温度对微孔发泡PP和HDPE材料冲击性能的影响

通过对比微孔发泡PP、HDPE以及相应的未发泡PP、HDPE在不同实验温度下的Izod冲击强度,研究实验温度对微孔发泡PP、PE材料冲击性能的影响。结果表明:在实验温度范围内微孔发泡PP、HDPE以及相应的未发泡PP、HDPE相比较,随实验温度的降低,两者的Izod冲击强度的变化规律存在差异;通过对不同实验温度的冲击断口SEM分析,微孔对PP、HDPE冲击强度的作用机理为:一是裂纹扩展时微孔周围的树脂变形(及孔的变形)消耗能量,二是微孔的存在松弛了裂纹尖端应力集中,并会诱使主裂纹分解成次生裂纹,使裂纹扩展的方向和方式都发生变化,表现为裂纹扩展的阻力,三是微孔的引入减小了试样(材料)的有效承载面积。

The Effects of Testing Temperature on Impact Proterties of Micro-Foamed PP and HDPE

Influence of testing temperature on Izod notched impact properties of micro-foamed PP and micro-foamed HDPE was studied.The result show that the Izod notched impact properties of micro-foamed PP and micro-foamed HDPE with the different of testing temperature lead to different change of law.Through the impact fracture surface morphology at different temperature was observed and analyzed by SEM,disclosed micropores will lead to changes of materials on mechanism of deformation-fracture under applied impact force field.First,around micropores of resin deformation will absorb energy under crack propagation;second,micropores blunting the crack tip,at the same time,micropores induced main crack decompose secondary crack lead to change of direction and manner of crack spread,this increase drag power.Third,micropores will decrease effect of loading sectional area.