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研究了一种在轻质碳酸钙（Ｌ－ＣａＣＯ３）填料存在下可生成较大量β－晶的聚丙烯（ＰＰ）与Ｌ－Ｃａ－ＣＯ３热熔复合而得的复合材料的拉伸断裂行为。发现在Ｌ－ＣａＣＯ３含量为２０％～２５％时，复合材料具有较好的断裂韧性和比母体ＰＰ大得多的断裂伸长率（ε）。当Ｌ－ＣａＣＯ３先用二核铝酸酯处理再与上述ＰＰ复合，所得的复合材料在Ｌ－ＣａＣＯ３含量为１０％～２５％时的断裂韧性和ε又有显著增加。复合材料的ε随Ｌ－ＣａＣＯ３含量而变化的规律基本上与ＰＰβ－晶含量随Ｌ－ＣａＣＯ３含量而变化的规律一致。扫描电镜观察表明，ε较大的复合材料在拉伸过程中形成丝状结构。分析认为复合材料的ε的增加主要是在拉伸过程中在Ｌ－ＣａＣＯ３粒子平行于拉伸方向的两极首先发生脱粘空化，并引起在Ｌ－ＣａＣＯ３粒子表面和周围树脂基体的ＰＰβ－晶发生塑性形变的结果。
The tensile fracture behavior of a composite obtained by hot melt fusion of polypropylene (PP) and L-Ca-CO3 in the presence of light calcium carbonate (L-CaCO3) filler was studied. It is found that the composites have better fracture toughness and elongation at break (ε) which is much larger than that of matrix PP with L-CaCO3 content of 20% -25%. When L-CaCO3 was first treated with dinuclear aluminate and then compounded with the above-mentioned PP, the fracture toughness and ε of the obtained composite material increased remarkably when the content of L-CaCO3 was 10% ~ 25%. The variation of ε of the composite with the content of L-CaCO3 is basically consistent with that of the content of PPβ-crystallites with the content of L-CaCO3. Scanning electron microscopy showed that the larger ε composite formed filamentous structure during the drawing process. It is considered that the increase of ε in the composites is mainly due to the de-bonding cavitation occurring in the two poles parallel to the stretching direction of the L-CaCO3 particles during stretching and the PPβ-crystallites on the surface and surrounding resin matrix of L-CaCO3 particles Plastic deformation of the results.