METHOD FOR INFRARED SPECTROSCOPIC DETERMINATION OF COMPOSITION OF ACRYLIC ACID COPOLYMERS Russian patent published in 2015 - IPC G01N33/00 G01N31/00 C08F20/18 

FIELD: chemistry.

SUBSTANCE: invention relates to investigation and analysis of high-molecular weight materials via infrared spectroscopy when determining the composition of polyacrylate and polyacrylonitrile copolymers to control the quality of carbon fibre. The method includes measuring the infrared absorption spectrum of films of test samples of polyacrylonitrile fibre using Fourier transform infrared spectroscopy in the 3000-800 cm^-1 region and determining the content of acrylonitrile and methyl acrylate from normalised spectra based on characteristic peaks thereof. During sample preparation, the number of sample preparation steps is maximally simplified and reduced and dimethyl sulphoxide which does not absorb in the operating infrared region is used. When processing the obtained infrared spectra, the method employs adjustment of the entire base line, smoothing of the shape of the peaks of the investigated compounds and decomposition of the composite peak at 1733±3 cm^-1 into components.

EFFECT: invention provides a method for reproducible, precision and sensitive determination of basic components of polyacrylonitrile.

2 cl, 3 tbl, 1 dwg