Measurement of Thermal Conductivity Using TMDSC: Solution to the Heat Flow Problem SINDEE L. SIMON* Department of Chemical Engineering University of Pittsburgh Pittsburgh, PA 15261 GREGORY B. McKENNA* Polymers Division NIST Gaithersburg, MD 20899 *Current Address: Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409 ABSTRACT: The dependence of the apparent heat capacity obtained from quasi-isothermal temperature-modulated differential scanning calorimetry (TM DS C) experiments and the thermal conductivity is determined for several cases. The relationships are based on the solution of the heat conduction equation which gives the temperature profile in the TM DS C sample. The temperature profile is then used to calculated the sinusoidal heat flow to the sample. We compare our results with those of other researchers. We also show the effect of thermal resistance on the results. INTRODUCTION EMPERATURE-MODULATED DIFFERENTIAL SCANNING calorimetry (TMDSC) is a new technique in thermal analysis in which a sinusoidal temperature per- turbation is used. The purported advantages of TMDSC include the ability to sepa- rate overlapping phenomena, as well as improved resolution and sensitivity.[1] There are problems associated with the interpretation of TMDSC data, especially when nonlinear processes, such as melting, reaction, or structural recovery [2,3] are involved. Thermal lag in the sample also presents problems for quantitative analysis of the heat capacity in TMDSC data since the apparent heat capacity de- ________________ Preprint: J. Reinforced Plastics and Composties, Vol. 18, No. 6, pp. 559-571 (1999).