Preparation Of Porous Materials With Infrared Energy Saving For Thermal Management Property

With the improvement of living standards,people have higher and higher requirements for thermal comfort.The global thermal management field consumes a lot of energy,causing certain environmental pollution and waste of resources.Based on infrared radiant heat management and regulation,no pollution and low energy consumption,it is cooperatively coupled with porous materials with large specific surface area,good heat insulation performance,and strong thermal stability,and can conduct heat management and regulation.In this thesis,different porous materials are used as raw materials,and multifunctional metal layers are constructed on the surface or inside of them to prepare thermal management materials with active heating,infrared heat insulation,water evaporation and heat dissipation,and phase change heat storage.Heat regulation under ambient temperature is expected to be used in human clothing and buildings.The specific research content is as follows:(1)Preparation of nano-Cu modified porous sponge composite material and research on thermal managementA porous sponge with flexible,foldable and compressible deformation capabilities was selected as the raw material,and copper nanoparticles were deposited on its surface by in-situ deposition method to obtain a dense nano-copper layer porous sponge(Cu-MES).The infrared heat insulation performance,thermoelectric performance,self-cleaning performance and stability performance of Cu-MES have been studied.The results show that the emissivity of Cu-MES in the infrared band is reduced from 97.5% of the raw material to 72.4%,which has good infrared insulation.With an external 7 V DC voltage,the surface temperature of the material rises from 18 ? to 40 ? within 30 s,showing excellent thermoelectric performance;at the same time,due to the larger water contact angle and smaller water sliding angle,the material has good self-cleaning performance and stability.Cu-MES material is used as a filler in clothing and buildings,and will bring thermal comfort to the human body in a cold environment.(2)Preparation of nano-Cu modified porous biomass aerogel composite material and research on thermal managementUsing sisal leaf as raw material,removing impurities such as hemicellulose by alkali treatment,bleaching the cellulose obtained by alkali extraction,and coating the cellulose surface with a uniform layer of nano-copper particles by liquid-phase chemical deposition to obtain nano-copper modified cellulose composite material,using freeze-drying technology to obtain a porous aerogel composite material(Cu-NPs/CFAs)loaded with copper nanoparticles.The nano-copper metal layer on the surface of Cu-NPs/CFAs increases the infrared reflectance of the material(91.2%),has a good thermal insulation effect,and the self-cleaning ability generated by the surface nanostructure and low surface energy increases the durability and stability of the material.The ultra-light properties of aerogel also make it promising in the field of thermal insulation.(3)Preparation of LDHs modified porous aerogel composite material and research on thermal managementUsing bacterial cellulose membrane(BCM)as raw material,using magnetron sputtering technology and hydrothermal reaction to prepare LDHs-modified bacterial cellulose membrane with rough surface(BCM@LDHs),which has high infrared emissivity(93.5%),showing good infrared heat dissipation performance.Bacterial cellulose aerogels are prepared by freeze-drying technology,using aerogel as a carrier and polyethylene glycol as a heat storage element to prepare aerogel phase change membranes(BCAs/PCMs)with large heat storage capacity.BCM@LDHs and BCAs/PCMs are stacked together under external pressure to form a composite membrane(BP-BL)material with both infrared heat dissipation and phase change heat storage.(4)Preparation of Ag-wood based on porous wood and research on thermal management propertiesUsing paulownia wood as the raw material,the impurities on the surface of the wood and the inside of the pores are removed by alkali treatment,and then magnetron sputtering technology is used to deposit a uniform silver nano layer on the cross section of the wood with the Ag target as the metal source to obtain Ag-Wood(Ag-W)two-layer structure thermal management material.The mesoporous channel of the material has a good capillary effect,which gives the material water evaporation and heat dissipation performance.At the same time,the deposited silver nano-layer increases the material's infrared reflectivity(26%-35%),and the nano-silver layer also has a good antibacterial effect.Under different infrared radiation intensities,the material water evaporation heat dissipation and infrared heat insulation produce a good coupling effect,and the material shows good heat insulation performance,which provides a new idea for the selection of thermal management materials.