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