基于应变硬化与微观结构相关性的PE管材耐慢速裂纹扩展性能研究

摘要

Slow crack growth (SCG) resistance is an important indicator for life time of polyethylene (PE) pipes in gas and water supply industry.Strain hardening modulus of PE100RC and PE100 specimens were calculated by strain hardening test method,and the correlation between strain hardening modulus and micro-structural parameters,such as weight average molecular weight,molecular weight distribution,comonomer content and type,lamella thickness,were studied for better understanding and evaluating of SCG resistance of PE pipes.The results show that compared to the other microstructural parameters,there is a more obvious relationship between comonomer type,lamella thickness and SCG resistance.The evaluation of SCG resistance can be improved by combining strain hardening characterization and microstructure parameters.The characterization of strain hardening and microstructure parameters of PE100RC are better than PE100,therefore the SCG resistance of PE10ORC is better.%对于应用于燃气和给水行业的聚乙烯(PE)管材,耐慢速裂纹扩展(SCG)性能是评价其是否能够长期服役的重要指标.采用应变硬化试验法得到PE100RC和PE100管材试样的应变硬化模量,并对其与重均分子量、分子量分布、共聚单体含量及类型、片晶厚度等微观结构参数之间的相关性进行研究,以期更为准确地理解和评价PE管材耐慢速裂纹扩展性能.结果表明,相对于其他微观结构参数,共聚单体类型和片晶厚度与PE管材的耐慢速裂纹扩展性能之间有更加明显的相关性;结合应变硬化模量与微观结构参数对PE管材慢速裂纹扩展性能进行评价可以提高其结果的准确性;PE100RC在应变硬化与微观结构参数表征上都比PE100表现得更优异,PE100RC具有更加优良的耐慢速裂纹扩展性能.