| 摘要 |
Ethylene with or without a copolymerizable monomer is polymerized at a pressure of at least 10,000 p.s.i. (e.g. up to 50,000 p.s.i.) in the joint presence of a trialkyl or tricycloalkyl borane and oxygen or a substance which acts as a source of oxygen under the reaction conditions, at least one half of the total amount of oxygen or source thereof being supplied to the reaction mixture after the pressure has been raised to at least 10,000 p.s.i. The polymerization may be in bulk, aqueous medium or in solution (e.g. hexane) and may be carried out with the flow impulses, chain transfer agents and mixed catalysts as described in Specifications 816,110, 891,903 and 921,542. The oxygen may be supplied as pure oxygen, air, as ethylene/oxygen mixtures or as a peroxide such as hydrogen or benzoyl peroxide. Of the specified boranes, that used in examples is triethyl borane. Reaction temperatures are suitably between -100 DEG and 100 DEG C. The products are substantially saturated, have a chain branching not exceeding 0.6 methyl groups per 100 carbon atoms, have a density greater than 0.935, a tensile strength greater than 3,000 p.s.i. and a Mw/Mn of less than 2. |
