The effect of an oxidative environment on HDPE morphology and mechanical performance were studied. Extruded HDPE film samples of thickness (~70 μm) (as-extruded and heat treated) were exposed to 5 ppm chlorinated water at 70 °C for up to 1250 h. As extruded samples had an initial crystallinity of 75% and heat treated samples an initial crystallinity of 83%. The initial molecular weight for all samples was approximately 200 kg-mol⁻¹. Changes in morphology and mechanical properties as a function of exposure time were evaluated. The most significant changes occur after 500 h exposure. Fourier-Transform Infrared Spectroscopy (FTIR) spectrum data indicate an increase in the carbonyl functional groups with increased exposure time. As the exposure time increased, the molecular weight (M_w) of the samples decreased, with M_w of the as extruded samples being consistently less than that of the heat treated samples. Crystallinity increased nearly linearly with exposure time. XRD data reveal that the interlamellar spacing decreases significantly between 500 and 750 h exposure, from 102 to 85 Å. Mechanical test data show a similar trend with tensile strength and strain at break. After exposure time of 500 h the samples become increasingly brittle. The combined morphology and mechanical data demonstrate, independent of exposure time, that there is a critical combination of molecular weight (<85 kg-mol⁻¹) and interlamellar spacing (<85 Å) corresponding to the transition from ductile to brittle behavior.

研究了氧化环境对HDPE形态和机械性能的影响。将厚度为（〜70μm）的挤压HDPE薄膜样品（挤压和热处理）在70°C的5 ppm氯化水中暴露长达1250小时。由于挤出的样品的初始结晶度为75％，而经热处理的样品的初始结晶度为83％。所有样品的初始分子量约为200 kg-mol ^-1。评估了形态和机械性能随暴露时间的变化。最显着的变化发生在暴露500小时后。傅里叶变换红外光谱（FTIR）光谱数据表明羰基官能团随暴露时间的增加而增加。随着曝光时间的增加，分子量（M _w）的样品减少，而挤压样品的M _w始终小于热处理样品的M _w。结晶度几乎随曝光时间线性增加。XRD数据显示，层间间距在暴露500到750小时之间从102到85Å显着减小。机械测试数据显示出类似的趋势，即抗张强度和断裂应变。暴露500小时后，样品变得越来越脆。组合的形态学和力学数据表明，与暴露时间无关，存在分子量（<85 kg-mol ^-1）和层间间距（<85Å）的关键组合，这对应于从延性到脆性行为的转变。