Thermodynamic properties of polylactones

Temperature dependences of isochoric heat capacity, temperatures and enthalpies of physical transitions for polyglycolide, poly(B-propiolactone), poly(y-butyrolactone), poly(b-valero lactone), POlY(E-caprolactone), polyundecanolactone, polytridecanolactone, and polypentade canolactone were studied between 13,8 and (340-550)K in a vacuum adiabatic calorimeter within a limit of experimental error oC about 0,2070. From the results obtained the functions ¡¡O (T)-¡¡O (O), SO (T), and 00 (T)-¡¡O (O)were calculated over the range O to (340 -550)K. Zero entropy of glassy polymers, S~(O), and dífference in zero enthalpies of glassy and crystal líne s tates, !titO)-}{'j(0), were estimated also. Regularities of changes in thermodynamic prop erties of polylactones, in dependence of the number of atomic groups in a repeating unit, were found that made it possible to evaluate the properties oC sorne polylactones the corresponding experimental data of which are not known.