| 摘要 |
Crystalline polyvinyl chloride exhibiting a crystalline type X-ray diffraction powder pattern may be prepared by a process which comprises contacting under polymerizing conditions vinyl chloride with a catalyst formed by reacting a compound of a metal of Group IVa, Va, VIa, VIIa or VIII of the Mendel</>aeeff Periodic Table with an organometallic compound of an alkali metal, alkaline earth metal, zinc or aluminium, said process being carried out in the presence of a complexing agent for said organometallic compound. Suitable complexing agents are ethers, tertiary amines, esters, ketones and nitroaromatics. The process may be conducted batchwise or continuously, in bulk or in the presence of an inert organic liquid diluent, such as aliphatic cycloaliphatic and aromatic hydrocarbons, halogenated hydrocarbons and ethers, the use of n-heptane and methylene chloride being exemplified. Many compounds suitable for the formation of the catalyst are listed and the use of vanadium trichloride, vanadium tetrachloride, vanadium oxydichloride, vanadium oxydiacetylacetonate tantalum p pentachloride, titanium tetrachloride, zirconium tetra-acetylacetonate, molybdenum pentachloride, chromium triacetylacetonate, manganese triacetylacetonate, cobalt diacetylacetonate and ferric acetylacetonate, and of aluminium triethyl, aluminium tri-isobutyl, diethyl aluminium chloride, di-isobutylaluminium hydride, magnesium diethyl, isobutyl lithium and lithium aluminium tetraisobutyl exemplified, together with tetrahydrofuran, diethyl ether, ethyl acetate and triethylamine as complexing agents. The polymerization may be stopped by adding ethanol or butanol, and the product washed with methanol or ethanol. The polymers may be compounded with stabilizers and plasticizers, and if desired with polyvinyl chloride made by conventional methods, and may be used in the preparation of films and fibres, and if desired oriented.
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