The impact of ionic hydration on water absorption by composite insulation

The importance of ionic hydration phenomenon in water absorption is introduced. A set of composite samples, fabricated from polyester resin and glass fiber, are exposed to a number of aqueous solutions. The change in sample weight of such composites, as a result of water absorption, is investigated. The variation of water pick up is determined as a function of ionic solution type, concentration and applied voltage. The time distribution of absorbed moisture by composite specimens is calculated from the measured values. The results, presented in this paper, are based on experimental work conducted under different conditions. Moisture absorption rates, attributed to the ionic hydration of various salt solutions, are compared with that of deioniozed water for all studied cases. The impact of barriers, in hindering the water to diffuse throughout the whole sample, is studied by monitoring the salt crystal deposits that result after drying the sample for enough time. The images of residual ionic crystals assist in determining the areas, where the moisture is distributed inside composite samples.