Effect of Tensile Rate and Sample Preparation Method on Tensile Properties for PP and PS

The effects of the tensile rate and samples preparation method on tensile strength and elongation after fracture for PP and PS were studied. The results showed that tensile strength of PP and PS increased with the increasing of tensile rate. But the elongation after fracture of these two materials presented different changes. The tensile strength and elongation after fracture of injection molding samples of PS were much higher than the compression molding samples of PS. The elongation after fracture of injection molding samples of PP increased 69% than the compression molding samples, but the tensile strength did not change obviously.