改性氧化石墨烯稳定Pickering乳液法制备高导热相变整体材料

采用表面引发原子转移自由基聚合法(SI-ATRP)改性氧化石墨烯(GO), 并用其稳定Pickering高内相乳液, 一步成型制得高导热氧化石墨烯/石蜡复合整体相变材料. 通过SI-ATRP方法, 在氧化石墨烯表面引入分子刷, 提高GO的分散性, 实现了低GO含量下优异的导热强化效果. 当GO添加量仅为相变复合材料整体的0.4%(质量分数)时, 其热导率(3.968 W?m^-1?K^-1)比纯石蜡的热导率(0.608 W?m^-1?K^-1)有较大提升. 通过测试发现, 在1000次循环后相变材料的泄漏率仅为1.1%~1.3%, 表现出良好的形状稳定性和热可靠性. 制备的新型形状稳定相变材料在温控、 储能应用中具有潜在的用途.

Preparation of High Thermal Conductivity Phase Change Monolithic Materials Based on Pickering Emulsion Stabilized by Surface Modified Graphene Oxide

Filling with nano-materials is a common method to improve the thermal conductivity of phase change composites， and the dispersibility of nanomaterials is a key factor in enhancing thermal conductivity. In this paper， surface-initiated atom transfer radical polymerization（SI-ATRP） was used to modify grapheme oxide（GO） firstly， and then the modified GO was employed to stabilize Pickering high internal phase emulsion. Finally GO/paraffin monolith with high thermal conductivity was obtained by one step polymerization. SI-ATRP introduced molecular brushes on GO to improve the dispersion of GO， which endowed the monolith with excellent heat conduction enhancement effect， even under low GO content. When the content of GO was only 0.4% of the composite material， its thermal conductivity（3.968 W?m^-1?K^-1） was greatly improved compared to the thermal conductivity of pure paraffin（0.608 W?m^-1?K^-1）. The leakage rate of phase change material was only 1.1%—1.3% after 1000 cycles， showing good shape stability and thermal reliability. The prepared shape-stable phase change material has potential applications in temperature control and energy storage applications.