Tuning the distribution of carbon nanotubes in styrene–acrylonitrile copolymer by a small amount of polycarbonate

In this study, we added a small amount of polycarbonate (PC), ranging from 1 to 9 wt%, to the composites of styrene–acrylonitrile copolymer (SAN) and multiwalled carbon nanotube (MWNT). When two types of SANs having 24 and 32 wt% AN (SAN24 and SAN32) were used, we found that the resistivity of the SAN/MWNT (0.5 wt%) composites significantly decreased with the addition of 1–3% of PC, and the effect was more pronounced in the case of SAN32. Transmission electron microscopy (TEM) images revealed that MWNTs, which were uniformly distributed on the pure SAN, tended to agglomerate and form an interconnected structure when an appropriate amount of PC was added. The reduced resistivity of the composites is mainly attributed to the connectivity of MWNTs facilitating electron transport. It is worth noting that the network structure disappears when the amount of PC exceeds 5 wt%, where the size of PC domains grows, and most of the MWNTs are entrapped in the PC phase, resulting in an increased resistivity of the composite. The rheological investigation of the composites revealed that the storage moduli of the composites were sensitive to the state of MWNT distribution, which was greatly altered by the type of SAN and the amount of PC.

Graphical abstract

Alteration of carbon nanotubes distribution in styrene–acrylonitrile due to the introduction of polycarbonate