Method for modifying medium and low temperature coal tar pitch by hydrogenating styrene-butadiene block copolymer

Abstract

The invention provides a method for modifying medium and low temperature coal pitch by hydrogenated styrene-butadiene segmented copolymer. The method for modifying the medium and low temperature coalpitch by hydrogenated styrene-butadiene segmented copolymer comprises the steps that the medium and low temperature coal pitch is smashed below 20 meshes, soluble components of the medium and low temperature coal pitch are extracted and filtered by tetrahydrofuran, and low ash content pitch is obtained after a solvent is recovered; and air is pumped in after the low ash content pitch is mixed withthe hydrogenated styrene-butadiene segmented copolymer, heating is carried out at the heating rate of 1 DEG C-10 DEG C / min to the reaction temperature 300 DEG C-360 DEG C for staying 2-6 hours, and asolid product after cooling to the room temperature is the modified pitch. The method for modifying the medium and low temperature coal pitch by hydrogenated styrene-butadiene segmented copolymer hasthe advantages of low costs and less usage amount of hydrogen-donor solvents.

Description

technical field [0001] The invention belongs to the technical field of preparation of pitch-based carbon fiber spinnable pitch, and in particular relates to a method for modifying medium-low temperature coal tar pitch by hydrogenated styrene-butadiene block copolymer. [0002] technical background [0003] Carbon fiber is an indispensable engineering material in the aerospace industry due to its high strength, high modulus, high temperature resistance, corrosion resistance, fatigue resistance, electrical conductivity and thermal conductivity, and is also widely used in transportation, machinery, sports and entertainment. . For a long time, Japan, the United States and Germany can produce spinnable pitch for making general-purpose pitch carbon fiber. The raw materials of pitch-based carbon fiber are petroleum residue, coal tar, petroleum pitch, coal tar pitch, etc. Medium and low temperature coal tar pitch is a by-product in the production process of the coal chemical industr...

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Problems solved by technology

Among them, high-temperature thermal polymerization has a large range of modification treatment for coal tar pitch and is easy to operate, but the softening point of the polymerized pitch has a wide distribution, which is not conducive to melt spinning; oxidative thermal polymerization is particularly effective for improving the softening point of pitch, but the quality of oxidatively modified pitch Difficult to control, and after introducing air or oxygen, there will be a large amount of non-condensable gas carrying asphalt smoke to be discharged, causing environmental pollution; catalytic synthesis and cross-linking synthesis usually use AlCl 3 As a catalyst, there is a problem of separation from the product. If there is residual catalyst, it will have a great impact on the subsequent spinning and carbonization of pitch fibers, and the acidic catalytic system also has the problem of corrosion to equipment, and the latter will be in the process of reaction. Phenomena such as dramatic changes in reaction temperature are very unfavorable to reaction control; hydrogenation modification thermal polymerization is to increase the H / C ratio and improve the naphthene structure with more hydrogen, which is beneficial to weaken the intermolecular force on the one hand, and on the other hand It is conducive to hydrogen transfer in the reaction system, helps to smooth the viscosity of the system, changes the fluidity of the system, avoids excessive polymerization of asphalt, and makes the liquid phase maintain longer, which is conducive to the preparation of high-quality modified asphalt. The hydrogen solvent is tetrahydronaphthalene. Due to its low boiling point (207.2°C), it is easily entrained and lost during high-temperature thermal polymerization, resulting in insufficient hydrogenation efficiency.

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