Abstract: The invention is a concurrently sintered and cross-linked ram extruded product formed by a mixture of an ultra high molecular weight polyethylene powder with a cross-linking agent, an electrically conductive agent and a lubricant. As little as 0.5 parts per 100 parts of polyethylene of the electrically conductive agent added to the ultra high molecular weight polyethylene powder coats the power to provide adequate conductivity without adversely affecting the mechanical properties of the product.

Abstract: A method of producing accurately sized sintered material of ultra high molecular weight polyethylene including the steps of mixing an organic peroxide and a lubricant with an ultra high molecular weight polyethylene powder having more than 1,000,000 of mean molecular weight by a viscosity method and more than 3,000,000 by a light scattering method, and forming a ram extrusion of the mixture. The transverse dimensional accuracy, or displacement, i.e. the difference between the maximum surface diameter and the minimum surface diameter at longitudinally spaced positions of the extruded product, is extremely small, thereby providing highly accurate size, roundness, etc. Further, a product is formed by the method having uniform electroconductivity.

Abstract: A process for producing high impact block copolyamide is described, comprising anion polymerizing .omega.-lactam in the presence of a prepolymer polymerization accelerator. The prepolymer is prepared by reacting a butadiene homopolymer and/or butadiene-acrylonitrile copolymer containing hydroxyl groups at the terminals thereof with polymethylene polyphenylene isocyanate or tolylene diisocyanate at an equivalent ratio of isocyanate group to hydroxyl group (NCO/OH) of 1:1 or more. With the thus-produced high impact block copolyamide, impact strength is greatly improved, and bleeding of polybutadiene is not observed.

Abstract: An acrylic copolymer vulcanizate, which is a sulfur-vulcanized product of an acrylic copolymer, the acrylic copolymer being obtained by the radical polymerization of a monomeric mixture consisting essentially of 100 parts by weight of at least one acrylic acid ester of an aliphatic alcohol containing 1 to 8 carbon atoms and about 1 to about 15 parts by weight of a 5-substituted-2-norbornene of the general formula ##STR1## wherein R represents .dbd.CH--CH.sub.2).sub. x CH.sub.3, in which x is 0 to 4, or --CH.dbd.CH.sub.2, in the presence of about 0.05 to about 3.0 parts by weight, per 100 parts by weight of the monomeric mixture, of a sulfur vulcanization accelerator which does not cause degradative chain transfer.

Abstract: An acrylic copolymer composition capable of being vulcanized with sulfur comprising the radical polymerization product of (1) a monomer mixture comprising an acrylic acid ester and ethylidene norbornene, (2) a monomer mixture comprising an acrylic acid ester, ethylidene norbornene and acrylonitrile, (3) a monomer mixture comprising an acrylic acid ester and vinyl norbornene, or (4) a monomer mixture comprising an acrylic acid ester, vinyl norbornene and at least one unsaturated compound selected from the group consisting of monovinyl compounds, monovinylidene compounds and monovinylene compounds.

Abstract: A polymer of .omega.-lactam is prepared by heating a mixture of at least one kind of .omega.-lactam, an anionic catalyst comprising the reaction product of a strong base and a .omega.-lactam, and an N-substituted ethyleneimine derivative represented by the general formula ##EQU1## wherein R represents an organic group as hereafter defined, and n is 2 or 3.