| 摘要 |
A film or filament made from a polymeric material comprising units of an ethylenic aromatic compound and units of at least one vinyl ester, vinyl alcohol, hydroxyalkyl vinyl ether or sulphide, or hydroxyalkyl ether in which the alkyl group is interrupted by one or more ether oxygen atoms, is cross-linked by treatment with hydrogen fluoride or mixture thereof with boron trifluoride as an alkylation catalyst, whereby the aromatic nuclei in the polymer are alkylated with the oxygen-containing monomer units. The resulting crosslinked products may be used in textile applications and, after appropriate chemical treatment, as ion-exchange materials. The polymers from which the films and filaments are made may be copolymers, graft polymers or blends of polymers. The examples describe the cross-linking of filaments made from a polyvinyl acetate-styrene graft polymer and a partial hydrolysis product thereof, a polyvinyl acetate-vinyl toluene graft polymer, a polyvinyl stearate-styrene graft polymer, graft polymers of styrene on polyvinyl hydroxyethyl ether and sulphide and polyvinyl 2-hydroxypropyl ether, and blends of polyvinyl acetate and polystyrene. Cross-linked filaments made from polyvinyl acetate-styrene graft polymers are given ion-exchange properties either by sulphonation or by chloromethylation, followed by animation. Also described is the preparation of the above polymers and also copolymers of tertbutyl acrylate and hydroxyethyl vinyl ether and sulphide, and copolymers of vinyl stearate and ethyl acrylate and acrylamide, by aqueous emulsion polymerization in the product of a catalyst mixture consisting of ammonium persulphate, sodium hydrosulphite, tert.-butyl hydroperoxide and ferric sulphate. The preparation of polyvinyl acetate-polystyrene blends is described, either by mixing aqueous dispersions or benzene solutions of the two polymers. |
