Surface resistivity of carbonaceous fiber/PTFE antistatic coatings

PAN(Polyacrylonitrile)-based carbonaceous fibers were prepared at the heat treatment temperature(HTT)range of 650 to 900 oC.The relationships among HTT,carbon content and volume resistivity of the carbonaceous fibers were investigated.The carbonaceous fibers/PTFE(Polytetrafluoroethylene)antistatic coatings were prepared by the spraying technology and the effects of carbonaceous fibers and pigments on surface resistivity of the coatings were systematically discussed.Micrographs provide insight into the antistatic mechanism of the coating.The results show that carbon content of the carbonaceous fibers increases from 68.8% to 74.8%(mass fraction)and the volume resistivity decreases drastically from 1.94×103 to 8.27×10-2 Ω·cm.The surface resistivity of the antistatic coating is adjustable between 105 and 108 Ω to fit the different antistatic materials.Static is dissipated by a conductive network of short fibers and the tunneling effect between the neighboring fibers and conductive pigments.Conductive pigments make the conductive network more perfect and improve the antistatic ability,but insulating pigments acting as barriers for the formation of conductive channel increases the surface resistivity of the coatings.The influence of pigments on the surface resistivity drops gradually with the decrease of the carbonaceous fibers volume resistivity.

Abstract： PAN （Polyacrylonitrile）-based carbonaceous fibers were prepared at the heat treatment temperature （HTT） range of 650 to 900 ℃. The relationships among HTT, carbon content and volume resistivity of the carbonaceous fibers were investigated. The carbonaceous fibers/PTFE （Polytetrafluoroethylene） antistatic coatings were prepared by the spraying technology and the effects of carbonaceous fibers and pigments on surface resistivity of the coatings were systematically discussed. Micrographs provide insight into the antistatic mechanism of the coating. The results show that carbon content of the carbonaceous fibers increases from 68.8% to 74.8% （mass fraction） and the volume resistivity decreases drastically from 1.94× 10^-3 to 8.27× 10 ^-2.cm. The surface resistivity of the antistatic coating is adjustable between 10^5 and 10^8Ω2 to fit the different antistatic materials. Static is dissipated by a conductive network of short fibers and the tunneling effect between the neighboring fibers and conductive pigments. Conductive pigments make the conductive network more perfect and improve the antistatic ability, but insulating pigments acting as barriers for the formation of conductive channel increases the surface resistivity of the coatings. The influence of pigments on the surface resistivity drops gradually with the decrease of the carbonaceous fibers volume resistivity.