| Autor: |
I.B. Rabinovich, B.V. Lebedev |
| Rok vydání: |
1979 |
| Předmět: |
|
| Zdroj: |
Polymer Science U.S.S.R.. 21:2234-2240 |
| ISSN: |
0032-3950 |
| DOI: |
10.1016/0032-3950(79)90162-x |
| Popis: |
By using the results to be found in the literature and our own about the temperature dependence of the heat contents of polymers, their melting temperature T m o , and enthalpy ΔH m o we estimated the difference in the zero enthalpies H g o (0) − H c o (0) of the glass-like and crystalline states of the examined polymers. From the found difference and the zero entropy S g o (0) of the polymer glasses published earlier we calculated the respective differences between the Gibbs energies G g o ( T ) − G c o ( T ) for the range from 0°K to the glass temperature T g o . The value of G g o (0) − G c o (0) was within the range 2–12 kJ·mole −1 for the various polymers; the temperature elevation from 0°K to T g o caused the latter to drop by a factor of 2. The enthalpy and Gibbs energy differences for polymer crystals and glasses chiefly depend on structural differences and those of the properties in these states; the part played by some degree of “tempering” of the polymer glass is relatively small. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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