbon atoms; X may be the same or different and independently represents a halogen atom or a hydrogen atom; and Al represents an aluminum atom) as a ring-opening polymerization catalyst. The ring-opening polymerization of lactide further effectively proceeds in the presence of at least one kind of metal compounds selected from the group consisting of aluminum compounds (except the alkylaluminum compounds represented by the above formula (1)), zinc compounds, titanium compounds, zirconium compounds, magnesium compounds, and calcium compounds.

Abstract: The present case relates to a process for the purification of lactide from a crude lactide vapor product stream which process comprises a rectification/condensation step leading to a lactide-enriched condensate.

Abstract: Embodiments of the polymerization process of the present invention are directed to polymerizing free radically polymerizable monomers in the presence of a polymerization medium initially comprising at least one transition metal catalyst and an atom transfer radical polymerization initiator. The polymerization medium may additionally comprise a reducing agent. The reducing agent may be added initially or during the polymerization process in a continuous or intermittent manner. The polymerization process may further comprises reacting the reducing agent with at least one of the transition metal catalyst in an oxidized state and a compound comprising a radically transferable atom or group to form a compound that does not participate significantly in control of the polymerization process.

Abstract: The invention concerns a process for preparing a block or comb copolymer comprising at least one hydrophilic portion and at least two hydrophobic portions, by anionic solvent-free polymerization of a prepolymer selected from a polyethylene glycol and a polyvinyl alcohol, and of a lactone or dilactone monomer. The process is carried out in the presence of an alkaline-earth metal hydride, in an inert atmosphere, and the polymerization step is not carried out under vacuum. The invention also concerns copolymers obtained by this process.

Abstract: The present invention relates to specific DL-lactide-?-caprolactone copolymers and the application of these polymers in the production of biodegradable medical applications. According to the present invention a polymeric material comprising poly(DL-lactide-co-?-caprolactone) is provided, which is obtained by the copolymerization of DL-lactide and ?-caprolactone, having a lactide content of 51-75 mol %, most preferably of 62-69 mol %. The materials of the present invention have excellent mechanical properties and may be used to provide articles for medical application, in particular nerve guides.

Abstract: To provide a process for producing a polyester ether poly- or mono-ol having a narrow molecular weight distribution, which is obtained by copolymerizing an initiator having hydroxyl groups with a cyclic ester compound and an alkylene oxide. It is possible to produce a polyester ether poly- or mono-ol having a molecular distribution (Mw/Mn) of from 1.02 to 1.4 by copolymerizing a cyclic ester compound which carbon number is from 3 to 9 and an alkylene oxide which carbon number is from 2 to 20 with an initiator having from 1 to 12 hydroxyl groups and having a number average molecular weight (Mn) of from 18 to 20,000 in the presence of a double-metal cyanide complex catalyst is having tert-butyl alcohol as at least a part of an organic ligand.

Abstract: A synthetic route is provided to prepare poly(?-hydroxycarboxylic acid) polymers via the ring-opening polymerization of ?-hydroxycarboxylic acid cyclic oligomers. The cyclic oligomers can be prepared directly from biorenewable sources, such as 3-hydroxypropionic acid. The method can be used to prepare high molecular weight polymers from the cyclic oligomers. Good molecular weight control can be obtained for both solution state and melt polymerizations.

Abstract: A mouldable, biodegradable medical material, comprising an epsilon caprolactone homopolymer. The material is useful as an implant and in particular for filling irregularly shaped cavities in biological tissue in vivo. The epsilon caprolactone homopolymer can be produced by polymerizing epsilon caprolactone monomers in the presence of a titanium alkoxide catalyst.

Abstract: Processes for feeding catalyst systems to a melt phase process for the manufacture of polyester polymers, and more particularly, to split catalyst solution feeds to the melt phase process to provide the target amount and ratio of catalyst metals.

Abstract: A process for producing an aliphatic polyester by subjecting a cyclic ester to ring-opening polymerization, which comprises adding water to a cyclic ester purified to the extent that a water content is at most 60 ppm to control an overall proton concentration in the cyclic ester, thereby controlling at least one physical property among melt viscosity, molecular weight and yellowness index of the resulting aliphatic polyester.

Abstract: The present invention provides a safe biodegradable and bioabsorbable polymer having an extremely low metal catalyst content, while retaining the properties desired for a medical implant or the like; and a process for producing the same. The present invention further provides a method for reducing the content of a metal catalyst in a biodegradable and absorbable polymer that can be applied on an industrial scale. A method for producing a biodegradable and bioabsorbable polymer having a metal catalyst content of less than 1 ppm in terms of a metal comprising the steps of (1) copolymerizing lactide and ?-caprolactone at a molar ratio ranging from 40/60 to 60/40 in the presence of the metal catalyst to produce a copolymer; and (2) washing the copolymer with a mixed solvent comprising acetic acid and isopropanol at a volume ratio ranging from 25/75 to 45/55 at less than 40° C., and drying the copolymer. 13.

Abstract: The present invention mainly relates to a carbon-carbon bond formation catalyzed by a complex comprising a novel and stable ligand and a metal center. The ligand uses a ring, particularly a phenyl group, or a hydrocarbon group to link an amino group and PR1R2, NR1R2, OR1, SR1, or AsR1R2 group for stabling the structure of the ligand.

Abstract: Method for preparing a polyhydroxyalkanoate (PHA) polymer by ring-opening polymerization of a lactone such as ?-butyrolactone, that is preferably racemic, in which the polymerization is carried out in the presence of an initiator of formula (II): in which: R3 represents a C1-15 alkyl group such as a methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl or tert-butyl group; or a benzyl group; R1 and R2, being identical or different, each represent a group chosen from C1-15 alkyl groups, such as methyl and tert-butyl groups; a cumyl group; an ?,?-dimethylbenzyl group; an adamantyl group; a trityl group; and a trialkylsilyl group; X represents O(R4), S(R4) or N(R4)(R5) where R4 and R5 each independently represent a C1-15 alkyl group such as a methyl or ethyl group; or a benzyl group; M is a metal from group 3 of the Periodic Table of the Elements such as Y, La or Nd. Polymers obtainable by this method, compositions using them and the use of these polymers and compositions.

Abstract: The present invention relates to a process for the preparation of branched biodegradable polymers comprising of the steps of: (a) preparing a macromonomer by ring-opening polymerization of at least one cyclic ester, cyclic carbonate, and/or cyclic carboxyanhydride in the presence of a branching agent and optionally a catalyst; and (b) subsequent polycondensation of the macromonomer, to a process for the preparation of a macromonomer by ring-opening polymerization of at least one cyclic ester, carbonate and/or N-carboxyanhydride in the presence of a defined branching agent and optionally a catalyst, according to step (a), and to the prepared macromonomer and branched biodegradable polymer and their uses.

Abstract: To provide a process for producing a polyester ether poly- or mono-ol having a narrow molecular weight distribution, which is obtained by copolymerizing an initiator having hydroxyl groups with a cyclic ester compound and an alkylene oxide. It is possible to produce a polyester ether poly- or mono-ol having a molecular distribution (Mw/Mn) of from 1.02 to 1.4 by copolymerizing a cyclic ester compound which carbon number is from 3 to 9 and an alkylene oxide which carbon number is from 2 to 20 with an initiator having from 1 to 12 hydroxyl groups and having a number average molecular weight (Mn) of from 18 to 20,000 in the presence of a double-metal cyanide complex catalyst is having tert-butyl alcohol as at least a part of an organic ligand.

Abstract: The present invention is directed to a poly(ethylene glycol)-grafted aliphatic polyester represented by Formula 1: wherein X is an aliphatic ester, R is hydrogen or C1-5 alkyl, Z is the binding moiety of an initiator or a chain transfer agent, m/l is from 0.1 to 50, n is from 2 to 50, w is 1 or greater, and y is from 1 to 200. Further disclosed is a method for preparing the poly(ethylene glycol)-grafted aliphatic polyester of the present invention.

Abstract: Monomer addition methodology is provided to adjust monomer addition rates to a polymerization reactor. Advantages of the invention include control of bioabsorbable copolymer structure, improvement of monomer conversion, control of reaction temperature, and reduced reaction time. The overall result is an improved process and enhanced product performance. The technology is particularly useful in the copolymerization of monomers with different reactivity ratios, such as glycolide/lactide copolymers and glycolide/caprolactone copolymers. Monomer reactivity ratios and reaction kinetics are utilized to adjust monomer addition rates.

Abstract: The present invention includes photocurable, liquid polymers incorporating coumarin ester endgroups into their molecular structure, which polymers are crosslinked upon irradiation with ultraviolet light by photochemically allowed [2+2] cycloaddition reactions among the chain ends, and which crosslinked polymers are useful in the preparation of medical devices, tissue engineering scaffolds, drug delivery systems and, in particular, in vivo preparation of implants in an open surgical procedure or laproscopically.

Abstract: A block copolymer is disclosed, which comprises a first block comprising polymerized units of an alkylene oxide and a second block comprising polymerized units of an alkylene oxide and a lactone, said copolymer being obtainable by polymerizing an alkylene oxide in the presence of an organic initiator to form said first block, and reacting the first block with a mixture of an alkylene oxide and a lactone. Such copolymers are found to have improved foam inhibition characteristics while maintaining their biodegradable properties.

Abstract: Disclosed is a method for preparing a biodegradable polymer in the form of uniform powder or spherical particles by dispersion polymerization without a grinding step. The method for preparing a biodegradable polyester includes dispersing a monomer in the presence of a catalyst in a dispersion solvent to form a solid or liquid phase for dispersion polymerization and thereby to yield a biodegradable aliphatic polyester in the form of spherical particles or powder, the monomer comprising a mixture of a first compound (e.g., lactide or glycolide) and a second compound being selected from the group consisting of polyhydric alcohols (e.g., glycerin, erythritol, penterythritol or dipentaerythritol) and carprolactone. The present invention readily prepares a biodegradable polymer having a high molecular weight in the form of uniform powder or spherical particles.

Abstract: An absorbable crystalline, monocentric polyaxial copolymer comprising a central carbon or nitrogen atom and at least three axes, each of which includes an amorphous flexible component adjacent and originating from the central atom and a rigid, crystallizable component extending outwardly from the amorphous, flexible component is disclosed along with the use of such copolymer in medical devices which may contain a bioactive agent. The present invention also relates to a suture, stents, stent mantles and sealing devices made from the polyaxial copolymer.

Abstract: A subject of the present invention is new compounds having a lanthanide and having a tridentate ligand, a process for their preparation and their use in particular as polymerization catalysts.

Abstract: The present invention uses a reactor that combines devices having a special portion structure to solve the difficulty of uniform blending due to the reactants becoming highly viscous, the difficulty of heat removal, and the increase in pressure loss, thus leading to continuous production of a polyester-based polymer stably having excellent quality.

Abstract: The invention relates to novel absorbable polyesters, produced by ring-opening polymerisation of hydroxycarboxylic acids in the presence of a polyol containing an electrolyte, in an extruder. In particular, the invention relates to novel polylactide glycolide polyesters which are essentially free of dextran sulphate and which are produced by ring-opening polymerisation of lactide and glycolide in the presence of dextran sulphate in the extruder; to the production of the same and to their use in depot medicaments.

Abstract: Copolymers of lactide and glycolide with high glycolide content. The average glycolate block length is less then about 3, which allows the copolymer to be soluble in slightly polar solvents such as methylene chloride.

Abstract: The present invention is generally directed to a process for producing lactide-based polymers and the polymers produced by this process. The polymers of the present invention are terpolymers formed by the copolymerization of a lactide monomer, a linking monomer and an epoxy-terminated monomer. In one embodiment of the invention, the polymers may be formed from fluorine-containing monomers or aromatic ring-containing monomers. The disclosed materials may display improved hydrolytic and thermal characteristics as compared to previously known lactide-based materials. For example, the lactide based terpolymers may have a glass transition temperature over 60° C. For instance, lactide-based thermoplastic terpolymers of the present invention can have a glass transition temperatures of about 80° C. or higher. Lactide-based thermoset networks of the invention can have glass transition temperatures of up to about 200° C.

Abstract: An absorbable crystalline, monocentric polyaxial copolymer comprising a central carbon or nitrogen atom and at least three axes, each of which includes an amorphous flexible component adjacent and originating from the central atom and a rigid, crystallizable component extending outwardly from the amorphous, flexible component is disclosed along with the use of such copolymer in medical devices which may contain a bioactive agent. The present invention also relates to a suture, stents, stent mantles and sealing devices made from the polyaxial copolymer.

Abstract: The present invention relates to a complex having the formula (I) wherein M is selected from Sn(II), Sn(IV), Al(III) and Mg(II); each of R1 and R2 is independently hydrocarbyl; R3 is H or hydrocarbyl; and X is a linker group. A further aspect of the invention relates to the use of said complex as a polymerisation initiator, particularly in the polymerisation of lactides.

Abstract: An absorbable crystalline, monocentric polyaxial copolymer comprising a central carbon or nitrogen atom and at least three axes, each of which includes an amorphous flexible component adjacent and originating from the central atom and a rigid, crystallizable component extending outwardly from the amorphous, flexible component is disclosed along with the use of such copolymer in medical devices which may contain a bioactive agent. The present invention also relates to a suture, stents, stent mantles and sealing devices made from the polyaxial copolymer.

Abstract: A process for producing a lactic acid polymer of 15,000 to 50,000 in weight-average molecular weight, the content of polymeric materials having not more than about 5,000 in weight-average molecular weight therein being not more than about 5% by weight, characterized by hydrolyzing a high molecular weight lactic acid polymer, placing the resultant solution comprising the hydrolyzed product under a condition capable of precipitating the objective lactic acid polymer, separating the precipitated lactic acid polymer and collecting them. The lactic acid polymer is useful as a matrix for sustained-release preparations. The sustained-release microcapsule preparation encapsulating a physiologically active substance can fully prevent the initial excessive release of the physiologically active substance from the microcapsules and keep a stable release rate over a long period of time.

Abstract: In polymerizing biodegradable polymer material, a compressed gas is used as a reaction solvent for a solution-polymerization, in order to prepare biodegradable polyester homopolymer and copolymer with a high molecular weight in a fine powder form with a particle size of 0.01˜1000 ?m.

Abstract: Compositions based on ?-caprolactone polymer, comprising at least one ?-caprolactone polymer and calcium carbonate. Process for preparing these compositions, which are used for manufacturing articles, in particular films, preferably obtained by extrusion blow-moulding or by flat-die extrusion.

Abstract: This invention relates to single-component and multi-component catalytic systems using aryl titanates. Aryl titanate compounds are useful as catalysts and co-catalysts in single-component and multi-component catalytic systems (e.g., for the polymerization of macrocyclic oligoesters and the depolymerization of polyesters). Multi-component catalytic systems using aryl titanates allow increased versatility in applications such as liquid molding.

Abstract: The invention relates to a method for producing polylactic acid, comprising the steps of obtaining lactic acid from starchy agricultural products by fermentation, ultrapurification of the lactic acid by ultrafiltration, nanofiltration and/or electrodialysis, concentration of the lactic acid and production of a prepolymer, cyclizing depolymerization to dilactide, purification of the dilactide, ring-opening polymerization of the dilactide and demonomerization of the polylactide.

Abstract: The present invention is directed to a process for making an absorbable polylactone copolymer prepared in part from about 2 to about 80 mole percent glycolide, which process utilizes a combination of a monofunctional polymerization initiator and a di-functional polymerization initiator, to achieve rates of crystallization of the copolymer of at least about 2 times faster than the rate of crystallization of a copolymer made by a similar process utilizing either the mono-functional or the di-functional polymerization initiator alone. Absorbable polylactone copolymers prepared by such processes and medical devices containing such copolymers are also disclosed.

Abstract: The object of the present invention is to provide a novel method for effectively producing a cyclic lactic acid oligomer, and a cyclic lactic acid oligomer produced by the method.

Abstract: An absorbable crystalline, monocentric polyaxial copolymer comprising a central carbon or nitrogen atom and at least three axes, each of which includes an amorphous flexible component adjacent and originating from the central atom and a rigid, crystallizable component extending outwardly from the amorphous, flexible component is disclosed along with the use of such copolymer in medical devices which may contain a bioactive agent. The present invention also relates to a suture, stents, stent mantles and sealing devices made from the polyaxial copolymer.

Abstract: The present invention is directed to a method for reducing waste accumulation by using an environmentally degradable disposable material. The disposable material, which includes a hydroxycarboxylic acid-containing polymer, degrades hydrolytically during operative and disposal stages in a controlled manner such that the disposal degradation rate of the material is accelerated relative to the operative degradation rate of the material.

Abstract: A polymer of a ring-opened functionalized epoxide is formed by the polymerization of a functionalized epoxide monomer having the structure E-CHR-G wherein E represents an epoxide group, R is hydrogen or an alkyl group, and G is a derivatizable group such as an unsaturated functionality or ester substituent.

Abstract: Copolymers of lactide and glycolide with high glycolide content. The average glycolate block length is less then about 3, which allows the copolymer to be soluble in slightly polar solvents such as methylene chloride.

Abstract: A process is provided for manufacturing homo- and copolyesters of lactic acid by ring scission polymerization of its cyclic monomers in the presence of an initiator. Polymerization is carried out in the molten phase in the presence of an initiator system containing a compound of tin and at least one additional initiator chosen from the compounds of metal of the fourth subgroup.

Abstract: The invention relates to polycondensation resins which are prepared by polycondensation of compounds having a low molecular weight and separation of small molecules in the presence of at least one hetergeneous catalyst. The invention also relates to polyaddition resins which are prepared by polyaddition in the presence of at least one heterogeneous catalyst. The invention further relates to the use of said polycondensation resins and polyaddition resins for the preparation of moulded parts, adhesives and coating materials.

Abstract: A polymerisation process for the preparation of vinylic polymers from the corresponding vinylic monomers which process comprises the step of reacting a vinylic monomer in the presence of a catalyst system comprising a) a metal complex of general formula (I) where A is selected from the group consisting of nickel, iron, cobalt, chromium, manganese, titanium, zirconium, vanadium and the rare earth metals; L1, L2, L3 and L4 are ligands and b) a Lewis acid of general formula (II) wherein at least one of W, Y or Z is capable of forming a co-ordination bond with A and the others of W, Y and Z are bulky groups; D is selected from the group consisting of aluminium, magnesium, zinc and boron.

Abstract: The invention concerns a method for obtaining oxacarbonyl polymers comprising steps which consist in: providing at least monomers comprising at least a cyclic oxacarbonyl function, an initiator, and in polymerising or copolymerising said monomers, in bulk or in solution, the initiator being selected among bicyclic guanidine compounds of formula (I) or (II) wherein one and/or the other of the cycles can be substituted, in at least any one of positions 2, 3, 4, 8, 9 and 10 of formula (I) or in at least any one of positions 2, 3, 7 and 8 of formula (II), by at least a radical selected among the alkyl groups with 1 to 6 carbon atoms, the cycloalkyl groups with 5 to 7 carbon atoms, polystyrene hydrocarbon chains.

Abstract: Syndiotactic poly(lactic acid) is formed by polymerization involving a cleavage of the same oxygen-acyl bond in a series of meso-lactide molecules to form polymer containing a series of units with stereocenters wherein adjacent stereocenters are of the opposite stereochemistry. The mechanism is catalyzed by chiral metal alkoxides that afford stereocontrol such as those formed by reacting or the opposite enantiomer with Al(OR)3 where R is straight chain or branched alkyl containing 1 to 20 carbon atoms, e.g., methyl or isopropyl, in solvent, with subsequent evaporation of solvent in vacuo.

Abstract: The invention relates to a method for producing an aliphatic polyester, utilizing starch as a raw material. The invention produces an aliphatic polyester by the steps of hydrolyzing starch to obtain glucose, oxidizing the glucose to obtain gluconolactone or gluconic acid, reducing the gluconolactone or the gluconic acid to obtain caproic acid, chlorinating the caproic acid to obtain 6-chlorocaproic acid, cyclizing the 6-chlorocaproic acid to obtain &egr;-caprolactone, and executing ring-opening polymerization of the &egr;-caprolactone.

Abstract: A stereospecific poly(lactic acid) is isotactic poly(lactic acid) having a number average molecular weight ranging from 10,000 to 200,000 grams per mole, with, on average, an equal number of poly (R) and poly (S) blocks where each block contains an average of 5 to 50 monomer units. Product was prepared by polymerizing rac-lactide in the presence of racemic catalyst consisting of: and the corresponding S-enantiomer or in the presence of racemic catalyst consisting of: and the corresponding S-enantiomer, wherein R is C1-C4 alkyl which is straight chain or branched.

Abstract: A polyoxyalkylene polyol or monool (I) of the general formula (1) below, in which not less than 40% of the terminally located hydroxyl-containing groups, namely —AO—H groups, are primary hydroxyl-containing groups of the general formula (2) below, or; a method of producing ring-opening polymerization products, by subjecting a heterocyclic compound to ring-opening addition polymerization with an active hydrogen-containing compound, using as a catalyst tris(pentafluorophenyl)borane, tris(pentafluorophenyl)aluminum, etc.

Abstract: The present invention is directed to a method for the direct, one-step synthesis of crystalline segmented glycolide copolymers having less than 80 percent glycolide-based sequences in the copolyester chain. The copolyester chain can also be formed using a polyether glycol as the initiator for the ring-opening copolymerization of glycolide and other cyclic monomers to form highly hydrophilic materials.

Abstract: The present invention includes photocurable, liquid polymers incorporating coumarin ester endgroups into their molecular structure, which polymers are crosslinked upon irradiation with ultraviolet light by photochemically allowed [2+2] cycloaddition reactions among the chain ends, and which crosslinked polymers are useful in the preparation of medical devices, tissue engineering scaffolds, drug delivery systems and, in particular, in vivo preparation of implants in an open surgical procedure or laproscopically.