GB952452A - Fluoropolymer compositions and methods of manufacturing them - Google Patents

Abstract

Polymeric materials are made by contacting a fluoropolymer in the form of an aqueous emulsion or a coagulated emulsion with ethylenically unsaturated monomeric material in liquid phase, and polymerizing the monomeric material in the absence of a free-radical producing catalyst to produce a material in which the polymerized monomer is distributed throughout the fluoropolymer. Fluoropolymers used are those consisting of a chain of carbon atoms in which more than half the sites available for bonds other than carbon-carbon bonds are occupied by fluorine atoms and the other sites are occupied by other halogen atoms, hydrogen atoms or more fluorine atoms, e.g. polytetrafluoroethylene, polychlorotrifluorethylene, polytrifluoroethylene, polyperfluoropropylene and a copolymer of vinylidene fluoride and chlorotrifluoroethylene. Monomers specified are aliphatic and aromatic unsaturated hydrocarbons, unsaturated acids, salts, esters, amides and nitriles, vinyl esters, allyl compounds, unsaturated amines and unsaturated ethers. The polymerization of the monomer is preferably effected by means of ionizing radiation, ultraviolet light or heat. The examples describe the following processes: (1) a mixture of styrene and a polytetrafluorethylene emulsion is subjected to high speed stirring and the resulting coagulum is irradiated from a cobalt-60 source; (2) a mixture of 4-vinylpyridine and a polytetrafluoroethylene emulsion is subjected to high speed stirring, the resulting coagulum is formed into sheets and exposed to ultra-violet light; (3) styrene is blended with an emulsion of a vinylidene fluoride-chlorotrifluoroethylene copolymer and the mixture is irradiated from a cobalt-60 source; and (4) a mixture of styrene and an emulsion of polytetrafluoroethylene is irradiated from a cobalt-60 source. Reference has been directed by the Comptroller to Specification 820,120.