低温聚乙烯防护层专用料DMA性能研究

Dynanic mechanical analysis performance of low temperature polyethylene protective layer

为满足油气管道在高寒区域、冻土区的冬季施工需求,设计单位提出管道低温聚乙烯防护层专用料(LTPE)的技术要求,并规定用动态机械分析(DMA)测试防护层的玻璃化转变温度。对DMA测试方法和相关国际标准进行分析研究,并测试所开发的LTPE的玻璃化转变温度。研究发现,标准中玻璃化转变温度有多种取值方法,损耗模量曲线的峰值明显,建议选择该峰值温度Tloss值作为LTPE技术要求中的玻璃化转变温度;测试的2种采用超低温改性母粒的聚乙烯(LTPE)都能满足玻璃化转变温度≤-40℃的要求,而且2种母粒并用具有协同作用。

In order to meet the winter construction requirements of oil and gas pipelines in alpine regions and permafrost regions,the technical requirements of low temperature polyethylene(LTPE)are proposed by the designer.The technical requirements stipulate that the glass transition temperature of the protective layer shall be measured by dynamic mechanical analysis(DMA).In this paper,DMA test methods and related international standards are analyzed,and the glass transition temperature of the developed LTPE is measured.It is found that there are many methods to determine the glass transition temperature in the standards,and the peak value of the loss modulus curve is obvious.It is suggested that the value of peak temperature Tloss can be selected as the glass transition temperature in the LTPE technical requirements;the two kinds of ultra-low temperature modified master-batch LTPE can meet the requirements of glass transition temperature equal or below-40℃,and there is a synergistic effect of the two master-batches.