多壁碳纳米管/硬脂酸-十八醇@脲醛树脂微胶囊的制备及表征

通过原位聚合法以硬脂酸-十八醇低共融复合相变材料（SA-OA，质量比为50.02%，相变温度为55℃）为芯材，三聚氰胺改性的脲醛树脂（UF）为壁材，氨基化多壁碳纳米管（MWCNTs-NH₂）为高导热填料制备了MWCNTs/SA-OA@UF相变微胶囊。采用FTIR、SEM、DSC、TGA和导热系数仪，对MWCNTs/SA-OA@UF相变微胶囊的化学结构、表面形貌、相变性能和导热性能进行表征。讨论了不同的MWCNTs修饰方法、不同乳化剂种类和MWCNTs-NH₂添加量对SA-OA@UF相变微胶囊的影响。结果表明:MWCNTs-NH₂在溶液中分散性良好；十二烷基苯磺酸钠（SDBS）和曲拉通X-100复配乳化剂使SA-OA@UF相变微胶囊的表面形貌更加光滑平整；添加质量比为0.5%的MWCNTs-NH₂，使MWCNTs/SA-OA@UF相变微胶囊的导热系数达到0.224 W/（m·K），提高了38%（55℃），包覆率提高了6.9%，粒度更加均一，热稳定性有明显提高。 

Preparation and characterization of MWCNTs/stearic acid-octadecyl alcohol@urea formaldehyde resin phase change microencapsules

The multi-walled carbon nanotubes/stearic acid-octadecyl alcohol@urea formaldehyde resin (MWCNTs/SA-OA@UF) phase change microcapsules with SA-OA eutectic composite phase change materials(at the mass ratio of 50.02%, phase change temperature was 55℃) as core material, UF modified by melamine as wall material and amino multi-walled carbon nanotubes (MWCNTs-NH₂) as highly thermally conductive filler were prepared by using in-situ polymerization method. The chemical structure, morphology, thermal properties and thermal conductivity of the MWCNTs/SA-OA@UF phase change microcapsules were characterized by FTIR, SEM, DSC, TGA and thermal conductivity meter. The effects of different MWCNT modification methods, different types of emulsifiers and the amount of MWCNTs-NH₂ added in the SA-OA@UF phase change microcapsules were discussed. The results show that the MWCNTs-NH₂ have good dispersibility in the solution; The compounded emulsifiers of sodium dodecyl benzene sulfonate(SDBS) and Triton X-100 make the surface morphology of the SA-OA@UF phase change microcapsules smoother and smoother; The addition of MWCNTs-NH₂ with the mass ratio of 0.5% make the MWCNTs/SA-OA@UF phase change microcapsule's thermal conductivity reaches 0.224 W/(m·K), which increases by 38% (55℃), the coating rate increases by 6.9%, the particle size is more uniform and the thermal stability is significantly improved.