纳米SiO_2和石墨改性相变储热微胶囊的研究

Research on the modification of microencapsulated phase change material for thermal energy storage by nano-SiO_2 and graphite

以固体石蜡为相变芯材,三聚氰胺-尿素-甲醛共缩聚树脂为囊壁,采用原位聚合法制备了微胶囊型相变储热材料;并针对该相变材料热导率低及亲水性差缺点,用石墨和纳米SiO2对芯材和微胶囊进行了导热性和表面性能的改性研究。采用光学显微镜(OM)、红外光谱仪(FTIR)、差示扫描量热仪(DSC)、热重分析仪(TGA)等对产品的表面形态、化学结构、热性能等进行了测试和表征。结果表明:石蜡微胶囊化后能保持原有的储热特性,相变焓为47.5J/g;球状微胶囊平均粒径为45μm,表面粗糙,石蜡包封率达80%;纳米SiO2改性后微胶囊亲水性、耐热性能、机械强度均增强;石墨改性后导热性提高。

Microencapsulated phase change material（MPCM） were prepared by using solid paraffin as core and melamine-urea-formaldehyde condensation resin as shell through in-situ polymerization.Problems such as low thermal conductivity and hydrophilicity were studied.The thermal conductivity of core and surface performance were modified by using graphite and nano-SiO2.The surface morphology,structure,thermal properties were measured and characterized by optical microscopy（OM）,infrared spectroscopy（FTIR）,differential scanning calorimetry（DSC）,thermal gravimetric analysis（TGA）.The results showed that：thermal storage can maintain original characteristics of phase change enthalpy 47.5J / g after paraffin microencapsulated.The mean diameter of microcapsule was 45μm with rough surface.Encapsulation efficiency of paraffin was up to 80%.After nano-SiO2 modification,hydrophilicity,thermal properties and mechanical strength have been enhanced and thermal conductivity have been increased after graphite modified.