Abstract:

Phase change microcapsules were prepared with paraffin as the core and gelatinized flour as the shell via adsorption deposition method. The chemical composition, morphology, thermal performance of the phase change microcapsules were characterized by the Fourier transform infrared spectroscopy, scanning electron microscope, thermogravimetric analysis and differential scanning calorimetry. The results showed that the microcapsules were ellipsoidal with particle sizes of 400—600nm, and the peak phase change temperature, latent heat and coating rate were 22.2℃, 110.5J/g and 66.7%, respectively. The microcapsules had good chemical and thermal stability. Phase change gypsum was prepared by adding the phase change microcapsules into gypsum matrix. The results demonstrated that the mechanical strength of the phase change gypsum decreased with the content of microcapsules, and adding wet microcapsules could reduce the mechanical strength loss. In a 5-month continuous endothermic and exothermic experiment, the phase change gypsum materials had no leakage and obvious thermal performance degradation. In summer afternoon, the internal temperature of the model phase change building decreased by 4.1℃ as compared with the external temperature. It showed that the phase change gypsum materials have certain temperature control ability.

Key words: gelatinized flour, phase change, microcapsule, gypsum, composites, surfactants

摘要：

采用吸附沉积法制备了以石蜡为芯材、糊化面粉为壁材的相变微胶囊，并使用红外光谱仪、扫描电子显微镜、热重分析仪和差示扫描量热仪对微胶囊的化学组成、形貌和热性能进行了研究。结果表明：相变微胶囊呈椭球形结构，粒径为400～600nm，其峰值相变温度、相变潜热值和包覆率分别为22.2℃、110.5J/g和66.7%，具有较好的化学稳定性和热稳定性。将相变微胶囊掺入石膏基体制备相变石膏建材，结果表明：相变石膏试块的力学强度随微胶囊含量的增加而下降，微胶囊以湿料方式添加有利于减少相变石膏试块力学强度的损失。在连续5个月的吸热-放热实验中，相变石膏建材未出现漏液和明显的热性能衰减；夏季午后，相变建筑模型内温较外界温度下降4.1℃，说明相变石膏建材具有一定的调控温度效果。

关键词: 糊化面粉, 相变, 微胶囊, 石膏, 复合材料, 表面活性剂