光缆护套料用高密度聚乙烯/线型低密度聚乙烯的界面作用与流变行为

采用熔融共混法制备了光缆护套料用高密度聚乙烯(HDPE)/线型低密度聚乙烯(LLDPE)与HDPE/茂金属线型低密度聚乙烯(m-LLDPE)2种共混物,讨论了共混物HDPE/LLDPE和HDPE/m-LLDPE及中密度聚乙烯(MDPE)与铝塑带之间的热合强度,并研究了共混物的力学性能、松弛行为及组分间的相容性。研究结果表明,HDPE/LLDPE(7∶3)共混物与铝塑带热合强度最高(27.2N/cm);熔融状态下,低频区HDPE/LLDPE的lgG′-lgω与线性偏离,且松弛指数(λ)随HDPE含量增加先减小后增大,表明分子链缠结先增强再减弱,为非均相体系;HDPE/LLDPE只表现出1个熔融峰,表明共混物组分具有良好相容性;因分子界面多重叠,HDPE/LLDPE(7∶3)具有更小分散相尺寸(2.74nm)与更高界面层厚度(1.02nm),组分相容性最好,且与热熔胶乙烯-醋酸乙烯共聚物(EVA)的界面张力最小。可见,采用来源广、价格相对低廉的HDPE与LLDPE共混可实现替代MDPE制备光缆护套料。

Interfacial Action and Rheological Behavior of High Density Polyethylene/Linear Low Density Polyethylene for Cable Sheathing Materials

Two blends(HDPE/LLDPE and HDPE/m-LLDPE)used for cable sheathing were prepared by melt blending.The sealing strength between HDPE/LLDPE,HDPE/m-LLDPE blends,MDPE and aluminum-plastic tape,as well as the mechanical properties,relaxation behavior and compatibility between the components of the blends were investigated.The results show that the HDPE/LLDPE(7∶3)blend has the highest heat strength(27.2 N/cm)with the aluminum plastic strip;in the molten state,the lgG′-lgωof HDPE/LLDPE deviates linearly in the low frequency region,and the relaxation indexλdecreases first and increases with the increase of HDPE content,indicating that the molecular chain entanglement increases first and weakens then,presenting a heterogeneous system;HDPE/LLDPE blend only shows a melting peak,indicating good compatibility between the two components;due to the overlapping of molecular interfaces,HDPE/LLDPE(7∶3)which shows the lowest interfacial tension with EVA has the smaller dispersed phase size(2.74 nm)and the higher interfacial layer thickness(1.02 nm),indicating the best component compatibility.It can be seen that the use of a wide range of relatively inexpensive HDPE and LLDPE blends can be used to prepare cable sheathing materials instead of MDPE.