不同自然暴露方法对聚丙烯老化的影响

采用直接大气暴露、玻璃板下暴露和百页窗下暴露3种自然暴露方法，研究了聚丙烯塑料外观、力学性能和熔融指数在海南自然暴露过程中的变化，考察了光、热、氧对聚丙烯老化的影响。结果表明：自然环境下，光和热均是引起聚丙烯老化降解的主要因素．并且光的作用更强．氧对聚丙烯老化的影响很小：冲击强度对聚丙烯的老化相当敏感．海南自然暴露9个月时．直接大气暴露的聚丙烯试样冲击强度保持率下降至原始的10％左右。

Effect of Different Natural Exposure Tests on PP Weathering

Three natural exposure tests, direct exposure, under glass, and under shutter were used to study the change of appearance, mechanical and MI properties of PP during natural exposure in Hainan. The influence of daylight, heat, oxygen on PP was investigated. The results showed that in natural environment, light and heat were the main factors initiate PP weathering and the effect of light was stronger. There was little effect of oxygen on PP weathering. Impact strength was sensitive to PP weathering. After natural exposure for nine months in Hainan, the remaining rate of impact strength of PP using direct natural exposure test was reduced to about 10%.