کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
675954 887743 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Using modulated DSC to investigate the origin of multiple thermal transitions in frozen 10% sucrose solutions
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Using modulated DSC to investigate the origin of multiple thermal transitions in frozen 10% sucrose solutions
چکیده انگلیسی

Modulated differential scanning calorimetry (MDSC) was used to investigate the effect of annealing on multiple thermal transitions in frozen aqueous sucrose solutions. Two thermal transitions were detected from the reversing heat flow. Here, to maintain consistency with terminology used in the practice of freeze-drying [1], the higher temperature is denoted, T′gT′g, and the lower transition is given the symbol, T″gT″g. The transition at low temperature is usually believed to be a true glass transition. However, the origin of the transition at high temperature is still highly controversial. Based upon a study of 10% sucrose solutions with different cooling histories and annealing conditions, we suggest that the transition at high temperature is also a glass transition. We conclude that the lower transition is a glass transition of a phase plasticized by a higher than equilibrium amount of unfrozen water, and the higher transition, T′gT′g, corresponds to a glass transition in a maximally freeze-concentrated solute phase.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Thermochimica Acta - Volume 444, Issue 2, 15 May 2006, Pages 141–147
نویسندگان
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