THERMODYNAMICS OF 2,2-DIMETHYLTRIMETHYLENE CARBONATE, OF ITS BULK-POLYMERIZATION PROCESS AND OF POLY(2,2-DIMETHYLTRIMETHYLENE CARBONATE) FROM 0 TO 470 K AT STANDARD PRESSURE

In the present work the thermodynamic properties of 2,2-dimethyltrimet hylene carbonate (DTC) and poly-2,2-dimethyltrimethylene carbonate (PD TC) were studied by precise calorimetry. In adiabatic and dynamic vacu um calorimeters the temperature dependence of the heat capacity of DTC and PDTC was studied between 5 and 470 K. Temperature and enthalpies of physical transitions were determined, and in an isothermal calorime ter energies of combustion of the above compounds were measured. From the results the thermodynamic functions C-p(o)(T), H-o(T)-H-o(O), S-o( T), G(o)(T)-H-o(O) were calculated for various physical states of the monomer and the polymer from 0 to 470 K. The standard enthalpies of co mbustion and thermochemical parameters of formation Delta H-f(o), Delt a S-f(o), Delta G(f)(o) of the objects studied were estimated at T = 2 98,15 K and p = 101,325 kPa. The zero entropy S-gl(o)(O) and configura tional entropy S-conf(o) of of PDTC in the glassy state and the differ ence in zero enthalpies of the polymer in the glassy and crystalline s tates H-gl(o)(O)-H-cr(o)(O) were estimated. The results were used to c alculate the thermodynamic parameters of the bulk polymerization of DT C (Delta H-pol(o), Delta S-pol(o), Delta G(pol)(o)) in the range of 0 to 420 K. It was established polymerization of DTC that for the proces s DTC --> PDTC, Delta G(pol)(o) < 0 if the polymer is crystalline and Delta G(pol)(o) > 0 in the case of amorphous PDTC (glassy or liquid). The ceiling temperature is T-c(o) = 500 K.