Study of nano-reinforcing fillers effect on the lap shear strength of epoxy adhesives

Nano-reinforcing fillers have shown outstanding mechanical properties and they could be used heavily as reinforcing materials associated to polymeric matrices for high performance applications. Multi-walled carbon nanotubes (MWCNT) and Nanoalumina (nano-Al2O3)–reinforced epoxy resin were developed to use as adhesives. In this study, the influence of different nanofillers on the adhesion and elongation at break of Diglycidyl ether of bisphenol-A (DGEBA)/Epoxy Novolac adhesives on an aluminum alloy (Al2024-T3) substrate was investigated. In fact, adhesive nanocomposites have been attained. The surface of substrate has been abraded by means of a sand paper of 150 grits (150#). A simple and effective approach to prepare the adhesives with uniformity and suitable dispersion of nanofillers in epoxy matrix is mechanical stirring combined with ultrasonication. The adhesion strength was measured by lap shear strength test (ASTM D1002) as a function of nano-Al2O3 and MWCNT loadings. The mechanical properties of different formulations were determined by shear test to define the influence of nanofillers on strength of epoxy adhesives. The results indicated that the lap shear strength was increased with addition of MWCNT and Nanoalumina (0.75, 1.125, 1.5, 2.25 and 3wt. %) up to a certain level of nanofiller content. The highest lap shear strength was obtained at 1.5wt% nano-Al2O3 loading. The nano-Al2O3 exhibited higher effect on enhancement of lap shear strength as compared to MWCNT. Since, the nature of epoxy resin is brittle; elongation at break of the developed adhesives did not change remarkably by incorporation of the nanofillers content. Transmission electron microscopy and scanning electron microscopy techniques depicted that nanofillers were homogeneously dispersed in the epoxy matrix at the optimized nanofiller loadings

کلیدواژه ها:

Adhesive nanocomposites ، lap shear strength ، epoxy resin