Molecular Dynamics Research On Normal Thermal Conductivity Of Swcnt/Epdm Composite

Thermal conductive materials are widely used in various fields of the national defense industry and economy. In recent years, with the rapid development of science, technology and industrial manufacture, a lot of new requirements have been put forward for materials in applications of many special occasions. Especially for thermal conductive materials, we hope material not only have good comprehensive performance, but also possess a higher thermal conductivity.High polymer material is one of the frequently-used thermal conductive materials. So, further investigation on thermal conductivity and thermal conduction mechanism is needed for high polymer materials. As we all know, carbon nanotubes are nano-sized materials with extra high thermal conductivity and have been used as thermal conductive filler for high polymer product. In accordance, this paper focus on rubber materials filled with carbon nanotubes, using equilibrium molecular dynamic method. First, this paper expounds on the relevant knowledge of thermal transport in carbon nanotube/polymer composites. Then, impact of structure defect on carbon nanotubes’ thermal conductivity is also investigated. And, atomic and molecular interactions in polymer materials are studied using AIREBO potential. Finally, we studied the thermal conductivity changes of EPDM rubber after filling in different kinds of carbon nanotubes with different sizes.For thermal conductivity of carbon nanotubes:Ideal defectless carbon nanotubes present good ability of thermal transportation due to its unique structure; however, the actual defect carbon nanotubes have varying degrees of lower changement of thermal conductivity. And, defects located on the edge have a greater impact on the thermal conductivity of carbon nanotubes. So actual application needs to guarantee the quality of carbon nanotubes, as far as possible avoid vacancy and other defects. Study of atomic and molecular interaction in EPDM composite show that the coefficient set in Torsion term of AIREBO potential is extremely important to the simulation of thermal conductivity. For thermal conductivity of carbon nanotube/EPDM composite:for carbon nanotubes with same length, as the change of diameter, thermal conductivity of its composite system doesn’t show certain regularity, stable at around100W/(m-K). At constant length in carbon nanotubes, with the increasing of diameter, number of carbon atoms increases, coupled with EPDM molecule belongs to high polymer chain molecules and has complex molecular structure, carbon atoms in carbon nanotubes/EPDM composite is likely to form different interaction, so that the simulation results of the present rules are not enough clear. Excellent one-dimensional heat conduction properties of carbon nanotubes are also suitable for carbon nanotubes/EPDM composites. Metal and half-metal carbon nanotubes are showing a lower thermal conductivity comparing with the semiconducting carbon nanotube and good electrical conductive carbon nanotubes has poor heat conduction ability.