Thermodynamics of 5,5-dimethylperhydro-1,3-oxazin-2-one, its polymerization in bulk and poly(5,5-dimethyl-2-oxo-1-oxa-3-azahexamethylene) between 0 K and 500 K

✍ Scribed by Boris Lebedev; Natal'ya Smirnova; Vadim Telnoy

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 908 KB
• Volume: 197
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1996.021971125

✦ Synopsis

Abstract

The thermodynamic properties of the six‐membered cyclic urethane, viz. 5,5‐dimethylperhydro‐1,3‐oxazin‐2‐one (DIO, 1) and the corresponding polymer, poly(5,5‐dimethyl‐2‐oxo‐1‐oxa‐3‐azahexamethylene) (PDIO, 2) were studied by calorimetry. The temperature dependence of the heat capacity at constant pressure C~p~^0^ of the monomer and the polymer was studied between 5 K and 500 K. Temperatures and enthalpies of physical transitions were determined. The energies of combustion of the above compounds were measured. From the results the thermodynamic functions C~p~^0^(T)–H^0^(O), S^0^(T) G^0^(T)–H^0^(O), were calculated for various physical states of the monomer and the polymer from 0 K to 500 K. The standard enthalpies of combustion Δ__H__~comb~^0^ and the thermochemical parameters of formation of DIO and PDIO were estimated at temperature T = 298,15 K and pressure p = 101,325 kPa. The zero entropy S~gt~^0^(O) and configurational entropy S~conf~^0^ of PDIO in the glassy state were evaluated. The thermodynamic parameters of the bulk polymerization of DIO were calculated in the range of 0 K to 400 K at standard pressure. It was established that an equilibrium of the polymerization reaction of DIO to PDIO is shifted towards the formation of the monomer in the whole temperature range studied from 0 K to 450 K.