Study On Preparation And Properties Of Nano W-VO₂ Intelligent Temperature-control Packaging Paper

Thermal-insulation temperature-control paper is applicated widely because of the advantages which includes convenience of use,excellent machinability and strong strength properties,etc..Because the fillers in the functional paper can improve infrared reflectivity and isolate heat radiation at high temperatures circumstance,which can reduce exterior heat to conduct to interior and it can also convert the heat that come from environment to latent heat.Thereby it can achieve the effect of thermal-insulation and temperature-control.At the same time,considering that the thermal-insulation temperature-control paper is mainly used in the outdoor,and it is usually exposure to the rainwater and sunbaked environments,so the thermal-insulation and hydrophobic properties of the paper should be excellent.In this paper,nano doped tungsten vanadium dioxide?W-VO₂?was used to prepare intelligent temperature-control packaging paper in two ways.The main contents and conclusions include:?1?Coating method:The high-stability small particle size anionic paraffin emulsion was prepared with stearic acid as a single emulsifier.And CMC/PMMA was prepared with carboxymethyl cellulose?CMC?as the modifier of polymethyl methacrylate?PMMA?,due to CMC is easy for chemical modifing and it has many functions because of its rich carboxyl groups and hydroxyl groups.The intelligent temperature-control microcapsules?PCMs/W-VO₂?with average particle size of 12?m were prepared with nano W-VO₂ and CMC/PMMA as inorganic-organic compound shell and anionic paraffin emulsion as the core shell by interfacial polymerization method.The paraffin content,phase-change temperature and melting enthalpy are about 50.06%,41.2?and 48.96 J/g,respectively.These prove that PCMs/W-VO₂ microcapsules have excellent phase-change property and sealing property.Then PCMs/W-VO₂ intelligent temperature-control waterborne coatings were prepared with waterborne acrylic resin as the main film-forming materials,PCMs/W-VO₂ microcapsules as the main thermal-insulation and temperature-control fillers and appropriate amount of flatting agent,dispersing agent,antifoaming agent,etc.,then the PCMs/W-VO₂ intelligent temperature-control packaging paper was prepared with white board as the substrates.The infrared transmission was reduced by 32%compared with packaging paper,the thermal-insulation temperature difference can reach 10.7?,the physical properties were improved and it has excellent thermal-insulation and temperature-control properties.The optimal of tensile index and tearing index are 6.84 kN/m and 22.69 mN�m²/g,respectively considering the cost of coatings.Finally,the coatings can balance the hydrophobic,thermal-insulation,temperature-control properties effectively and enhance the water vapor barrier property significantly by adding nano modified SiO₂,although the addition of nano modified SiO₂ has reduced the thermal-insulation and temperature-control properties of the coatings.?2?Machine loading method:Firstly,the nano W-VO₂ is easy to be lost along with water and agglomerate but difficult to disperse during papermaking process because of the small particle size and large density.Therefore,retention of nano W-VO₂ was enhanced by surface modification and appropriate dispersion conditions.Then,the phase-change property and stability were characterized to ensure that the nano W-VO₂ intelligent temperature-control packaging paper can be multiple reversible phase-changes.At last,the papermaking technology and phase-change mechanism of the nano W-VO₂ intelligent temperature-control packaging paper were discussed,which provided theoretical basis for the manufacturing and the suggestions for the application fields.The particle size of nano modified W-VO₂ is uniform and scattered evenly between particles.The nano W-VO₂ intelligent temperature-control packaging paper are tolerant for most of the solvents,but it is easy to damage by strong acid and alkali.And the phase-change temperature is about 45?,which can control the temperature by controlling incident infrared radiation.Intelligent temperature-control packaging paper can combine with intelligent temperature-control and heat-reflection,which achieve the purpose of temperature-control and energy-saving functions,and improve the temperature-control property,hydrophobic property and other deficiencies of traditional thermal-insulation temperature-control materials.So it can be used to control the temperature accurately in chemicals,precision instruments and other protection areas.