Micro-mechanisms of deformation in polyethylene/clay micro- and nanocomposites

Incorporation of clay in polymers is known to improve mechanical properties such as tensile modulus and tensile strength, but to generally decrease elongation at break and toughness. However, recent studies reported an increase in elongation at break for linear low density polyethylene based nanocomposites. In this work, the tensile properties of clay micro- and nanocomposites based on high density polyethylene (HDPE), low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) of similar molecular weights were evaluated. LLDPE micro- and nanocomposites exhibited an extraordinary enhancement in toughness compared to LDPE or HDPE microcomposites. Based on electron microscopy and on acoustic emission and volume strain measurements during tensile testing, micro-mechanisms of deformation in polyethylene/clay micro- and nanocomposites were proposed.