Method for testing polyacrylonitrile preoxidized fiber cyclic structure volume fraction

Abstract

The invention relates to a method for testing the volume fraction of the cyclic structure of pan-based stabilized fiber, which belongs to the analyzing-testing field. The method comprises applying an X-ray low angle scattering angular instrument, being provided with Cu radiation of a multi-layer film mirror monochromator and a slit source aligning system, arraying pre-oxidized polyacrylonitrile fiber samples in parallel to take a flat panel shape, measuring the meridional scattering intensity curves of samples, separating out the long period diffraction peak of X-ray low angle scattering from the curves, calculating out the integrated intensity of the diffraction peak, and calculating out the volume fraction of pre-oxidized fiber cyclic structure by a formula through the relationship between the diffraction peak integrated intensity of a laminated structure and the volume fraction of a ring-shaped stable structure. The method can give the accurate volume fraction of cyclized phase inpre-oxidized fiber, can point out the quantitative relationship between the production condition and the number of the cyclized phase, can scientifically assure the optimum pre-oxidized production condition, and can service for production and relative theoretical research.

Description

Test method for the volume fraction of polyacrylonitrile pre-oxidized silk cyclized structure technical field The invention belongs to the field of analysis and testing, and is mainly aimed at an X-ray small-angle scattering precise testing method for the volume fraction of polyacrylonitrile preoxygenated wire cyclization structure. Background technique Pre-oxidation treatment is the main process link in the fiber production process. The chain-like molecular bundles in polyacrylonitrile (PAN) precursors are pre-oxidized at 200°C to 300°C and converted into ring-shaped stable structures, and can be pyrolyzed into high-performance PAN bases in the state of fibers during the subsequent high-temperature carbonization treatment. carbon fiber. Whether the degree of pre-oxidation is appropriate or not is currently mainly observed by infrared spectroscopy and X-ray wide-angle diffraction methods, because what these two methods observe is not the linear sacrifice parameter of the ...

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Problems solved by technology

Whether the degree of pre-oxidation is appropriate or not is currently mainly observed by infrared spectroscopy and X-ray wide-angle diffraction methods, because what these two methods observe is not the linear sacrifice parameter of the volume or weight of the cyclized structure, so in the research work It is inconvenient to apply it in production

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