Synthesis And Property Of Paraffin@SnO₂ And Paraffin@SnO₂/GO Microcapsule Phase Change Materials

Paraffin is a kind of organic phase change energy storage material with high energy density and stable chemical properties.However,the thermal conductivity and light absorption of paraffin are poor,and it is easy to leak during phase transition.These problems seriously restrict the application range of paraffin in the field of energy storage.Microencapsulation technology is used to encapsulate phase change materials such as paraffin in the inner micro-space of high thermal conductivity inorganic shell material,which not only can effectively avoid leakage problems,but also improve the thermal conductivity and absorbance performance of microcapsules.In addition,the visible light absorption capacity of the microcapsules modified by the graphene oxide is significantly improved,and the heat storage of the solar energy can be efficiently realized.In this paper,paraffin phase change microcapsules with tin dioxide as shell material and phase change composites with graphene oxide modified tin dioxide as composite shell were prepared by in-situ chemical deposition.The chemical composition and crystal structure of the phase-change composites were characterized by FT-IR,XRD and Raman.The surface microstructure of the samples was observed by SEM.DSC,TGA and thermal conductivity coefficient were used to measure the thermophysical properties of the composites.The light absorption,thermal conductivity and photothermal conversion efficiency of microcapsule slurry were measured.The main achievements are shown as follows:Under the emulsification of sodium lauryl sulfate,the surface of paraffin droplets has a negative charge,and the paraffin@SnO₂ phase change composite material is obtained by electrostatic deposition on the surface of paraffin.The effects of different core-shell ratios on the micromorphology,thermal energy storage capacity and photothermal properties of microcapsules were investigated.On the basis of the above,the shell material was modified with graphene oxide,and the paraffin@SnO₂/GO phase change microcapsules was successfully prepared.In addition,the effects of graphene oxide on the properties of phase change composites were analyzed in detail,and the thermal conductivity,visible light absorption,heat storage capacity and photothermal conversion performance of graphene oxide modified microcapsule suspension slurry were further studied.The thermal stability of the two microcapsules was obviously better than that of pure paraffin,and the thermal storage performance of the suspension prepared by them was significantly improved compared with that of water.The light absorption of the microcapsule was improved to a certain extent due to the existence of shell materials,while the thermal conductivity,absorbance and photothermal conversion performance of the phase change compositemodified by graphene oxide were significantly improved compared with the unmodified microcapsule.