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首页> 外文期刊>Journal of Polymers and the Environment >Mechanism of Microstructural Change of High-Density Polyethylene Under Different Outdoor Climates in China
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Mechanism of Microstructural Change of High-Density Polyethylene Under Different Outdoor Climates in China

机译：不同户外气候下高密度聚乙烯微观结构变化的机理

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摘要

This work aims to understand the microstructural change mechanism of high-density polyethylene (HDPE) exposed at five national standard natural exposure stations (at Qionghai, Ruoqiang, Lhasa, Qingdao, and Hailar) for four years, which represented the five typical climates over China. It was found that the natural weathering of HDPE was the synergistic result of multi-factors such as temperature, irradiation, oxygen, etc. Based on the carbonyl index, the degradation degree in decreasing order was Ruoqiang, Qionghai, Lhasa, Qingdao and Hailar, but the microstructural change mechanism of HDPE was similar. The molecular structure was modified and mass molecular defects formed such as carbonyl and hydrogen groups during the degradation. The new freed molecular chains released from the amorphous region self-nucleated, and then formed new imperfect crystals because of the suppression of molecular defects. With the deposition of molecular defects, the chemi-crystallization ceased. Positron annihilation lifetime spectroscopy indicated the free volume hole shrank continually with exposure time mainly due to the interaction between molecular defects, and a part of amorphous region transformed into crystalline region by chemi-crystallization. In addition, the crystallization and re-melting behavior of degraded HDPE samples had been investigated in order to promote the recycling of waste degraded polymer materials. The results indicated that the crystalline temperature and the second melting temperature decreased with exposure time.
机译：这项工作旨在了解在五个国家标准的自然暴露站（琼海，若梁，拉萨，青岛和海拉尔）暴露的高密度聚乙烯（HDPE）的微观结构变化机制四年，这代表了中国五大典型气候。结果发现，HDPE的自然风化是基于羰基指数的温度，辐照，氧等等多因素的协同结果，降低秩序下降的降解程度是瑞强，琼海，拉萨，青岛和海尔尔，但HDPE的微观结构变化机制相似。分子结构被修饰，在降解期间形成羰基和氢基团的质量分子缺陷。新的释放分子链从无定形区域释放自核，然后由于抑制分子缺陷而形成了新的缺陷晶体。随着分子缺陷的沉积，Chemi结晶停止。正电子湮没寿命光谱表明，通过分子缺陷之间的相互作用和通过化学结晶转化为结晶区域的非晶区域的相互作用，通过曝光时间连续地表明自由体积孔浓缩。此外，研究了降解的HDPE样品的结晶和再熔化行为，以促进废物降解聚合物材料的再循环。结果表明，结晶温度和第二熔化温度随暴露时间而降低。

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  • 来源
    《Journal of Polymers and the Environment》 |2020年第10期|2616-2630|共15页
  • 作者

    Tao Xinyu; Xiong Jian; Liao Xia; Zhu Jingjun; An Zhu; Yang Qi; Huang Yajiang; Li Guangxian;

  • 作者单位

    Sichuan Univ Coll Polymer Sci & Engn State Key Lab Polymer Mat Engn Chengdu 610065 Sichuan Peoples R China;

    Sichuan Univ Coll Polymer Sci & Engn State Key Lab Polymer Mat Engn Chengdu 610065 Sichuan Peoples R China;

    Sichuan Univ Coll Polymer Sci & Engn State Key Lab Polymer Mat Engn Chengdu 610065 Sichuan Peoples R China;

    Sichuan Univ Inst Nucl Sci & Technol Minist Educ Key Lab Radiat Phys & Technol Chengdu 610064 Sichuan Peoples R China;

    Sichuan Univ Inst Nucl Sci & Technol Minist Educ Key Lab Radiat Phys & Technol Chengdu 610064 Sichuan Peoples R China;

    Sichuan Univ Coll Polymer Sci & Engn State Key Lab Polymer Mat Engn Chengdu 610065 Sichuan Peoples R China;

    Sichuan Univ Coll Polymer Sci & Engn State Key Lab Polymer Mat Engn Chengdu 610065 Sichuan Peoples R China;

    Sichuan Univ Coll Polymer Sci & Engn State Key Lab Polymer Mat Engn Chengdu 610065 Sichuan Peoples R China;

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  • 原文格式 PDF
  • 正文语种 eng
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  • 关键词

    High-density polyethylene; Natural weathering; Microstructural change; Free volume; Positron annihilation lifetime spectroscopy;

    机译：高密度聚乙烯;自然风化;微观结构变化;自由体积;正电子湮没寿命光谱;

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