PROPERTIES OF IONIZING RADIATION CURED POLYMER MATRICES FOR CARBON FIBER COMPOSITES AFTER AGEING DUE TO MOISTURE ABSORPTION AND THERMAL TREATMENT

摘要

Radiation curing is an alternative way to the more traditional thermal processes in order to produce epoxy resin based matrices for carbon fiber composites, for aerospace and advanced automotive applications. The advantages of this process lie in the possibility to work at room temperature and in very short times, with positive consequences in the properties of the products, in the equipment maintenance costs and in the environmental sustainability. Likewise to the thermal processes, the research is mainly devoted to the determination of both the best formulations and the best process conditions in order to optimise the final properties of the material. The main requirements for aerospace and advanced automotive applications are a high operating temperature (high Tg), a high stiffness (high elastic modulus), a high toughness (high fracture energy) and a high solvent resistance. In order to achieve there properties the formulation generally consists of blends of epoxy resins and high modulus and high Tg thermoplastics. Considering that during their life the materials have to operate in different environmental conditions (various external temperatures, various moisture contents, etc.) it is very important to know how thermal and mechanical properties of the polymer matrices are modified after the exposure to different temperature and moisture absorption cycles. In this work ionizing radiation cured epoxy based polymeric matrices for carbon fibre composites have been subjected to different thermal and moisture absorption ageing cycles and the influence of these treatments on the thermal and mechanical properties has been investigated through dynamic mechanical thermal analysis and mechanical flexural tests.