Synthesis And Characterization Of Photo-thermal Conversion Energy Storage And Energy Saving Films

Due to pure phase-change materials cannot use full-band solar radiation,as a carbon nanomaterial,graphene has the characteristics of UV-visible-near-infrared absorption and high thermal conductivity.Therefore,we select it as a photo-thermal conversion material,and blend it with polyethylene glycol(PEG)by means of ultrasound-assisted physical blending to build a composite phase change material that integrates photo-thermal conversion and phase change energy storage,to achieve effective use of visible light.At the same time,the composite phase change material was prepared into a thin film,and its performance was preliminary studied.micro-morphology,crystal phase,functional groups of the composite phase-change materials were analyzed by Scanning Electron Microscopy(SEM),X-ray Diffraction(XRD),and Transform Infrared Spectrometer(FT-IR).The thermal storage properties and photo-thermal conversion properties of the composite phase-change materials were characterized by Differential Scanning Calorimetry(DSC),UV spectrophotometer and self-assembled photothermal conversion systems.Firstly,GO/PEG composite phase change materials were prepared by physical blending with phase change material PEG via using the full band absorption and photo-thermal conversion function of graphene.The composite phase change material has a layered structure,and PEG is distributed on the surface of graphene between the sheets of graphene.With the increase of the GO content,the stacking between the layers becomes more complicated and the surface is relatively rough.The phase transition temperature of the composite phase change material is 50.5?,and the latent heat of phase change is more than 80 J/g,which has good heat storage performance.The composite phase-change material has absorption in the visible light range(300-800 nm),can store energy through light drive,has high light-to-heat conversion and energy storage efficiency,and ? is greater than 0.75.Secondly,the azobenzene derivatives with high light absorbency are used to covalently modify graphene to increase the absorbance in the visible light region,and then the modified graphene and the phase change material PEG are physically blended to prepare the light.Thermal conversion and energy storage of composite materials.The results showed that the GO and azobenzene molecules were grafted together by amide bonds(-NH-CO-),and the pitch of the modified graphene sheets became smaller.In the composite phase change material,PEG is distributed on the surface of the graphene between the sheets of the graphene or through strong interactions such as hydrogen bonding,resulting in a rough surface of the material and more complicated layer stacking.The composite phase change material has a high latent heat of phase change,phase change enthalpy exceeds 85 J/g,and has good heat storage performance,and its phase transition temperature is 50.6?.In the visible light band,the composite phase-change material has higher light absorption,and has higher light-heat conversion and energy storage efficiency,and ? is greater than 0.8.Finally,the obtained composite phase change material is prepared into a thin film material,and the content of the composite phase change material cannot be too much,not more than 15%,otherwise it will affect the lighting.The film material has good flexibility and mechanical properties,and its acid and alkali corrosion resistance is also good,and it also has good energy storage properties.