Abstract

Natural weathering was performed in a Saharan region to characterize its effect on low-density polyethylene (LDPE) films used for greenhouse coverings. The morphological changes, followed by differential scanning calorimetry (DSC), showed that the damages caused by the oxidation of tie molecules increased the lamellae thickness, its distribution and the crystallinity. Wide-angles X-ray diffraction (WAXD) was used to follow both the structural and morphological changes of the film. The WAXD crystallinity increase had the same trend as that determined by DSC. Field emission scanning electron microscopy (FESEM) of the films surfaces and cross-sections showed that the degradability increased with exposure time. Atomic force microscopy (AFM) analysis was used to evaluate changes in the surface morphology and roughness. Ageing caused a change of the surface topography of the LDPE films as observed by the increase of surface roughness which is indicated by the increase of the roughness parameters. Simultaneously the peaks-spacing \(\bar {d}\) decreased.

中文翻译：

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自然风化的低密度聚乙烯薄膜的氧化老化和结构表征

摘要

在撒哈拉沙漠地区进行了自然风化，以表征其对用于温室覆盖物的低密度聚乙烯（LDPE）薄膜的影响。形态变化，然后用差示扫描量热法（DSC），表明由键分子氧化引起的破坏增加了薄片的厚度，其分布和结晶度。广角X射线衍射（WAXD）用于跟踪薄膜的结构和形态变化。WAXD结晶度增加的趋势与DSC测定的趋势相同。薄膜表面和截面的场发射扫描电子显微镜（FESEM）表明，降解能力随曝光时间的增加而增加。原子力显微镜（AFM）分析用于评估表面形态和粗糙度的变化。如通过表面粗糙度的增加所观察到的，老化引起LDPE膜的表面形貌的改变，这由粗糙度参数的增加所指示。同时峰间距\（\ bar {d} \）减少了。