Parametric study on bonding strength of CNT impregnated adhesive to repair composite structure

초록

In this study, to bond composite structures, adhesive characteristics under various adhesive process conditions, as CNT impregnation, surface treatment and application of electric field during a curing process, were compared. For composite structure, uni-directional prepregs were stacked and hot-pressed. CNT impregnated adhesive was produced by mixing CNT with acetone and base material of two-part epoxy adhesives and followed by volatilizing acetone. As adhesive process conditions, surface was treated by plasma and sanding, respectively. CNT was impregnated by each different weight fraction, 0%, 0.1% and 0.5%. Electric field was applied to give an effect on CNT alignment. To compare adhesive bonding strength, single-lap shear tests were performed. Without CNT, plasma treatment showed an increase of shear strength by 25% than a normal surface treatment. With CNT, during a test, prepreg delamination occured before the fracture of adhesive zone. It was caused by that the leakage of adhesive on the end of specimen induces non-homogeneous stress distribution in adhesive zone and layer delamination partly. However, it was shown that the more CNT fraction causes an increase of shear strength.