Thermal Properties of Single Walled Carbon Nanotube-Silicone Nanocomposites JU XU, KAFIL M. RAZEEB, SAIBAL ROY Tyndall National Institute, Lee Malting, Prospect Row, Cork, Ireland Received 14 March 2008; revised 10 June 2008; accepted 11 June 2008 DOI: 10.1002/polb.21519 Published online in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: The effect of single walled carbon nanotube (SWCNT) fillers on the low temperature thermal properties and curing behavior of SWCNT-silicone nanocompo- site are reported for the first time. The SWCNT-silicone composites were prepared by different mixing procedures and characterized by differential scanning calorimetry (DSC). Solution mix, with the aid of sonication and soaking achieved better disper- sion of SWCNTs in the silicone. The adding of SWCNTs in polymer seriously hin- dered the curing of silicone elastomer. The hindrance increased with increasing con- centration of SWCNT and the quality of dispersion. The glass transition tempera- tures (T g ) of the nanocomposites were found to be independent of the SWCNT addition, although, the steps in the heat capacity (Dc p ) of the glass transition were smaller with increasing SWCNTs concentration. The melt crystallization behavior was strongly dependent on the concentration and dispersion of SWCNT in the poly- mer. The cooling scan showed that the higher concentration and the better dispersion of SWCNTs in the silicone resulted in higher percentage of melt crystallization of this nanocomposite. The correlation of the change of thermal properties to the disper- sion of CNT in polymer may be used to determine the quality of SWCNT dispersion in silicone polymer. V V C 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1845– 1852, 2008 Keywords: crystallization; curing of polymers; differential scanning calorimetry (DSC); dispersions; heat capacity INTRODUCTION For many years, silicone has been widely used in applications such as sealant, adhesive, lubricant, and medical implant, due to its advanced proper- ties of good flexibility, low surface tension, excel- lent electrical properties, good weatherproofing ability, nonflammability, high gas permeability, as well as their stability toward heat and chemicals. However, unfilled silicone elastomer usually has poor mechanical and low electrical/thermal con- ductive properties. 1 Inorganic fillers such as fumed or precipitated silica, carbon black, boron nitride have normally been used to improve the above properties. 2–4 Recently, great interests have been shown on carbon nanotube (CNT) as a poly- mer composite filler due to its advantages of small size, high aspect ratio and particularly high me- chanical, electrical and thermal properties. 5 The combined advantages of CNTs as a filler and sili- cone as a matrix may bring multifunctional prop- erties such as high electrical/thermal conductivity properties, high flexibility, thermal stability and chemical resistivity into this nanocomposite, which is difficult to obtain using traditional in- organic fillers or other polymer matrix. 6–8 So far, most of the works published using CNT filled Journal of Polymer Science: Part B: Polymer Physics, Vol. 46, 1845–1852 (2008) V V C 2008 Wiley Periodicals, Inc. Correspondence to: K. M. Razeeb (E-mail: kafil. mahmood@tyndall.ie) 1845