Internal pressures and thermal pressure coefficients for solid polymers

The temperature and pressure dependence of the thermal pressure coefficient and internal pressure for eight polymer solids are calculated. The principal results are as follows: (1) The pressure dependence of the thermal pressure coefficient at constant temperature is relatively small. (2) For some solid polymers, as a function of temperature, a maximum in the thermal pressure coefficient is predicted in the solid region, and the temperatures corresponding to the maximum values are estimated. (3) For most solid polymers, the zeropressure internal pressure increases with increasing temperature over the entire temperature range to the glass transition temperature or the melting point. © 1995 John Wiley & Sons, Inc.