Spectrophotometry for measuring residual phosphorus content in benzoxazole class polyfibre or film

A technology of polybenzoxazole and spectrophotometry, which is applied in the direction of color/spectral characteristic measurement, analysis by making materials undergo chemical reactions, and material analysis by observing the influence of chemical indicators, etc., which can solve complex operations, Problems such as expensive instruments and degradation of fiber mechanical properties, etc., to achieve the effect of simple equipment and easy operation

Inactive Publication Date: 2004-12-29
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] In order to make the fiber achieve higher strength and modulus, the residual phosphorus content in the fiber after rinsing should be as low as possible, not more than 8000ppm. Excessive residual solvent will decompose during heat treatment and produce a large number of cavities in the fiber, making There are a large number of defects inside the fiber, resulting in a decrease in the mechanical properties of the fiber
There are many methods for determining phosphorus content in fibers or films, such as elemental analysis, atomic emission spectrometry, atomic absorption spectrometry, X-ray fluorescence spectrometry (XRF), gravimetric analysis, etc., but these methods are either expensive or complicated to operate ,Time-consuming

Method used

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  • Spectrophotometry for measuring residual phosphorus content in benzoxazole class polyfibre or film
  • Spectrophotometry for measuring residual phosphorus content in benzoxazole class polyfibre or film
  • Spectrophotometry for measuring residual phosphorus content in benzoxazole class polyfibre or film

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Phosphorus standard solution: Weigh 0.1791g of potassium dihydrogen phosphate dried at 105°C (1 hour) and dissolve it in water, transfer it to a 250mL volumetric flask, dilute to the mark, and use it as the stock solution; dilute the stock solution accurately 50 times (with Accurately take 5mL with the pipette, transfer to a 250mL volumetric flask, dilute to the mark), and make 0.01mg (P0 4 3- ) / mL (3 μgP / mL) phosphorus standard solution;

[0051] Ammonium molybdate-sulfuric acid solution: slowly add 100mL 98% concentrated sulfuric acid into 500mL deionized water, mix with 400mL2.5% ammonium molybdate solution after cooling;

[0052] Stannous chloride-glycerin solution: 2.5g SnCl 2 .2H 2 Dissolve O in 100mL glycerin, dissolve in a warm water bath, and store in a brown solution bottle;

[0053] Ammonium molybdate solution: Dissolve 25g of ammonium molybdate in an appropriate amount of deionized water, transfer to a 250mL volumetric flask, and dilute to the mark;

[...

Embodiment 2

[0057] Take 9 mL of phosphorus standard solution, 7 mL of ammonium molybdate-sulfuric acid solution, 5 drops of stannous chloride-glycerol solution, develop color for 10 min, and scan at wavelengths between 500 and 940 nm to obtain absorbance at different wavelengths and make absorption curves, such as figure 1 .

[0058] So the following example determines that the measured wavelength is monochromatic light within 690nm.

Embodiment 3

[0060] Use a pipette to take 10mL of the solution to be tested into a 50mL volumetric flask, add water to dilute to 30mL, add 7mL of ammonium molybdate-sulfuric acid mixture, 5 drops of stannous chloride-glycerin mixture, constant volume, shake well, and let stand for 10min color. Table 1 lists the phosphorus content determination results of the same fiber when the solutions containing sulfuric acid-ammonia water and solutions without sulfuric acid-ammonia water are used as reference.

[0061] Table 1 Different reference determination results

[0062] The reference is the test without sulfuric acid-ammonia The reference is the sample with sulfuric acid-ammonia

[0063] sample blank blank

[0064] Calculated phosphorus content (%) 2.98 2.84

[0065] Error caused by ammonia water (%) 4.9

[0066] Note: The volume of the ammonium sulfate solution added is the same as the volume taken when the sample is ...

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Abstract

The spectrophotometric process of measuring the residual phosphate amount in polybenzoazole fiber or film includes the following steps: dissolving the polybenzoazole fiber in strong protonic acid, adding precipitant to precipitate polymer, collecting phosphoric acid solution, adding alkali to regulate solution pH to neutrality, adding molybdate, regulating with acid matter to proper acidity for color development reaction, adding reductant to convert the measured component into colored compound and final absorbency measurement. The process has simple instrument used, simple operation, high feasibility and high precision, and may be used in lab and factory.

Description

technical field [0001] The invention relates to a test method, in particular to a test method for residual phosphorus content in polybenzoxazole polymer fibers or films. Background technique [0002] Polybenzoxazole polymers are dry sprayed and wet spun in the liquid crystal state of polyphosphoric acid solution, and the fibers are coagulated, washed and dried to obtain polybenzoxazole fibers, which contain polybenzoxazole Polymers contain different amounts of solvent acids in different stages of spinning, drying, post-treatment, etc. The content and complete removal of solvents have a great impact on the mechanical properties of fibers, so it is very important to accurately grasp the content of solvent acids in fibers Important issues. [0003] The polybenzoxazole polymer can be an AB type unit, as shown in structural formula 1(a), or an AA / BB type unit, as shown in structural formula 1(b): [0004] [0005] Among them, Ar represents an aromatic group, so polybenzoxazo...

Claims

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Application Information

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IPC IPC(8): G01N21/31G01N21/78
Inventor 韩哲文张敏唐来安庄启昕吴平平
Owner EAST CHINA UNIV OF SCI & TECH
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