【摘要】 本研究对木糖醇、赤藓糖醇和d-甘露糖醇及其两两组合制备的3种二元共晶糖醇的储/释热特性进行了测试,以期筛选出可用于中低温相变储热的糖醇和共晶糖醇。采用差示扫描量热仪对6种材料的相变温度和相变焓进行了非等温表征。同时采用恒温加热和冷却装置对其固液相变行为进行了等温测试并分析其储/释热特性。结果表明,熔点在80～100℃之间的木糖醇与含有木糖醇的2种二元共晶糖醇在等温及非等温冷却条件下均不能从熔融态重新结晶。熔点约为114℃的赤藓糖醇/d-甘露糖醇(摩尔比:84:16)共晶体系则发生冷结晶现象。赤藓糖醇和d-甘露糖醇的重结晶性能均良好,但存在严重的过冷现象。当设定的冷却温差为108.8℃时,等温冷却所测得赤藓糖醇的过冷度高达25～30℃。上述糖醇及共晶糖醇均存在结晶释热问题,需在实际应用中予以解决。更多还原

【Abstract】 In this study, the heat storage/retrieval performance is tested for xylitol, erythritol,d-mannitol and 3 binary eutectic mixtures prepared by mixing any two of them, thus to select the suitable pure and mixture sugar alcohols for low-to-medium temperature latent heat storage. The phase change temperatures and enthalpies of these materials are characterized non-isothermally using differential scanning calorimetry. Meanwhile, the solid-liquid phase change behaviors are also tested on a constant-temperature heating/cooling setup, in order to analyze the isothermal heat storage/retrieval performance. The results show that xylitol and 2 xylitol-based binary eutectic mixtures, all having a melting temperature between 80℃ and 100 ℃, are unable to recrystallize from their respective melt during cooling under both non-isothermal and isothermal conditions. The rest binary eutectic system, i.e., erythritol/d-mannitol(molar ratio: 84:16) with a melting temperature about 114℃, experiences cold crystallization during reheating. In spite of favorable recrystallization performance, erythritol and d-mannitol suffer from severe supercooling. The supercooling degree of erythritol is determined to be 25～30℃ while being cooled at a subcooling degree of 108.8℃. These pure and mixture sugar alcohols all have recrystallization-related issues, which must be addressed prior to being involved in practical applications.更多还原