56 56 Volume 50 Issue 1 July 2011 Pages 56-60 International Scientific Journal published monthly by the World Academy of Materials and Manufacturing Engineering © Copyright by International OCSCO World Press. All rights reserved. 2011 Measurement of heat capacity and thermal conductivity of HDPE/expanded graphite nanocomposites by differential scanning calorimetry I. Tavman a, *, Y. Aydogdu b , M. Kök b , A. Turgut a , A. Ezan a a Mechanical Engineering Department, Dokuz Eylul University, 35100 Bornova Izmir, Turkey b Department of Physics, Faculty of Arts and Sciences, Fırat University, 23169 Elazıg, Turkey * Corresponding author: E-mail address: ismail.tavman@deu.edu.tr Received 19.04.2011; published in revised form 01.07.2011 ABSTRACT Purpose: In this study, heat capacity and thermal conductivity of nanocomposites formed by high density polyethylene (HDPE) matrix and expanded graphite (EG) conductive filling material were investigated. Design/methodology/approach: Nanocomposites containing up to 20 weight percent of expanded graphite filler material were prepared by mixing them in a Brabender Plasticorder. Two grades of expanded graphite fillers were used namely expanded graphite with 5 μm (EG5) and 50 μm (EG50) in diameter. Heat capacity and thermal conductivity of pure HDPE and the nanocomposites were measured using differential scanning calorimetry (DSC). Findings: A substantial increase in thermal conductivity was observed with the addition of expanded graphite to HDPE. Thermal conductivity increased from 0.442 W/m.K for pure HDPE to 0.938 W/m.K for nanocomposites containing 7% by weight of expended graphite. Heat capacity increases with the increase in temperature for both pure HDPE and the nanocomposites filled with expanded graphite and no appreciable difference in the values of heat capacity were detected due to particle size. Heat capacity decreased with increasing graphite particle content for both particle size, following the low of mixtures. Practical implications: Layers of expanded graphite have become of intense interest as fillers in polymeric nanocomposites. Upon mixing the expanded graphite intercalates and exfoliates into nanometer thickness sheets due to their sheet-like structure and week bonds normal to the graphite sheets. That way they have very big surface area and high aspect ratio (200-1500) what results in a formation of percolating network at very low filler content. The nanoparticles usage results in significant improvement in thermal, mechanical, and electrical properties of polymers even with very low loading levels compared with microparticles. Originality/value: To see the effect of conducting fillers on thermal conductivity and heat capacity two different sizes of expanded graphite were used. Keywords: Conductive nanocomposites; Expanded graphite; HDPE; Heat capacity; Thermal conductivity Reference to this paper should be given in the following way: I. Tavman, Y. Aydogdu, M. Kök, A. Turgut, A. Ezan, Measurement of heat capacity and thermal conductivity of HDPE/expanded graphite nanocomposites by differential scanning calorimetry, Archives of Materials Science and Engineering 50/1 (2011) 56-60. TECHNICAL PAPER