Abstract
The tensile properties of PP⁄SEBS blend syntactic foams with the relative densities from 0.5 to 1.0 are characterized at the nominal strain rates of 1, 10 and 100 s-1. Then, the influences of the tensile properties of the matrix materials on the macroscopic tensile properties of the syntactic foams are studied by comparing the experimental results of PP⁄SEBS and PP⁄EPR⁄talc syntactic foams. It is found that the apparent elastic moduli of PP⁄SEBS and PP⁄EPR⁄talc foams obey the Gibson-Ashby law at the nominal strain rate of 100 s-1, which indicates that the microstructural deformation mechanisms of syntactic foams would be correlated well with the Gibson-Ashby model when the matrix materials are the glass phase. The yield stress of PP⁄SEBS foam obeys the simple rule of mixture at the relative densities larger than 0.9. However, the yield stress of PP⁄EPR⁄talc foam does not obey the simple mixing rule because the debonding of the blended inorganic talc filler against PP matrix is dominant characteristic for the yield stress. This localized microscopic damage mechanism makes the yield stress predicted by the simple mixing rule less accurate. The material ductility of PP⁄SEBS foam decreases drastically once the microballoons are blended in the matrix material.
