Reprint of "Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry"

The heat capacity (C-P) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the C-P values are now reported for the wide 5-600 K range. The experimental C-P of solid sucrose at 5-300 K was used to calculate the vibrational, solid C-P based on the vibrational molecular motions. The calculated solid and liquid C-P together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (T-m) of the crystalline sucrose was identified in a broad 442-465 K range with a heat of fusion of 40-46 J/mol determined at heating rates 0.5-20 K/min, respectively. The equilibrium T-m and heat of fusion of crystalline sucrose were estimated at zero heating rate as T-m(o) = 424.4K and Delta H-f(o) = 32 kJ/mol, respectively. The glass transition temperature (T-g) of amorphous sucrose was at 331 K with a change in C-P of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that T-m was 483 K and T-g was 364K. Superheating effects were observed during the melting with the maximum value around 46K at 1000 K/s. (C) 2014 Elsevier B.V. All rights reserved.