Liquid‐sensing behaviors of carbon black/polypropylene and carbon nanotubes/polypropylene composites: A comparative study

Liquid‐sensing behaviors of carbon black (CB)/polypropylene (PP) and carbon nanotubes (CNTs)/PP‐conductive polymer composites (CPCs) were studied in detail. It was found that the CB/PP showed a higher liquid‐sensing intensity but a poorer reproducibility toward the “good solvent” xylene. The main origin is that the conductive works formed by CB, the zero‐dimensional filler, are vulnerable to the swelling effect of PP during the immersion‐drying runs (IDRs), whereas CNTs in the CNTs/PP with a large aspect ratio have better capacity in maintaining the conductive networks. To investigate the influence of the remaining solvent on the evolution of conductive networks, liquid‐sensing tests of the two composites after long‐term immersion in xylene were investigated. Results showed that the liquid‐sensing behaviors of CNTs/PP changed less weakly compared with that of the CB/PP. Liquid‐sensing behaviors of the two composites, cyclohexane and tetrachloromethane, to the “poor solvents” were also studied. The results of this article indicate that liquid‐sensing behaviors of the CPCs were affected by the microstructure of the conductive filler, the solubility parameter, and the molar volume of the solvent significantly. POLYM. COMPOS., 36:205–213, 2015. © 2014 Society of Plastics Engineers