中国塑料 ›› 2020, Vol. 34 ›› Issue (8): 9-16.DOI: 10.19491/j.issn.1001-9278.2020.08.002

• 材料与性能 • 上一篇    下一篇

超声辅助双螺杆机制备高密度聚乙烯/超高分子量聚乙烯复合材料及性能研究

李彦晓, 张岩, 何雪莲()   

  1. 华东理工大学化工学院,多相结构材料化学工程重点实验室,上海 200237
  • 收稿日期:2020-02-10 出版日期:2020-08-26 发布日期:2020-08-26
  • 基金资助:
    国家自然科学基金面上项目(51573048)

Preparation and Performance of PE⁃HD/PE⁃UHMW Blends by Ultrasonic⁃assisted Twin⁃screw Extrusion

Yanxiao LI, Yan ZHANG, Xuelian HE()   

  1. China Shanghai Key Laboratory of Multiphase Material Chemical Engineering, School of Chemical Engineering East China University of Science and Technology, Shanghai 200237, China
  • Received:2020-02-10 Online:2020-08-26 Published:2020-08-26
  • Contact: Xuelian HE E-mail:hexl@ecust.edu.cn

摘要:

利用超声辅助双螺杆挤出机制备高密度聚乙烯(PE-HD)/超高分子量聚乙烯(PE-UHMW复合材料,并考察PE-UHMW含量对复合材料流变性能、结晶行为及力学性能的影响。结果表明,当PE-UHMW的含量不超过2.0 %(质量分数,下同)时,PE-UHMW在PE-HD基体内均匀分散,不存在相分离;由于PE-UHMW的相对分子质量非常大,分子链非常长,缠结程度大,其分子链松驰时间较长,有利于形成结晶前驱体,直至成核,随着PE-UHMW含量的增加,有利于成核,晶核数目明显增加,同时,PE-UHMW与PE-HD的缠结程度变大,约束了PE-HD分子链的运动,使其吸附于晶核心表面,分子链折叠排列形成结晶,最终复合材料体系的结晶度逐渐增大,片晶增厚;加入PE-UHMW后,复合材料的屈服强度、拉伸强度和断裂伸长率均明显提高。

关键词: 聚乙烯, 流变, 结晶动力学, 力学性能

Abstract:

Ultra high molecular weight polyethylene (PE-UHMW) and high density polyethylene (PE-HD) have a similar molecular composition and structure, and therefore they have relatively good compatibility. In this paper, the PE-HD/PE-UHMW blends were prepared by ultrasonic-assisted twin-screw extrusion, and the effect of PE-UHMW content on the crystallization behavior, compatibility and final mechanical properties of the blends was investigated. The results indicated that the PE-UHMW phase achieved a uniform dispersion without phase separation in the PE-HD matrix at the content lower than 2.0 wt%. As the content of PE-UHMW increases, there is a significant increase in nucleation number for the PE-UHMW domain, which is beneficial to crystallization. Moreover, the degree of entanglement also increases gradually with an increase of PE-HD content. This makes more PE-HD molecules involved in the chain?folding crystallization with the nucleus formed by PE-UHMW, leading to a gradual increase of crystallinity. As a result, the yield strength, breaking strength and elongation at break of the blends were improved significantly with an increase of PE-UHMW content.

Key words: polyethylene, rheology, crystallization kinetics, mechanical property

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