Preparation And Properties Of Tetradecanol Form-stable Composite Phase Change Materials

Tetradecanol?TD?is currently one of the most interesting phase change material,which has a high latent heat,low degree of supercooling,high cycle life and no corrosion,etc.But still there is the problem of liquid leakage and poor thermal conductivity problems in practical application.In order to solve this problem,the sol-gel method was used with tetraethyl orthosilieate?TEOS?and inorganic aluminum salts acted as precursor,respectively to prepare the TD/SiO₂ and TD/Al?OH?₃composite phase change materials.Some factors were discussed to study the impact of the thermal performance,such as the amount of the tetradecanol,the different precursor and response handling methods and so on.On the basis of previously experiments,the composite phase change materials of GP/TD/SiO₂ and MWCNTs/TD/SiO₂ were prepared with higher thermal conductivity.At the same time comparative study the different doping amount of graphite and multi-walled carbon nanotubes,how impact on the performance of phase change and thermal conductivity.TD/SiO₂ composite form-stable phase change materials were synthesized by sol-gel with TEOS as precursor.The preparation methods and the PCM component loading weight were discussed,how impact on the material form-stable effects,the phase transition.Their structure and thermal properties were characterized by appearance status,SEM,FT-IR,XRD,DSC,TG and thermal cycle test.The results showed that the phase change enthalpy of TD/SiO₂?65%?was 141.1J/g.TD and SiO₂combined physically,the crystallization properties were a little decrease because the crystallization of TD were limited by the inorganic network.The form-stable phase change materials has good thermal stability and longer service life.TD/Al?OH?₃ composite form-stable phase change materials were synthesized by sol-gel with inorganic aluminum salt as precursor.The different precursor and the PCM component loading weight were discussed,how impact on the material form-stable effects,the phase transition.Their structure and thermal properties were characterized by appearance status,SEM,FT-IR,XRD,DSC,TG and thermal cycle test.The results showed that the phase change enthalpy of TD/Al?OH?₃?60%?was46.86J/g.TD and Al?OH?₃ combined physically,the crystallization properties were a little decrease because the crystallization of TD were limited by the inorganic network.And these form-stable PCMs had good thermal stabilities even 100?higher than their phase transition temperature.The TD/SiO₂ phase change composite materials for thermal energy storage with doped graphite?GP?and multi-walled carbon nanotubes?MWCNTs?as thermal enhancers were synthesized using sol-gel and ultrasound methods.Their structure and thermal properties were characterized by FT-IR,XRD,DSC,TG and thermal conductivity instrumen.The results show that thermal conductive agent was added which does not change the crystalline performance and phase transition temperature of TD.With increasing the amount of GP?MWCNTs,the value of enthalpy trends vary.The results indicated that the phase change enthalpies of the GP/TD/SiO₂composites may not significantly change changed with the amounts of thermal enhancer lower than 3.0%,compared with the 60%-TD/SiO2,MWCNTs/TD/SiO2composites has increased nearly 13J/g or so,thermal conductivity were increased by about 30%;and when the doping amounts increased beyond 5.6%,with increasing the doping amounts,the thermal conductivities of the composites increased greatly;the thermal conductivity of the 10.7%-MWCNTs/TD/SiO₂ can be up to 0.734W/?m·K?,compared with the 60%-TD/SiO₂,and phase change enthalpy decreased about 10%.