Polymerization of hepta-1,5-diene on complex catalysts

Abstract

THE difficulty of obtaining vulcanizable rubbers by the copolymerization of a-olefins consists mainly in the method of introducing double bonds into the copolymer. Attempts to synthesize a polymer of this type from ethylene or propylene with the addition of acetylene or diene hydrocarbons have been unsuccessful [1-3]. I t seemed to ~s to be possible to obtain the desired polymer by the copolymerization of ~-olefins with non-conjugated dienes containing both internal and external double bonds. I t was assumed that the external double bonds would take part in the polymerization and the unreactive internal double bonds would remain unaffected. As the subject of investigation, we selected hepta-l,5-diene. The first stage of the work consisted in a s tudy of the homopolymerization of hepta-l,5-diene in solution under the influence of catalysts of the Ziegler-Natta type. At the present time, it is known that in the presence of Ziegler-Natta catalysts, compounds containing two non-conjugated vinyl groups give polymers consisting of cyclic units [5. 6].