Preparation And Properties Of Composite Phase Change Materials Based On HTC/PAAAM

With the rapid advancement and development of global industries,it's very important to improve the efficiency of energy use.Phase change materials(PCMs)are increasingly meaningful in the field of energy science,especially for thermal storagerelease technology,it is also one of the main ways to improve energy efficiency.Among varied types of PCMs,solid-liquid phase change materials possess high latent heat of phase change,but their applications were limited by the low thermal conductivity and excessive fluidity in the phase transition process,therefore,the synthesis of form-stable PCMs with high thermal conductivity is significant for researching.In this paper,three phase change materials with high application value,SD/HTC/PAAAM,OB/HTC/PAAAM and OG/HTC/PAAAM,were prepared.Where the poly(acrylamide-co-acrylic acid)(PAAAM)was used as support materials,and hydrothermal carbon spheres(HTC)was used as high thermal conductivity filler for inorganic-inorganic,organic-inorganic and organic-organic binary solid-liquid phase change material systems.After successfully preparing the samples,the infrared spectroscopy,X-ray powder diffraction analysis and scanning electron microscopy were used to analyze the reaction materials and the products of the form-stable phase change materials.The results of infrared spectroscopy and X-ray powder diffraction analysis showed that the structural characteristics of the phase change materials were basically consistent before and after the doping.Scanning electron microscopy showed that the phase change materials and the HTC were closely and evenly distributed in the cross-network structure of PAAAM.The results of DSC and thermal conductivity tests on the phase change materials showed that three kinds of ideal form-stable change materials with high thermal conductivity have been obtained.The melting enthalpy of SD/HTC/PAAAM is 203.3 J/g when the doping ratio is 700/10/28.The thermal conductivity is significantly improved compared to SD/PAAAM,and the supercooling degree is only 7.9 °C,which means the inherent supercooling issue of inorganic solid-liquid phase change materials has been improved,furthermore,it exhibited good recyclability in 101 cycles.OB/HTC/PAAAM has a melting enthalpy of 311.8 J/g with the doping ratio of 100/3/8,and the thermal conductivity is 205.4% higher than that of OB/PAAAM.Compared with the DSC curves of OB and OB/HTC/PAAAM,the phase separation problem of binary phase change material,OB,has been fully solved.The degree of supercooling is only 5.9 °C,and there is no significant change in thermal properties after 101 cycles of melting-crystallizing.When the doping ratio of OG/HTC/PAAAM is 100/2.5/6,the melting enthalpy is 313.2 J/g,the thermal conductivity is relatively increased by 205.5%,and the DSC curves is basically consistent before and after 101 cycles.