Branching in 1-polybutene

Whereas in the Py-GC of polyethylene and PE and polypropylene, the splitting up of the main chain is virtually the only result of thermal reaction, the stripping off of side-chains in polybutene-1 is clearly indicated by the nature of the pyrolysis products. 

In the case of polybutene-1 a mechanism involving stripping off of side-chains is involved in the formation of ethylene  

In actual fact a considerable yield of ethylene is obtained from polybutene-1, whereas the production of propylene is much smaller because this can only emanate from the principal chain. The complicated structure of polybutene-1, as compared with the structures of PE and polypropylene, gives rise to the formation of a markedly larger number of structurally isomeric degradation products. Theoretically with a maximum molecular size of Cg, 37 different hydrocarbon decomposition products should be obtainable from polybntene-1 and, in fact, Voigt [68] was able to identify, or indicate the probable existence of 33 compounds for polybutene-1. 

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