摘要
利用差示扫描量热仪(Pyris-DiamondDSC),研究了乙二醇(甘醇)和丙三醇(甘油)水溶液的过冷行为、水合性质和它们的玻璃化转变温度及反玻璃化温度,分析了它们与分子中羟基个数的关系.进行了12组共24种不同浓度(质量分数)的溶液的差示扫描量热实验.过冷度的实验结果表明,在浓度相等的情况下,两种低温保护剂水溶液冻结的过冷度有相同的变化规律.水合实验的结果表明,浓度相同时,二者结合水的能力大体相当.玻璃化转变的实验表明,二者玻璃化转变温度与反玻璃化温度存在明显差异.
In order to examine possible relationship between freezing properties and the number of hydroxyl group in solute molecules, a differential scanning calorimeter(Pyris Diamond DSC)was employed to study the thermal behaviors(supercooling degree of heterogeneous nucleating temperature, hydration properties, glass transition and devitrification) of ethylene glycol and glycerol aqueous solutions. Experiments were conducted on 12 groups (24 in total) aqueous solutions with different concentrations. At the same concentrations(mass fraction, w), the supercooling behaviors of these two polyols aqueous solutions followed similar rules of change. At concentration of 0～5%(w), supercooling degrees decreased first and then increased with increasing concentration. But at concentration of 5%～25%(w), experimental results showed that supercooling behaviors became disorder. At concentrations >25%, supercooling degrees enhanced monotonically with the increasing solutes contents. Hydration experiments showed that the unfreezable water content in aqueous solutions of these two polyols solutions had no significant difference(ratios of unfreezable water contents are 1.04～1.15 ) with the same mass percentage. However, the temperature of glass transition and devitrification exhibited distinct difference. It can be concluded that 'hydroxyl group concentration'of this two polyols aqueous solutions could predict supercooling behaviors and hydration capabilities. Neither mass percentage nor molality of these two polyols solutions could characterize glass transition and devitrification temperature.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2004年第2期123-128,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金重点资助项目(59836240)
国家自然科学基金青年基金(50206013)
上海市教委重点学科资助项目~~
