Abstract: Modified phenolic resins and cured resins prepared therefrom.

Abstract: Modified phenolic resins and cured resins prepared therefrom.

Abstract: The present invention provides an improved, ballistic-resistant composite article of manufacture which comprises a network of high strength fibers having a tensile modulus of at least about 500 grams/denier and an energy-to-break of at least about 22 Joules/gram. An elastomeric matrix material substantially coats each of the individual fibers, and has a tensile modulus of less than about 6,000 psi, measured at 25.degree. C.

Abstract: The present invention provides an improved, complex composite article of manufacture which comprises a network of high strength fibers having a tensile modulus of at least about 160 grams/denier and a tenacity of at least about 7 g/denier. An elastomeric matrix material substantially coats each of the individual fibers, and has a tensile modulus of less than about 6,000 psi, measured at 25.degree. C. The fibers in the matrix are provided with at least one additional rigid layer on a major surface of the fibers in the matrix to produce a rigid complex composite. Composites of this construction have improved resistance to environmental hazards, improved impact resistance, and are unexpectedly effective as ballistic resistant articles such as armor or helmets.

Abstract: A thermotropic polyester carbonate containing aromatic diacyl moieties, aromatic dihydroxy moieties and carbonate moieties, wherein up to 50 mole percent of the aromatic dioxy moieties are replaced with aliphatic dihydroxy moiety, such as 2,2-dimethyl-1,3-propanediol.

Abstract: A process of blending two or more polymers having varying viscosities by blending the polymers in the melt in the presence of a solid particulate material to form polymer blends having improved dispersion of the polymer.

Abstract: Polyvinyl alcohol of molecular weight over 500,000 (i.e. 1,500,000 to 2,500,000) is spun as a dilute solution (2-15%) in a relatively non-volatile solvent such as glycerin. The resultant gel fiber is extracted with a volatile solvent such as methanol and dried. Upon stretching at one or more stages during the process, fibers of tenacity above 10 g/denier and modulus above 200 g/denier (e.g. 18 and 450, respectively) are produced.

Abstract: Fibers prepared by spinning, drawing and drying dilute solutions of ultrahigh molecular weight polyethylene or polypropylene are modified by including in the dilute solution a polymeric additive. The polyethylene fibers so prepared have melting points above 140.degree. C. and exhibit improved adherence to matrices, resistance to fibrillation and other advantageous properties. Additives include lower molecular weight polyolefins, oxidized polyolefins, olefin copolymers, polyolefin graft copolymers and polyoxymethylenes.

Abstract: A thermotropic oligomer such as a polyester is blended with a high molecular weight thermoplastic polymer such as poly(ethylene terephthalate) to raise the modulus value of the composition compared to the polymer alone, especially at the glass transition temperature of the polymer and above.

Abstract: High tenacity, high modulus ultrahigh molecular weight fibers of polyethylene or polypropylene are coated with polyethylene, polypropylene or an ethylene and/or propylene copolymer. The coating improves certain properties of the monofilament or multifilament, including adhesion to various matrices in complex composites and resistance of the fiber to fibrillation.

Abstract: Solutions of ultrahigh molecular weight polymers such as polyethylene in a relatively non-volatile solvent are extruded through an aperture at constant concentration through the aperture and cooled to form a first gel of indefinite length. The first gels are extracted with a volatile solvent to form a second gel and the second gel is dried to form a low porosity xerogel. The first gel, second gel or xerogel, or a combination, are stretched. Among the products obtainable are polyethylene fibers of greater than 30 or even 40 g/denier tenacity and of modulus greater than 1000 or even 1600 or 2000 g/denier.

Abstract: High tenacity, high modulus ultrahigh molecular weight fibers of polyethylene or polypropylene are coated with polyethylene, polypropylene or an ethylene and/or propylene copolymer. The coating improves certain properties of the monofilament or multifilament, including adhesion to various matrices in complex composites and resistance of the fiber to fibrillation.

Abstract: Solutions of ultrahigh molecular weight polymers such as polyethylene in a relatively nonvolatile solvent are extruded through an aperture at constant concentration through the aperture and cooled to form a first gel of indefinite length. The first gels are extracted with a volatile solvent to form a second gel and the second gel is dried to form a low porosity xerogel. The first gel, second gel or xerogel, or a combination, are stretched. Among the products obtainable are polyethylene fibers of greater than 30 or even 40 g/denier tenacity and of modulus greater than 1000 or even 1600 or 2000 g/denier.

Abstract: A composite containing a network of ultrahigh molecular weight polyethylene or polypropylene fibers of high tenacity and modulus and a matrix which has ethylene or propylene crystallinity, e.g. polyethylene, polypropylene or copolymers. The composite can be formed by heating the matrix to its melting or sticking temperature around the fibers. The composite retains a high proportion of the tenacity of the fiber.

Abstract: Articles such as vests, helmets and structural elements containing a network of ultrahigh molecular weight, high strength, high modulus polyethylene or polypropylene fibers. The fibers, and especially polyethylene fibers of 15, 20, 25, 30 or more g/denier tenacity, and 300, 500, 1,000, 1,500 or more g/denier tensile modulus impart exceptional ballistic resistance to the articles in spite of the melting points, e.g. 145.degree.-151.degree. C. for the polyethylene fibers and 168.degree.-171.degree. C. for the polypropylene fibers, which are high for these polymers, but substantially lower than the 200.degree. C. or more melting point previously thought necessary for good ballistic resistance.

Abstract: Fibers prepared by spinning, drawing and drying dilute solutions of ultrahigh molecular weight polyethylene or polypropylene are modified by including in the dilute solution a polymeric additive. The polyethylene fibers so prepared have melting points above 140.degree. C. and exhibit improved adherence to matrices, resistance to fibrillation and other advantageous properties. Additives include lower molecular weight polyolefins, oxidized polyolefins, olefin copolymers, polyolefin graft copolymers and polyoxymethylenes.

Abstract: Polyvinyl alcohol of molecular weight over 500,000 (i.e. 1,500,000 to 2,500,000) is spun as a dilute solution (2-15%) in a relatively non-volatile solvent such as glycerin. The resultant gel fiber is extracted with a volatile solvent such as methanol and dried. Upon stretching at one or more stages during the process, fibers of tenacity above 10 g/denier and modulus above 200 g/denier (e.g. 18 and 450, respectively) are produced.

Abstract: Thermotropic poly(ester carbonates) such as the terephthalate/carbonate of a mixture of hydroquinose, resorcinol, tert-butylhydroquinone and methylhydroquinone. With a major proportion of the more readily available hydroquinone and resorcinol, thermotropic properties (liquid crystallinity in the melt) are observed.

Abstract: Purified aromatic dicyanates are cured with a catalyst which is an Mn(II), Ag(II), Fe(III), Bi(III), In(III) or Hf(IV) salt at 150.degree.-200.degree. C. and then at 200.degree.-300.degree. C. for a time sufficient to cure the dicyanate without causing color formations to the extent of a Yellowness Index over 30. In some forms the dicyanate is combined with the catalyst and a thermoplastic.

Abstract: Solutions of ultrahigh molecular weight polymers such as polyethylene in a relatively non-volatile solvent are extruded through an aperture at constant concentration through the aperture and cooled to form a first gel of indefinite length. The first gels are extracted with a volatile solvent to form a second gel and the second gel is dried to form a low porosity xerogel. The first gel, second gel or xerogel, or a combination, are stretched. Among the products obtainable are polyethylene fibers of greater than 30 or even 40 g/denier tenacity and of modulus greater than 1000 or even 1600 or 2000 g/denier.