E-DPD Simulation On Thermal Conductive Polymer Composites

In the field of composite materials,the thermal property of polymer composite has been a hot research issue.Thermal conductivity of polymer-based composites is strongly depended on the filled with thermal conductive fillers and whether the formation of a heat conduction path in the system.Due to polymer matrix composites has better insulation,a unique processing and structural characteristics,prompting it occupies an irreplaceable superior performance,which applied to the process of developing of science and technology.However,most of the polymer material is a poor heat conductor,so the single material of polymer could not be able to meet the needs of industrial production in some application areas.Therefore,to prepare polymer matrix composites with high thermal conductivity is inevitable.For example,adding some high thermal conductivity fillers in the polymer materials can be very good to improve the performance of thermal conductivity.Furthermore,it is very difficult for researchers to use experimental methods to control and characterize the heat conduction mechanism of the thermal conductivity of composite materials and thermal conductive fillers form the network structure of thermal conductivity.Computer simulation could be well simulation study of the microstructure of the polymer composite,explain and analyze the performance of thermal conductivity of composite materials in the micro level.This paper based on the energy-conservation dissipative particle dynamics simulation model(e-DPD)to study the microstructure of composite materials and the effect on the thermal conductivity of composite materials self-assembly configuration,the concrete contents are as following:The micro structure morphology of the composite effect on the performance of the thermal conductivity of the composite has been researched.When the thermal conductive fillers in the composite system on the direction of heat flow and heat transfer within a radius form the ideal thermal conductive pathways can greatly improve the coefficient of thermal conductivity,but it still cannot be achieved for the current technology to improve so much the performance of thermal conductivity of composite system.For solving of thermal decomposition of the total heat flow of composite material system,the results of the research show that the main reason for increasing the composite material coefficient of thermal conductivity is mainly caused by the heat flow between the thermal conductive fillers.When the thermal conductive fillers in the composite system on the direction of heat flow and heat transfer without a radius of the formation of a pseudo heat conduction path,it also can be effectively improve the performance of thermal conductivity,so that we can reduce the amount of filling packing in the composite system.Choosing two different morphologies of high thermal conductive fillers to study the morphology,size and filling content on thermal conductivity of composite materials.Studies have shown that the thermal conductivity of composite system with two different morphologies of high thermal conductive fillers can be improved with increasing the filling contents of thermal conductive fillers,but it is significantly for the thermal conductivity of adding the lamellar fillers composite system higher than the cubic-center fillers composite system.Changing the size of the cubic-center fillers in composite materials,the smaller size of cubic-center fillers,the greater of the heat flux of the composites,from the decomposition of total heat fluxes figure can be seen that the smaller size of the cubic-center fillers,the greater of the heat flow between the fillers and the polymer,meaning that smaller size of filler could be able to disperse in polymer matrix,it significantly to improve the thermal conductivity of composites.For different sizes of lamellar fillers(L3,L4,L9 and L16)of composite system,the thermal conductivity of composites with L4 is higher than other composites.Making three sizes of lamellar fillers(L3,L4 and L9)be orientated and dispersed in the composites,the thermal conductivity of the orientation of the lamellar filler is better than the dispersion of the complex system,and the coefficient of thermal conductivity system of composite material with orientating of L4 is highest.With the selected fillers in the system,the self-assembly configuration on thermal performance of composite materials is researched.we selected symmetry two block polymer(A16B16)for matrix,the morphology,filling content and the distribution of thermal conductive fillers as well as thermal conductive fillers on the selection of the matrix form the micro phase of the composite structure can affect the performance of thermal conductivity of composite materials.In this section,the maximum value of the filling content of the fillers is 12.5%,to guarantee the thermal conductive fillers will not change the layered structure of the diblock copolymers.The value of thermal conductivity of three different shapes fillers(P1,R5 and L25)of the composite systems is compared,L25>R5>P1.With increasing the filling content of fillers,the thermal conductive of different shapes,and the coefficient of thermal conductivity of composite system is also increased.As can be seen from the VMD diagram,the lamellar fillers can be well dispersed in the diblock copolymer,and could be oriented distribution in the B phase and two phase interface,so it is easy to form network chain of thermal conductivity in composite system.The thermal conductivity of the enrichment phase of thermal conductive fillers is distributed in B phase and phase interface is higher than fillers in the A and B phase dispersed distribution of blending system of self-assembly configuration,and it is advantageous to improve the performance of thermal conductivity of composite system Take two kinds of homopolymer(A32 and B32)as the matrix,changing the A32 and B32 hybrid ration、thermal conductive fillers morphology and distribution on the selection of the matrix form the micro phase of the composite structure influence on the performance of thermal conductivity of composite materials.The filling contents of thermal conductive filler is 5%,changing the ratio of compound A32 and B32,and adding different morphology of thermal conductive fillers in the composite system(P1,R5 and L25)the results show that A32:B32=29:9,the L25 is well effect the thermal conductivity of composite system.As can be seen from VMD figures,the L25 could lead to a better orientation distribution in matrix,and it good for improving the heat conduction performance.And it also shows that the thermal conductive filler concentration distribution in the B phase and two phase interface than the thermal conductive fillers scattered distribution in two phases when blending system of self-assembly configuration is more advantageous to improvement performance of thermal conductivity of composite system.