Thermodynamics of Aliphatic Cyclic Urethanes, of Their Ring-Opening Polymerization, and of Corresponding Polyurethanes
| Autor: | B. V. Lebedev, Viktoria V. Veridusova, Helmut Keul, Hartwig Höcker |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
chemistry.chemical_classification
Standard enthalpy of reaction Condensation polymer Polymers and Plastics Bulk polymerization Organic Chemistry Polymer Condensed Matter Physics Heat capacity Ring-opening polymerization Standard enthalpy of formation chemistry Polymerization Polymer chemistry Materials Chemistry Physical and Theoretical Chemistry |
| Zdroj: | Macromolecular Chemistry and Physics. 203:1114 |
| ISSN: | 1521-3935 1022-1352 |
| DOI: | 10.1002/1521-3935(20020501)203:8<1114::aid-macp1114>3.0.co;2-p |
| Popis: | For some cyclic aliphatic urethanes (dimethylene urethane, trimethylene urethane, 2-methyltrimethylene urethane, 2,2-dimethyltrimethylene urethane, tetramethylene urethane) and the corresponding linear polyurethanes (poly(dimethylene urethane), poly(trimethylene urethane), poly(2-methyltrimethylene urethane), poly(2,2-dimethyltrimethylene urethane), poly(tetramethylene urethane)) the temperatur dependence of the heat capacity, C p 0 , were investigated in the range of 5-10 K to 300-450 K, and temperatures and enthalpies of physical transitions were determined at standard pressure. From the experimental data the standard thermodynamic functions, i.e. enthalpies H 0 (T)-H 0 (0), enropies S 0 (T), and Gibbs functions G 0 (T)-H 0 (0) were calculated in the range of 0 to 300-450 K for all compounds studied. The configuational entropies, S 0 conf , of the polymers in the glassy and partly crystalline state were estimated. The energies of combustion of the substances were determined experimentally and the standard enthalpies of combustion Δ comb H 0 and thermodynamic parameters of formation Δ f H 0 , Δ f S 0 , Δ f G 0 , were calculated at T = 298.15 K. The results obtained were used to calculate the standard thermodynamic parameters of ring-opening polymerization of cyclourethanes in bulk wtih in the range of 0 to 300-450 K. From the thermodynamic functions, the energies of combustion and the thermodynamic parameters of formation of cyclic monomers and polymers, and the dependence of the above properties on the chemical structure of the compounds were obtained. Estimations of the corresponding properties were made for the monomers and polymers not yet studied experimentally. |
| Databáze: | OpenAIRE |
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