Preparation Of Graphene Oxide/Methoxy Polyethylene Glycol/Polypropylene Phase Change Fiber

Phase change fiber(PCF)is a kind of smart fiber prepared by combining phase change materials with polymer matrix.Phase change fibers can be used to maintain the textile temperature by storing or releasing heat to response the rising or dropping ambient temperature.However,the organic‘solid-liquid'phase change materials are likely to leak during spinning process and daily use.Therefore,it is necessary to fix the phase change materials in polymer matrix for long duration time.In this paper,methoxy polyethylene glycol(MPEG)was selected as the phase change material due to the suitable phase change temperature,high enthalpy value,and good thermal stability.In order to solve the leak problem of organic‘solid-liquid'phase change materials during melt processing,spongy graphene oxide(SG)with rich functional groups was used as the carrier material to fix MPEG.A form-stable phase change material(FSPCM)was prepared by combining MPEG and SG with chemical-physical method.A physical combined SG/MPEG composite was also prepared.Polypropylene(PP)/FSPCM and PP/(SG/MPEG)composite was prepared in a twin-screw extruder and melt-spun into fiber eventually.The main research contents of this paper are as blow:(1)Preparation and properties of spongy graphene oxide grafted methoxy polyethylene glycol form-stable phase change materialsFSPCM was prepared by combing chemical and physical methods with dicyclohexylcarbodiimide(DCC)and 4-dimethylaminopyridine(DMAP)as catalysts,where SG was used as the carrier to fix the MPEG phase change material.Fourier transform infrared spectrometer(FTIR),laser Raman spectrometer,differential scanning calorimeter(DSC),thermal stability and heating stage were used to evaluate the structure and performance of FSPCM.The results indicate that esterification reaction occurs between MPEG and SG.In the case of FSPCM with 6 wt%of SG,FSPCM presented high-temperature form-stability without any liquid leakage at 250°C.The melting temperature and crystallization temperature are 37.5°C and 26.1°C,respectively.The melting enthalpy and crystallization enthalpy reach to 129.7 J/g and 126.3 J/g,respectively.(2)Preparation and properties of polypropylene/spongy graphene oxide grafted methoxy polyethylene glycol blend materialPP/FSPCM 6 was prepared by blending PP with 10wt%of FSPCM 6 in a micro twin-screw extruder.PP/FSPCM 6 phase change fibers were taken-up by winding machine to simulate phase change fibers.The structure and properties of PP/FSPCM 6 composite were characterized by Lycra optical microscope,DSC,and thermal conductivity tester.The results showed that melting temperature and crystallization temperature of PP/FSPCM 6 blend material are 29.3°C and-5.0°C,respectively.The melting enthalpy and crystallization enthalpy values are 11.6 J/g and10.1 J/g,respectively.FSPCM 6 was well dispersed in PP matrix without significant agglomeration phenomenon.(3)Preparation and properties of polypropylene/spongy graphene oxide/methoxy polyethylene glycol phase change fiber.PP/(SG/MPEG 10)and PP/FSPCM 6 was prepared by blending 11 wt%of SG/MPEG 10 or FSPCM 6 and 89 wt%of PP in a micro twin-screw extruder.PP/(SG/MPEG 10)phase change fiber and PP/FSPCM 6 phase change fiber was melt-spun in a lab spinning machine.The structure and properties of fiber were evaluated by FTIR,Lycra optical microscope,DSC,and thermal conductivity tester.The results showed that form-stable material were uniformly distributed in the core of fiber.The phase change temperature of PP/(SG/MPEG 10)phase change fiber and PP/FSPCM 6 phase change fiber are 35.4°C and 39.6°C,respectively.The phase change enthalpy are 7.3 J/g and 8.7 J/g,respectively.The phase change enthalpy of PP/FSPCM 6 fiber is higher than that of PP/(SG/MPEG 10)phase change fiber.Heat storage/heat release curve reflected that the temperature rise and fall times were delayed by 176 s and 62 s,indicating a high energy storage temperature adjustment effect of PP/FSPCM 6 phase change fiber.The thermal conductivity of PP/FSPCM 6 phase change fiber is 0.23 W·m^-1·K^-1,which was 15%higher than pure PP fiber due to the existence of 0.5 wt%SG.