电晕极化提高油气管道3PE补口搭接区粘结强度的机理  

Corona Poling Mechanism Responsible for Increase of Adhesive Strength of Girth-Welded Zone of Three-Layer Polyethylene Coating Used for Oil and Gas Pipelines

作　　者：孙玉伟 赵勇强 傅骏雄 晏利君 王涛[1] 李海坤 

机构地区：[1]中国石油天然气管道局国内事业部,河北廊坊610500 [2]中国石油天然气管道局局机关,河北廊坊610500 [3]中国石油天然气管道局中油管道机械制造有限责任公司,河北廊坊610500 [4]中国石油天然气管道局油气输送安全国家工程实验室,河北廊坊610500

出　　处：《材料保护》2014年第11期20-22,7,共3页Materials Protection

摘　　要：对3PE(3层结构的聚乙烯)防腐蚀层聚乙烯表面进行电晕极化可以提高其粘接强度,为了解其改善机理,采用X射线光电子能谱仪分析3PE防腐蚀层电晕极化后的结构;采用差热扫描量热仪模拟PE表面羧基与环氧的缩合反应。采用热水浸泡研究了电晕极化前后聚乙烯的粘结效果。结果表明:通过电晕极化,聚乙烯表面生成了羧基、羟基等极性官能团,其中C,O,N元素的含量分别(原子分数)为75.8%,20.7%,3.5%,在含O官能团中,COH,C=O,CO(OH)所占比例(原子分数)分别为48.3%,20.8%,30.9%;羧基与环氧160℃开始发生反应,在235℃时可达到反应放热峰值;90℃热水浸泡7 d后,未电晕极化聚乙烯的粘结完全失效,环氧涂层出现部分脱落,而电晕极化聚乙烯的粘结强度仍保持7 MPa以上。Corona poling of the three- layer polyethylene(denoted as3PE) anticorrosion coating was conducted so as to increase its adhesive strength upon welding.The structure of the 3PE anticorrosion coating after corona poling treatment was analyzed by X- ray photoelectron spectroscopy,and the condensation reactions between carboxylic group and epoxy group on the surface of the 3PE coating were investigated and simulated with a differential scanning calorimeter.Moreover,the adhesive performance of the PE layer before and after corona poling treatment was examined with immersion tests in hot water,and the corona poling mechanism which was responsible for the increase of the adhesive strength of the welded joint of the 3PE coating was discussed.Results indicated that polar groups such as carboxyl and hydroxyl were generated on the surface of the3 PE coating after corona poling treatment,and these polar groups consisted of 75.8%C(atomic fraction;the same hereafter),20.7%0,and 3.5%N.Besides,O-containing groups including COH,C=0,and CO(OH) amounted to 48.3%,20.8%,and30.9%.The carboxvlic group and epoxy group started to reaction at 160 ℃,and the exothermal peak emerged at 235 ℃.Moreover,after being immersed in water at 90 ℃ for 7 d,the 3 PE coating without corona poling treatment underwent complete adhesive failure in association with detachment of the epoxy layer,but the same coaling after corona poling treatment exhibited an adhesive strength of above 7 MPa under the same testing conditions.

关 键 词：补口 电晕极化 聚乙烯 化学粘结 热水浸泡 粘结强度 机理 

分 类 号：TE973[石油与天然气工程—石油机械设备]