Polyethylene (PE), a common thermoplastic polymer, is gaining prominence in the construction and packaging industries due to its exceptional mechanical properties, chemical resistance, safety, and integrity. However, internal defects can occur during manufacturing and throughout its service life. Neglecting this problem results in the disposal of plastic and, consequently, the accumulation of plastic waste and environmental issues, which have caused much criticism. A common method to repair the thermoplastics is welding, which introduces seams and localized thermal residual stress fields resulting in areas where damage can nucleate, potentially leading to cracks and failure over time. These cracks often start at the nanoscale and propagate to larger length scales until failure occurs. The objective of this research paper is to develop welding processes, with improved integrity and lifespan for PE. Additionally, it aims to investigate and assess the impact of PE welding on parent materials at nano- and micron-scales, to understand limitations that are challenging to overcome in such welding processes. The study involves joining PE panels together under various pre-heating and post-cooling conditions, followed by evaluating the environmental stress cracking resistance of the welds and the durability of the repaired components. The crystallinity and morphology of the PE material in the weld area and its surrounding regions were analysed using Small Angle X-ray Scattering (SAXS), and the findings were compared with results obtained from optical microscopy and Differential Scanning Calorimetry. The study concludes that SAXS results offer exceptional information about the parent PE and weld material within the welding zone.

中文翻译：

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使用小角 X 射线散射表征焊接聚乙烯的纳米结构

聚乙烯 (PE) 是一种常见的热塑性聚合物，由于其卓越的机械性能、耐化学性、安全性和完整性，在建筑和包装行业中越来越受到重视。然而，在制造过程中及其整个使用寿命期间可能会出现内部缺陷。忽视这个问题会导致塑料的处置，从而导致塑料废物的积累和环境问题，引起了很多批评。修复热塑性塑料的常用方法是焊接，它会引入接缝和局部热残余应力场，从而导致损坏可能成核的区域，随着时间的推移，可能会导致裂纹和失效。这些裂纹通常从纳米尺度开始，并传播到更大的长度尺度，直到发生故障。本研究论文的目的是开发焊接工艺，提高 PE 的完整性和使用寿命。此外，它还旨在研究和评估 PE 焊接对纳米和微米尺度母材的影响，以了解此类焊接工艺中难以克服的局限性。该研究涉及在各种预热和后冷却条件下将 PE 板连接在一起，然后评估焊缝的耐环境应力开裂性和修复部件的耐久性。使用小角 X 射线散射 (SAXS) 对焊接区域及其周围区域的 PE 材料的结晶度和形貌进行了分析，并将结果与​​光学显微镜和差示扫描量热法获得的结果进行了比较。研究得出结论，SAXS 结果提供了有关焊接区域内母体 PE 和焊接材料的特殊信息。