Homogenized preparation method of high molecular weight and high concentration polyacrylonitrile-based carbon fiber spinning dope

Abstract

The invention provides a homogenization preparation method for a high-molecular weight and high-concentration polyacrylonitrile-based carbon fiber spinning solution. The method employs an inorganic solvent for solution polymerization; by controlling the concentration (total solid) of a polymer solution in a polymerization reaction stage and adding an appropriate molecular weight regulator, a polymer solution with low concentration, low viscosity and high molecular weight can be obtained; then, via a process of multi-stage decompression dehydration and defoaming, a polymer solution with high concentration can be obtained. The method is simple and is suitable for industrialization; a spinning solution obtained from the method is free of gel-particles generated because of local overheating in a polymerizing pot and is free of secondary gel-particles in the following dehydration process, has improved uniformity and meets the requirement for high-density solidification; the spinning solution can guarantee smoothness and steadiness of a post-processing process and the quality of obtained protofilaments is higher and more stable.

Description

technical field [0001] The invention belongs to the technical field of textile processing, and in particular relates to a homogenized preparation method of high-molecular-weight and high-concentration polyacrylonitrile-based carbon fiber spinning dope. Background technique [0002] From the perspective of polymer chain structure, high molecular weight and high stereoregularity are the main ways to improve the performance of carbon fibers. High molecular weight and dense structure can improve the strength of polyacrylonitrile precursors and make the mechanical properties of fibers better. The high molecular weight and high stereoregularity of carbon fiber precursors are closely related to the homogenization of polyacrylonitrile-based carbon fiber spinning dope. Because the cyano group in the PAN chain has a large dipole, the PAN molecular chain is arranged in a helical columnar form. When these helical chains are put together, the adjacent cyano groups will be arranged in an ...

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Problems solved by technology

In the Chinese application with the patent No. 200810227312, the density of the original silk structure is improved by increasing the concentration of the spinning stock solution. When polyacrylonitrile is dissolved, a low boiling point dilution solubilizer is added to the traditional dissolution system to obtain a uniform low Viscosity of the polyacrylonitrile solution, and then decompression devolatilization after filtration, so that the solid content of the solution is improved, and finally obtain a uniform high solid content (high concentration) polyacrylonitrile spinning stock solution, in this method due to adding Solvents will inevitably form a type of impurity in the raw silk, which is not conducive to the preparation of carbon fibers with demanding applications

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