摘要
高密度聚乙烯(HDPE)管道轻便、坚固、耐用,因此广泛应用于替代老化管道。应用同步辐射X射线衍射和散射技术,深入研究两种HDPE的结晶度、片层取向、长周期和取向因子。分析了聚合物分子结构对HDPE结构和性能的影响,并进行原位剪切实验以研究双峰和单峰HDPE样品的剪切诱导结晶。研究表明,所有样品都形成了离散的初级片层和次级片层,且双峰HDPE中的次级片层生长速度高于单峰HDPE。剪切易导致HDPE产生沿着剪切方向的取向,并提高其结晶度。剪切后,双峰HDPE具有比单峰HDPE样品更高的片层取向,且双峰HDPE具有相对较高的结晶度。具有短支链(SCB)的大部分中等高分子量(MMW)分子链易受剪切诱导形成结晶核。
High-density polyethylene （HDPE） pipes are light, strong, extremely tough and very durable, and therefore have widespread applications in water pipeline to replace aging pipeline. In this paper, synchrotron radiation X-ray diffraction and scattering techniques were applied to intensively study crystallinity, lamellae orientation, long period and orientation of HDPE. The effect of polymer molecular structure on the structure and properties of HDPE were analyzed. In situ shear experiments were pertormed to study the shear-induced crystallization of bimodal and unimodal HDPE samples. It was found that discrete primary lamellae and secondary lamellae are formed in all samples. The secondary lamellae grow taster in bimodal HDPE than in unimodal HDPE. Shear generally results in oriented lamellae along the shear direction and enhances the crystallization. After shear, the bimodal HDPE has higher lamellar orientation than the unimodal HDPE samples, whereas the bimodal HDPE has relatively higher crystallinity. It is revealed that large fractions of medium-high molecular weight （MMW） chains with short chain branching（SCB）are effective to generate shear-induced nuclei.
作者
高苏闽
刘亚涛
HSIAO S Benjamin
邵惠丽
张耀鹏
GAO Su-min;LIU Ya-tao;HSIAO S Benjamin;SHAO Hui-li;ZHANG Yao-peng(State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China;Institute of New Energy Material Chemistry, School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University, Tianjin 300350, China;Department of Chemistry, Stony Brook University, New York 11790, USA)
出处
《上海塑料》
2018年第1期53-58,共6页
Shanghai Plastics
基金
上海市曙光人才计划(15SG30)
