Abstract: Aramid polymers with small amounts of alkyl- and/or alkoxy-substitution on their aromatic diamine and/or aromatic diacid monomeric units are disclosed. Such aramid polymers show improved properties compared to similar aramids without the substitution. The aramids described herein are useful for films or fibers, for example, as employed in the manufacture of packaging, ropes, filter bags, or composites. The invention also includes a process for making such polymers, involving subjecting fibers or films made from such aramid polymers to heat treatment under tension.

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: Thermoplastic poly(imide-esters) and poly(imide-amides) with repeat units derived from the title amino acid. In the polymer the amino group becomes part of an imide group and the carboxyl group becomes part of an ester or amide group. The polymers have a good balance of properties, making them useful for melt forming shaped articles, films and fibers.

Abstract: Aramids, which in the drawn state have high tensile strengths tensile elongations, and tensile moduli, are made from units derived from selected 2,2'-disubstituted-4,4'-bibenzoic acids, 3,4'-oxydibenzoic acid or 3,4'-dicarboxybenzophenone, p-phenylenediamine, and optionally terephthalic acid. The aramids are useful for ropes and composites.

Abstract: Aramids having repeat units derived from p-phenylenediamine, 4,4'-bis(3-aminophenoxy)biphenyl and terephthalic acid. These aramids have good strength properties, particularly after drawing, and good high temperature properties. The aramids are useful for fibers and films.

Abstract: Aramids, which in the drawn state have high tensile strengths tensile elongations, and tensile moduli, are made from units derived from p-phenylenediamine, terephthalic acid, a substituted terephthalic acid, and 4,4'-bibenzoic acid or 2,6-naphthalene dicarboxylic acid. The aramids are useful for ropes and composites.

Abstract: High molecular weight polyamides having benzidine linkages are prepared using certain substituted benzidine monomers.

Abstract: Isotropic polyesters containing a repeat unit derived from 4,4'-bis(3-hydroxyphenoxy)biphenyl, and especially poly(imide-esters) containing that diol, trimellitic anhydride and at least one diamine and/or aminocarboxylic acid. Such polyesters have a good combination of physical and melt properties, making them easy to shape and them useful for mechanical parts and fibers.

Abstract: Anisotropic solutions are prepared from poly[2,2'-bis(trifluoromethyl)benzidine terephthalamide] or poly[2,2'-bis(1,1,2,2-tetrafluoroethoxy)benzidine terephthalamide] in amide solvents containing certain chlorides in specified amount. Crystalline fibers are prepared from the polymers.

Abstract: Aramid block copolymers which contains blocks whose polymer chains are flexible, and blocks whose polymer chains are flexible in solution and in undrawn polymer, but relatively rigid in drawn polymer, are disclosed. The aramids are tough materials with high modulus and tensile strength. Also disclosed is a process for making such block copolymers. The copolymers are useful as fibers and films, for example in ropes and composites.

Abstract: Aramid block copolymers which contains blocks which are crystalline and blocks that are noncrystalline after drawing and where polymer chains are flexible in solution and in undrawn polymer, but relatively rigid in drawn polymer, are disclosed. The aramids are tough materials with high modulus and tensile strength. Also disclosed is a process for making such block copolymers. The copolymers are useful as fibers and films, for example in ropes and composites.

Abstract: Certain substituted benzidines enable the preparation of linear chain, high molecular weight polyimides based on benzidine.

Abstract: High molecular weight aromatic polyamides with pendant carboxyl groups.

Abstract: Tough, high strength fibers of copolyesters from hydroquinone, isophthalic acid and 4,4'-oxydibenzoic acid in defined proportions.

Abstract: Amorphous fibers or fibrids of poly [4,4'-(2,2'-dicarboxy) biphenyleneterephthalamide] are strengthened and heat stabilized by a relaxed heat-treatment. The fiber or fibrids are heated at temperatures in the range of 310.degree. C. to 365.degree. C. and preferably at temperatures above 325.degree. C. but below decomposition temperatures. The heating is conducted for at least 2 minutes, preferably from 5 to 15 minutes. Increases in tenacity of at least 25%, preferably at least 50% or more are attained. The fiber or fibrids are treated while free of ternsion as they would be in a loose batt, woven or knitted fibric or paper.

Abstract: Anisotropic solutions are prepared from poly]2,2'-bis(trifluoromethyl)benzidine terephthalamide] in amide solvents containing certain chlorides in specified amounts. Crystalline fibers are prepared from the polymers.

Abstract: High molecular weight aromatic polyamides with pendant carboxyl groups.

Abstract: The reactivity of aromatic copolyamide fiber and film is enhanced by incorporation of small amounts of 4,4'-diaminodiphenic acid units in the polymer chain.

Abstract: Amorphous para-oriented aromatic homo- and co-polyamides are prepared from terephthaloyl chloride or 2,6-naphthoyl chloride and 2,2'-dibromo-5,5'-dimethoxy-[1,1'-biphenyl]-4,4'-diamine with up to 92.5 mol % of certain other diamines.

Abstract: A method is described for preparation of polyamides using unstable diamines.