Humid Ageing of Organic Matrix Composites

摘要: In this chapter, several aspects of the ageing phenomena induced by water in organic matrix composites are examined, essentially from physico-chemical point view. It is first important to recognize that there two main categories humid ageing. First physical processes, mainly linked stress state swelling and sometimes plasticization. This kind can occur matrices relatively high hydrophilicity (affinity with water). Highly crosslinked amine cured epoxies typical examples behavior. The second category involves a chemical reaction (hydrolysis) between material water. Unsaturated polyesters category. They display low moderate hydrophilicity, plasticization have minor effects, but hydrolysis induces deep polymer embrittlement and, eventually, osmotic cracking. Whatever mechanism, it needs penetrate into depends on concentration its distribution sample thickness. reason why sections respectively dedicated solubility diffusivity matrices, interphases composites. each case, elementary processes distinguished, examine effects temperature establish structure–property relationships. shown that, most these aspects, research remains largely open. last section devoted hydrolysis, kinetic modeling, including case diffusion controlled consequences properties. Structure reactivity relationships briefly presented. very cracking, which be considered as consequence also examined.