The Glass Temperature and the Specific Heat of Apiezon N and T Greases

Abstract

The frequent use of Apiezon grease as a thermal bonding agent at cryogenic temperatures has led to interest in its physical properties [¹]. Westrum, Chou, Osborne, and Flotow [²] have carried out heat-capacity measurements on a 32.54-g sample of Apiezon T grease. Their results reveal a broad anomaly in the temperature range 205 to 320°K. In a recent note on the specific heat of Apiezon N grease, Bunting, Ashworth, and Steeple [³] have also reported a broad anomalous region (see Fig. 1). Their results disclose a foothill extending from 200 to 260°K and a peak which has a maximum value at about 296°K. It is the purpose of this paper to comment on the specific-heat anomalies and to present evidence that the upturn in the specific heat of Apiezon N and T greases is associated with the glass transition [⁴] temperature T _g.

Work supported by the Aerospace Research Laboratories, Office of Aerospace Research, United States Air Force, Contract No. F33615–67-C-1027.