Abstract: The present invention relates to a method for dry coalescing and kneading powders, for the exfoliation thereof, comprising the steps of providing a polytetrafluoro-ethylene aqueous suspension or emulsion, stirring to flocculate the emulsion, fully drying the emulsion and dispersing the obtained concentrated material through the powders to be processed.

Abstract: An electrically conductive non-porous polyolefin composition comprising a homogeneous mixture of propyleneethylene copolymer containing 20 mol % to 35 mol % ethylene and at least 30 parts by weight of finely divided conductive carbon, e.g. carbon black, per 100 parts by weight of copolymer. This composition may be made by mixing under conditions of high shear, e.g. in a Banbury mixer, and at a temperature of at least 100.degree. C the propylene-ethylene copolymer and the finely divided conductive carbon, the mixing being continued until a homogeneous blend is obtained. A bi-polar sheet for an electrochemical cell may be formed by obtaining a homogeneous blend of polyolefin and finely divided conductive carbon by the above-mentioned process and thereafter forming the composition into the shape of a bi-polar plate.

Abstract: A rigid or semi rigid self-skinned cellular plastic structure which is heat recoverable and thermoelastic is prepared by a process wherein a plastisol or pregelified dry-blend of a homo- or copolymer of vinylchloride (PVC dispersion resin), a polymerizable polyfunctional allyl or vinyl monomer (o-diallyl phthalate), and a peroxide catalyst is prepared, and the plastisol or dryblend is heated so that the reacting mass is free to expand without restraint in at least one direction with a temperature rise of 10.degree.-30.degree.C/minute at least up to the temperature at which expansion of the reaction mass starts. This cellular structure is rigid at normal temperatures and behaves like an elastomer at high temperatures. The product can be subjected to fabrication techniques such as sheet molding, encapsulation expansion from compressed foam etc.