特殊形态结构导电高分子复合材料的电学性能

先使聚丙烯接枝马来酸酐(PP-g-MAH)与炭黑(CB)反应,再与聚丙烯/尼龙6(PP/PA6)共混制备出CB位于两相界面处的PP/PA6/PP-g-MAH/CB导电高分子复合材料,研究了材料的特殊结构和电学性能。结果表明,在PP/PA6/CB体系中CB粒子分布在PA6相,体系的逾渗阈值为2%;而在PP/PA6/PP-g-MAH/CB体系中,CB被PP-g-MAH诱导分布在两相界面处。PP/PA6两相为海岛结构时,PP/PA6/PP-g-MAH/CB体系仍可导电。PP/PA6/PP-g-MAH/CB体系的逾渗阈值降至1.6%,低于PP/PA6/CB体系。体系的正温度效应(PTC)强度远高于PP/PA6/CB体系,在90-135℃范围内不出现负温度效应(NTC)。PP/PA6/PP-g-MAH/CB体系的电学性能归结于其特殊的界面形态结构:导电通道由位于共混物界面处的PP-g-MAH和CB构建而成。

Electrical Properties of Conductive Polymer Composites With Special Morphology

The maleic anhydride grafted polypropylene(PP-g-MAH) was first reacted with carbon black(CB) and then blended with polypropylene/nylon6(PP/PA6) to prepare the PP/PA6/PP-gMAH /CB composites.The special morphology and electrical properties of the composites were investigated. The results show that in PP/PA6/CB blends,CB preferentially localizes in the PA6 phase and the percolation threshold is 2%.However,in the PP/PA6/PP-g-MAH/CB blends,CB particles can be induced by PP-g-MAH to localize at the interface.The composites of PP/PA6/PP-g-MAH/CB have conductivity even when PA6 and PP phases form sea-island morphology.The percolation threshold of PP/PA6/PP-g-MAH/CB is 1.6%,which is lower than that of PP/PA6/CB.Moreover,the PTC(positive temperature coefficient) intensity of PP/PA6/PP-g-MAH/CB composites is stronger than that of PP/PA6/CB,and the negative temperature coefficient(NTC) effect was eliminated within the temperature range of 90 and 135℃.The electrical properties of PP/PA6/PP-g-MAH/CB can be explained in terms of its special interface morphology:PP-g-MAH and CB localize at interface to form the conductive pathways.