PDF《Pure Appl. Chem., Vol. 72, No. 11,》

4 [22]. It is clearly shown that the thermal decomposition of this material proceeds by two-step mass loss, and when we see the DTA curve, it is much clearer because we can see two exothermic peaks. Even if we change the rate of heating, the nature of the two-step decomposition essentially does not change. However, when we observe the same decomposition process in the same atmosphere by SCTA, namely, sample-controlled TG (SCTG or CRTG), the results we obtained are quite different, as shown in Fig.

5 [22]. Because the temperature changes smoothly and does not change discontinuously to keep a constant mass loss rate, we can conclude that the decomposition proceeds by a single-step process. T. OZAWA ?

2000 IUPAC, Pure and Applied Chemistry 72, 2083C2099

2086 Fig.

3 EGA curves of thermal decomposition of two samples of poly(methyl methacrylate) under high vacuum [20]. The symbol i is the ion current. ?

2000 IUPAC, Pure and Applied Chemistry 72, 2083C2099 Temperature control modes in thermal analysis

2087 Fig.

4 TGCDTA curve of thermal decomposition of polyimide film in air flow by constant rate heating at

10 °C/min [21]. The temperature difference T by DTA is shown in an arbitrary unit. Fig.

5 SCTG curve of polyimide film in air flow obtained at mass loss rate of 0.06%/minC1 [21]. The temperature difference by DTA is also shown. To examine these contradictory results, kinetic........