Interfacial effects in glass fibre composites as a function of unsaturatedpolyester resin composition

The tensile strengths of polyester laminates have been examined with respec t to E-glass fibre-unsaturated polyester resin (UPR) interfacial properties . The tensile strengths of the polyester laminates were determined as a mea sure of interfacial bond strength. In accordance with the principles of Fac torial Design several compositions of UPRs were prepared varying three fact ors: the saturated to unsaturated acid ratio, the branched to linear ether glycol ratio and the amount of styrene. The influence of UPR composition on the tensile strength of polyester laminates is owing to the effects on fle xibility of the cured UPR. The compositions with lower degrees of unsaturat ion and with higher amount of linear ether glycol increase the flexibility of UPRs, improve adhesion with E-glass fibre and consequently increase the tensile strength of the polyester laminates. (C) 2001 Elsevier Science Ltd. All rights reserved.