Thermodynamics of depolymerization of biotechnological poly[(R)-3-hydroxybutyrate] with formation of (R,R,R)-4,8,12-trimethyl-1,5,9-trioxadodeca-2,6,10-trione and of its polymerization with ring-opening to highly isotactic poly[(R)-3-hydroxybutyrate] from 0 to 500 K at standard pressure

✍ Scribed by Boris V. Lebedev; Tat'yana A. Bykova; Elena G. Kiparisova; Valery G. Vasil'yev

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 1002 KB
• Volume: 197
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1996.021970431

✦ Synopsis

Abstract

In adiabatic vacuum and dynamic calorimeters the temperature dependence of the heat capacity C of (R,R,R‐4,8,12‐trimethyl‐1,5,9‐trioxadodeca‐2,6,10‐trione a twelve‐membered cyclic trilactone), biotechnological poly[(R)‐3‐hydroxybutyrate] and highly isotactic poly[(R)‐3‐hydroxybutyrate] was studied between 5 K and 500 K; temperatures and enthalpies of melting of the above mentioned substances were measured. In a calorimeter with a static bomb and an isothermal shield the energy of combustion of the same substances was measured. From the results the thermodynamic functions C (T), H^0^(T) − H^0^ (0), S^0^ (T), G^0^ (T) − H^0^ (0) were calculated in the range of 0 K to 500 K and thermochemical parameters Δ__H__, Δ__H__, Δ__S__, Δ__G__ were estimated at T = 298,15 K and standard pressure. The thermodynamic parameters of depolymerization of the biotechnological polymer to the 12‐membered trilactone Δ__H__, Δ__S__ Δ__G__ and of the polymerization of the monomer formed in the highly isotactic poly[(R)‐3‐hydroxybutyrate] Δ__H__, Δ__S__, Δ__G__ were calculated for 0 K to 500 K.