Preparation,Structure And Properties Of Myristic Acid Based Shape Stabilized Composite Phase Change Materials

As people pay more and more attention to building energy consumption,the combination of traditional building materials and phase change energy storage materials has gradually become a research hotspot in the field of building energy conservation.In this paper,a new type of building material with the function of energy storage and temperature regulation was prepared with gypsum as the load carrier.Two ternary phase change materials,myristic acid palmitic acid tetradecanol(MA-PA-TD)and myristic acid stearic acid lauric acid(MA-SA-LA),were prepared by melt blending method.Expanded graphite(EG)was used as porous adsorption material to prepare ternary composite phase change materials with expanded graphite support by physical adsorption.The phase change energy storage gypsum board was formed by gypsum and MA-SALA/EG phase change material.The performance of phase change energy storage gypsum board was tested by DSC,FT-IR and SEM.Phase change energy storage gypsum board was formed by gypsum and MA-SA-LA/EG phase change material.The performance of phase change energy storage gypsum board was tested by DSC,FT-IR and SEM,The main research work is as follows:The minimum eutectic mass ratios of ma-pa,MA-SA,MA-PA / TD and MA-SA / La were70 : 30,77 :23,54 :46 and 37:63,respectively.The eutectic transformation temperatures are43.7 ?,43.6 ?,28.6 ? and 29 ?,respectively.The results show that the low CO melting temperature of ma-pa,MA-SA,MA-PA-TD and MA-SA-LA is 45.98 ?,47.13 ?,29.64 ? and28.81 ? respectively,which is less different from that of the composite phase change materials after 300 cold and thermal cycles,and keeps good stability.The structure characteristics of the two phase change materials were analyzed by infrared spectroscopy.The results showed that the characteristic peaks of MA-PA-TDand MA-SA-LA are consistent with the characteristic peaks of pure materials,which are combined by molecular forces.The optimum mass ratio of MA-PA-TD / EG and MA-SA-LA / EG is 8:1.DSC results show that the phase transition temperatures of MA-PA-TD / EG and MA-SA-LA / EG before and after cycling are 34.14 ?,34.39 ? and 30.21 ?,30.33 ? respectively.The mixture has good stability.The results show that the heat storage and release rate of MA-PA-TD/ EG is 67% faster than that of MA-PA-TD,the heat storage and release rate of MA-SA-LA / EG is 63% faster than that of MA-SA-LA,and the heat storage and release rate of MA-PA-TD / EG is 74% and 76% faster than that of MA-PA-TD in the process of solid-liquid phase change.At the same time,SEM analysis showed that MA-PA-TD and MA-SA-LA were evenly distributed in the pores of eg through capillary force.Therefore,the two kinds of expanded graphite based composite phase change materials are suitable for practical application in construction.Using MA-SA-LA /EG as phase change material and gypsum,the phase change energy storage gypsum board with the optimum content of MA-SA-LA /EG of 20% was prepared.The melting temperature and melting latent heat were 27.64 ? and 19.05 J / g respectively by DSC.After 300 cycles,the mass loss rate of phase change energy storage gypsum board is 0.51%.Micro morphology analysis showed that the pores of gypsum board were filled evenly with the addition of MA-SA-LA / EG composite phase change material,and the appearance was compact.The temperature damping ratio of phase change energy storage gypsum board with 5%,10%,15% and 20% MA-SA-LA /EG was increased by 0.12,0.19,0.31 and 0.39 compared with that of pure gypsum board,which effectively improved the heat storage and temperature regulation ability of phase change energy storage gypsum board.