Temperature-modulated calorimetry of the frequency dependence of the glass transition of poly(ethylene terephthalate) and ....

Conference · Sat Mar 01 00:00:00 EST 1997

OSTI ID:459977

Wunderlich, B; Okazaki, I ^[1]

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1. Oak Ridge National Lab., TN (United States); Tennessee Univ., Knoxville, TN (United States). Dept. of Chemistry

Temperature-modulated differential scanning calorimetry, TMDSC, is new technique that permits to measure the apparent heat capacity vs modulation frequency. The method is briefly described and a quasi- isothermal measurement method is used to derive the kinetic parameters for PET and PS. A first-order kinetics expression was used to describe the approach to equilibrium and point out the limits caused by asymmetry and cooperativity of the kinetics. Use of a complex description of heat capacity and entropy is discussed. Activation energies vary from 75 to 350 kJ/mol, dependent on thermal pretreatment and the preexponential factor is correlated with the activation energy.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 459977
• Report Number(s): CONF-970443-3; ON: DE97002639; CNN: Grant MR-92-00520
• Resource Relation: Conference: 213. national meeting of the American Chemical Society, San Francisco, CA (United States), 13-17 Apr 1997; Other Information: PBD: [1997]
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
POLYESTERS
PHASE TRANSFORMATIONS
POLYSTYRENE
VITRIFICATION
AMORPHOUS STATE
KINETICS