Photocuring Preparation And Properties Of Polyethylene Glycol Phase Change Composites

In recent years,development of sustainable energy technology and improving energy utilization have become an inevitable trend to solve energy shortage and environmental pollution.Thermal energy storage(TES)is an effective way to improve energy efficiency.It can be used to collect and store thermal energy,and release thermal energy when needed,which helps solve the problem of not matching energy supply and demand in time and space.Phase change energy storage technology is the key to TES.The use of phase change materials(PCM)to absorb or release a large amount of potential heat during the phase change process,while maintaining the system temperature constant,and then achieve sustainable energy use.Among the many types of PCMs,the solid-liquid PCM is widely used in the energy storage system due to the characteristics of high latent heat density.However,the solid-liquid PCM has certain liquidity in the melting state,and it is easy to leak.In addition,the low thermal conductivity is also a common problem in the actual application of solid-liquid PCM.In response to the above problems,the development of new high thermal conductivity phase change materials with stable shapes has become a research hotspot in the field of latent thermal energy storage.In various types of PCMs,polyethylene glycol(PEG)has the advantages of high enthalpy of phase transformation,good chemical stability and thermal stability,appropriate phase temperature,non-toxic and other advantages,as the most promising solid-liquid PCM has been extensively studied.In response to the problem of poor shape stability and low thermal guidance rate in the application process of solid-liquid phase change materials,this article proposes a simple and efficient preparation method of shape stable and high thermal conductivity composite phase change materials(PCM).Differentiated polyethylene glycols with different molecular weights are scattered into ultraviolet light resin containing neopentyl glycol dimethacrylate(NPGDMA),and NPGDMA resin monomers are solidified under the action of ultraviolet light to form a cross-linking structure for phase change component to provide supporting structure,which effectively avoids the leakage of polyethylene glycol.By adding a certain amount of boron nitride(BN)as the thermal filler,the thermal conductivity of the polyethylene glycol composite PCM is increased.The dissertation successfully prepared two new types of ultraviolet lighting curable phase change composite materials suitable for low-temperature thermal energy storage(TES).The infrared spectrum,XRD,and SEM were used to conduct structural representation and appearance observation of sample test samples.Considering the shape stability,leakage situation and energy storage effect of the material,the best proportion of PEG2000 to NPGDMA in PEG2000/NPGDMA/BN composite PCM is 9:1.By measuring and analyzing the thermal conductivity,it was determined that the optimal addition amount of BN was 5 wt%,which increased the thermal conductivity by 52.1% compared to pure PEG2000.After DSC tested,PEG2000/NPGDMA/BN has good thermal storage capacity,and its enthalpy of melting and crystallization can reach 139.3 J/g and 128.4 J/g,respectively.101 thermal cycle tests were performed on PEG2000/NPGDMA/BN.Compared with the first cycle,the melting and crystallization enthalpy of the samples after 101 cycles were reduced by about 7.1% and 3.0%,indicating that PEG2000/NPGDMA/BN compound PCM has excellent thermal circulation performance.Use the same process method to conduct a research and thermal performance of the prepared PEG6000 base composite PCM.The results show that the optimal proportion of PEG6000 and NPGDMA in PEG6000/NPGDMA/BN is 9:1,and the best addition of BN thermal filler is 5 wt%,which increased the thermal conductivity by 51.4%compared with pure PEG6000.The melting temperature of PEG6000/NPGDMA/BN is 57.9 °C,and the energy storage density can reach up to 147.4 J/g.Compared with PEG2000 based phase change composite materials,PEG6000 based phase change composite materials have better heat storage capacity.After 101 thermal circulation,the phase change heat of the sample decreases by about 5.7%,which also has good thermal cycle capacity.The results of thermal test show that the prepared composite PCM has good thermal stability below 200 °C.Provide a preparation method of photocuring for future related studies.