Preparation And Properties Of Stearic Acid Composite Phase Change Materials

In recent years,more and more energy is needed with the development of the science and technology.The limited reserves of fossil fuels have made effective energy utilization a key issue.Phase change material as an energy storage material,which can release and store energy by phase transition,has attracted much attention.Stearic acid/active carbon,stearic acid/expanded graphite,stearic acid-myristic acid/active carbon,stearic acid-myristic acid/expanded graphite,stearic acid-decanoic acid/active carbon,and stearic acid-decanoic acid/expanded graphite shape-stabilized composite phase change materials were synthesized by physical absorption process with stearic acid,stearic acid-myristic acid,and stearic acid-decanoic acid as phase change materials,active carbon and expanded graphite as encapsulating materials.The thermal stability,absorption,structure,and thermal properties of the samples were characterized by thermogravimetric analyzer,Fourier transformation infrared spectroscopy,and differential scanning calorimeter,et al.The samples were shape-stabilized and exhibited a good thermal stability in their phase transition processes.The amount of stearic acid in the stearic acid/active carbon composite phase change materials is up to 79.48 wt% in this experiment,the corresponding melting and solidifying temperatures are 52.83 ? and 51.74 ?,respectively,and the melting and solidifying enthalpies are 108.2 J/g and 105.3 J/g,respectively.The amount of stearic acid in the stearic acid/expanded graphite composite phase change materials is up to 98.89 wt% in this experiment,the corresponding melting and solidifying temperatures are 52.65 °C and 53.00 °C,respectively,and the melting and solidifying enthalpies are 168.2 J/g and 165.4 J/g,respectively.The phase change temperatures of stearic acid-myristic acid can be tuned in the temperature area of 41.50?~53.91? by adjusting the ratio of stearic acid and myristic acid.The phase change temperatures of stearic acid-decanoic acid can be tuned in the temperature area of 16.95?~51.80? by adjusting the ratio of stearic acid and decanoic acid.