Material degradation has marked impact on the long-term properties and service life of membrane structures. This study is aimed at assessing and understanding the deterioration in visual aspect, surface microstructure, and mechanical properties of a polyvinylidene fluoride (PVDF) polymer after engineering applications. Three groups of PVDF-coated fabrics were removed from different membrane structures in China, which have been used for 15, 16, and 19 years, respectively. Firstly, spectrocolorimetry tests were carried out to determine the evolution of chromaticity and lightness. Other methods such as contact angle and thickness measurements were used to characterize the physical properties. Then, surface morphology was observed by using scanning electron microscope (SEM) technology. Moreover, a series of uniaxial tensile tests and tearing tests were performed to obtain the mechanical indicators including uniaxial tensile strength, strain at break, tearing strength, and uniaxial elastic modulus. In order to further study the degradation mechanism, infrared spectroscopy was used to characterize the molecular structure of aged fabrics. Finally, Principal Component Analysis (PCA) provided a comprehensive description of correlations between surface microstructure, physical properties, and mechanical properties. This paper offers a further understanding of the design, qualification, and durability evaluation of membrane structures.

中文翻译：

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工程应用后PVDF涂层织物的降解：基于统计分析的表面微观结构、物理性能和机械性能之间的相关性

材料降解对膜结构的长期性能和使用寿命有显着影响。本研究旨在评估和理解工程应用后聚偏二氟乙烯 (PVDF) 聚合物在视觉方面、表面微观结构和机械性能方面的劣化。从我国不同的膜结构中取出三组PVDF涂层织物，分别使用了15年、16年和19年。首先，进行分光色度测试以确定色度和亮度的演变。其他方法如接触角和厚度测量用于表征物理性质。然后，使用扫描电子显微镜（SEM）技术观察表面形貌。而且，进行一系列单轴拉伸试验和撕裂试验，得到单轴拉伸强度、断裂应变、撕裂强度、单轴弹性模量等力学指标。为了进一步研究降解机理，采用红外光谱表征老化织物的分子结构。最后，主成分分析 (PCA) 提供了表面微观结构、物理性能和机械性能之间相关性的全面描述。本文提供了对膜结构的设计、鉴定和耐久性评估的进一步理解。红外光谱用于表征老化织物的分子结构。最后，主成分分析 (PCA) 提供了表面微观结构、物理性能和机械性能之间相关性的全面描述。本文提供了对膜结构的设计、鉴定和耐久性评估的进一步理解。红外光谱用于表征老化织物的分子结构。最后，主成分分析 (PCA) 提供了表面微观结构、物理性能和机械性能之间相关性的全面描述。本文提供了对膜结构的设计、鉴定和耐久性评估的进一步理解。