Preparation And Properties Of Microencapsulated Phase Change Materials Containing 1-dodecanol Thermally Enhanced By Graphene Oxide

As a kind of clean energy material,solid-liquid phase change material can store and release thermal energy efficiently in a certain temperature range,but it has the disadvantages of poor stability,easy leakage and corrosion in the molten state,which greatly limits its application in the field of building energy saving,waste heat recovery,solar energy collection,intelligent temperature-regulating textile and so on.Therefore,it is of great practical significance to explore the packaging technology that can solve the existing problems of solid-liquid phase change materials,and microencapsulation of phase change materials is an effective method.In addition,the thermal conductivity of phase change microcapsules determines their thermal response efficiency to the environment and affects their practical application value.1-Dodecanol is an organic solid-liquid phase change material with low cost,high latent heat of phase transition and suitable phase transition temperature,which has attracted widespread attention from researchers.In this paper,1-dodecanol was selected as the main raw material.On the basis of the synthesis of 1-dodecanol/polymethyl methacrylate phase change microcapsules,graphene oxide was added to enhance the thermal conductivity of phase change heat storage microcapsules.In order to further enhance the overall thermal conductivity of 1-dodecanol microcapsules,silica was chosen to encapsulate 1-dodecanol material,and the influence of graphene oxide on its related properties was explored.Finally,the preparation technology and properties of 1-dodecanol microcapsules of two shell materials were comprehensively analyzed,and their differences were compared,which provided some references for the development of organic-inorganic composite phase change microcapsules with excellent comprehensive properties.Firstly,a phase change heat storage microcapsule with 1-dodecanol as the core and polymethyl methacrylate?PMMA?as the shell was prepared by microsuspension polymerization.The effects of emulsifier,crosslinking agent and core-shell ratio on the latent heat of microcapsules were analyzed by DSC.When the dosage of emulsifier?SDS?was 3wt%,the dosage of crosslinking agent?DVB?was 15 wt%and the core-shell ratio was 1:1,the latent heat of melting phase change of microcapsules was 102.9 J/g.Then GO was added to 1-dodecanol/PMMA phase change heat storage microcapsules,and the influence of GO on microcapsules was analyzed by FTIR,DSC,SEM,TG and Hot Disk.The experimental results showed that adding 0.4wt%GO to the oil phase could increase the thermal conductivity of the microcapsules by 44%,but the latent heat of the microcapsules decreased with the increase of the amount of GO.In order to further improve the thermal conductivity of 1-dodecanol microcapsule,Si O₂with good thermal conductivity was selected as the shell material.A phase change heat storage microcapsule with 1-dodecanol as the core and Si O₂as the shell was prepared by sol-gel method,the effects of p H,emulsifier and core-shell ratio on the latent heat of phase change and morphology of microcapsules were analyzed by DSC and SEM.When the p H value of the reaction system was 6?7,the dosage of emulsifier was 10 wt%,and the core-shell ratio was 1:1,the latent heat of melting phase change of the microcapsules was 117.7 J/g,and the microscopic morphology is spherical.Subsequently,the effects of different addition methods and amounts of GO on microcapsules were analyzed by FTIR,XRD,Raman,DSC,SEM,TEM,TG and Hot Disk.The experimental results showed that M3 addition method had the least effect on the latent heat of microcapsules.When 1.2 wt%GO was added,the thermal conductivity of 1-dodecanol/silica microcapsules increased by 56.8%,and the presence of GO reduced 1-dodecanol leakage.Finally,the preparation technology,micro-morphology,encapsulation rate,thermal conductivity and stability of 1-dodecanol phase change heat storage microcapsules of two shell materials were analyzed and compared.The preparation process of 1-dodecanol/silica phase change microcapsule is 4 times longer than that of 1-dodecanol/PMMA,but the thermal conductivity of the former is 54.5%higher than that of the latter,which is more conducive to the thermal response of 1-dodecanol material.The addition of GO to the microcapsules with two kinds of shell materials can effectively improve the thermal conductivity of the microcapsules.However,GO has different effects on the encapsulation rate and encapsulation stability of the two kinds of microcapsules because GO is added in different ways.