PP／针形纳米CaCO_3复合材料的力学性能

Mechanical properties of PP/needle-like nano-CaCO_3 composites

用硬脂酸皂化改性针形纳米CaCO3表面后,将其与聚丙烯(PP)共混、挤出和注塑,制成PP／CaCO3纳米复合材料。与纯PP相比,填充针形纳米CaCO3的体积分数为4.21％时,PP体系的冲击强度和断裂伸长率分别提高了49％,339％,拉伸强度下降2．7％。改性后的纳米CaCO3与PP之间的界面作用与改性前相比有所减弱,冲击断面扫描电子显微镜照片显示,针形纳米CaCO3均匀地分散在PP基体中。偏光显微照片显示,针形纳米CaCO3对PP有明显的异相成核作用。

Composites consisting of polypropylene （PP） and needle-like nano-calcium carbonate （nano-CaCO3） superficially treated with sodium stearate were prepared by melt extrusion in a single screw extruder. When volume fraction of nano-CaCO3 attained 4.21%, the impact strength and elongation at break of the PP-based system increased by 49% and 339%, respectively, whereas its tensile strength lowered by 2.7%, compared with pure PP. The interfacial interaction between the modified nano-CaCO3 particles and PP matrix got weakened to a certain extent compared with its counterpart containing unmodified nano-CaCO3. The observation of impact fracture surface of the composites by scanning electron microscope verified that the nano-CaCO3 particles were dispersed homogeneously in the PP matrix. The polarized light microscopic photo confirmed the heterogeneous nucleation the nano-CaCO3 particles acted in the crystallization process of PP.