Studies on toughness of polyolefin resins .4. Effect of crystallinity on brittle-ductile transition in polyethylene

The brittle-ductile transition temperature (BDTT) of polyethylene was evaluated using the Charpy impact test. The effect of the crystallinity on BDTT was the main concern in this study. Higher density resins revealed lower BDTT. On the other hand, whitening of the deformed region during the tensile test and craze-like failure during the tensile test with a notch increased for higher density resins more than for lower density resins. Therefore, a crack shielding effect by microvoid formation at yielding zone near the notch is proposed as the toughening mechanism on Charpy impact test for higher density resins.