Morphology and PTC behaviour of EVOH/CB and HDPE/CB Nanocomposite

초록

Poly (ethylene-co-vinyl alcohol)/carbon black (EVOH/CB) composites were prepared by solvent-casting and simple saponification method. The percolation threshold of the solvent-casted EVA/CB was about 20wt%. It can be observed that there is a dramatic decrease in resistivity at the CB content of 10wt% after 1h saponification time. SEM observation showed that an increase of VOH units would raise the filler particles segregate to the non-crystalline regions which results in forming new electroconductive pathway and lowering the resistivity of nanocomposites. Moreover, 1h-saponified EVA/CB composite almost resembles melt-mixed polyethylene (HDPE)/CB composite. 1h-saponified EVA and hot-pressed HDPE are covered with micro-voids that leave a dimple-like structure on the surface. As the percolation threshold is achieved, such as EVA/CB25-1h and HDPE/CB20, CB aggregates are usually located in oval cavities larger than the particles themselves. In this study, the morphology, electrical resistivity thermal and positive temperature coefficient (PTC) behavior of EVOH/CB and HDPE/CB composites system were evaluated.