Morphology and mechanical property of epoxy-clay nanocomposites prepared by ultrasonication

Epoxy-clay nanocomposites have been synthesized using organically modified montmorillonite nanoclay, Nanomer I.30E as nano-reinforcement in diglycidyl ether of bisphenol A (DGEBA) epoxy using ultrasonication. X-ray diffraction and TEM analysis showed that the interlayer spacing of clay increased as a result of sonication mixing. It was observed that the morphology of the resultant nanocomposites were dominated by disordered intercalated morphology with some ordered intercalated structure. Tensile tests results illustrated that while the addition of nanoclay increased the modulus of elasticity, noticeable reduction in strength and failure strain was observed. Fractographic analysis was curried out for the tensile fracture surfaces using SEM which illustrated that the roughness of the nanocomposites surface were high compared with the smooth surfaces of the pure epoxy indicating an improvement in the fracture toughness. It also demonstrated that during tensile loading for nanocomposites the cracks were initiated at either clay aggregates or microvoids which explained the reduction in strength for nanocomposites.