Elsevier

New Carbon Materials

Volume 35, Issue 5, September 2020, Pages 591-598
New Carbon Materials

RESEARCH PAPER
Polymerization kinetics and control of the components of a mesophase pitch

https://doi.org/10.1016/S1872-5805(20)60512-1Get rights and content

Abstract

It is important to increase the content of pyridine soluble in mesophase pitch to improve its spinnability. A naphthalene isotropic pitch was used as the raw material to prepare mesophase pitch by polymerization. The components of the polymerized products were analyzed by solvent extraction with benzene and pyridine, and classified as benzene soluble (BS), pyridine insoluble (PI) and benzene insoluble but pyridine soluble (BI-PS). The effects of polymerization temperature, time and the components of the raw material on the distribution of the components and optical texture of the mesophase pitch were investigated. The reaction kinetic constants were calculated assuming a consecutive reaction from BS to BI-PS, then to PI. Results show that a mesophase pitch with a relatively uniform distribution of components is obtained after reaction at 430 °C for 20 h from an isotropic pitch pre-polymerized at 400 °C for 10 h. The mesophase pitch synthesis reaction has a significant auto-acceleration effect in that the reaction rate constant of a heavy component is larger than a light one. The reaction rate becomes faster and faster as the molecular weight of the pitch increases in the latter stage of the synthesis reaction. Therefore, the initial component of raw pitch, reaction temperature and time have a decisive influence on the distribution of components in the mesophase pitch.

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  • The recent progress in pitch derived carbon fibers applications. A Review

    2021, South African Journal of Chemical Engineering
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    The resulting fibers-precursors from the mesophase pitch should undergo thermal stabilization (in air at temperatures from 250 °C to 350 °C) and carbonization at high temperatures (up to 2000 °C) (Jin et al., 2021). In (Liang et al., 2020), the authors show that an increase in carbonization temperature has a positive effect on the strength and modulus of elasticity of the resulting carbon fibers. They discovered that temperature also exerts an influence on the structure of fibers: at a temperature of carbonization up to 1500 °C carbon fibers have a structure of columns, while at a temperature of up to 1700 °C, they have a ribbon wavy structure.

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