| 摘要 |
<p>Copolymers of trioxan and a cyclic carboxylic ester or an olefinically unsaturated compound are prepared by copolymerizing under anhydrous conditions in the presence of a carbonium tetrafluoroborate catalyst. Specified classes of comonomer are: lactones, styrene and substituted styrenes, vinyl ethers, N-vinyl-and C-vinyl-substituted aromatic heterocyclic compounds, ethylenically unsaturated aliphatic and alicyclic hydrocarbons, and allyl compounds. The catalyst may be used as the free or solvated ionic species. The polymerization may take place in an inert liquid medium, a dry inert atmosphere such as nitrogen or carbon dioxide, at temperatures above 50 DEG C., and with the catalyst dissolved, e.g. in nitroethane. The copolymers may be stabilized by esterification or by incorporating various nitrogen-containing compounds and phenols. The copolymers may be mixed with lubricants and fillers, in addition to the stabilizers, and may be moulded into films, fibres and protective coatings. The catalyst residues may be removed from the copolymers by washing with an aqueous medium or an organic solvent. In the examples, trioxan-styrene copolymers were prepared by copolymerizing in the presence of cyclohexane and using the following catalysts: (1) triphenyl methyl tetrafluoroborate in nitroethane and (2) and (3) dioxolinium tetrafluoroborate in nitromethane.</p> |
