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.