THE THERMODYNAMICS OF HEPTANAL POLYMERIZA TION AND POLYHEPTANAL IN THE TEMPERATURE-RANGE 0 - 380-K AT NORMAL-PRESSURE

Temperature dependence of heat capacity of polyheptanal was studied us ing an adiabatic vacuum calorimeter in the temperature range 5 - 340 K and using an automated differential calorimeter in the temperature ra nge 300 - 380 K. Thermodynamic parameters of physical transformations of the polymer were obtained. Using this data, we calculated the therm odynamic functions of the polymer in the temperature range 0 - 375 K. The enthalpy of complete depolymerization of polyheptanal in acetic ac id and the enthalpy of mixing of monomers with acetic acid were measur ed with an automatic differential calorimeter. Based on the calorimetr y measurements and the published data on thermodynamic properties of h eptanal, the enthalpy, entropy, and the Gibbs function were calculated for the process of bulk polymerization in the temperature range 0 - 3 80 K and at p = 101325 kPa. The upper limiting temperatures are estima ted at which polymerization of liquid monomer yields crystalline and e lastic polymers.