Preparation And Modification Of Ionomer-based Flexible Composite Phase Change Materials

Latent heat storage is the storage and release of thermal energy through phase changes of materials.It is really stands out as its high energy storage density,good chemical stability and simple application.And the most important part of latent heat storage technology is the immobilization of phase change materials.Thus,studies on composite phase change materials which with polymer material as matrix materials is a hot spot in recent research.In this paper,EPDM was sulfonated to construct micro-crosslinking structures and internal ionic micro-domains.Sulfonated EPDM was used as the matrix material,CA-PA was used as the phase change materials,and the ionomer-based flexible composite phase change materials was prepared by mixing and compression molding.Main details are as follows:(1)Studies on modification of ionomer matrix of flexible composite phase change materials by regulating the type and ratio of cation species.The interaction between the cations and the sulfoacid groups determines various properties of ionomers.Since the different kind of cations have different forces on the sulfoacid groups,micro-crosslinked structures will be affected and so that the encapsulation ability will be affected too.So properties of ionomers can be adjusted by changing the cation species which within the ionomers.In this paper,salts with 2n2+?Ba2+?Pb2+and their combinations were used as neutralizer in ionomers to prepare flexible composite phase change materials with different cation species.And then,thermal energy storage properties,thermal stability,exudation properties and mechanical properties of these composite phase change materials were studied.The results show that composite phase change materials with the combination of Zn2+and Ba2+as cations of ionomers with higher thermal energy storage enthalpy and more stable encapsulation ability of phase change materials.(2)In order to improve the thermal energy storage properties of the cation-optimized ionomer-based flexible composite phase change materials,ionomers with the composite of Zn2+and Ba2+as cations was used as matrix materials.Composite phase change materials with different contents of CA-PA were prepared.The exudation performance,thermal energy storage enthalpy and thermal stability of composite phase change materials with different content of CA-PA were studied.The results show that when the cation of ionomers is the composite of Zn2+and Ba2+and the CA-PA content is 45wt%,the composite phase change material has higher thermal energy storage enthalpy,less exudation and best overall properties.(3)The thermal conductivity of phase change materials is poor,which will affect the thermal energy storage process.To improve the heat transfer efficiency of composite phase change materials,three kinds of inorganic heat conducting particles were introduced to modify the composite phase change materials.Three kind of inorganic heat conducting particles are BN,Al2O3 and EG.The thermal conductivity,thermal stability,thermal energy storage enthalpy and exudation performance of composite phase change materials with different content of inorganic heat conducting particles were studied.The results show that when the content of BN is 25wt%,the composite phase change material has the best thermal conductivity.