用J积分法表征聚碳酸酯/弹性体合金的韧性

Study on Toughness of PC/Elastomer Blends Based on J-integral Method

采用J积分法表征聚碳酸酯(PC)/弹性体共混体系的韧性。结果表明,当加入弹性体后,体系断裂韧性J_(IC)明显提高,提高了约80％。在弹性体含量为5％～15％时,断裂韧性J_(IC)变化不大。撕裂模量T_m随着弹性体含量的增加而增大,在弹性体含量为10％时增加了12.5倍。弹性体增韧PC的原因主要在于提高其抗裂纹扩展能量。采用SEM观察材料中的裂纹在平面应变下的发展过程发现,起裂前裂尖出现钝化和靴状超钝化现象,从微观上解释了材料韧性提高的原因。

The toughness of PC/elastomer blends has been characterized with J -integral method in this paper. The results indicated that the fracture toughness (JIC) was raised by 80% when adding elastomer into PC. But elastomer contents in the range of 5 to 10 per cent result in little change of JIC. The tearing modulus ( Tm) was increased with adding elastomer, e. g. Tm was increased by 12.5 times when the elastomer content reached 10 per cent. The toughening behavior of elastomer was mainly due to the increase of energy required against crack propagation. The study on morphology involved in the crack growth in the plane strain was carried out by scanning electron microscope. The results showed that the blunting and superblunting crack tip had occurred before the crack initiating and explained the reason why the toughness of the material was improved in the light of microstrucure.