Investigation of effect of borax particles on bonding and strength of adhesively bonded composites

In this study, the influence of microscale particles borax filler dispersion in the epoxy adhesive on tensile test, three point bending test of adhesively bonded single-lap and double-lap joints were experimentally investigated. Borax filler was used as additive material within the epoxy, having different mass ratios (5, 10, 15, 20, 25% wt.). Test samples were produced by plain woven S-glass fiber. Tensile test and three point bending tests were applied for single lap joint. According to the result of tensile test the maximum shear strength increased by 28.84% compared with pure epoxy at weight rate of borax 15%, and beyond that ratio it tends to decrease. According to the result of three point bending test the maximum strength increased by 13.86% compared with pure epoxy at weight rate of borax 15% , and beyond that ratio it tends to decrease. Only tensile test was applied to the double-lap joints. According to the result of tensile test the maximum strength increased by 43% compared with pure epoxy at weight rate of borax 25%. By these results it can be said that the best ratio of borax that can be used as additive material within the epoxy to improve the shear strength for single and double-lap joints are 15% - 25% respectively, in addition, reducing the cost of materials used.