采用环境应力开裂速度测定仪对聚乙烯燃气管道料蠕变开裂性能的研究

Study on Creep Cracking Properties of PE Compounds Used for Fuel Gas Pipe Making with Polymer Environmental Stress Cracking Speed Tester

采用ＰＥＳＣ—１型高分子材料环境应力开裂速度测定仪研究了７种聚乙烯燃气管道料的蠕变开裂性能。Ｇａｓ－１是实用中的燃气管道料。Ｐｒｅ－１因其Ｂｅｌ法开裂时间大于１０００ｈ成为有待进一步评价的基础树脂。由Ｐｒｅ－１与各种色母料或改性剂配混成５种配混料：Ｐｒｅ－１０１、Ｐｒｅ－１０２、Ｐｒｅ－１０３、Ｐｒｅ－１０４和Ｐｒｅ－１０５。通过实验得到了开裂过程（即裂纹的增长量△ａ）与时间ｔ的关系。开裂过程含有一诱导期ｔｉ，然后是裂纹增长期，裂纹增长速度为ａ。ｔｉ和ａ可以表征材料的蠕变开裂性能。Ｋ１０＝０２ＭＰａｍ１／２时，Ｇａｓ－１的ｔｉ大于３４０ｈ，Ｋ１０＝０．３ＭＰａｍ１／２时，Ｇａｓ－１的ｔｉ和ａ分别为８５ｈ和００１１５ｍｍｈ－１。Ｐｒｅ－１的蠕变开裂性能远不如Ｇａｓ－１，在Ｋ１０＝０．２ＭＰａｍ１／２时的ｔｉ和ａ分别为７４ｈ和０．００７６ｍｍｈ－１，在Ｋ１０＝０．３ＭＰａｍ１／２时的ｔｉ和ａ分别为２４ｈ和０．０３２３ｍｍｈ－１。配混料中的色母料和改性剂使基础树脂Ｐｒｅ－１的蠕变开裂性能进一步降低。

The creep cracking properties of 7 PE compounds used for fuel gas pipe making were studied with PESC-1 polymer Environmental Stress Cracking Speed Tester G as _1 is the material in current practice of fuel gas pipe making P re -1 is the resin for further assessment because its cracking time by Bell method is more than 1000h Five compounds are prepared from P re -1 and color master batches or polymeric modifiers:P re -101,P re -102,p re -103,P re -104 and P re -105 The cracking history that is the relation of crack growth Δa and time t is obtainde from experiment There is an incubation period t and then a crack growth period with crack propagation speed in the cracking history, t i and are used for characterizing material′s creep cracking properties At initial stress intensity factor K 10 0.2 MPam 1/2 ,t i of G as -1 is more than 340h At K 10 = 0.3 MPam 1/2 , t i and of G as -1 are 85h and 0 0115mmh -1 respectively P re -1 is much wores than G as -1 in respect to creep cracking properties At K 10 =0.2MPam 1/2 , t i and of P re -1 are 74h and 0 0076mmh -1 respectively.At K 10 =0.3MPam 1/2 , t i and of P re -1 are 24h and 0.0323mmh -1 respectively The color master batches or polymeric modifiers in the compounds worsen the creep cracking properties of P re -1