In order to solve the problems of low thermal conductivity and easy liquid leakage of a stearic acid(SA),the composite phase change material(PCM)was prepared by adding boron nitride(BN)and expanded graphite(EG)to melt...In order to solve the problems of low thermal conductivity and easy liquid leakage of a stearic acid(SA),the composite phase change material(PCM)was prepared by adding boron nitride(BN)and expanded graphite(EG)to melted SA,and its thermal conductivity,crystal structure,chemical stability,thermal stability,cycle stability,leakage characteristics,heat storage/release characteristics,and temperature response characteristics were char-acterized.The results showed that the addition of BN and EG significantly improved the thermal conductivity of the material,and they efficiently adsorbed melted SA.The maximum load of SA was 76 wt.%and there was almost no liquid leakage.Moreover,the melting enthalpy and temperature were 154.20 J·g^(−1) and 67.85℃,re-spectively.Compared with pure SA,the SA/BN/EG composite showed a lower melting temperature and a higher freezing temperature.In addition,when the mass fraction of BN and EG was 12 wt.%,the thermal conductivity of the composite was 6.349 W·m^(−1)·K^(−1),which was 18.619 times that of SA.More importantly,the composite showed good stability for 50 cycles of heating and cooling,and the SA/BN/EG-12 hardly decomposes below 200℃,which implies that the working performance of the composite PCM is relatively stable within the tem-perature range of 100℃.Therefore,the composite can exhibit excellent thermal stability in the field of building heating.展开更多
基金This research was supported by the National Natural Science Foundation of China(No.51766012)the Natural Science Foundation of Inner Mongolia(No.2019MS05025)+1 种基金the Inner Mongolia Science and Technology Major Project(No.2019ZD014,No.2021ZD0030)the Science and Technology Research Project of Inner Mongolia Autonomous Region(No.2021GG0252).
文摘In order to solve the problems of low thermal conductivity and easy liquid leakage of a stearic acid(SA),the composite phase change material(PCM)was prepared by adding boron nitride(BN)and expanded graphite(EG)to melted SA,and its thermal conductivity,crystal structure,chemical stability,thermal stability,cycle stability,leakage characteristics,heat storage/release characteristics,and temperature response characteristics were char-acterized.The results showed that the addition of BN and EG significantly improved the thermal conductivity of the material,and they efficiently adsorbed melted SA.The maximum load of SA was 76 wt.%and there was almost no liquid leakage.Moreover,the melting enthalpy and temperature were 154.20 J·g^(−1) and 67.85℃,re-spectively.Compared with pure SA,the SA/BN/EG composite showed a lower melting temperature and a higher freezing temperature.In addition,when the mass fraction of BN and EG was 12 wt.%,the thermal conductivity of the composite was 6.349 W·m^(−1)·K^(−1),which was 18.619 times that of SA.More importantly,the composite showed good stability for 50 cycles of heating and cooling,and the SA/BN/EG-12 hardly decomposes below 200℃,which implies that the working performance of the composite PCM is relatively stable within the tem-perature range of 100℃.Therefore,the composite can exhibit excellent thermal stability in the field of building heating.
