Thermodynamics of linear poly(pentamethylene urethane) and poly(hexamethylene urethane) in the range from 0 to 450 K

The thermodn. properties - the temp. dependence of heat capacity and the temps. and enthalpies of phys. transitions - of poly(pentamethylene urethane) and poly(hexamethylene urethane) have been studied over the range 6 to 450 K by precision adiabatic vacuum and dynamic calorimetry. Their energies of combustion, DcU, have been measured in a calorimeter with a static bomb and an isothermal shield. The calorimetric data were used to det. the temp. dependences of the heat capacity C0p=f(T) for poly(pentamethylene urethane) and poly(hexamethylene urethane) in cryst. and amorphous states, to calc. the thermodn. parameters of the glass transition and the glassy state, the thermodn. quantities of fusion and the thermodn. functions C0p(T), H0(T) - H0(0), S0(T) - S0(0) and G0(T) - H0(0) of the polymers for the temp. range from 0 to 450 K. The enthalpy of combustion DcH0 and the std. thermodn. characteristics of formation, namely, the enthalpy, DfH0, entropy, DfS0 and Gibbs function, DfG0, of the substances under discussion were estd. at T = 298.15 K. The regions of thermal resistance for the tested compds. were detd. calorimetrically.