导电炭黑改性PE-RT抗静电复合材料的形貌与性能

以耐热聚乙烯(PE-RT)管材料为基体,以乙烯-醋酸乙烯共聚物(EVA)载体导电炭黑母粒(记作CBE)为导电介质,配以3.86wt%的聚乙烯-辛烯共聚弹性体(POE),采用双螺杆挤出工艺制备了具有导电网状结构形貌的PE-RT抗静电管材料,降低了复合体系的逾渗阈值,并将其与添加导电炭黑(记作CB)的体系进行对比,研究了CB/PE-RT和CBE/POE/PE-RT复合体系的导电性能、微观形貌、流变性能、力学性能及热稳定性能。结果表明:POE和EVA可以产生协同作用,POE的加入改变了PE-RT与EVA的黏弹性差异,EVA在基体中达到逾渗而形成连续的网络结构。CB优先分散在黏度低、极性较高的EVA相中,且POE能够抑制CB由EVA相向PERT相的迁移,CB在EVA相中容易达到逾渗,最终由于双逾渗作用而形成导电网络结构。CB能够提高PE-RT的结晶性能及CBE/POE/PE-RT复合体系的热稳定性能,且CB对CBE/POE/PE-RT复合体系的力学性能影响较小,在一定程度上解决了目前填充型导电体系中导电性能与力学性能之间的矛盾,并且POE对复合体系起到了增塑作用,保持了PE-RT管材可弯曲的优点,拓展了塑料管材的应用范围。

Morphology and properties of PE-RT antistatic composites modified by conductive carbon black

Using heat-resistant polyethylene (PE-RT) pipe materials as matrix, conductive carbon black master batch (remarked as CBE) carried by ethylene-vinyl acetate copolymer (EVA) as conductive medium, with 3.86wt% of polyethylene-octene copolymer elastomer (POE), via twin-screw extrusion process, PE-RT antistatic pipe material with conductive mesh structure was prepared, reducing the percolation threshold of composite system, and comparing it to system with addition of conductive carbon black (remarked as CB) to study the electrical properties, morphology structure, rheological properties, mechanical properties and thermal stability in CB/PE-RT and CBE/POE/PE-RT composite system. The results show that it produces a synergistic effect between POE and EVA, the addition of POE changes the differences of viscoelastic between PE-RT and EVA, so that EVA reaches percolation to form a continuous network structure in matrix, and CB disperses preferentially in EVA phase with low viscosity, higher polar, POE plays an inhibitory effect on migration of CB from EVA phase to PE-RT phase, then CB reaches percolation in EVA phase easily. Finally it forms a conductive network structure because of dual role of percolation. CB improves the crystallization property of PE-RT and thermal stability of CBE/POE/PE-RT composite system, and CB has little effects on the mechanical properties of CBE/POE/PE-RT composite system, to a certain extent, it solves the contradiction between conductivity and mechanical properties of filled-type conductivity systems. POE has a plasticizing effect on composite system, maintaining the advantages of PE-RT pipes that can be bent, expanding the application scope of plastic pipe.