Mesophase Pitch Fibers Research Articles

Oxidation Stabilization of Spun Mesophase Pitch Fiber

Mesophase petroleum pitch fiber was oxidized by two kinds of mixed gases of O2 and N2 and oxygen consumption rates were measured under several isothermal conditions between 160°C and 240°C. Oxidized pitch fiber obtained was carbonized to evaluate its infusibility and also analyzed to examine its elemental composition and structure change during the reaction by using several instrumental analytical method such as elemental analysis, electron spectroscopy for chemical analysis and fourier transform infrared analysis.It was found that 4/3 mole of oxygen atom is fixed in the fiber and 2/3 mole of water is released during the consumption of one mole of oxygen gas. Both of total amount of oxygen consumed and elemental compositions of carbon, hydrogen and oxygen were found to be constant at completion of the stabilization reaction under any experimental condition conducted.It can be concluded that concentration of the fixed oxygen in the surface layer of the fiber is different from that in the inner region. It can also be assumed that the active site in the molecules that constitute pitch fiber is aliphatic chain and that oxidation reaction proceed with forming of carbonyl group.

A study of the oxidation of mesophase

Oxidation of the mesophase pitch is an essential step in the stabilization of mesophase pitch fibers. The detailed mechanism of this oxidation is almost unknown; thus, this work presents the results of the application of modern characterization techniques to study the mechanism of the oxidation process and to analyze the structural changes which occur during oxidation. The weight change occurring during the heating of 100% mesophase particles in air was measured using a thermal-gravimetric technique. Changes in intermolecular spacing were deduced from electron diffraction data, and relative oxygen profiles were obtained from the results of ultrathin window Energy Dispersive Analysis of X-rays (EDS). Electron Spectroscopy for Chemical Analysis (ESCA) was used to quantify the relative data obtained. Diffusive Reflectance Fourier Transform Infrared Spectroscopy (DRFTIR) was used to identify some of the functional groups resulting from the oxidation.

Enhanced Stabilization Reactivity of Coal Tar Based Mesophase Pitch Fiber by Blending PVC Pitch

Abstract PVC pitch prepared at 420 °C for 2 h was blended into a coal tar based mesophase pitch to enhance the stabilization reactivity of the whole pitch fibers. No deterioration of spinnability was recognized after the blending, suggesting their high compatibility. The oxidative stabilization in the air at 270 °C took 120 min for the stabilization of the parent mesophase pitch fibers to maintain its fiber form during the carbonization up to 600 °C, while the pitch fibers from the blends with PVC pitch in 5 or 10 wt% took 80 min to be stabilized. Blended PVC pitch is supposed to be oxidized more easily to react with coal tar derived molecules, enhancing the stabilization reactivity of the whole fiber.

Electrical conductivity, mechanical properties and stability of intercalated graphite fibers

Different acceptor compounds (bromine, nitric acid, metal chlorides) have been intercalated into graphitized carbon fibers. Electrical conductivity has been followed during intercalation and synthesis experimental conditions have been determined in order to obtain the lower electrical resistivity. Tensile strengths and Young's moduli have been measured and some air stability tests in particular under high current density have been made. Taking in account simultaneously all these parameters, the better intercalated graphite fibers are, at first vapor grown fibers, then some mesophase pitch fibers intercalated with copper chloride.

4576811 Process for adjusting the fiber structure of mesophase pitch fibers

4576811 Process for adjusting the fiber structure of mesophase pitch fibers