Influences of Tensile Rates and Filler Content on Mechanical Properties for PP-GB Composites

Abstract

Tensile properties are important use performances of materials. In the present paper, the tensile properties, such as elastic modulus (Ec)and yield strength of glass bead-filled polypropylene (PP)composites were measured by using an Instron material tester at room temperature and varied tensile rates, to identify the effects of tensile rates and filler concentration on these tensile properties. The fillers were A-glass beads, and the surface was pretreated with silane coupling agent. The fillers and PP with different proportion were compounded in a twin-screw extruder in temperature range of 160-230 C to produce the composites. The results showed that the Ec increased nonlinearly with increasing the filler content at lower tensile rates, while it did not vary practically with the filler concentration at the highest tensile rate. When the filler content was a constant, Ec was approximately an exponential function of tensile strain rates, except for individual data points. The tensile yield stress (σyc)decreased nonlinearly with the addition of the filler volume fraction (ϕf at lower tensile rates, while it decreased almost linearly with the increase of ϕf at highest tensile rate. Similarly, σyc increased with increasing tensile strain rates as a form of index function. Furthermore, for these composites the relationship among Ec, σyc, tensile strain rates and ϕf were discussed.