Markedly improved photo-oxidation stability of α form isotactic polypropylene with nodular morphology

Degradation Behaviors and Mechanism of Nitrile Butadiene Rubber Caused by Insulating Medium C5F10O

C₅F₁₀O is a promising insulating medium in the manufacturing of environmentally friendly gas-insulated switchgears (GISs). The fact that it is not known whether it is compatible with sealing materials used in GISs limits its application. In this paper, the deterioration behaviors and mechanism of nitrile butadiene rubber (NBR) after prolonged exposure to C₅F₁₀O are studied. The influence of C₅F₁₀O/N₂ mixture on the deterioration process of NBR is analyzed through a thermal accelerated ageing experiment. The interaction mechanism between C₅F₁₀O and NBR is considered based on microscopic detection and density functional theory. Subsequently, the effect of this interaction on the elasticity of NBR is calculated through molecular dynamics simulations. According to the results, the polymer chain of NBR can slowly react with C₅F₁₀O, leading to deterioration of its surface elasticity and loss of inside additives, mainly ZnO and CaCO₃. This consequently reduces the compression modulus of NBR. The interaction is related to CF₃ radicals formed by the primary decomposition of C₅F₁₀O. The molecular structure of NBR will be changed in the molecular dynamics simulations due to the addition reaction with CF₃ on NBR's backbone or branched chains, resulting in changes in Lame constants and a decrease in elastic parameters.