Preparation And Properties Of PEG/PUA Flexible Phase Change Composites Based On UV Curing

Recently,energy shortages and environmental pollution have become a source of considerable concern,and there is an urgent need for sustainable energy.Thermal energy storage(TES)is an effective way to reuse large amounts of thermal energy by improving energy efficiency through the use of sensible and latent heat.TES has attracted widespread attention because of its ability to regulate the imbalance between energy supply and demand in time and place.In particular,the application of latent heat storage based on phase-change materials(PCMs)is an effective way to expand the application of thermal energy in defined operating temperatures.Conventional phase change materials often suffer from rigidity,hardness and susceptibility to leakage due to their crystalline properties,limiting its use in real-life applications.In this paper,polyethylene glycol(PEG)is selected as the phase change material and polyurethane acrylate(PUA)as the flexible matrix,so as to enhance its mechanical properties and reduce the leakage rate.The thermal conductivity of the phase change composites is then improved by adding a high thermal conductivity filler,boron nitride(BN).The main contents of this paper include:(1)PEG/PUA flexible phase change materials were prepared rapidly by UV curing method.The effects of different PEG contents on the performance of the materials were investigated.The high-strength three-dimensional network structure formed by PUA after UV curing can prevent the flow of molten PEG.Simultaneously,a large number of hydrogen bonds are formed between the hydroxyl groups of PEG and the carbonyl groups of PUA.The results show that the FPCM has excellent mechanical ability,reversible optical performance,flexibility which is not dependent on temperature,and good leak-proofing performance.(2)The PEG/PUA/BN thermally conductive flexible phase change material was rapidly prepared by UV curing method.The effects of different BN contents on the performance of the materials were investigated.According to the SEM cross-section,PEG and BN can be completely coated by PUA matrix and distributed evenly in PUA matrix,and no obvious agglomeration phenomenon occurs in two-dimensional sheet BN,which can form a complete heat conduction pathway.The thermal conductivity of the material is proportional to the content of BN,and the thermal conductivity of the prepared sample reaches up to 0.73 W/(m·K),which is nearly three times higher than that of pure PEG.In terms of mechanical properties,the addition of BN decreases the tensile strength and elongation at break,but the material still has good mechanical properties.In the leakage rate test experiments,the PEG/PUA/BN thermally conductive and flexible phase change material showed excellent shape stability and good leakage prevention performance.