Experience with SC-DSC at Yoshida Laboratory

At Nanba laboratory, Professor Nanba was the predecessor of Professor Yoshida. A DSC apparatus was purchased with a Government subsidy for aiding scientific research in the early 1970 s. To determine the thermal decomposition characteristics of unstable substances, the literature was surveyed 1 in collaboration with S.Takeyama (Kinki University), then a student in the master s course of The University of Tokyo. As a result, DSC was found to be of very wide application. Moreover, a preliminary experiment showed that sealed cells were necessary for studying the decomposition reaction of self—reactive substances. For most self—reactive substances, evaporation or sublimation may occur before exothermic decomposition during DSC measurement made in an open cell at room temperature. This makes it impossible to measure an accurate heat of decomposition. 

Sealed cells were made on an experimental basis by K.Okawa (Okawa Seiki Co., Ltd.) 

1 1 the first was made of aluminium. Experiments with this cell showed that an interfering peak appeared and no clear-cut peaks due to the decomposition of a sample could be obtained. Next, a sealed cell was made of soft stainless steel. Clear-cut peaks could be obtained by the use of this cell. At this time, the pressure-proof property of the cell was found to be 4.5 1 MPa as determined from the temperature at which, when filled with water and then heated, it blew up. 

A study of the kinetics of thermal decomposition reactions using pentaerythritol tetranitrate(PETN), a high explosive, as the model substance was first conducted by SC-DSC. In this study, information was obtained that was relative to the characteristics of the DSC technique. However, the question as to how the results of analyses of this type were useful for practical work arose, and studies in this area were stopped. Subsequently, studies have proceeded on the evaluation of hazards by collecting as much data on self-reactive substances as possible. 

In the beginning, the authors made SC-DSC measurements on combination explosives R . The report on these measurements was translated into English at the U.S. Department of Energy. We have been consulted by several companies with respect to the evaluation of hazards of self—reactive substances. In these instances, we have inevitably referred to SC-DSC data. 

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