The Influence of Carbon Nanotubes Contents on Electrical and Flammability Properties of Poly(Lactic Acid)/Multiwalled Carbon Nanotubes Nanocomposites

摘要

The effects of carboxylic functionalized multi-walled carbon nanotubes (CNT) contents on electrical and flammability properties of poly(lactic) acid (PLA)/CNT nanocomposites were investigated. The PLA/CNT nanocomposites were prepared by melt-blending method, where the CNT contents were varied from 1 to 9 phr. From flammability properties analysis, nanocomposites with 9 phr CNT showed the highest limiting oxygen index (LOI) of 26.5 vol% as compared to 19.5 vol% of neat PLA. All nanocomposites with higher than 5 phr CNT contents also passed the VO class of UL-94 vertical burning test rating. The direct current electrical test revealed that the electrical conductivity increased by approximately seven orders of magnitude from 2.19 × 10~(-11) S/m of neat PLA to 2.00 × 10~(-4) S/m for PLA/CNT nanocomposites with 5 phr CNT contents. The electrical conductivity of PLA/CNT continues to increase beyond 5 phr contents, with 2.26 × 10~(-3) S/m and 4.29 × 10~(-3) S/m respectively for 7 and 9 phr contents. The good dispersion of CNT leads to formation of electron conducting CNT networks throughout the insulating PLA matrix.