Thermal Conductivity Of Expanded Graphite Enhanced By Resin Through In-situ Polymerization

With typical graphite structure,excellent thermal conductivity and other outstanding properties,expanded graphite(EG)prepared by applying an instantaneous high heart shoot to the graphite intercalation compounds(GIC)is often used to design and synthesis of composite materials in order to improve the performance.The separate EG or CEG is easy to be broken,which leads it difficult to use separately in practice.The use of expanded graphite particles or compressed expanded graphite(CEG)as the matrix has a great influence on the thermal conductivity of the composites.The CEG conductive network is easily destroyed in the preparation process of the composite to reduce the thermal conductivity,so the research on the influencing factors in the preparation to obtain the high thermal conductivity of expanded graphite composite material is a very scientific and practical significant project.In this paper,in-situ polymerization and impregnation were used to prepare CEG Composites and the effects of different factors on the thermal conductivity of CEG composites were studied.Then phase change materials were prepared with CEG composite as the support system.The specific contents are as follows:The CEG composites prepared by in-situ polymerization can obtain higher thermal conductivity than the impregnation method under the same conditions.The thermal conductivity of the composites decreased with the increase of the resin content.This is the inevitable result since the thermal conductivity of resin is much lower than that of graphite.The concentration of the solution and the density of the expanded graphite are important factors affecting the thermal conductivity of the composites.The expanded graphite has abundant kinds of pores,which makes the CEG strong adsorption capacity to formaldehyde and oil.As a result,the effect of the total solution concentration on the composite material is difficult to predict,and the pore size distribution will change with the bulk density of the matrix.The results show that the adsorption properties of expanded graphite can be excluded in accordance with the experimental method.The higher concentration leads the higher resin content and the lower thermal conductivity.The larger density of the matrix leads the lower resin content and the higher thermal conductivity.On the other hand,the phase change energy storage materials were prepared by using the resin reinforced expanded graphite and paraffin.The thermal conductivity of the composites obtained in-situ polymerization is higher than composites with pure CEG enhanced paraffin or with CEG impregnated resin,which tells in situ polymerization can effectively improve the graphite conductive network.In summary,in situ polymerization is an effective way to improve the thermal conductivity of expanded graphite composites.There are many factors that affect the thermal conductivity of the expanded graphite composites,such as the preparation method,the total concentration of the solution,the bulk density of the matrix,and even the different solvents.