français vers anglais Technique / Génie Ingénierie (général) polyethylene; polymers

I am not sure what is the best term to use in English for this. I think that it literally means 'oxidative chain break' but that doesn't sound right somehow. I came across 'oxidative chain scission'. The context below is taken from a detailed study of polyethylene tubes (PE) used in drinking water networks and the fact that they appear to be prematurely aged by contact with Chlorine Dioxide (CIO2), causing certain of them to crack.
I think the 'oxydante' should have an 's' on the end as it is qualifying 'chaines' - unless I have got this term completely confused (?).

D’un point de vue phénoménologique, les résultats obtenus dans le cadre de l’étude théorique sur des résines vierges de polyéthylène (sans additifs)permettent l’identification de certains mécanismes engagés dans la dégradation du PE par le ClO2. Ainsi, le ClO2 engendre dans les premiers temps de contact une réticulation du PE rapidement suivie par une coupure de chaînes oxydante hautement fragilisante pour la tenue mécanique du PE.

.... causes cross-linking of the PE, quickly followed by
{.............................} which has a highly embrittling effect on the PE's mechanical properties.

I would be most grateful for some help with this term as applied to stress/resistance testing of plastics.