柔性复合管内衬材料耐介质性能研究

Dielectric resistance of lining material of flexible composite pipe

研究了耐油聚乙烯(PE)和PE100级高密度聚乙烯(简称PE100)的相对分子质量及其分布、结晶度、氧化诱导时间、力学性能、微观组织形态等。使用70%(w)正庚烷、20%(w)环己烷和10%(w)甲苯组成的有机混合液浸泡24 h,对比分析了浸泡前后两种材料的结构与性能。结果表明:耐油PE的相对分子质量低,呈相对分子质量分布为11.63的宽峰分布,且高相对分子质量部分含量更高,PE100的相对分子质量高,呈双峰分布;耐油PE的结晶度为49.53%,氧化诱导时间为52.46 min;浸泡后,耐油PE晶区占比有所升高,尺寸变化率仅为PE100的50%,平均质量变化率增加0.97%,屈服应力从22.41 MPa增至22.44 MPa,增加了0.13%,断口形貌兼具韧窝和层状结构,浸泡后耐油PE保持更好的完整性,表现出更优的耐介质侵蚀性能。

The relative molecular mass and its distribution,crystallinity,oxidation induction period,mechanical properties and microstructure of oil-resistant polyethylene(PE)and high density polyethylene PE100 were investigated.The structure and properties of the materials were compared before and after soaking in organic mixture of the mass fration of 70%of heptane,20%of cyclohexane and 10%of toluene for 24 h.The result show that the molecular mass of oil-resistant PE is lower,presenting a wide peak distribution with an index of 11.63,and the proportion of high molecular mass components is higher.The molecular mass of PE100 is higher,presenting a bimodal distribution.Oil resistant PE has a higher crystallinity of 49.53%and a longer oxidation induction period of 52.46 min.The proportion of oil-resistant PE crystal area increases after soaking,whose size change rate is only 50%of that of PE100,whose average mass change rate increases by 0.97%,whose yield strength increases by 0.13%from 22.41 MPa to 22.44 MPa,whose fracture morphology is both dimple and lamellar structure.The oil-resistant PE keeps better integrity after soaking,representing better resistance to dielectric erosion.