Magnetic Field Processing Impact On The Structure And Performance Of Nano-carbon Material/polyethylene Composites

Besides the nature of the polymer and filler itself, the property of the polymermatrix composites is also connected with distribution state and orientation degreeof fillers. Nano carbon materials (nano graphite, graphene, carbon nanotubes, etc.)present the anisotropy of electricity conductivity and thermal conductivity due tothe special carbon atoms arrangement, and can make a certain response to themagnetic field. Therefore, it is expected to control the distribution andorientation of nano carbon materials in the nano carbon materials/polymercomposites by applying the magnetic field under the molten state, and thenexcellent performance nano-composites can be obtained.In the paper, nano graphite/polyethylene and carbon nanotubes polyethylenecomposite materials were prepared by melt blending. By applying steady highmagnetic field in the hot forming process of the composite material, the influenceof the magnetic field treatment on the structure, conductivity and thermalconductivity properties was studied and the conductivity properties of thecomposite material with different orientation degree of nano graphite and carbonnanotubes was calculated by the simulation. Experimental results show that nanographite and carbon nanotubes are along the magnetic field orientation in thepolyethylene, and the axial orientation of flake graphite layer and the carbonnanotubes are parallel to the magnetic field after magnetic treatment. Thecomposite treated by magnetic field has the higher conductivity and coefficientof thermal conductivity, and the orientation degree of nano graphite and carbonnanotubes and the conductivity of the composites increase with polyethyleneviscosity decreasing. Simulation results show that under the case of the certain nano-graphite and carbon nanotubes size, the conductivity of the compositesincreases with mass fraction of nano-carbon filler increasing; at the same massfraction of the filler, the conductivity of composite materials increase with theradius-thickness ratio of the nano-graphite or the aspect ratio of carbonnanotubes increasing; the conductivity of the composite increases with thedirection angle of nano-graphite layers or carbon nanotubes axial direction andthe applied electric field reducing. Experimental results are in good agreementwith the simulation results.