Abstract: The application discloses compositions which can be shaped to form yarns, fibers, films, membranes and fibrids. They contain a particular statistical or ordered copolyamide, with an inherent viscosity of at least 1, or units containing radicals of which at least 5% are flexible radicals and the others are rigid radicals. These compositions make it possible to produce yarns, fibers, films, membranes and fibrids possessing superior mechanical properties, which find applications in the textile field, as reinforcements in composite materials in the rubber industry and coated fabrics.

Abstract: A process is disclosed for the discontinuous production of a polyamide having the generic formula: ##STR1## and an inherent viscosity of at least 3, wherein 50 to 100% of the radicals R are p-phenylene radicals and 0 to 50% are n-butylene radicals. Terephthaloyl chloride, and optionally adipoyl chloride, are reacted in stoichiometric amounts with a solution of paraphenylenediamine and/or of 4,4'-diaminoadipanilide in a mixture of N-methylpyrrolidone-2 and calcium chloride which is homogeneous and substantially anhydrous, with a molar ratio of CaCl.sub.2 / unit: ##STR2## of at least 0.7, and under conditions such that the final composition contains 5 to 16% by weight of polymer, relative to the N-methylpyrrolidone-2. The polymer obtained can be converted into films, fibers and high-performance yarns for reinforcing composite materials or articles made of rubber.

Abstract: A continuous process is disclosed for the production of poly-(para-phenylene terephthalamide) and its copolymers, having an inherent viscosity of at least 3. Molten terephthaloyl chloride, and optionally adipoyl chloride, are reacted in stoichiometric amounts with a solution of para-phenylenediamine and/or of 4,4'-diaminoadipanilide, and optionally of a prepolymer formed from at least one chloride and at least one diamine from amongst those mentioned above, in a mixture of N-methylpyrrolidone-2 and calcium chloride which is homogeneous and substantially anhydrous, with a molar ratio of CaCl.sub.2 /unit: ##STR1## of at least 1, and preferably at least 1.15, and under conditions such that the final composition contains at least 5% by weight of polymer, relative to the N-methylpyrrolidone-2, where R represents p-phenylene or p-phenylene and up to 50% of n-butylene of the total polymer units.

Abstract: The application discloses compositions which can be shaped to form yarns, fibers, films, membranes and fibrids. They contain a particular statistical or ordered copolyamide, with an inherent viscosity of at least 1, or units containing radicals of which at least 5% are flexible radicals and the others are rigid radicals. These compositions make it possible to produce yarns, fibers, films, membranes and fibrids possessing superior mechanical properties, which find applications in the textile field, as reinforcements in composite materials in the rubber industry and coated fabrics.