Which factor contributes to aging in polymer insulators?

• A. UV exposure leading to loss of hydrophobicity.
• B. UV exposure reducing mechanical wear.
• C. Moisture alone with no UV.
• D. Thermal cycling only.

Answer: (C)

Moisture can drive aging in polymer insulators by directly interacting with the material and any surface contaminants. Water molecules can diffuse into the polymer and, under electrical stress, promote hydrolytic or ionic processes that slowly break down the polymer network or soften the material. Even without UV, this uptake reduces hydrophobicity, making the surface more easily wetted and enabling leakage currents and surface tracking. Repeated wetting and drying cycles can cause microcracks and erosion, degrading mechanical strength and insulation performance over time. While UV exposure accelerates aging by causing bond breakage and loss of hydrophobicity, moisture alone still contributes significantly by altering chemical and physical properties essential for long-term reliability. In short, water interaction weakens the barrier properties of the polymer and creates conditions that lead to aging.