利用冻干显微镜研究了溶液冷冻干燥过程中降温速率、升华压力、溶液质量分数对干燥层塌陷温度Tc的影响,采用差示扫描量热法测量了溶液的玻璃化转变温度Tg′。实验结果表明,对于10%蔗糖/水二元溶液,降温速率虽然能改变冰晶大小,但对塌陷温度没有明显的影响。而对于10%叔丁醇/10%蔗糖/水三元溶液,Tg′和Tc均随降温速率增大而显著降低。压力对塌陷温度影响不大。溶液质量分数不同,塌陷温度略有变化。
Freeze-drying microscopy was used to investigate the effect of freezing rate,pressure and mass fraction on the collapse temperature(Tc) during freeze-drying of aqueous solutions,and differential scanning calorimetry was used to investigate the glass transition temperature(T′g) of the maximally freeze concentrated solution.The experimental results showed that for 10% sucrose/water binary solution,the freezing rate had little effect on Tc although it could affect the size of ice crystals.For 10% tertiary butyl alcohol/10% sucrose/water ternary solution,both T′g and Tc decreased with the increase of freezing rate.Few variations in collapse temperatures could be expected when varying the pressure.For sucrose aqueous solutions at different mass fractions(5%~25%),the variation of collapse temperature was less than 1℃.