Analysis of DSC thermal curves for assigning a characteristic glass transition temperature, dependent on either the type or thermal history of the polymer
- Solomat Ltd., Devon (United Kingdom)
DSC was used to study the thermal curve characteristics of four classical polymer glasses: polycarbonate (PC), anionic polystyrene (aPS), polysulfone, and polymethyl methacrylate (PMMA). The onset, peak, and fictive temperatures as well as endotherm characteristics were studied over two decades of heating and cooling rates. Assuming that the fictive temperature is independent of heating rate, the usefulness of T{sub onset} and ambiguity of T{sub peak} are demonstrated. The useful [heat/cool] ratio allows use of T{sub onset} to calculate the effective cooling rate of the sample (which is easier to calculate than T{sub fictive}). Comparison with results from annealed samples are shown. The fictive and onset temperatures can be used together to improve the reliability of glass temperature characterization and results are surprisingly constant between the four different types of glasses, leading to a method of providing a single temperature to characterize the thermal history/morphology using a DSC thermal curve. The peak temperature is nearly independent of thermal history, and so provides a characterization parameter that is insensitive to manufacturing and molding procedures.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 136466
- Report Number(s):
- CONF-930398-; ISSN 0066-0558; TRN: IM9552%%8
- Journal Information:
- American Society for Testing and Materials, Special Technical Publication, Journal Issue: 1249; Conference: American Society of Testing and Materials (ASTM) meeting on glass transition, Atlanta, GA (United States), 4-5 Mar 1993; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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