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Thermodynamics of Aliphatic Cyclic Urethanes, of Their Ring‐Opening Polymerization, and of Corresponding Polyurethanes
Author(s) -
Lebedev Boris,
Veridusova Viktoria,
Höcker Hartwig,
Keul Helmut
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20020501)203:8<1114::aid-macp1114>3.0.co;2-p
Subject(s) - polymer , standard enthalpy of formation , polymerization , monomer , heat capacity , chemistry , polymer chemistry , thermodynamics , atmospheric temperature range , gibbs free energy , materials science , organic chemistry , physics
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 temperature dependence of the heat capacity, C 0 p , 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), entropies 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 configurational 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 with 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.