Flexural characteristics of sunlight-aged polyester composites: influence of processing variables

Abstract

[EN] This work presents the results of flexural tests carried out on samples aged for different periods of time in a UV-Visible light chamber. The processing variables studied were the type of reinforcing fabric, the resin type, and the cure conditions. The evolution of flexural characteristics with time exposure adjusts to a mathematical model that corresponds to a damped exponential curve. The aging degree varies between 16 and 41%, depending on the preparation of the composites and the mechanical characteristics of the material. The aged material featured losses of its mechanical properties, and more on toughness than on strength properties. The kind of unsaturated o-phthalic polyester resin used showed no influence on the loss of mechanical properties. High cure temperatures decreased the loss of toughness to a higher degree than that observed for the loss of strength. The configuration of the reinforced fabrics used also influenced the mechanical properties: a mixed taffeta-multiaxial reinforced configuration leads to a high loss index on toughness properties and modulus of the composite.