Effect of anodization on the graphitization of PAN-based carbon fibers of PAN-based carbon fibers

Abstract

One-step pretreatment, anodization, is used to activate the polyacrylonitrile (PAN)-based carbon fi bers instead of the routine two-step pretreatment, sensitization with SnCl 2 and activation with PdCl 2 . The effect of the anodization pretreatment on the graphitization of PAN-based carbon fi bers is investigated as a function of Ni-P catalyst. The PAN-based carbon fi bers are anodized in H 3 PO 4 electrolyte resulting in the formation of active sites, which thereby facilitates the following electroless Ni-P coating. Carbon fi bers in the presence and absence of Ni-P coatings are heat treated and the structural changes are characterized by X-ray diffraction and Raman spectroscopy, both of which indicate that the graphitization of PAN-based carbon fi bers are accelerated by both the anodization treatment and the catalysts Ni-P. Using the anodized carbon fi bers, the routine two-step pretreatment, sensitization and activation, is not needed.

Effects of Hot Pressing Temperature and Pressure on Dielectric Properties of Aramid Insulating Paper

“…Aramid fibrids have an amorphous structure, and the glass transition temperature of amorphous aramid polymer molecules is about 280 • C. Considering the effect of pressure, the fibrid can also recrystallize when its temperature is lower than the glass transition temperature. Too high a temperature and pressure will destroy the chemical bonds of aramid macromolecules and reduce the relative molecular mass [14], so in the test process, the hot pressing temperature was set to 220-260 • C, and the pressure was set to 8-16 MPa. In aramid insulating paper, the precipitant fiber content usually accounts for more than half.…”