University of Connecticut |
Polymer Program SeminarQuantitative DSC and TMDSC of Polymers Friday, March 5, 2004 11:00 am , IMS Room 20 All started with differential thermal analysis, DTA, in 1904. DTA was qualitative in the measurement of heat, but quantitative in temperature. Differential scanning calorimetry, DSC, became popular in the 1970s. In certain temperature regions it has replaced the cumbersome adiabatic calorimetry, but much published work with the DSC was unfortunately not more quantitative than done by the old DTA. The new temperature-modulated DSC, TMDSC, was invented in 1992. It adds temperature modulation to the DSC so that reversible processes can be identified, a key information for thermodynamics. With the new data analysis based on simple computer programs, TMDSC can make very precise heat determinations as function of heating and cooling rates (frequency). It, unfortunately, seems to follow the same fate in producing qualitative data instead of quantitative ones, despite being able to distinguish equilibrium from nonequilibrium. Today one can answer many questions one might have wanted to ask in 1900 as long as one follows the simple steps to quantitative DSC and TMDSC. Most interesting are the study of the third phase in semicrystalline polymers, the rigid-amorphous Fraction, RAF, and the observation of a reversible crystallization and melting within the global, metastable, nanophase-separated structure.
This seminar series is sponsored by generous grants from U.S. Surgical Corporation and Rogers Corporation. |