CIESC Journal ›› 2020, Vol. 71 ›› Issue (2): 871-878.DOI: 10.11949/0438-1157.20191196

• Material science and engineering, nanotechnology • Previous Articles     Next Articles

Effect of hard segment content on microcellular foaming process of thermoplastic polyether ester elastomer using supercritical CO 2 as blowing agent

Rui JIANG1(),Dongdong HU1,Tao LIU1,2,Ling ZHAO1,2()   

  1. 1.State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
    2.School of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046, Xinjiang, China
  • Received:2019-10-12 Revised:2019-12-26 Online:2020-02-05 Published:2020-02-05
  • Contact: Ling ZHAO

热塑性聚醚酯弹性体硬段含量对其超临界CO 2发泡行为的影响

蒋瑞1(),胡冬冬1,刘涛1,2,赵玲1,2()   

  1. 1.华东理工大学化工学院,化学工程联合国家重点实验室,上海 200237
    2.新疆大学化学化工学院,新疆 乌鲁木齐 830046
  • 通讯作者: 赵玲
  • 作者简介:蒋瑞(1991—),男,博士研究生, 030130876@mail.ecust.edu.cn
  • 基金资助:
    国家重点研发计划项目(2016YFB0302200)

Abstract:

Solid-state foaming process of TPEE composed of poly(tetra methylene glycol) (PTMG)“soft”blocks and poly(butylene terephthalate) (PBT)“hard”blocks using supercritical CO 2 (scCO 2) as the blowing agent was investigated. Plastic foams with average cell diameter of 2-17 μm and expansion ratio of 1-6 folds were prepared from TPEE. Three kinds of TPEE copolymers with different block ratio were used to investigate the influence of hard segment content on foaming behavior. The CO 2 dissolved into soft segments (PTMG) and hard segments (PBT) were carefully characterized by sorption process, meanwhile the gas diffusion coefficient was fitted from the Fick s diffusion law. The results show that the solubility and diffusivity of CO 2 in soft segments (PTMG) is significantly higher than that in hard segments (PBT). When the hard segment content rose from 29% to 65%, the melting point rose from 162.6℃ to 201.9℃ with a crystallinity rising from 20% to 40%. TPEE copolymers were foamed in a high-pressure chamber by using scCO 2. The effect of temperature and block ratio on the cell morphology was investigated. It was found that the content of hard segment had great influence on the solid-state foaming process. With higher hard segment content, the processing window was broadened and shifted to higher temperature.

Key words: polymer processing, supercritical carbon dioxide, foam, elastomer, crystallization

摘要:

研究了以聚对苯二甲酸丙二醇酯(PBT)为硬段,聚四氢呋喃醚(PTMG)为软段的热塑性聚醚酯弹性体(TPEE)在超临界CO 2作用下的固态发泡行为,考察了硬段含量的差异对结晶行为,CO 2在TPEE中溶解度及扩散行为,以及固态发泡行为的影响。发现硬段含量的差异对TPEE结晶行为影响尤为显著,当硬段含量由29%上升到65%时,其熔点从162.6℃上升至201.9℃,且结晶度由20%上升到40%。结晶的存在抑制了CO 2在基体内的溶解度且阻碍了其在基体内的扩散。由不同硬段的TPEE中CO 2溶解度和扩散过程的变化可知,CO 2更倾向于溶解在TPEE软区内,而由结晶为主构成的硬区中CO 2溶解量较低。通过研究高压CO 2环境下的TPEE等温结晶过程发现,经扩散进入TPEE软区内的CO 2可以提升TPEE链段运动能力,诱导未结晶链段通过规整堆叠而结晶。在CO 2压力15 MPa经快速降压发泡聚醚酯弹性体,发现随着硬段含量的增加,其温度发泡窗口向高温区移动,当硬段含量为29%时,发泡温度区间为50~160℃,平均孔径4.6~16.5 μm,泡孔密度8.1×10 7~7.5×10 8cells/cm 3,发泡倍率1.1~5.8;当硬段含量为65%时,发泡温度区间为165~195 ℃,平均孔径1.8~6.8 μm,泡孔密度2.6×10 8~1.1×10 11 cells/cm 3,发泡倍率1.0~4.2。

关键词: 聚合物加工, 超临界二氧化碳, 泡沫, 弹性体, 结晶

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