Abstract: There are disclosed a para-aramid shaped article having a density of 1.390-1.470/cm.sup.3. The para-aramid has an inherent viscosity .eta.inh of at least 3.5 and contains metal ions of 500 ppm or less, the metal ions being combined with acid end groups linked with the para-aramid molecules. The invention also relates to a process for preparing the same. Due to a reduced rate of moisture sorption, a reduced hygroscopic expansion coefficient and excellent mechanical properties, the para-aramid of the present shaped article is suitable for use for reinforcing fiber materials for a composite material and for a magnetic recording medium.

Abstract: The present invention provide a method for preparing asymmetric separation membrane having thin skin layer having reduced numbers of pin holes on the surface of the membrane for separating water/organic solvent or gas. Imide type asymmetric hollow fiber membrane according to the present invention has superior separation degree and permeability of water/organic solvent or gas over general imide type asymmetric hollow fiber membrane.

Abstract: A process is disclosed for making para-aramid filaments of especially high strength by extruding a solution of para-aramid through fine capillaries and drying the resulting filaments under high tension.

Abstract: A blood purification membrane having a membrane thickness of 10 to 35 .mu.m, an inner diameter of 100 to 300 .mu.m, a porosity of 50 to 85%, a water permeability (ultrafiltration rate) at 37.degree. C. of not less than 20 ml/m.sup.2 .multidot.Hr.multidot.mmHg and a sieving coefficient of albumin of not more than 0.01, a substantially homogeneous interior structure, and a smooth surface structure. A process for producing the membrane and a module are also provided.

Abstract: Crimped polybenzazole staple fibers which satisfy the following specifications at the same time:(1) 2.ltoreq.number of crimps (number/inch).ltoreq.40(2) 2.ltoreq.crimp index (%).ltoreq.30(3) 0.3.ltoreq.crimp index/number of crimps.ltoreq.3.0; methods for manufacturing crimped polybenzazole staple fibers; and the rotary cutter therefor. The crimped polybenzazole staple fibers of the present invention are superior in crimp property and are useful for manufacturing spun yarn and unwoven fabric. According to the method of the present invention, crimped polybenzazole staple fibers superior in spinnability can be manufactured with ease. In addition, the cutting blade of the present invention stands a long time use for manufacturing staple fibers from a continuous filaments tow of high tenacity fibers.

Abstract: A polyimide fiber having textile physical property characteristics and the process of melt extruding same from a polyimide powder. Polyimide powder formed as the reaction product of the monomers 3,4'-ODA and ODPA, and endcapped with phthalic anhydride to control the molecular weight thereof, is melt extruded in the temperature range of 340.degree. C. to 360.degree. C. and at heights of 100.5 inches, 209 inches and 364.5 inches. The fibers obtained have a diameter in the range of 0.0068 inch to 0.0147 inch; a mean tensile strength in the range of 15.6 to 23.1 ksi; a mean modulus of 406 to 465 ksi; and a mean elongation in the range of 14 to 103%.

Abstract: A method of making a hollow fiber membrane comprises extruding a membrane-forming polymer solution through the annulus of a tube-in-orifice spinneret (12) to form a nascent hollow membrane (32), there being a lumen coagulant in the lumen of the nascent membrane, and the outside of the nascent membrane being contacted with an external coagulant (34). The external coagulant has a solvent content which is such that, at the interface between the nascent membrane and the external coagulant, liquid--liquid phase separation rather than gelation is thermodynamically the favored process, and the membrane is then subjected to a vapor-phase non-solvent environment to induce precipitation of the phase-separated polymer.

Abstract: A process for preparing high strength carbon fiber from PAN-fiber wherein the time of the oxidation step is reduced from 30-90 minutes to about 8-15 minutes and product prepared therefrom.

Abstract: High strength poly(p-phenylene terephthalamide) fibers are rendered electrically conductive with sulfonic acid ring-substituted polyaniline.

Abstract: The present invention provides processes for producing polybenzazole fibers where a spinning dope containing a polybenzazole polymer in an acid solvent is extruded through a spinning nozzle, followed by coagulation in a coagulating medium and washing with a fluid capable of dissolving the acid solvent; thereafter, in one process, the fiber obtained by the coagulation under specific conditions and the subsequent washing is dried in a heating zone with at least 80% part based on the total length thereof being set at a temperature of 240.degree. C. or higher, and in the other process, the fiber obtained by the coagulation under the conventional conditions and the subsequent washing is neutralized with a basic solution, followed by washing with a fluid capable of dissolving the basic solution, and then dried at a specific temperature set depending upon the residual moisture content in the fiber.

Abstract: A continuous process for preparing nonwoven fabrics of polybenzazole filaments, which comprises spinning at least two polybenzazole dope filaments simultaneously, and intermingling and depositing the filaments on a substantially planar collecting surface, thereby forming a nonwoven fabric.

Abstract: The present invention relates to a process for obtaining PAI fibres by spinning PAI in solution and to the fibres thus obtained. They are obtained by dry or wet spinning into dimethylalkyleneurea followed by removal of the solvent and overdrawing at high temperature. The yarns and fibres obtained are produced from PAI based on tolylene or meta-phenylene diisocyanate, and on an aromatic acid anhydride and/or an aromatic dianhydride, and optionally on one or a number of diacid compounds. They exhibit an outstanding thermomechanical behavior and make it possible to gain access to very low linear densities.

Abstract: A method of making a conductive fiber in which the conductive fiber is formed from a mixture including at least one fiber forming material and conductive magnetic materials, and the conductive magnetic materials are migrated toward the periphery of the fiber by application of a magnetic field to the fiber. The conductive fibers having the conductive magnetic materials located at the periphery of the fiber are preferably incorporated into an electrostatic cleaning device for use in an electrostatographic printing device.

Abstract: A biodegradable or digestible matrix is provided suitable for use as a controlled release of an agriculturally active agent such as insecticides, fungicides, fertilizers, plant growth regulants, etc. The matrix comprises an amylaceous material optionally in association with a synthetic polymer and is formed under elevated temperature and pressure.

Abstract: A process for the production of polyimide fibers includes having the fiber spun from a fully aromatic polyamide acid solution in an aprotic amide solvent in an aqueous-organic bath and subjected to plasticization drafting. It is washed until a 2-4 wt. % content of the organic solvent per fiber is attained and treated with organic or inorganic acids until a 0.5-1.0 wt. % content thereof per fiber is attained. Thereafter, fibers are dried and heat-treated.

Abstract: Aramids which after drawing have high tensile strengths and tensile moduli are made from units derived from selected 2,2'-disubstituted-4,4'-diaminobiphenyls, p-phenylenediamine, oxydianiline and terephthalic acid. Also disclosed is a process for drawing such aramids at least 1.5%, which results in the drawn aramid having significant crystallinity and higher tensile strength. The aramids are useful for ropes and composites.

Abstract: Perfluorinated cycloalkane solvents for dissolving high melting polymers containing tetrafluoroethylene, are disclosed. These solvents dissolve such polymers more rapidly, and/or are more stable, than previously known solvents. Also disclosed is a process for dissolution of the polymers and their resulting solutions. The solutions are useful for making polymer films, coatings and for encapsulating objects.

Abstract: The invention relates to a process for preparing multifilament, wet-spun elastane threads with increased spinning output, which is achieved by largely removing entrained water from the filaments after leaving the spinning bath and then fixing the threads on at least two rollers at a temperature of at least 200.degree. C. for at least 3 seconds.

Abstract: A process for wet spinning a meta-aramid polymer solutions having a salt content of at least 3 percent by weight produces a one step, fully wet drawable fiber that has desirable physical properties without subjecting the fiber to hot stretching.

Abstract: A process for producing mass-colored fiber or film, comprises the steps of:a) preparing a premix by grinding a composition comprising a polar aprotic organic solvent, 5 to 30% by weight of an aromatic polyamide and 0.

Abstract: A process for preparing a textile fiber of sulfonated poly(p-phenylene terephthalamide) that is rapidly dyeable to deep shades.

Abstract: A process for producing an aromatic polyamide film comprising forming a thin layer of an optically isotropic dope in which an aromatic polyamide is dissolved in a polar amide, immersing the thin layer dope in a polar solvent kept at a temperature not higher than -20.degree. C. to coagulate the dope to form a film and drying the film in the presence of an isocyanate compound. Said process can produce directly a transparent film from an aromatic polyamide dope without requiring the step of dissolving the aromatic polyamide in conc. sulfuric acid, does not require any acid resistant equipment and is inexpensive.

Abstract: Soluble wholly aromatic polyamide is obtained by low-temperature polycondensation in an amide solvent such as N-methyl-2-pyrrolidone. The reaction mixture is neutralized with an alkali and spun into fibers by wet spinning, coagulated in a salt-free aqueous solution of an organic solvent, preferably the polymerization solvent, and subsequently drawn in another aqueous solution of the same organic solvent, both solutions being substantially at ambient temperatures below 50.degree. C. but above freezing, More than 60% of the total fiber drawing is executed in this low-temperature draw stage.

Abstract: A hollow polysulfonic fiber intended for a selectively transmissive membrane contains a hydrophilic polymer which is cross-linked into a water-insoluble form (for example polyvinylpyrrolidone) and is used in the form of a hydrogel containing water. A method for the production of a membrane module consists in spinning a hollow fiber by the use of a spinning solution containing a polysulfonic resin and a hydrophilic polymer, wetting the fiber above the saturated moisture content, and then, with the wet condition maintained, subjecting the fiber to the processes of module molding and radiation induced cross-linking, these processes being performed in either order. The method provides a selectively transmissive hollow polysulfone fiber membrane which displays less elution into water and a sharp molecular weight fractionation, so as to be usable safely in the fields of medicine and foodstuffs.

Abstract: A process for preparing PAN fibers under precipitation polymerization conditions in an aqueous solvent system.

Abstract: An aramid monofilament having high mechanical properties is provided. This monofilament has a slightly structured skin and resists fibrillation and abrasion. In addition, a process for the production of this monofilament is also provided. The process includes the following steps:(i) a solution of aromatic polyamide(s) is extruded as a liquid jet in a spinneret through a capillary; (ii) the jet is drawn from the capillary in a non-coagulating layer of fluid and (iii) the drawn liquid vein is introduced into a coagulating medium in order to form the monofilament, which is subsequently washed, dried and contacted with a solvent for said monofilament to produce the slightly structured skin. The aramid monofilament is characterized by the following relationships:1.7.ltoreq.Ti.ltoreq.260;40.ltoreq.D.ltoreq.480;T.gtoreq.180-D/3;Mi.gtoreq.1600;Ar>2.00; andEr>20-D/30.In the above relationship, Ti represents linear density in tex, D represents diameter in .mu.

Abstract: A poly(p-phenylene terephthalamide) composition is disclosed comprising 50 to 95 weight percent PPD-T and 5 to 50 weight percent PVP along with a process for making the composition and articles made from the composition.

Abstract: A process for the manufacturing of elastic articles such as fibers, yarns, or films, from substantially pure selectively hydrogenated block copolymers, comprising at least two blocks predominantly derived from monoalkylene aromatic monomer and at least one block predominantly derived from one or more conjugated dienes and having a number average molecular weight of at least 70,000, comprising the steps of preparing a solution or a gel of said block copolymer with an apolar organic non-aromatic solvent and processing said solution or gel through a fiber forming orifice.

Abstract: A process is disclosed for preparing a poly(phenylene sulfide) (PPS) separation membrane in which a PPS is treated with oxygen to increase its bulk viscosity to at least about 20,000 poise. The treated PPS is then dissolved in a solvent and cast or extruded, followed by a precipitation step.

Abstract: This invention relates in general to a method for the formation of films having a controlled molecular orientation prepared from rod-like extended chain aromatic-heterocyclic ordered polymers, and containing a binder in the micro-infrastructure. Such films have high tensile strength, modulus, and environmental resistance characteristics.

Abstract: A para-aramide dope of low degree of polymerization exhibiting an optical anisotropy containing 4-10% by weight of a para-aramide having an inherent viscosity of 1.0-2.5 dl/g and 2-10% by weight of an alkali metal chloride or an alkaline earth metal chloride in a polar amide solvent;a para-aramide fiber obtained by spinning the above-mentioned para-aramide dope of low degree of polymerization;a para-aramide pulp obtained by cutting the above-mentioned para-aramide fiber into a short fiber, mechanically fibrillating the short fiber with a high shearing force and thereafter drying the fibrillated short fiber;a process for producing a para-aramide fiber which comprises adding 0.94-0.99 mole of a para-oriented aromatic dicarboxylic acid halide to 1.00 mole of a para-oriented aromatic diamine in a polar amide solvent in which 2-10% by weight of an alkali metal chloride or an alkaline earth metal chloride is dissolved, carrying out a polymerization at a temperature of -20.degree. C. to 50.degree. C.

Abstract: Improved polybenzoxazole fibers are made by a process for finishing a spun and drawn dope fiber, which contains polybenzoxazole polymer and polyphosphoric acid, including the steps of:(a) coagulating the dope fiber in an aqueous coagulant;(b) washing the coagulated fiber with an aqueous washing fluid for less than 72 hours under conditions such that the fiber contains no more than 8,000 ppm residual phosphorus (1 ppm=1 part per million, by weight);(c) drying the fiber at a temperature of no more than 300.degree. C. until it retains no more than about 3 weight percent residual moisture; and(d) heat-treating the fiber at a temperature of at least about 300.degree. C. under tension.

Abstract: Quaternary ammonium polyarylamides are provided that are useful in articles of manufacture that require minimal ionic impurities. The polyarylamides are produced by reacting certain polyamides together with quaternary ammonium bases of the formula R.sup.4.sub.4 N.sup.+ X.sup.-, wherein each R.sup.4 is independently selected from hydrocarbyl or substituted hydrocarbyl, provided that at least one of the R.sup.4 groups contains at least one beta hydrogen atom. There is also provided the process for producing the polyarylamides, the process for making articles of manufacture from the polyarylamides, and a process for modifying the surfaces of such polyamides.

Abstract: An improved process for spinning aramids from solution using the air gap wet spinning method involves using a coagulant that contains 1 to 1000 ppm by weight of an organic polymer that acts as a drag reducer. Improved productivity and/or finer aramid fibers is obtained with no deterioration of fiber physical properties.

Abstract: Aramid and polybenzimidazole fibers and films of improved flame resistance are obtained by impregnation with tungsten hexachloride.

Abstract: A process for preparing polyimide fibers involves the preparation of a polymer in p-chlorophenol from reactants comprising 2,2'-dimethyl-4,4'-diaminobiphenyl and a tetracarboxylic anhydride. Following its preparation, the polyimide fibers can be spun directly from the reaction mixture. In a preferred embodiment, the dianhydride comprises 3,3',4,4'-biphenyltetracarboxylic dianhydride.

Abstract: A high temperature resistant fiber, especially a polyimide fiber, having a dielectric constant less than 3 is prepared by first reacting 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane with 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride in an aprotic solvent to form a polyamic acid resin solution. The polyamic acid resin solution is then extruded into a coagulation medium to form polyamic acid fibers, which are thermally cured to their polyimide form. Alternatively, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane with 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride to form a polyamic acid, and the polyamic acid is chemically converted to its polyimide form. The polyimide is then dissolved in a solvent to form a polyimide resin solution, and the polyimide resin is extruded into a coagulation medium to form a polyimide wet gel filament. In order to obtain polyimide fibers of increased tensile properties, the polyimide wet gel filaments are stretched at elevated temperatures.

Abstract: Films containing polybenzazole polymer dissolved in a solvent can be mechanically stretched to provide biaxial orientation. The resulting dope film can be coagulated. The polymer film has improved properties in the direction in which stretching occurs.

Abstract: An apparatus for making aromatic heterocyclic polymeric fibers having enhanced compressive strength is disclosed. Individual polymeric fibers, while being made according to otherwise conventional methods, are full twisted as they are drawn from a spinnerette hole so that their internal fibrils and microfibrils become entangled. The twisting is performed before coagulation of the fibers. The entangled fibrils and microfibrils are believed to provide mutual support to adjacent fibrils/microfibrils to resist buckling under compression.

Abstract: A process for the rapid precipitation polymerization of acrylonitrile and a minor amount of a vinyl carboxylic acid comonomer in an environment of less than 10 ppm metal-ions to produce an acrylonitrile copolymer which, when pyrolyzed in an oxidizing atmosphere, produces a high quality carbon fiber.

Abstract: In the preparation of poly(m-phenylene isophthalamide) filaments, hydrogen chloride is removed from as-produced amide solution of poly(m-phenylene isophthalamide) by contact with basic ion exchange resin.

Abstract: A process for making a PPD-T fiber having an elongation to break of greater than 7%.

Abstract: Improved films that contain molecular composites or block copolymers of lyotropic liquid crystalline polymer and thermoplastic polymer can be made by the steps of:(1) washing a dope film, that contains a solvent and the molecular composite or block copolymer;(2) stretching the wet, never-dried film from Step (1) in at least one direction; and(3) drying the film from Step (2).The films have improved mechanical properties and can be used in structural applications.

Abstract: As-spun fiber made from PPD-T with 0.5 to 3.0% sulfur as bound sulfonic acid or sulfonate groups, is disclosed. The fiber and has inherent viscosity greater than 4.5, as-spun yarn tenacity greater than 20 grams per denier, heat-aged strength retention of greater than 90%, and dipped cord strength greater than 18 gram per denier. The process for making the fiber includes PPD-T sulfonation by exposure to high concentration sulfuric acid in dope preparation under carefully controlled temperature and time.

Abstract: An automated system for casting hollow fiber membranes into a variety of prescribed shapes, including spiral, linear, circular and rectangular. The system also has the capability to change the configuration during casting, which increases productivity. A co-extrusion die is rotated over a stationary coagulation bath A computer is used to control the motion of the die to make a membrane with the desired shape The nozzle is oriented in a manner that will compensate for distortions that occur in wall thickness in the area of a bend. In addition, the nozzle's annulus is offset to make the leading portion of the annulus slightly thicker and the trailing portion thinner at the point where the fluids exit the nozzle, which results in a uniformly symmetric wall thickness. A system embodying the invention includes X, Y and .theta.-directional servomotors 1A-1C (FIG. 1), each of which is coupled to an associated position encoder 2A-2C.

Abstract: A process for preparing subdenier fibers and structures thereof from isotropic polymer solutions is disclosed. The process comprises extruding a stream of the polymer solution into a chamber, introducing a pressurized gas into the chamber, directing the gas in the flow direction of and in surrounding contact with the stream within the chamber, passing both the gas and the stream into a zone of lower pressure at a velocity sufficient to attenuate the stream and fragment it into fibers, and contacting the fragmented stream in the zone with a coagulating fluid.

Abstract: Films made from polybenzazole dopes can quickly be leached to remove polyphosphoric acid and other residual solvents by passing a leaching fluid such as steam through pores in the wet, never dried film. The process can reach acceptable residual phosphorous levels (1500-2000 ppm) in as little as about 2 or 3 minutes.

Abstract: Articles (other than fiber) made from polybenzazole dopes can quickly be washed to remove polyphosphoric acid by a combination of initially washing with an acidic liquid and second washing with a hot leaching fluid at at least about 60.degree. C. The process can reach acceptable residual phosphorous levels (1500-2000 ppm) in as little as about 2 or 3 minutes.

Abstract: This invention is directed to continuous polyester filaments in tufted form for composing quality carpets having a pleasing appearance. The carpets are formed by use of continuous polyester filaments comprising polyethylene terephthalate resin having at least 85 mol % of ethylene terephthalate. The filament is completed by being placed in a curling stuffing box and applying a flow of heated air.

Abstract: Improved polybenzoxazole fibers are made by a process for finishing a spun and drawn dope fiber, which contains polybenzoxazole polymer and a solvent acid, including the steps of: (a) coagulating the dope fiber in an aqueous coagulant: (b) washing the coagulated fiber with an aqueous washing fluid for less than 72 hours under conditions such that the fiber contains no more than 8,000 ppm residual solvent acid (1 ppm=1 part per million, by weight); (c) drying the fiber at a temperature of no more than 300.degree. C. until it retains no more than about 2 weight percent residual moisture; and (d) heat-treating the fiber at a temperature of at least about 300.degree. C. under tension.