Fracture toughness of high density polyethylene/SEBS-g-MA/montmorillonite nanocomposites

摘要

High density polyethylene (HDPE)-organoclay nanocomposites toughened with maleated styrene-ethylene-butylene-styrene (SEBS-g-MA) elastomer were prepared by melt compounding. The essential work of fracture (EWF) approach under tensile and impact loadings were used to evaluate the fracture toughness of HDPE/Org-MMT nanocomposites with and without elastomers. Tensile EWF results showed that this model cannot be used to describe the fracture behavior of pure HDPE and its nanocomposites at room temperature due to the absence of gross yielding and necking. Consequently, tensile EWF test was conducted at 70 deg C in which gross yielding and necking took place. Furthermore, SEBS-g-MA additions were found to exhibit beneficial effect to enhance the specific essential work of fracture of HDPE/2 percent Org-MMT and HDPE/4 percent Org-MMT nanocomposites. Such enhanced tensile fracture toughness was attributed to shear yielding of the matrix. Impact EWF measurement revealed that the HDPE/4 percent Org-MMT nanocomposite exhibited the lowest fracture toughness. A nearly twofold increase in impact fracture toughness of the HDPE/2 percent Org-MMT and HDPE/4 percent Org-MMT nanocomposites was achieved by adding 10 percent SEBS-g-MA.