Preparation And Properties Of Electrospun Functional Form-stable Phase Change Composite Fibers

The eutectic mass ratios and thermal energy storage properties of a series of fatty acid binary, ternary, quaternary and quinary eutectics were calaulated and investigated by using schreder equation and differential scanning calorimeter(DSC). The prepared different kinds of fatty acid multielement eutectics have the same excellent properties as the fatty acids. And the phase change temperatures of multielement eutectics were significantly lower than those of individual fatty acids, which can meet the need of the practical climatic requirements. The successful preparation of new kinds of fatty acid multielement eutectics enriched the varieties of phase change materials(PCMs) and increased the selectivity of practical applications.The ten kinds of fatty acid binary eutectics were respectivily encapsulated into the supporting matrices of polyethylene terephthalate(PET) to prevent their leakage from composite fibers during phace change processes by electrospinning technology. The maximum load of electrospun PET fibers for fatty acid binary eutectics were determined according to different PET concerntrations. The phase change temperatures and enthalpies of form-stable phase change composite fibers can be adjusted by changing the types and mass ratios of fatty acid binary eutectics in the composite phase change fiber systems.The distributions of glycerol monostearate(GMS) component acting as solid-liquid PCMs and PET supporting materials in prepared composite phase change fibers were systematically determined and influences of GMS content on morphological structure, thermal energy storage properties, thermal stability and mechanical properties of form-stable phase change composite fibers were also studied. The two phase separation(i.e., GMS phase and PET phase) was clearly observed with the increase of GMS content in composite fibers. The GMS acting as the dispersed phase broke the continuous phase structure of electrospun PET fibers, which resulted in the decrease of mechanical properties of composite phase change fibers.The graphene oxide(GO) with high thermal conductivity were used to improve the thermal energy storage and retrieval rates of electrospun methyl stearate/polyacrylonitrile(MES/PAN) form-stable phase change composite fibers. Influences of GO addition on the chemical properties, structural morphologies, mechanical properties, thermal energy storage properties, thermal stability and thermal energy storage/retrieval rates of the MES/PAN/GO composite fibers were investigated. The results revealed that the incorporation of GO effectively enhanced the mechanical properties, thermal stability, as well as heat storage and release rates of the phase change composite fibers.Magnetron sputtering technology was applied to improve the thermal energy storage and release rates of form-stable PCMs. The Ag nanostructure films were firstly deposied on the surface of polymer fibers(e.g., PAN and PU), and then the fatty acid ternary, qurternary and quinary eutectics were respectively adsorbed or distributed into the three-dimensional porous network structures of Ag-coated PAN or PU fiber membrnes selecting as supporting materials by physical adsorption method to prepare a series of form-stable phase change composite fibers membranes with different thermal enengy storage properties. The morphological structure and thermal energy storage properties of the prepapred form-stable phase change composite fibers membranes were systematically studied and the effects of sputter coating times on thermal energy storage and release rates of composite fibers membranes were also investigated. The results indicated that the thermal energy storage and release rates of form-stable phase change composite fibers membranes were significantly improved by depositing Ag nanostructure films with high thermal conductivity into the phase change systems. Therefore, the magnetron sputter coating can be acting as a new and efficient method to improve the thermal energy storage and release rates of form-stable PCMs.