Thermal Degradation Process of UHMWPE

The propagation of thermal degradation can be considered as the reverse reaction to the isomerization. Taking into account the existence of primary radicals generated by thermal breakdown, they can undergo (3 carbon rupture resulting in the formation of ethylene and again, a primary radical  

the primary radicals undergo radical transfer reactions both intramolecular and intermolecular followed by a decomposition reaction. 

In the case of intramolecular reaction, these radicals isomerize via intramolecular removal of a hydrogen atom producing secondary radicals, much more stable Intramolecular transfer  

In the case of intermolecular radical transference, the reactions that take place are the following  

The reaction of the secondary radicals results in the formation of vinyl groups, whereas the reaction of tertiary radicals leading to the formation of vinylene groups [74,75], 

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