Preparation And Properties Of Epdm-Based Thermally Conductive,Elastic And Shape-Shabilized Phase Change Materials By Emulsification Method

The energy shortage and environmental pollution are becoming more and more serious with the rapid development of economy.Phase change materials?PCMs?have received wide attention due to their excellent heat storage capacity,environmental-friendly and high performance scalability.Leakage problems of PCMs during use have made it particularly important to modify them.Encapsulation of PCMs in polymer materials by emulsification is an effective method for preparing shape-stabilized phase change materials?SSPCMs?.The polymer can enhance the mechanical properties of the PCMs,and fits well with the power device and the heat sink to provide damping.At the same time,the polymer plays as a supporting and shape-stabilized role to prevent the PCMs from leaking.In some application fields,PCMs are also required to have high thermal conductivity,and the introduction of high thermal conductivity fillers therein is the main method for thermally enhanced modification.?1?In this paper,paraffin was choosed as the PCMs,and ethylene propylene diene monomer?EPDM?was used as the polymer supporting material.Phase change latex?PCL?was prepared by an emulsification method.The effects of emulsifier type,emulsifier content,emulsification rate and paraffin content on PCL performance were investigated.The excellent overall performance of PCL was obtained with Span-80 and 1-dodecanesulphonic acid sodium salt as the emulsifier and their content as 6.0%,the emulsification rate as16000 r·min^-1 and the paraffin content as 70%.SSPCMs were obtained by hot press vulcanization.Through various performance tests,it is shown that an increase in paraffin content leads to an increase in leakage rate of SSPCMs and a decrease in thermal conductivity.SSPCMs have excellent overall performance when the paraffin content is50%.?2?By Pickering emulsification method,graphene oxide?GO?was introduced into PCL as a co-emulsifier using its amphiphilicity,and GO is coated on the surface of PCL latex particles.Elastic shape-stabilized phase change materials?ESPCMs?were obtained by chemical reduction and hot press vulcanization.Performance tests show that ESPCMs have significant improvement in barrier properties,mechanical properties,thermal conductivity and heat storage performance compared to SSPCMs attributed to the introduction of GO.The 48-hour leakage rate of ESPCMs-0.5 is only 0.3%,and the tensile strength and elongation at break reach 2.26 MPa and 1660%,which achieves the purpose of further improving the anti-leakage performance and mechanical properties of GO at low content.?3?Positively-modified graphene?GE?was introduced into PCL by latex blending.GE and latex particles were tightly combined for the adsorption characteristic of GE and then hot-press vulcanization to obtain a thermally conductive and thermally conductive shape-stabilized phase change materials?TSPCMs?.The thermal conductivity test shows that the thermal conductivity of TSCPMs-2.0 is 0.985 W·m^-1·K^-1,which is 169.9%and47.7%higher than that of SSPCMs-50 and ESPCMs-2.0 respectively.The actual enthalpy and theoretical value error was only-1.00%,and leakage rate was only 0.621%after the 48h leakage test.