Preparation And Characterization Of Phase Change Hydrogels And Phase Change Microcapsules

The development of innovative encapsulating technologies are particularly important to solve the problems in the use of phase change materials,such as excessive supercooling,serious phase segregation,easy aging and so on.In this paper,acrylamide was used as the main monomer of the polymer,the polyacrylamide hydrogel with excellent tensile and elastic properties was achieved by the chelating effect of sodium alginate and calcium ions in the gel network.A kind of phase change energy storage hydrogel was prepared by the combination of inorganic phase change material Na2SO4·10H2O with three-dimensional polyacrylamide network.The hydrogel have owned both the function of energy storage and good mechanical properties,and the shape is stable in the process of phase change.The form-stable phase change hydrogel(PCH)could overcome the flaw of extra container packing.With the increase dosage of NaSO4·10H2O,the appearance hydrogel tends to be translucent;enthalpy gradually increases;the tensile properties and compressive properties of the hydrogel has a certain degree of decline,while the supercooling degree,crystallization temperature and melting temperature show a certain regularity.The prepared hydrogel has good mechanical properties and stable energy storage effect,which combines the advantages of organic and inorganic materials,tries to solve the supercooling and phase segregation existing in inorganic phase change material.Compared to the traditional phase change material the prepared composite PCH has a broader application prospect.Based on the prospective of multi-function,a kind of composite phase change microcapsule with heat storage and fluorescent properties is designed.Through condensation reaction which was caused by two kinds of silicon monomers in the interface of oil and water,the fluorescence of rare earth nano-Y2O3 and phase change material polyethylene glycol were both encapsuled by polydimethylsiloxane which served as shell material.Characterized by a series of experiments,the prepared microcapsules has not only good photoluminescence properties,but also owns good thermal properties despite of the decline in enthalpy comparing with the pure PEG,which can meet the needs of practical application.It has demonstrated by the experiments that the technology of encapsulating PEG with silicone shell can effectively reduce the supercooling degree of the phase change material.The prepared composite phase change energy storage microcapsule has an innovative application and wide development value in the field of new energy storage materials.