Study On Preparation And Photo-thermal Conversion Of Polymer Supported Thermally Conductive Form-stable Composite Phase Change Materials

Organic solid-liquid phase change energy storage materials have attracted much attention on photothermal utilization due to its suitable phase transition temperature and high thermal energy storage density.The most important issues that phase change materials need to solve in solar applications are leakage,low thermal conductivity and poor energy conversion.Based on this,this research designs polymer-supported form-stable composite phase-change energy storage materials with high solar absorption,high thermal conductivity,and high photothermal conversion efficiency.The influence of carbon and polymer support matrix on the thermal conductivity,energy storage effect and photothermal conversion ability of composite phase change materials were investigated,and the micromorphology,composition,thermal properties and photothermal conversion ability of composite materials were analized.The results of this study are as follows:Firstly,cured unsaturated polyester resin was selected as the support materials,polyethylene glycol was used as the organic phase change energy storage materials,and expanded graphite was added as thermal conductivity reinforcing materials to prepare unsaturated polyester resin/expanded graphite/polyethylene glycol composite phase change materials.The effect of each component content on the properties of form-stable phase change materials was studied.Due to the interaction between polyethylene glycol,cured resin and expanded graphite,this shaped phase change composite has enhanced thermal stability.When the ratio of polyethylene glycol to unsaturated polyester resin in the sample is controlled to4:1,the thermal conductivity of the composite material S4 doped with 7 wt% expanded graphite is 1150% higher than that of pure polyethylene glycol,and the phase transition is The enthalpy reached 97.37 J/g,and the photothermal conversion efficiency reached a maximum of 93.3%.Secondly,melamine sponge as the support material,paraffin as the organic phase change component,and reduced graphene oxide and zirconium carbide as the solar absorption and thermal conductivity additives to prepare form-stable composite phase change materials by vacuum impregnation process.The rich network skeleton structure of the reduced graphene oxide-modified melamine sponge provides huge surface tension and capillary force to support paraffin,thereby,ensuring the stability of the shape before and after the phase change.And the composites with different zirconium carbide content have excellent solar enrichment properties,excellent heat storage capabilities and suitable heat transfer properties.The latent enthalpy reached 137 J/g when doped with 0.01 wt% zirconium carbide.The photothermal conversion efficiency was as high as 81%,and the maximum thermal conductivity of the composite phase change energy storage materials was 121% higher than that of pure paraffin.Finally,the elastic olefin block copolymer/graphene nanosheets were prepared by using an elastic olefin block copolymer as a support material and a graphene nanosheet as a thermally conductive reinforcing material.Palmitic acid was filled in the soft block of the elastic olefin block copolymer.The ratio of palmitic acid to the elastomer is controlled to 4:1in all samples.The latent enthalpy of melting reaches 145.52 J/g while ensuring excellent shape stability.Due to the support of the elastomeric olefin block copolymer,the prepared composites have excellent thermally-induced elastic properties and toughness at high temperatures.Due to the support of the elastomeric olefin block copolymer,the prepared composite material has excellent heat-induced elastic properties and toughness at high temperatures.The thermal conductivity of the composite phase change materials with 4 wt%graphene nanoplates was increased by 155% compared to pure palmitic acid,and the photothermal conversion efficiency was 86.21%.