Modification of Thermal Conductivity of PMMA and PC by making their Nanocomposites with Carbon Nanotubes

Abstract

PMMA and Poly carbonate (PC) are wonderful low cost materials which can be easily tailored and shaped. However they have poor mechanical, thermal and electrical properties which are required to be enhanced in several applications where along with high strength, a quick heat transfer becomes a necessity. Carbon nanotubes (CNT) are excellent new materials having extraordinary mechanical and transport properties. In this paper we report results of fabricating composites of varying concentrations of CNTs with PMMA and PC and measurements of thermal conductivity data by a simple transient heat flow. The samples in disk shapes of around 2 cm diameters and 0.2 cm thickness with CNT concentrations varying up to 10 wt percent were fabricated. By keeping one end of the discs at steam temperature, the temperature of the other end was noted for each sample after 10 s. The rise in temperature was correlated with thermal conductivity which was appropriately calibrated. We found that both PMMA and PC measured high thermal conductivity with increase in the concentration of CNTs. The thermal conductivity of PMMA rose from about 0.2 W/mK to 0.4 W/mK at 10 wtpercent of CNT whereas for PC, it rose from about 0.2 W/mK to 0.9 W/mK at 10 wt percent of CNT. It is thus observed that modification in thermal properties is easily achieved by making CNT based composites using only up to 10 wt percent of CNTs in PMMA and PC and enabling quicker heat dissipation in these materials.