In order to explore the effect of thermal aging on the electrical and mechanical properties of PP insulation

four types of polypropylene(PP)/elastomer blending cable insulation materials were selected for a 135 ℃ accelerated thermal aging experiment.The effects of thermal aging on the physicochemical

electrical

and mechanical properties were analyzed according to the comparison of different PP/elastomer blending materials.The evolution patterns of the microstructure and electrical properties of PP/elastomer blending insulation under thermal oxygen aging were revealed. The experimental results indicated that

the mechanical properties of the four samples deteriorate with the aging time.On the one hand

the migration and aggregation of the elastomer lead to a disruption of the sea-island structure between PP and elastomer

thus the tensile performance of the PP/elastomer blending insulation is decreased. On the other hand

the molecular chains and the spherulitic structure of PP were damaged.The comparison shows that two of the samples have a smaller increase in the average particle size of the elastomer after aging

a smaller increase in carbonyl index

and smaller changes in electrical and mechanical properties

which indicates the two samples have the best aging resistance.This main reason is that

the compatibility between polypropylene and elastomer in the two samples is good

as well as the compatibility stability after thermal oxidative aging. The results of this paper show that

the compatibility of elastomer with polypropylene and the compatibility stability after thermal oxygen aging are key factors

which determines the thermal oxygen aging performance of the main insulation of PP/elastomer blending cable.