Study On Preparation And Properties Of Polyethylene Glycol Phase Change Material

Polyethylene glycol is an excellent cool storage material,but the poor thermal conductivity and poor storage performance become it’s major defect.The PEG/EG is composite of polyethylene glycol(PEG)as plhase change material and expanded graphite(EG)as thermal conductivity enhancer and adsorption substrate,and analysis the improvement of composite materials’ properties.(1)Muffle furnace heat expansion method is used to prepare EG.To find the best preparation conditions,there is a requirement to measure different preparation conditions.Using the Scanning Electronic Microscopy(SEM)to observe the microstructure of expanded graphite and PEG/EG composites.We had drew a colclusion that,under 800 ℃ treatment temperature and 30s heat treatment time become the best conditions to prepare the EG;The mass fraction of EG in the composite materials being 8wt.%can solve the leakage problem.(2)By using the DSC to analysis effect on thermal conductivity of composite materials of different EG content.FLA447 were carried out to study the cottent of EG and degree of pressure effect on thermal conductivity of PEG/EG composites.Using the SEM to observe microstructure of different thermal conductivity composite under different EG content and pressure.(3)To make the PEG phase transition temperature range from～5.0℃ to 14.6℃,mixing different molecular weight of PEG is necessary.Adding oxalic acid to increase the crystallinity of PEG1000.When the oxalic acid content was 0.25wt.%,the phase change enthalpy of oxalic acid/PEG1000(193.7kJ/kg)is 1.55 times that of pure PEG1000.(4)In order to get the cool storage curve and explore different element how to effect the cool storage process of different mass fraction,the engineering survey method was used to measure cool storage process of phase-change material.Experiments proved that the cool storage process improves with the mass fraction increasing;The polyethylene glycol of the composite reduce the impact of cool storage process from coolant temperature and quality of the coolant;The composite method of PEG/EG can apply to different formula weight polyethylene glycol.The experimental study results show that material compounding method can enhance thermal and cool storage properties and solve leakage problem.Material blending method and oxalic acid addition can improve the performance of phase change materials.