Influence of lactic acid-grafted multi-walled carbon nanotube (LA-g-MWCNT) on the electrical and rheological properties of polycarbonate/poly(lactic acid)/LA-g-MWCNT composites

摘要

The effects of lactic acid-grafted multi-walled carbon nanotube (LA-g-MWCNT) on the electrical and rheological properties of the polycarbonate (PC)/poly(lactic acid) (PLA)/LA-g-MWCNT composite were studied. To increase dispersion of the conductive filler in the PC/PLA (70/30) blend, chemically-modified MWCNT, which is LA-g-MWCNT, was used as a compatibilizer between the conductive filler and polymers. For the PC/PLA/LA-g-MWCNT composite, the increased values of the electrical conductivity, electromagnetic interference shielding effectiveness, and complex viscosity were observed compared to those of PC/PLA/MWCNT composite. The results suggested that the increased dispersion of the LA-g-MWCNT in the PC/PLA (70/30) blend is caused by increased connectivity of the MWCNT-MWCNT network structure of the composite. The interfacial tension of the PLA/ MWCNT composite was lower than that of the PC/MWCNT composite. The lower value of interfacial tension of the PLA/MWCNT composite affected the dispersion of the MWCNT in the PLA phase (dispersed phase) more than in the PC phase (continuous phase). After hydrolysis, the PC/PLA/LA-g-MWCNT composite showed higher electrical conductivity than the PC/PLA/MWCNT composites. As a result, it is suggested that the increased dispersion of the LA-g-MWCNT in the PC/PLA blend has affected the increase in the electrical conductivity and lowering of the hydrolytic degradation of the PC/PLA/LA-g-MWCNT composite compared to the PC/PLA/MWCNT composite.