The effect of finely-divided fillers on the adhesion strengths of epoxy-based adhesives

It was aimed to investigate the effect of five different fillers on the adhesion strength of the metal parts used in different industries by using T-peel and lap-shear tests with respect to ASTM D 1876 and ASTM D 1002 respectively. EPIKOTE® 828 and DURATEK® epoxy resin types were used as adhesives with curing EPIKURE® 3090 modified polyamidoamine adduct and DURATEK® polyamide curing agents respectively. Curing temperatures were increased, while curing times were decreased. Five different fillers used are calcite with a mean particle diameter of 4.97 μm, talc extra with an average particle diameter of 4.91 μm, and barite extra with a mean particle diameter of 4.76 μm supplied by ESEN MIKRONIZE, calcite with an average particle diameter of 0.7 μm and coated calcite with a mean particle diameter of 0.9 μm provided by ERCIYES MIKRON. The effect of five different fillers on adhesion strength was investigated with choosing the best regression model fitted to data by using two different epoxy resin systems. The best values in shear and peel tests were attained with calcite having the particle diameter of 0.7 μm in both type of epoxy resins providing a good agreement between experimental and theoretical results.