Effect of magnetic field treatment on the electrical conductivity of low-density polyethylene and its composites with CNTs

Low-density polyethylene (LDPE) and carbon nanotube (CNT) composites (CNT/LDPE) were treated during their hot-press molding using a strong static magnetic field. The effect of the magnetic field on the direct current electrical conductivity of these materials was investigated and the mechanism for the effect was analyzed by differential scanning calorimetry, polarized light microscopy and atomic force microscopy. Results indicate that the magnetic field treatment increases the degree of crystallization and the volume resistivity of the composites. The induced magnetic moment in the CNTs caused by the magnetic field leads to an improved orientation of the CNTs in LDPE along the magnetic field direction during molding, which causes an increase in the electrical conductivity of the CNT/LDPE composites in the magnetic field direction and an increase of nonlinear conductivity characteristics. The increased amplitude of electrical conductivity of the composites increases with the increasing amount of CNTs added.