Abstract
The rates of transmission of water through epoxy resin laminates have been measured for three different kinds of fibrous reinforcements, and at two temperatures. The efficacy of four non-metallic moisture barrier layers has also been investigated. Of the organic fibre laminates, polyethylene fibre reinforced epoxy materials were the most resistant to moisture transport; but glass laminates were comparable if filled with 50 phr of alumina trihydrate. The durability of the barrier layers when subjected to mild mechanical abrasion and low energy impact after water transmission were also determined. Water transmission rate (WTR) values were always much higher at 65°C than at 30°C, and especially so in the case of the filled glass laminates. Impact and abrasion had a more severe effect on WTR at the higher than the lower temperature. All the barrier layers studied had a beneficial effect, but all require improved adhesion to the substrate in wet conditions.