高分子量PE-HD的添加对双峰聚乙烯抗熔垂性能的影响  

Effect of adding high molecular weight PE-HD on sag resistance of bimodal polyethylene

作　　者：金裕程 王璟璠 赵世成 JIN Yucheng;WANG Jingfan;ZHAO Shicheng(PeteoChina East China Chemicals Marketing Company,Shanghai 200122,China;Shanghai Key Laboratory of Multiphase Materials ChemicalEngineering,School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]中国石油天然气股份有限公司华东化工销售分公司,上海200122 [2]华东理工大学化工学院,上海市多相结构材料化学工程重点实验室,上海200237

出　　处：《工程塑料应用》2024年第9期154-159,共6页Engineering Plastics Application

摘　　要：针对管材用双峰聚乙烯抗熔垂性能不足,导致大口径厚壁管材壁厚尺寸不均的现象,首先应用高温凝胶渗透色谱仪表征了双峰聚乙烯的平均分子量、分子量分布以及短支链分布,对表征结果进行分析发现低分子量部分占比较大是影响双峰聚乙烯抗熔垂性能的重要原因。然后,应用熔体流动速率(MFR)仪、微量混合流变仪、旋转流变仪等研究了高分子量高密度聚乙烯(PE-HD)添加量对双峰聚乙烯抗熔垂性能的影响,同时研究了高分子量PE-HD的添加对双峰聚乙烯结晶熔融行为的影响。结果表明,平均分子量为80万的PE-HD的少量添加就能够明显降低双峰聚乙烯的MFR,提高其挤出加工过程的扭矩和熔体黏度,同时提高体系的零剪切黏度(η0)和松弛时间(λ),而MFR越低、η0和λ越高说明双峰聚乙烯的抗熔垂性能越好,因此实验结果表明高分子量PE-HD的添加能够有效改善双峰聚乙烯的抗熔垂性能。添加少量的平均分子量为80万的PE-HD会降低PE-HD100S的结晶峰值温度并提高其熔融峰值温度。上述研究结果能够对双峰聚乙烯的抗熔垂改性和管材应用起到一定的指导作用。According to the problems that the bimodal polyethylene for pipes exhibits insufficient sag resistance,leading to uneven wall thickness in large-diameter thick-walled pipes,firstly,the high-temperature gel permeation chromatography was employed to characterize average molecular weight,molecular weight distribution,and short-chain branch distribution of the bimodal polyethylene.By analyzing the characterization results,it was found that the significant proportion of low molecular weight fractions is a crucial factor affecting sag resistance of the bimodal polyethylene.Subsequently,a melt flow rate(MFR)tester,a micro compounder rheometer,and a rotational rheometer were used to investigate the effects of adding high molecular weight high density polyethylene(PE-HD)on sag resistance of the bimodal polyethylene,then the effects of the high molecular weight PE-HD on the crystallization and melting behaviors of the bimodal polyethylene were also examined.The results reveal that incorporating a small amount of PE-HD with an average molecular weight of 800000 substantially reduces the MFR of the bimodal polyethylene.This addition increases the torque and melt viscosity during extrusion processing and enhances the zero shear viscosity(η0)and relaxation time(λ)of the system.A lower MFR,coupled with higherη0 andλ,indicates sag resistance of the bimodal polyethylene is improved.Consequently,the experimental results demonstrate that the addition of high molecular weight PE-HD can effectively enhance the sag resistance of the bimodal polyethylene.The incorporation of a small amount of PE-HD with an average molecular weight of 800000 can lower the crystallization peak temperature of the bimodal polyethylene while increase its melting peak temper-ature.The results of above study provide valuable insights for sag resistance modification and pipe application of the bimodal poly-ethylene.

关 键 词：双峰聚乙烯 高温凝胶渗透色谱 抗熔垂性能 流变行为 结晶行为 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]