SEDL / STP / STP1402-EB / STP10704S

Obtaining Kinetic Parameters Using Modulated Temperature

Blaine, RL
Applications manager, TA Instruments, Inc., New Castle, DE

Pages: 14    Published: Jan 2001

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Abstract

Flynn and Dickens demonstrated in 1976 that continuous kinetic information may be derived from thermogravimetry profiles using a periodic temperature square wave signal. Blaine extended this approach to the sine wave. Extension of the sine wave approach to differential scanning calorimetry, however, requires consideration of the effects of the heat capacity heat flow, not present in thermogravimetry. The heat capacity term is always present and is theoretically 90° out of phase with the kinetic heat flow. Sine wave signals of the same period, however, add together to produce a sine wave of intermediate phase. To understand the effects of these mixed signals, a partial series of models is proposed for modeling pure crystalline and polymer melts on the way to a more complete understanding and measurement of kinetic parameters.