HDPE/竹粉复合材料的界面演变及流变特性

Rheological properties and interface evolution of high density polyethylene/bamboo flour composites

采用扫描电子显微镜-X射线能谱仪跟踪硅烷偶联剂中Si元素在高密度聚乙烯(HDPE)基竹塑共混体系界面处的分布,并结合旋转流变仪研究了共混体系加工过程中的界面演变过程。发现随着加工时间的延长,界面处Si元素的含量相对增加,体系的动态模量、黏度升高。表明偶联剂连接的竹粉与HDPE分子链间的相互作用增强,界面层厚度增加。共混体系的动态流变测试结果表明,竹粉填充体系在低频末端区的线性黏弹行为显著不同于HDPE基体,表现出"类固体"特性,动态流变测试对偶联剂的加入所引起的体系的黏弹行为及结构变化响应较敏感。Cole-Cole曲线可反映竹粉粒子网络结构及竹粉与HDPE基体界面相关的松弛信息,体现体系界面性质及竹粉与分子链间网络结构的变化。

The interface evolution of high density polyethylene(HDPE)/bamboo flour composites processing were investigated through tracking the distribution of silicon with scanning electronic microscope-X-ray energy dispersive spectrometer(SEM-EDS),and evolution of interface was studied during the process of blending system combining with rotational rhemometer. It is founded that the content of interface silicon and dynamic modulus and viscosity increase with processing time. These phenomena reflect the increase of interaction between bamboo flour and HDPE molecular-chains and interface layer thickness. The rheological results show that viscoelastic behavior of blends are significantly different from that of HDPE matrix at lower frequency and exhibit the"solid-like"rheological behavior. It is suggested that dynamic rheological testing is sensitively response for the changes in morphologies and viscoelastic behavior of blends which resulted by the addition of silicon coupling agent. The relaxation information about interface evolution and interaction between bamboo flour and matrix can be characterized by Cole-Cole curve.