湿法改性HAp填充PLA复合材料的结构表征与性能测试

Structure Characterization and Performance Test of PLA Composites Filled with HAp by Wet Modified

以硬脂酸(HSt)为改性剂,采用湿法改性的方式,在高压反应釜中改性纳米羟基磷灰石(HAp),并将改性的HAp与聚乳酸(PLA)复合后挤出造粒-注塑加工成型。通过傅里叶红外光谱(FTIR)、激光粒度仪、X射线衍射仪(XRD)、扫描电镜(SEM)测试了HAp表面改性效果及PLA复合材料的微观结构,并通过热重(TGA)、微机控制热变形维卡软化试验机和万能电子拉力机测试了复合材料的热性能和物理机械性能。结果表明,通过高压反应釜的湿法改性,改性后HSt包覆在HAp的表面,HAp粒子直径增大; HSt改善了PLA与HAp的界面相容性,促进了结晶,细化了晶粒尺寸,使PLA复合材料从脆性断裂演变成韧性断裂;热变形温度、拉伸强度和冲击强度都明显增加。

Nano-hydroxyapatite( HAp) was modified by stearic acid( HSt) as modifier in a highpressure reactor by wet modification method. The modified HAp was compounded with polylactic acid( PLA)and extruded into granulation-injection moulding process. The surface modification effect of HAp and the microstructures of PLA composites were tested by Fourier transform infrared spectroscopy( FTIR), laser particle size analyzer,X-ray diffraction( XRD) and scanning electron microscopy( SEM). The thermal and mechanical properties of the composites were tested by thermogravimetric analysis( TGA),microprocessor controlled thermal deformation Vicat softening test machine and universal electronic tension machine. The results show that the diameter of HAp particles increases when HSt is coated on the surface of HAp by wet modification in autoclave. HSt improves the interfacial compatibility between PLA and HAp, promotes crystallization,refines grain size,and changes the PLA composites from brittle fracture to ductile fracture.The hot deformation temperature,tensile strength and impact strength increase significantly.