Thermal conductivity and heat capacity of liquid and glassy poly(vinyl acetate) under pressure

The dependence of thermal conductivity λ and heat capacity per unit volume pcp on temperature and pressure for poly(vinyl acetate) has been measured by a transient hot‐wire probe technique. The measurements were made under pressures up to 0.5 GPa over a temperature range of 270–470 K. The temperature coefficient of thermal conductivity (∂ lnλ/∂T)p was found to increase with pressure for both the liquid and the glassy state. The change in heat capacity per unit volume in the region of the glass‐transition temperature was found to decrease with increasing pressure. The Ehrenfest relation does not explain the variation of the pressure coefficient of the glass‐transition temperature.