ANYL 145 |
| The liquid heat capacities Cp, of amorphous poly(lactic acid) PLA and partially liquid state of starch, starch-water have been computed as the sum of vibrational, external, and conformational contributions. The vibrational contribution was calculated as the heat capacity arising from group and skeletal vibrations. The external contribution was estimated from experimental data of the thermal expansivity and compressibility in the liquid state. The conformational heat capacity has been evaluated from a fit of experimental data to an Ising-like model for two discrete states, characterized by parameters linked to stiffness, cooperativity, and degeneracy. For the starch-water system the additional changes in the conformational heat capacity arise from the interaction of the carbohydrate chains with water in the whole region of temperature. The calculated liquid Cp with the solid Cp was employed in the quantitative thermal analysis of the experimental Cp of biodegradable polymer PLA, starch, and starch-water. |
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General Posters
7:00 PM-9:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Analytical Chemistry |