Abstract: The invention relates to a method for reducing the caprolactam content of polyamide 6 obtained especially by hydrolytic polymerization of epsilon-caprolactam. The method is characterized by the use of an additive that forms isocyanuric acid under the influence of heat. The additive or the isocyanuric acid produced externally under the influence of heat is added (a) to the polymerization or (b) to a melt of polyamide 6. This enables the caprolactam content of the polyamide 6 to be reduced considerably compared to that of usual commercial polyamide 6. In particular, the resulting polyamide 6 shows good characteristics for reprocessing e.g. into fiber and molding masses by melt extension.

Abstract: A novel polyimide resin consisting essentially of 3,3?,4,4?-benzophenonetetracarboxylic dianhydride (BTDA), 3,4,3?,4?-biphenyltetracarboxylic dianhydride (BPDA), 2,2 bis (3?,4?-dicarboxy phenyl) hexafluoro propane dianhydride (6FDA), 2-(3,4-dicarboxyphenyl)-1-phenylacetylene anhydride (4-PEPA) and an aromatic diamine.

Abstract: Polyimide sulfone resins are provided with a glass transition temperature of from 200–350° C., residual volatile species concentration of less than 500 ppm and a total reactive end group concentration of less than about 120 milliequivalents/kilogram resin. The resins have high heat capability and good melt stability. Methods to prepare the said resins and articles made from the resins are also provided.

Abstract: A polyamide obtained by polycondensation of a diamine component containing at least 50 mol % of 2-methyl-1, 5-pentanediamine and a dicarboxylic acid component containing at least 50 mol % of azelaic acid, comprising the following properties of (1) to (4), (1) when a stretched film is polarized in an electric field of 200 MV/m, a remanent polarization is at least 30 mC/m2, (2) the relative viscosity of a 1 g/dl solution of the polyamide in 96% concentrated sulfuric acid at 25 ° C. is 1.3 to 5.0, (3) the glass transition temperature is 80° C. or less and a calorific value at a cooling crystallization exotherm peak is 5 J/g or less, and (4) it is soluble in an amount of at least 5 mass % at 25 ° C. in at least one selected from methanol, ethanol and 2-propanol, and a resin composition containing the above polyamide and an electrically conductive material.

Abstract: A process for a single-stage melt polymerization for the production of a high molecular weight polybenzimidazole which comprises the steps of: providing a reaction vessel having a means for agitation and a means for vacuum; charging the reaction vessel with reactants selected from: (A) a tetraaminiobiphenyl (TAB), and (B) a diphenyl isophthalate (DPIP); reacting the reactants under constant agitation and under a vacuum with an inert gas sweep; maintaining a reactant temperature which does not exceed 290° C. under constant agitation allowing pressure in the vessel to increase, with an inert gas sweep until a phase change is achieved, when the temperature reaches 250° C. pressure is increased to a slight positive pressure; and increase the reactant temperature and pressure within said reaction vessel while maintaining constant agitation and inert gas sweep, while maintaining a slight positive pressure. Preferably the vessel used in the instant invention is a high intensity reaction vessel.

Abstract: A photoactive side-chain polymer from the class of polyimides, polyamide acids and esters thereof, comprising as a side-chain a dendritic block incorporating photoactive groups at its surface. The dendritic block preferably represents a unit of formulae Ia, Ib or a combination of them, for example formulae Ic, wherein the broken line symbolizes the linkage to the polyimide main chain. The polymer may be used as an orientation layer for liquid crystals and in the construction of unstructured and structured optical elements and multi-layer systems.

Abstract: A polycarbodiimide copolymer which comprises at least one structural unit selected from rubber residues represented by the following formulae (1) and (2) in a number “m”: and a structural unit represented by the following formula (3) in a number “n”: and which comprises on both termini a terminal structural unit derived from a monoisocyanate, wherein m is an integer of 2 or more, n is an integer of 1 or more, m+n is from 3 to 1,500 and m/(m+n) is from 1/1,500 to ?. The polycarbodiimide is capable of keeping the inherent heat resistance and also showing excellent flexibility. Films and molding materials having high heat resistance and flexibility can be obtained.

Abstract: The present invention relates to the use of water soluble melanin in solid plastic films of polyvinyl alcohol to be used in conjunction with other plastics to make laminated sheets or lenses. Such laminates will be used as filters to protect against photochemical damage from electromagnetic radiation.

Abstract: To provide a sulfonic acid group-containing polymer having improved hot water resistance and radical resistance (durability), a solid polymer electrolyte including the polymer, and a proton-conducting membrane including the electrolyte, the polymer electrolyte includes a sulfonated product of a polymer shown by the following general formula (I): wherein X, Y, and Z are bonded randomly, alternately, or in blocks, y represents an integer of two or more, and each of x and z represents an integer of zero or more, where x+z>2.

Abstract: The present invention relates to a polyimide adhesive composition having a polyimide derived from an aromatic dianhydride and a diamine component, where the diamine component is preferably about 50 to 90 mole % of an aliphatic diamine and about 10 to 50 mole % of an aromatic diamine. In one embodiment, the aliphatic diamine has the structural formula H2N—R—NH2 wherein R is hydrocarbon from C4 to C16 and the polyimide adhesive has a glass transition temperature in the range of from 150° C. to 200° C. The present invention also relates to compositions comprising the polyimide adhesive of the present invention, including polyimide metal-clad laminate useful as flexible circuit when metal traces are formed out of the metal used in flexible, rigid, or flex-rigid circuit applications.

Abstract: There is disclosed a process for continuously producing a polyarylene sulfide which comprises reacting a sulfur source with a dihalogenated aromatic compound in an aprotic organic solvent, characterized by maintaining the content of the dihalogenated aromatic compound in the polymerization liquid after the substantial completion of the polymerization reaction at 5 mg/g or higher. It is made possible by the process according to the present invention to efficiently produce the polyarylene sulfide which has a high molecular weight and is excellent in thermal stability.

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 new class of hybrid organic-inorganic materials, and methods of synthesis, that can be used as a proton exchange membrane in a direct methanol fuel cell. In contrast with Nafion® PEM materials, which have random sulfonation, the new class of materials have ordered sulfonation achieved through self-assembly of alternating polyimide segments of different molecular weights comprising, for example, highly sulfonated hydrophilic PDA-DASA polyimide segment alternating with an unsulfonated hydrophobic 6FDA-DAS polyimide segment. An inorganic phase, e.g., 0.5–5 wt % TEOS, can be incorporated in the sulfonated polyimide copolymer to further improve its properties. The new materials exhibit reduced swelling when exposed to water, increased thermal stability, and decreased O2 and H2 gas permeability, while retaining proton conductivities similar to Nafion®. These improved properties may allow direct methanol fuel cells to operate at higher temperatures and with higher efficiencies due to reduced methanol crossover.

Abstract: The present invention relates to novel polyimides derived from 6FDA and from 3,3-dihydroxy-4,4?-diaminobiphenyl and novel polyimides derived from PMDA and from Bis-AP-AF, having alkyl, arylalkyl, heteroarylalkyl, (cycloalkyl)alkyl, fluoroalkyl or siloxane side groups. The present invention also relates to a method of producing nematic liquid-crystal devices, which comprises the steps consisting in: depositing one of the polyimides according to the invention on a substrate; annealing the polyimide in one or more steps; and defining an azimuthal orientation of the polyimide coating.

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: An object of present invention is to provide a diamine and an acid dianhydride having photoreactivity and thermoreactivity and a polyimide composition containing the diamine and the acid dianhydride as monomer components, and specifically to synthesize a diamine and an acid dianhydride having a photoreactive and thermoreactive group containing a double bond or triple bond such as cinnamic acid, chalcone, benzalacetophenone, stilbene, coumarin, pyrone, allyl, propargyl, and acetylene or a derivative skeleton thereof so as to exhibit photoreactivity and thermoreactivity specific to the reactive group, thereby providing a polyimide composition containing the diamine and the acid dianhydride.

Abstract: A terminal-crosslinkable polyamic acid oligomer having 1) heat resistance indicated by Tg of 300° C. or more and a pyrolysis temperature of 500° C. or more, 2) toughness, and 3) capability of allowing an increase in concentration. The polyamic acid oligomer is obtained by reacting an aromatic tetracarboxylic dianhydride including 2,2?,3,3?-biphenyltetracarboxylic dianhydride, an aromatic diamine compound, and a reactive crosslinking agent including an amino group or acid anhydride group and a crosslinkable group in the molecule, and includes a crosslinkable group at the molecular terminal.

Abstract: This invention relates to the composition and a solvent-free process for preparing novel imide oligomers and polymers specifically formulated with effective amounts of a dianhydride such as 2,3,3?,4-biphenyltetra carboxylic dianydride (a-BPDA), at least one aromatic diamine and an endcapped of 4-phenylethynylphthalic anhydride (PEPA) or nadic anhydride to produce imide oligomers that possess a low-melt viscosity of 1–60 poise at 260–280° C. When the imide oligomer melt is cured at about 371° C. in a press or autoclave under 100–500 psi, the melt resulted in a thermoset polyimide having a glass transition temperature (Tg) equal to and above 310° C. A novel feature of this process is that the monomers; namely the dianhydrides, diamines and the endcaps, are melt processable to form imide oligomers at temperatures ranging between 232–280° C. (450–535° F.) without any solvent.

Abstract: An anti-fogging, stretched, multilayer film comprising a layer having an anti-fogging agent incorporated therein, the film having evaluated values for anti-fogging property of 28 mm2 or more at temperatures of ?5° C. and 15° C., respectively.

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.