Properties of Coal Tar Pitch Modified with Acid and Oxidation Treatment

Abstract

To achieve lower price and high performance of pitch carbon fiber, coal tar pitch has to restructure through high-purity process, thermal and acid treatment process, and separation process. Thermal treatment and different oxidation treatments were used to increase the softening point and yield of the precursor pitch for carbon fiber. These treatments have the effect on the properties of carbon fiber because they cause considerable change in the chemical composition of pitches. Low molecular weight materials could be removed by the thermal treatment. The oxygen containing structure formed by the acid treatments would promote the poly-condensation and polymerization reactions. The oxidation treatment with sulfuric acid, nitric acid, and air blowing would lead to the remarkable change in the chemical composition of pitches, and resulted in considerable increase in the softening point and yield of the pitches.

Coal Liquefaction Residues Based Carbon Nanofibers Film Prepared by Electrospinning: An Effective Approach to Coal Waste Management

“…As shown in Figure 4b, the exothermic peaks in the DSC curves of the L-CLRA/PAN film shift to lower temperature, which might originate from the higher oxygen functional group in L-CLRA/ PAN film. 16,29 Meanwhile, the heat release of the cyclization reaction decreases from 536 J g −1 in CLRA/PAN film to 387 J g −1 in L-CLRA/PAN film, which makes cyclization reaction more easy to occur. The differences between G-CLRA/PAN film and L/G-CLRA/PAN film are depicted in Figure 4c,d 30 respectively, becomes stronger for L/G-CLRA/PAN.…”

Synthesis of Carbon Nanofibers Film from Coal Liquefaction Residues: Effect of HNO3 Pretreatment

“…To improve the oxidizing stability of SP pitch-based CFs, optimization of the start temperature, heating rate, or multistep has been employed. ,, Although the aforementioned methods can improve the preparation of low SP pitch-based CF, spinnability is reduced and the cost is greatly increased. Previous research has found that high oxidizing conditions, such as in the presence of iodine, chlorine, or a stronger oxidizing agent, , can accelerate polymerization. Because of its strong oxidizing property and solution controllability, HNO 3 solution has been frequently chosen as the oxidizing agent to improve the stabilization process and avoid fiber melting …”

Electrospun Coal Liquefaction Residues/Polyacrylonitrile Composite Carbon Nanofiber Nonwoven Fabrics as High-Performance Electrodes for Lithium/Potassium Batteries

“…Qiu et al also prepared lightweight carbon foam, CF/carbon foam composite, and microfibers by using the CLR. However, no reports are found about preparation of CF from CLR using the electrospinning method because of the low softening point (SP < 200 °C) of the organic fractions, which is unstable in air for the conventional stabilization process. , Vilaplana-Ortego et al demonstrated that low softening petroleum pitch-based CF can be made by adopting HNO 3 as oxidizing agent during stabilisation . Herein, we prepared CF non-woven fabrics by using a mixture of PAN and PA derived from CLR as the electrospinning precursor followed by HNO 3 pre-oxidization, air stabilization, and carbonization.…”