The thermal decomposition of di-tert-butyl peroxide (DTBP) was investigated with a differential scanning calorimeter (DSC) and a high sensitivity calorimeter (C80) in this report. DTBP is one of the organic peroxides and used as standard sample of the accelerating rate calorimeter. The heat of reaction of the DTBP/toluene solutions with various mass and concentrations were examined with the DSC. The relationship between the sample mass of various DTBP concentrations and the converted heat of reaction of pure DTBP per one gram (ΔHconvd) was examined. The ΔHconvd values of the small mass were larger than the values of the large mass when the samples from 5 wt% to 20 wt% of DTBP concentration were measured. The similar tendency of ΔHconvd was obtained in the C80 measurements. When the sample mass was almost constant in the DSC measurement, the measured ΔHconvd value decreased against the increase of DTBP concertation. The reduction rate of ΔHconvd of small sample mass was larger than that of large sample mass. The ΔHconvd value should be constant though the sample mass and concentration were changed. It is considered that the decomposition reaction of the vapor generated from DTBP/toluene solution occurred in the sample vessel of the DSC and C80. The ratio of the free volume in the sample vessel against the sample volume is introduced to explain the ΔHconvd values of various mass and concentrations measured with the DSC and the C80. It is elucidate that the reaction of vapor of DTBP/toluene solution plays important role in the thermal decomposition.
differential scanning calorimeter, high sensitive calorimeter, heat of reaction, thermal decomposition