Rubber‐filler interaction effects on the solid state dynamic mechanical properties of polyethylene/EPDM/calcium carbonate composites

摘要

AbstractComposites of polyethylene, ethylene propylene diene rubber (EPDM), and calcium carbonate are milled and analyzed by solid state dynamic mechanical spectroscopy. The torsion pendulum measurements show that the multicomponent composites exhibit complex viscoelastic behavior. In composites of polyethylene and calcium carbonate, the experimentally observed modulus enhancement is greater than that expected from the properties of the constituent materials, assuming well‐dispersed inclusions. In composites of polyethylene, rubber, and calcium carbonate, interactions of the rubber with the filler surface are significant. Specifically, maleic anhydride modification of the EPDM results in rubber‐filler interactions that drastically influence the properties of the composite. The maleic anhydride modification results in a morphology with more rubber around the filler particles and thus an enhanced rubber glass transition peak. The rubber‐filler interaction has been attributed to salt formation at the filler surface. The interaction was also detected by solid state proton nuclear magnetic resonance (NMR) relaxation experiments. Treatment of the filler surface with gamma‐aminopropyltriethoxysilane (γ‐APS) or gamma‐methacryloxypropyltrimethoxysilane (γ‐MPS) has significant influence on the dynamic mechan