Endlife criterion

First, it has been considered that embrittlement occurs when the endlife criterion is reached in the superficial elementary layer. For polymers predominantly undergoing chain scission during their oxidation, embrittlement corresponds to a critical number of chain scissions Sp 16), But, for polymers undergoing both chain scission and crosslinking, such as PE, the problem remains totally open. 

Polymer sensitivity to macromolecular changes resulting from oxidation is a key factor from the mechanical point of view. As an example, mechanical embrittlement occurs in polypropylene (PP) for a number of chain scissions 10 times lower than in an amorphous polymer. Thus, at equal reactivity, according to this mechanical endlife criterion, PP will be 10 times less stable than an amorphous polymer. 

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See also in sourсe #XX -- [ , , , , , , ]

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