Thermal analysis of tertiary butyl alcohol/sucrose/water ternary system.
The purpose of this work is to investigate the freezing properties of tertiary butyl alcohol (TBA)/sucrose/water ternary system. Differential scanning calorimetry (DSC) is employed to determine the glass transition temperature of the maximally freeze-concentrated solution Tg' and the crystallization (or devitrification) temperature Tr. DSC measurements show that the presence of sucrose hinders the crystallization of TBA during cooling. The residual TBA in the glassy state will cause a decrease in Tg' and will crystallize during heating. An increase in the cooling rate causes a decrease in Tg'. For 10% TBA/10% sucrose/water ternary system, the critical heating rate is approximately 250 degrees C/min. Annealing treatment at temperatures below Tg' causes the crystallization of TBA, which indicates that TBA molecules still have appreciable mobility even at temperatures below Tg'. When the ratio of TBA to sucrose is less than 0.2, TBA cannot crystallize during cooling.
Zuo
Jian-Guo
JG
Institute of Cryomedicine and Food Freezing, Shanghai University of Science and Technology, Shanghai, China.
Hua
Tse-Chao
TC
Liu
Bao-Lin
BL
Zhou
Guo-Yan
GY
D002152:Calorimetry, Differential Scanning / Q000379:methods*; D003460:Crystallization; D004055:Differential Thermal Analysis; D005612:Freeze Drying; D013395:Sucrose / Q000032:analysis*; D013696:Temperature; D014867:Water / Q000032:analysis*; D020002:tert-Butyl Alcohol / Q000032:analysis*
D014867:Water; D013395:Sucrose; D020002:tert-Butyl Alcohol