1-己烯共聚双峰聚乙烯产品开发研究

The Development of Bi-modal Polyethylene Product Copolymerized with 1-Hexene

介绍了双峰聚乙烯发展现状,并对自主生产的1-丁烯共聚料与进口1-己烯共聚料进行对比,通过凝胶渗透色谱(GPC),差示扫描量热分析(DSC)和红外光谱(FTIR)等表征方法,研究微观结构上的差异,发现短支链的长度比短支链的数量对双峰聚乙烯牌号的抗慢性裂纹增长有着更为显著的影响,含有较长短支链和较短支链间链段的双峰聚乙烯拥有较好的抗慢性裂纹增长性能。基于此,提出高性能双峰高密度聚乙烯(HDPE)燃气管专用料质量指标:重均分子量(M_W)为200000~240000,共聚单体为C6及其以上α-烯烃,共聚单体含量(质量分数)为0.8%~2.5%,结晶度为50%~57%,分子量分布为15~35。同时进行了工业试生产,发现产品的耐慢速裂纹增长性能优异。

The development status of bimodal polyethylene was introduced and the self-produced 1-butene copolymer product was compared with the imported 1-hexene copolymer product.The microstructure difference was analyzed by gel permeation chromatography(GPC),differential scanning caborimetry(DSC),Fourier infrared spectroscopy(FTIR),and so on.It was found that the length of short branched-chain had a more significant effect on the anti-chronic crack growth of bimodal polyethylene than the number of short branched-chain.The bimodal polyethylene with longer branched-chain and shorter interbranched-chain segments had better anti-chronic crack growth performance.Based on this,the quality indexes of high-performance bimodal high density polyethylene(HDPE)gas pipe material were proposed:the weight-average molecular weight was 200000-240000,the comonomer was C6 orα-olefin with longer length,the content of comonomer was 0.8%-2.5%,the crystallinity was 50%-57%,and the molecular weight distribution was 15-35.The industrial trial production results showed that the product had excellent resistance to slow crack growth.