Delamination behaviour of glass/polyester composites after water absorption

Two-layer laminates were developed by using glass fabric with plain weave as the reinforcement and unsaturated polyester the matrix. The fabrication was carried out with the vacuum assisted resin infusion method. Samples were immersed in distilled water for various period which included 7, 14 and 21 days. The environmental temperature during the water treatment was kept about 29 °C. The interlaminar behaviour of the treated samples was tested by using an instrument designed for fusible interlining pilling intensity evaluation in the fashion field. By separating the fabricated two-layer composite, the resulted peeling intensity may be regarded as a representative of the interlaminar bonding strength. Significant improvement of the peel bond strength after the water immersion suggests that water environment improve the bonding strength between the layers. This is attributed to the function of the water molecules penetrated into the composites.