Preparation And Thermal Storage Properties Of Core-shell Phase Change Fibers Based On PVA

Phase change materials(PCM)has great application potential in thermal energy storage,improving energy efficiency and reducing environmental pollution.Traditional PCM has the disadvantages of leakage,excessive deformation and single function.Phase change fibers(PCF)with core-shell structure and thermal storage property can effectively solve the problem of liquid leakage and excessive deformation by coating PCM into polymer fibers.At present,a large amount of organic solvent is used in the process of preparing PCF,which causes environmental pollution.In this paper,PCF with polyethylene oxide(PEO)and lauric acid(LA)as the core and polyvinyl alcohol(PVA)as the shell were prepared by electrospinning and wet spinning in aqueous solution,respectively.In addition,magnetic Fe3O4 nanoparticles are added and the surface of PCF is chemical crosslinking to achieve its multifunctionalization and improvement of mechanical property,thus to expand the application field.The main contents are as follow:(1)Coaxial phase change fibers(CPCF)with core-shell structure were prepared by coaxial electrospinning technology with PEO as the core layer and PVA as the shell layer using H2 O as solvent.With the increase of the core/shell speed ratio,the diameter of the core layer gradually increases,the shell layer gradually becomes thinner,and the latent heat gradually increases.When the core/shell speed ratio is 3:1,the ΔHm/ΔHc of CPCF reaches 106.96/101.91 J/g,respectively,the encapsulation rate of PCM is as high as 78.02%,and the thermal stability and cycle stability are excellent.In addition,CPCF has excellent thermal management ability,and the maximum temperature of the resistor chip coated CPCF is 3.7,12.1 and 26.6 °C lower than that of the blank resistor chip at output powers of 2.5,3.5 and 5 W,respectively.CPCF maintained its original thermal properties after crosslinking,while the ultimate stress increased by 4.1 MPa to 14.0MPa.(2)Magnetic coaxial phase change fibers(MCPCF)with core-shell structure were prepared by coaxial electrospinning technology with PEO and Fe3O4 nanoparticles as the core layer and PVA as the shell layer.When the addition of Fe3O4 is 20 wt%,theΔHm/ΔHc of MCPCF is 93.36/92.11 J/g,respectively,the encapsulation rate of PCM is as high as 64.52%,and the thermal stability and cycle stability are excellent.MCPCF achieves an average electromagnetic shielding performance of 3 d B and realizes 50%electromagnetic wave absorption.In addition,MCPCF has good thermal management ability,and the maximum temperature of the resistor chip coated MCPCF is 14.0 and7.4 °C lower than that of the blank resistor chip at the output power of 3.5 and 5 W,respectively.MCPCF maintained its original thermal properties after crosslinking,while the ultimate stress increased by 3.9 MPa to 8.3 MPa.(3)Microsphere phase change fiber(MPCF)with core-shell structure was prepared by wet spinning technology with LA as the core layer and PVA as the shell layer.With the increase of LA,the latent heat of MPCF increases gradually.When the mass ratio of LA to PVA is 1:1,the ΔHm/ΔHc of MPCF is 61.29/61.91 J/g,respectively,the encapsulation rate of PCM reaches 34.26%,and the thermal stability and cycle stability are excellent,providing a new idea for the preparation of PCF from oil-soluble PCM in aqueous solution.