Preparation And Characterization Of Microencapsulated Phase Change Materials Containing Palmitic Acid

Phase change materials is a new type of functional materials which absorbs or releases huge latent heat through the phase change process.Microencapsulated phase change materials is a shape-stabilized phase change materials which is obtained by packaging technology of microcapsules.As one of the energy-saving materials,microencapsulated phase change material has been widely used in the fields of energy saving building materials,smart thermostat fiber,latent functionally thermal fluid.Dispersing the core material in the continuous phase is the basis for the microcapsule preparation.The palmitic acid dispersion was prepared by selecting sodium dodecyl sulfate and polyvinyl alcohol as emulsifier and dispersant.The dispersion could stay stable for 6 months at room temperature.The maximum solid content was up to 30% and the viscosity was less than 200 mPa·s.The phase change energy storage microcapsules were prepared by in situ polymerization using methyl methacrylate and styrene as the monomeric wall material.It was found that the addition of the crosslinking agent could enhance the mechanical strength of the wall,accordingly,the heat resistance and thermal storage performance of the microcapsules were improved.Selecting the ratio of methyl methacrylate and pentaerythritol tetraacrylate was 7:3,the heat-resistance temperature of microcapsules was up to 271 °C and the loading level of was 51.4% when the core-shell ratio is 1:1.With the core-shell ratio increasing,the core loading level of microcapsules will grow,but the yield and loading efficiency will reduce.So the core-shell ratio should be decided by the actual demand.