Improved qualitative and quantitative analysis method of modified polyacrylonitrile fiber

Abstract

The invention discloses an improved qualitative and quantitative analysis method of modified polyacrylonitrile fiber, comprising the sequential steps of quality determining, sampling, drying and weighing, dissolving, drying and weighing, and calculating, wherein the quality determining step includes adding nitric acid into fiber, if it is determined that the form of the fiber is breaking form, using cyclohexanone in the subsequent dissolving step as a solvent to carry out dissolving, and if it is determined that the form of the fiber is swelling form, using acetone in the subsequent dissolvingstep as a solvent to carry out dissolving. The method herein has the advantages that different dissolving agents and dissolving conditions are utilized for fibers with different forms according to the state of the fibers with nitric acid during quality determining, namely a novel acetone process for swelling form is utilized, a cyclohexanone process for the breaking form is utilized, the flexibility is high, the efficiency is high, safety is good for personnel, and environmental friendliness is good.

Description

technical field [0001] The invention belongs to the field of textile testing, in particular to an improved qualitative and quantitative analysis method for modified polyacrylonitrile fibers. Background technique [0002] In the prior art, for the modified polyacrylonitrile fiber, the principle of its qualitative and quantitative analysis method is: the modified polyacrylonitrile fiber is dissolved and removed from the mixture of known dry mass with a cyclohexanone reagent near boiling point; The residue is washed, dried and weighed, and the corrected mass is used to calculate the percentage of the dry mass of the mixture, and the mass percentage of the modified polyacrylonitrile fiber and other fibers is obtained from the difference. [0003] Specifically, the dissolving step is: add cyclohexanone to the distillation flask at a ratio of 100ML per gram of sample, and install the extraction vessel. In the extraction vessel, first put the sample and the porous baffle and slight...

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Problems solved by technology

[0004] However, this test process has the following problems: 1. The test takes a long time and the efficiency is low: the test cycle alone is greater than 1H; 2. Poor safety to humans: cyclohexanone is flammable and toxic, and the test uses a product with a boiling point of 156°C. Cyclohexanone is used as a dissolution reagent, although it is tested in an extractor, there are still potential safety hazards. In addition, although the technician wears a gas mask, the volatilization of the reagent is still harmful to the body; 3. Poor environmental safety: the storage of waste liquid after the test , because of its flammable and toxic nature, if the bottle is broken, it will pollute the environment and is not environmentally friendly

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