Thermodynamic properties of polylactones

Temperature dependences of isochoric heat capacity, temperatures and enthalpies of physical transitions for polyglycolide, poly(β‐propiolactone), poly(γ‐butyrolactone), poly(λ‐valerolactone), poly(ε‐caprolactone), polyundecanolactone, polytridecanolactone, and polypentadecanolactone were studied between 13,8 and (340 – 550) K in a vacuum adiabatic calorimeter within a limit of experimental error of about 0,2%. From the results obtained the functions H 0 – H 0 (O), S 0 ( T ), and G 0 ( T ) – H 0 (O) were calculated over the range 0 to (340 – 550) K. Zero entropy of glassy polymers, S g 0 (O), and difference in zero enthalpies of glassy and crystalline states, H g (O) – H c 0 (O), were estimated also. Regularities of changes in thermodynamic properties of polylactones, in dependence of the number of atomic groups in a repeating unit, were found that made it possible to evaluate the properties of some polylactones the corresponding experimental data of which are not known.