Calorimetry of High Polymers. III. A New Type of Adiabatic Jacket and Calorimeter

This paper describes a new type of adiabatic jacket and a modified calorimeter designed especially for the measurement of the specific heats of high polymers in the range −20 to +300°C. New features of the adiabatic jacket include the use of two dissimilar metals to increase temperature uniformity and a new method of closing and controlling the temperature of the ends. Calibration data using Al2O3 had an average precision of ±0.07 percent, although the uncertainty in an individual measurement, while ±0.1 percent up to 160°C. may reach ±0.5 percent at 300°C. Further studies of the use of an alternating current watthour meter in calorimetry are reported.