GB808667A - Ethylene polymerisation - Google Patents

Abstract

Solid polymers or interpolymers of ethylene are prepared by subjecting ethylene alone or with a polymerizable monomer, to elevated temperatures and super-atmospheric pressures in the presence as a catalyst, of a tetrazene of general formula <FORM:0808667/IV (a)/1> where R, R1 may be alkyl, cyclo-alkyl, or aryl groups or R may be alkyl and R1 aryl or cycloalkyl and R may equal R1, and R and R1 may be part of the same ring structure and be substituted or non-substituted. Examples are 1,1:4,4 - tetraethyltetrazene - 2, 1,4 - diethyl, 1,4-dipropyl, tetrazene-2, 1,4-dimethyl, 1,4-di-(p - bromophenyl) - tetrazene - 2, 1,4 - diisopropyl, 1,4 - di - p - tolyl - tetrazene - 2, 1,4 - bis - cyclopentamethylenetetrazene - 2, 1,4 - diallyl, 1,4 - dicyclohexyl - tetrazene - 2, 1,4 - bis - (21,31 - dehydrocyclopentamethylene) - tetrazene - 2, N,N1 - azomorpholine, and 1,4 - di - (2 - diethylaminoethyl), 1,4 - di - (1 - methylcyclohexyl), tetrazene-2. Interpolymerizable monomers mentioned are styrene, vinyl acetate and chloride, methyl methacrylate, N-vinyl carbazole and phthalimide. Pressures above 500, preferably 1000 to 2000 atmospheres and temperatures between 100 DEG and 400 DEG C. may be used. The process may be carried out in the presence or absence of an added inert liquid medium and may be batchwise or continuous. Chain transfer agents, e.g. hydrogen, carbon tetrachloride, chloroform, and antioxidants may also be present. Specification 797,344 is referred to.