Abstract
In this paper a simple method is proposed to carry out temperature-modulated calorimetry with multiple frequencies. The method is based on modulation with a complex sawtooth. The harmonics of the Fourier series of the measured heat-flow rate and temperature are used to extract data pertaining to the frequencies of the 1st, 3rd, 5th, 7th and 9th harmonic. The complex sawtooth produces similar modulation amplitudes of the temperature of the first four harmonics. In temperature-modulated differential scanning calorimetry with a period of less than about 150s, corrections by extrapolation to zero frequency are commonly needed. With the proposed method, these extrapolations can be done in a single experiment. Difficulties of baseline subtraction and other possible instrumentation and software problems are discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 181-190 |
| Number of pages | 10 |
| Journal | Thermochimica Acta |
| Volume | 348 |
| Issue number | 1-2 |
| DOIs | |
| State | Published - 28 Apr 2000 |
| Externally published | Yes |
Bibliographical note
Funding Information:This work was supported by the Division of Materials Research, National Science Foundation, Polymers Program, Grant No. DMR-9703692 and the Division of Materials Sciences, Office of Basic Energy Sciences, US Department of Energy at Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corp. for the U.S. Department of Energy, under contract number DE-AC05-96OR22464.
Keywords
- Fourier transformation
- Heat capacity
- Higher harmonics
- Sawtooth modulation
- Temperature-modulated differential scanning calorimetry (TMDSC)