聚丙烯/硅藻土复合材料断口形貌的二维分形特征研究

摘要

Two types of polypropylene (PP)/diatomate composites,PP/281 and PP/700,were prepared via melt blending,their impact strength (σⅣ) was evaluated by impact tests,and their fractography obtained from impact testing was observed by scanning electron microscopy.The profile curve of the fractography was extracted by an Image Pro-Plus image processing software,and their fractal dimension (DL) was calculated by a structure function method.The relationship between DL and σⅣ was investigated intensively.The results indicated that the fracture of PP and its composites with diatomate exhibit an evident fractal feature,and DL was in the range of 1.6474～1.7361,which could be used to characterize the fractography of PP/Diatomate composites quantitatively.PP/281 composites had a maximum DL of 1.7361 at a filling fraction (Φi) of 10 vol ％,whereas PP/700 composites showed a maximum DL of l.7143 at the Φi of 5 vol ％.The relationship between DL and σⅣ had a positive correlation and was exponential.%采用熔融共混法制备了2种硅藻土填充聚丙烯(PP/硅藻土)复合材料PP/281和PP/700,采用扫描电子显微镜观察了冲击断口形貌,运用图像处理软件IPP提取了复合材料断口形貌的二维轮廓曲线;应用结构函数法测算了断口形貌二维轮廓曲线的分形维数(DL),定量表征了复合材料的断口形貌特征;探讨了DL与复合材料冲击强度(σⅣ)的关系.结果表明,PP及其PP/硅藻土复合材料的断口形貌具有显著的分形特征,其中纯PP的DL值为1.6375,PP/硅藻土复合材料的DL值介于1.6474～1.7361之间;在所考察的硅藻土体积填充分数(Φi)范围内,PP/281复合材料的DL值在Φi为10％时有最大值1.7361,PP/700复合材料在Φi为5％时具有最大值1.7143;δIV值与DL值正相关,且呈近似指数函数关系.