石墨和纳米SiO_2改性P(MMA-co-AA)/石蜡相变储热微胶囊的制备及性能研究

Study on the preparation and the properties of P(MMA-co-AA)/paraffin phase change thermal storage microcapsules modified by graphite and nano-SiO_2

采用悬浮聚合法制备了以甲基丙烯酸甲酯-丙烯酸共聚物为壁材,固体石蜡为芯材的相变微胶囊,并使用石墨和纳米SiO_2对微胶囊的壁材进行改性。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)等对微胶囊的表面形态、化学结构及热性能等进行了测试和表征。结果表明,当复配乳化剂Tween-80与SDBS的质量比为6∶4,芯壳质量比为5∶10,纳米SiO_2添加量为3%,石墨添加量为0.2%时,纳米SiO_2及石墨在壁材中分布均匀,微胶囊的平均产率为96.04%,平均包覆率为84.86%。微胶囊为规则球形,平均粒径为210μm,相变焓为69.9 J/g。经改性后,该微胶囊的机械强度和导热性提高。

Phase change microcapsules were synthesized by suspension polymerization with methyl methacrylate-acrylic acid copolymer as wall and solid paraffin as core. The wall material was modified by graphite and nano-SiO2. The thermal properties, morphology and chemical structure of mierocapsules were characterized by differential scanning calorimetry （DSC）, thermal gravimetric analysis（TGA）,optical microscope（OM） and fourier transform infrared spectrometer（FTIR）,and so on. The results show that when the ratio of Tween-80 and SDBS is 6：4 and the core/shell is 5：10,the mass fraction of nano-SiO2 is 3% and graphite is 0.2% in wall,nano-SiO2 and graphite are distributed uniformly in the wall. The average yield of microcapsules is 96.04% and the cladding rate is 84.86%. The microcapsules are sphere and the average size of them is about 210 μm. The phase transition enthalpy of mi- crocapsules is 69.9 J/g. The heat transfer and mechanical strength of the microcapsules are improved.