Saeed Gilak Hakimabadi’s research while affiliated with Iran Polymer and Petrochemical Institute and other places

... Polymeric insulators, like SiR, EPDM, and epoxy, age due to exposure to the outdoor environment, causing partial degradation of their dielectric, thermal, and mechanical properties [43][44][45]. Electrical stresses and environmental stresses weakly affect polymeric sheds, causing degradation and surface tracking, which in turn leads to puncturing and surface erosion [46,47]. Environmental stresses like acid rain ,UV radiation, and moisture cause the ageing of polymeric insulators [44,48,49]. ...

Reference:

Advancing High-Voltage Polymeric Insulators: A Comprehensive Review on the Impact of Nanotechnology on Material Properties