EXPERIMENTAL-DESIGN AS A ROUTE FOR IMPROVING THE PERFORMANCES OF FORMULATED EPOXY ADHESIVES

Experimental design was used to put in order the formulation factors o f an epoxy adhesive. The influence on the reactivity (Delta H), the gl ass transition (T-g) and mechanical performances (R-m) of factors such as the nature of the epoxy, the hardener, the plasticizers, fillers, and cure promoter, was investigated by DSC and the three point flexure test. A high reactivity is provider: by the DGEBA resin coupled to th e DETA hardener and a reactive plasticizer. The glass transition is ma inly influenced by the nature of the hardener and the presence of the plasticizer. The maximal strain recorded on aluminum and steel is impr oved by the DGEBA/polyamide hardener with a slight excess of epoxy res in, while the EPN/DETA system must be used with respect to the stoichi ometric composition. (C) 1997 Elsevier Science Ltd.