| 摘要 |
A granular copolymer of tetrafluoroethylene and 0.003-1.5 mole per cent of a perfluorovinyl compound of formula CF2 = CFX, where X is perfluoroalkyl, o -hydroperfluoroalkyl, oxyperfluoroalkyl, oxy-o -hydroperfluoroalkyl and polyether homologues of oxyperfluoroalkyl; or perfluoro - 2 - methylene - 4 - methyl, 1,3-dioxolone is claimed which predominantly consists of spheroidal particles of average diameter 300-1800m . The comonomer may be hexafluoropropylene or perfluoropropyl perfluorovinyl ether. The copolymers may be prepared by polymerizing the monomers under pressure and heat in a mixture of water, ammonium persulphate, and Na2B4O7 or ammonium carbonate or hydroxide. |
