高密度聚乙烯管材光氧老化性能及寿命预测

采用荧光紫外灯人工加速老化方法模拟自然太阳光对高密度聚乙烯（PE?HD）管材和热熔接头的光氧老化，在不同温度下（50、60、70 ℃），使用UVA?340型标准荧光紫外灯管在光照和冷凝2种循环模式下模拟老化，并利用傅里叶变换红外光谱仪（FTIR）对老化后的管材和接头试样进行了分析表征，通过差示扫描量热仪（DSC）测量了管材和接头的氧化诱导时间（OIT）。结果表明，随着老化时间的延长，接头的烯烃和羰基吸收峰强度高于管材，光氧老化程度加剧；随着温度和老化时间的增长，管材和接头的OIT不断降低，在同等条件下，管材的OIT高于接头；基于动力学曲线线性化方法拟合OIT和自然太阳光与荧光紫外灯辐照量关系，提出的PE?HD管材管件自然光老化的寿命预测模型显示，常温下暴露在自然环境下的接头的寿命比管材缩短了33.76 %。

Photo?oxidation Aging Performance and Life Prediction for High?density Polyethylene Pipe

An artificial accelerated aging method was adopted to simulate the photo?oxygen aging process of high?density polyethylene （PE?HD） pipes and butt fusion joints under the natural sunlight. A UVA?340 standard fluorescent ultraviolet lamp was used to simulate the aging process in the two cycle modes of light and condensation at different temperatures of 50 ℃， 60 ℃ and 70 ℃. Infrared spectroscopy was also conducted to analyze the chemical structures of the aged pipe and joint samples. The results indicated that with an increase in aging time， the joint showed higher peak intensity for the olefin and carbonyl absorption in the joint than that in the pipe due to the increase of the photo?oxidation aging degree. Meanwhile， the oxidation induction time of pipes and joints were measured with different aging time at different temperatures. The oxidation induction time and the relationship between natural sunlight and fluorescent ultraviolet lamp irradiation were fitted by means of the kinetic curve linearization method， and a life prediction model for the natural light aging of high?density polyethylene pipes was proposed. The results indicated that the lifespan of PE?HD butt fusion joints exposed to the natural environment was 33.76 % shorter than that of the pipes at room temperature.