加工工艺对炭黑填充聚合物双基体复合材料导电性能的影响

Effect of Processing Technology on the Electrical Conductivity of Polymer Blends Filled with Carbon Black

制备了炭黑(CB)填充高密度聚乙烯(HDPE)/乙烯-醋酸乙烯酯共聚物(EVA)双基体复合材料,研究了加料顺序、混合时间对复合材料导电性能的影响.结果表明,CB主要分布在HDPE相中;采用CB首先填充EVA然后与HDPE混合,或采用EVA/HDPE共混物与CB混合的加工策略,均可获得导电性较优的导电复合材料.然而,混合过程显著影响CB填充双基体复合材料的导电性.采用EVA/HDPE共混物与CB混合法加工复合材料,导电性受相形态演化影响较小.

Effects of carbon black （CB） particle distribution, feeding sequence and blending time on the electrical conductivity of high density polyethylene （ HDPE ）/ethylene-vinyl acrylate copolymer （EVA） blends filled with CB were investigated by using scanning electron microscope （SEM） and transmission electron microscope（TEM）. The results reveal that CB particles distribute selectively in HDPE phase due to better flexibility of HDPE chains than that of EVA. Feeding order significantly influences the electrical conductivity of the composites by affecting the distributed status of CB particles in the two immiscible phases, i. e. HDPE phase and EVA phase. In order to gain high electrical conductivity, CB should be firstly added into EVA and then HDPE is added, or EVA and HDPE are initially blended uniformly and then CB particles are added. Blending time also has remarkable effect on the electrical conductivity of the composites. With the increase of blending time,the electrical resistivity of all the polymer composites with different feeding sequences decreases firstly and then increases. In later stage of blending, the electrical resistivity of HDPE/EVA-CB changes slightly with blending time compared with the other two blend systems. The phase morphology evolution dominates the conductivity of HDPE/CB-EVA during blending,however,distribution of CB particles dominates the conductivity of HDPE/EVA-CB. To achieve better electrical conductivity, appropriate feeding sequence and blending time should be adopted.