A method for qualitatively and quantitatively analyzing fiber content based on fiber precipitation characteristics

Abstract

The method mainly relates to the fields of chemistry and textiles, uses the appearance and turbidity measurement principle of various fibers after being dissolved in different chemical reagents, uses a spectrophotometer to measure absorbance, makes qualitative analysis, uses a target fiber gradient sample to draw a standard working curve, calculates fiber content according to a linear equation, and makes quantitative analysis on the target fiber. The detection method is based on the background technologies of the dissolution method and water quality detection, innovates, uses the water quality turbidity detection absorbance determination method in fiber content analysis, better solves the qualitative and quantitative analysis problems of various textile fibers, takes polyamide as an example, and specifically introduces the specific test method of the fiber. The method can reduce test steps and improve test efficiency, cooperates with a fiber dissolving instrument and the like, and can make more innovation and development and utilization.

Description

TECHNICAL FIELD

[0001] The project relates to the field of chemical detection of textile fiber component content; in particular to a specific analysis method for qualitative and quantitative analysis of fiber content by using a spectrophotometer and fiber precipitation characteristics. BACKGROUND

[0002] According to the Textile Fiber Identification Test Methods Part 4: Dissolution Method FZ / T01057.4 of the National Development and Reform Commission, in the detection and identification of textile fibers, the dissolution method preliminarily solves the qualitative analysis and identification of various types of textile fibers. In the detection of textile fiber content, there are mainly combustion method, microscope method, melting point method, infrared spectroscopy method, dissolution method, etc., but there is no spectrophotometry because the technology is not mature. With the development of modern science and technology and the continuous improvement of social material and cultural life level, the traditional analysis method cannot meet various needs in analysis efficiency and accuracy, especially the dissolution method with high use and accuracy, which is relatively complex in identification and analysis for some fibers with similar chemical properties, and cannot directly perform quantitative analysis. SUMMARY

[0003] The present application is a method for qualitative and quantitative analysis of fiber component content based on fiber precipitation characteristics using a spectrophotometer, which mainly solves the problems of complex identification and analysis of some fibers with similar chemical properties in the dissolution method and the problem of not being able to directly perform quantitative analysis.

[0004] In order to solve the above technical problems, the technical scheme adopted by the present application is to provide an innovative detection method, which is based on the background technology of dissolution method and water quality detection, uses different chemical reagents to dissolve various types of fibers under their respective specific working conditions, produces a turbidity relationship, uses a spectrophotometer to measure the absorbance of the filtrate of various types of textile fiber samples after dissolution, dilution and filtration, and compares and analyzes the measured parameters; the gradient sample filtrate formed by the treated standard substance or target single fiber is detected, the standard working curve (linear regression equation) of the detection parameters is drawn, and the fiber content is calculated by using the standard curve equation, which mainly solves the problem of quantitative analysis of textile fibers, and effectively solves the problems of qualitative and quantitative analysis and identification of various types of textile fibers through comprehensive comparison and analysis, identification of fiber components and calculation of content. The specific steps are as follows (see the flow chart Figure 1 ):

[0005] A. After the type of fiber (chemical fiber, natural fiber) is preliminarily judged by a biological microscope, the single fiber fabric or blended fabric is fully dissolved and filtered according to the dissolution method;

[0006] B. The filtrate is turbid by using the fiber precipitation characteristics;

[0007] C, using the turbidity measurement principle to precipitate the filtrate, using a spectrophotometer to detect the absorbance by transmission light method, or using other instruments such as measuring scattered light to measure turbidity, comparing and qualitatively analyzing the data;

[0008] D, using standard materials or target fiber single fiber samples to draw a standard working curve (linear regression equation);

[0009] E, using the standard curve equation to calculate the fiber content for quantitative analysis.

[0010] The present application makes full use of the precipitation characteristics of fibers in different reagents to form a special "fiber spectrophotometric detection method" and achieves beneficial effects:

[0011] First, the accurate absorbance measurement characteristics of the spectrophotometer and the dissolution, precipitation and coagulation characteristics of textile fibers in specific chemical reagents are fully utilized, and the qualitative and quantitative analysis problems of various textile fibers in detection and identification are better solved;

[0012] Second, for colored fabrics, after higher proportion of dissolution and dilution, the influence of color on absorbance is further reduced, and the application range is further expanded;

[0013] Third, it can reduce test steps such as drying and weighing, improve test efficiency, expand the thinking of chemical detection and analysis, and is more practical;

[0014] Fourth, it perfects and makes up for the shortcomings in textile fiber detection and identification, making it possible to fully automate qualitative and quantitative analysis of fiber components. BRIEF DESCRIPTION OF DRAWINGS

[0015] ATTACHED Figure 1 : flow chart of the method of the present application;

[0016] ATTACHED Figure 2 : Test correction absorbance and content working curve: the working curve of polyamide fiber content and turbid liquid absorbance formed after the polyamide fiber of different content ratio was dissolved in 20% HCL solution with bath ratio 1:100, then the filtrate was diluted with water 50 times. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings, so that the advantages and features of the present application can be more easily understood by those skilled in the art, and the scope of protection of the present application can be more clearly defined.

[0018] The present application includes:

[0019] A qualitative and quantitative analysis method of polyamide fiber based on precipitation characteristics using a spectrophotometer, comprising: using a spectrophotometer to qualitatively identify the blended fabric of polyamide and vinylon fibers with similar chemical properties, solving the problems of complex and low efficiency of qualitative analysis of polyamide using dissolution method, and the problem that dissolution method cannot directly quantitatively analyze polyamide fiber, and using the principle that polyamide fiber can be dissolved in 20% HCL, and the dissolved solution will produce precipitation phenomenon and turbidity when encountering water. The specific implementation is as follows:

[0020] Qualitative analysis: under normal temperature conditions, polyamide fiber is fully dissolved in 20% HCL, and the dissolved solution will produce precipitation phenomenon and turbidity when encountering water, at this time, vinylon fiber cannot be precipitated under the same conditions, and the spectrophotometer is used to measure the absorbance for identification and differentiation;

[0021] Quantitative analysis: through the bath ratio 1:100 dissolution and 1 times water dilution test, it is found that under the premise of the qualitative test method of vinylon or polyamide, in the range of 0.1% to 3% fiber content, under the condition of spectrophotometer wavelength 680nm, there is a linear relationship between the measured absorbance of polyamide fiber and the percentage value of specific content range. This discovery gives us great inspiration for the new method of polyamide fiber content detection, which provides theoretical support.

[0022] Using the principle that polyamide dissolution solution will produce precipitation phenomenon and turbidity when encountering water, we use polyamide (polyamide) and polyester fiber standard single lining fabric, dilute with 20% HCL in a certain proportion to construct dissolution solution with different effective polyamide content, and then dilute with distilled water or deionized water again, measure and record the absorbance, and make the standard working curve of absorbance and content. Then the test fabric is dissolved and diluted, the absorbance is tested, and the working curve (linear regression equation) is used to calculate the content of the test fabric.

[0023] Linear regression equation and corresponding symbol special meaning:

[0024]

[0025] : the coefficient of independent variable in the regression equation; : the constant term in the regression equation; Σx i y i =x1y1+x2y2+x3y3+...+x n y n (the sum of the product of each gradient fiber content value and absorbance value); : n times of the average product of each gradient fiber content value and absorbance value; Σx i ²=x1²+x2²+x3²+...+x n ² (the sum of the square of each gradient fiber content value); : n times of the average value square of the content of each gradient fiber (n is the amount of gradient experiment data).

[0026] According to Figure 2 The working curve drawn by using the standard nylon (polyamide) single fiber lining fabric as raw material has good linear correlation in the range of 3% to 100% fiber content under 50 times water dilution. The combination sample formed by the standard nylon (polyamide) single fiber lining fabric and the standard polyester fiber single fiber lining fabric and the colored nylon blended fabric with known content are used as verification samples for content testing. It is found that the absolute error maximum of the calculation results of the combination sample of the standard nylon (polyamide) single fiber lining fabric at 15 times of each gradient content and the known content is 3.6%, and the absolute error average is 1.5%. The absolute error maximum of the calculation results of various colored nylon blended fabrics at 30 times of each gradient content is 7.8%, and the absolute error average is 3.3%.

[0027] The main technical means adopted is that the nylon fabric to be tested is placed in hydrochloric acid solution according to a bath ratio of 1:100 for sufficient dissolution, water is used for 50 times or more dilution, the absorbance is measured by using a spectrophotometer, and the content is calculated by using a standard working curve, which has strong nylon content detection capacity.

[0028] At this time, different schemes and different dilution ratios are constructed, and the components and contents of other fibers are quantitatively analyzed by using the spectrophotometric method.

[0029] In another embodiment, the polyester fiber is dissolved in concentrated sulfuric acid (mass fraction 98%, bath ratio 1:500). When the dissolved solution is added to water with only half the volume, fiber precipitation images are generated and turbidity is generated. The absorbance is detected in the process of concentrated sulfuric acid dilution and heating (within half an hour of standing), and in the range of 20% to 80% content, the absorbance and the content still have high linear correlation, and the content of the polyester fiber to be tested can be calculated by using a linear equation.

[0030] The above only describes the embodiments of the present application, and does not limit the patent range of the present application, and any equivalent structure or equivalent flow transformation made by using the content of the specification and drawings of the present application, or direct or indirect application in other related technical fields, are also included in the patent protection range of the present application.

Claims

1. A method for analyzing fiber content based on fiber precipitation characteristics, the features comprising: A, after preliminary judgment with biological microscope, dissolve the blended fabric of nylon and vinylon in 20% hydrochloric acid, filter; B, add water to dilute the filtrate to make the filtrate turbid by using the fiber precipitation characteristics; C, measure the absorbance of the filtrate of the precipitated fiber by using the turbidity measurement principle, and perform qualitative analysis according to the test results; D, draw a standard working curve by using the standard single lining fabric of nylon and polyester fiber or the single fiber sample of nylon fiber; E, calculate the content of nylon fiber by using the standard curve equation, and perform quantitative analysis.

2. The method for analyzing the fiber content based on the fiber precipitation characteristics according to claim 1, characterized by: Observe the cross section and longitudinal section of the fiber by using the biological microscope to determine the approximate type of the fiber; filter the dissolved solution by using a coarse filter device to collect the filtrate.

3. The method for analyzing the fiber content based on the fiber precipitation characteristics according to claim 1, characterized by: Measure the absorbance of the filtrate of the precipitated fiber by using the turbidity measurement principle, including measuring the transmitted light and scattered light by using the instrument.

4. The method for analyzing the fiber content based on the fiber precipitation characteristics according to claim 1, characterized by: According to the turbidity measurement principle, the absorbance measurement characteristics of the spectrophotometer are used to prepare standard precipitated liquid with different gradient target fiber content, measure the absorbance, and draw a standard working curve.

5. The method for analyzing the fiber content based on the fiber precipitation characteristics according to claim 4, characterized by: The linear relationship of the absorbance of the precipitated liquid with different gradient target fiber content is used to calculate the fiber content by using the standard curve equation, and quantitative analysis is performed.

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