PNNL

Abstract

The mechanical properties and response of two composites based polypropylene (PP) have been determined for small strains and for a range of strain rates in the quasi static domain. These two materials are the talc-filled and non-filled high impact PP. Uni-axial tensile tests were performed at different strain rates in order to characterize the mechanical response and the strain rate effect. Experimental results showed that both unfilled and talc-filled high impact polypropylene were sensitive to strain rate and have a non linear behavior even at relatively low strains. SEM analysis has been conducted to obtain a better comprehension of deformation mechanisms involved during loading by observations of the microstructure evolution. For each of these two materials, two existing modeling approaches are proposed. The first one is a three-parameter nonlinear constitutive model based on the experimental results. The second is a micromechanically-based approach for the elastic-viscoplastic behavior of the composite materials. The stress-strain curves predicted by these models are in fairly good agreement with our experimental results.