Study On Quantitative Analysis Method Of Wool Cotton Blended Products

In recent years,

1 test preparation

1.1 sample preparation

Wool, mulberry silk and cotton yarn should be selected separately.

1.2 instruments and reagents

Analytical balance: accuracy: 0.0002g; constant temperature oven; drier; glass sand core crucible; Soxhlet extractor; grinding glass mouth with triangular glass flask: Volume 250mL; electrothermal constant temperature water bath pot; vacuum pump filter.

Petroleum ether: distilled water at 40 ~60 C; distilled water; sodium hypochlorite solution (sodium hypochlorite solution is calibrated, so that its concentration is within 0.9mol/L~1.1mol/L); dilute acetic acid solution; dilute ammonia solution.

1.3 sample pretreatment

Take the sample 5g or so in the Soxhlet extractor, extract 1H with petroleum ether, circulate at least 6 times every h hours. After the petroleum ether in the sample is evaporated, immerse the sample in cold water, soak 1H, then immerse 1h in (60 + 5) C of water, the ratio of water to sample is 100:1, and stir the mixture at all times, then suck or centrifuge to dehydrate and dry.

After pretreatment, three kinds of fibers were mixed into [2] at different ratios.

2 experiment

2.1 test principle

According to the plan three of the GB/T2910.2 - 2009 quantitative analysis of textiles: second part: three component fiber mixture, two samples were taken. The first sample was used to remove wool and mulberry silk residual cotton with sodium hypochlorite solution. Second samples were removed with 75% sulfuric acid solution to remove the remaining wool from cotton and silkworm silk. Then the net dry percent content of each component was calculated according to the formula three in the standard [3].

2.2 test method

1) dissolution of cotton and mulberry silk by sulfuric acid method

The dry weight wool, mulberry silk and cotton fiber were added into the triangular flask respectively. Each sample was added to 75% sulfuric acid solution of 100mL. After full oscillation and wetting, the samples were placed in a certain temperature water bath. The flask was vibrated vigorously every 10min and the dissolution of each fiber was observed.

The correction coefficient of wool mass loss is d value. Combined with the dissolution of each fiber, the most suitable water bath temperature and dissolution time are selected from the test results as the test conditions to dissolve cotton and mulberry silk in the mixed samples.

2) dissolving wool and mulberry silk by sodium hypochlorite method

According to GB/T2910.4 - 2009, textile quantitative chemical analysis (fourth parts): mixtures of certain protein fibers and some other fibers (hypochlorite), and wool and mulberry silk dissolved in sodium hypochlorite solution.

The mixed samples were put into the triangular flask. Each sample was added with 100mL sodium hypochlorite solution to make the sample fully wetted, and 40min was vigorously oscillated at (20 + 2) centigrade water bath conditions.

Then the insoluble fiber was pferred into the crucible of the glass sand core, vacuum suction and drainage, then cleaned with water in turn, neutralized by dilute acetic acid, and the water was continuously washed with insoluble fiber and vacuum sucked and draining.

Finally, the insoluble fiber was dried, cooled and weighed [4].

3 results and discussion

3.1 test results

1) study on sulfuric acid test conditions

The wool, mulberry silk and cotton were dissolved in 75% sulfuric acid solution at different temperatures, and the results were shown in Table 1.

The dissolution of wool, mulberry silk and cotton in 75% sulfuric acid at different temperatures within 11 hours

Through the experimental observation, it is found that cotton can quickly dissolve in the 75% sulfuric acid solution regardless of the water bath temperature. The higher the water bath temperature is, the faster the dissolution is. The time for complete dissolution is 20min~30min. Mulberry silk is more difficult to dissolve in 75% sulfuric acid solution. After 1h, when the water bath temperature is 25, 30 and 35 degrees, a small amount of mulberry silk is not dissolved. When the water bath temperature is 40 and 45 degrees, the mulberry silk can be completely dissolved.

At the same time, the D value of insoluble fiber was investigated.

According to table 1, the damage of wool is 40 and the D value is 0.992.

Therefore, when using 75% sulfuric acid solution to remove cotton and mulberry silk, the test conditions were water bath temperature of 40 1H.

2) three component test results

According to the above test conditions and GB/T2910.4 - 2009, the fiber content of two blended samples was tested, and the results are shown in Table 2.

Table 2% dry matter percentage of wool / mulberry silk / cotton blended samples

4 Conclusion

According to GB/T2910.2 - 2009, GB/T2910.4 - 2009 and the sulfuric acid method established by myself, the fiber content of wool / mulberry silk / cotton three component blend fabric has been successfully determined.

This method fills in the blanks of the national standard for wool / mulberry silk / cotton content determination method, and is easy to operate and has good practicability and reliability.

The method is applied to routine testing work with satisfactory results.

Reference:

[1] Miao Jianping, Ji Xiaodan. Research on the quantitative testing method of wool /Tencel fiber / polyester blended products [J]. China fiber inspection, 2004,6:16-17.

[2]GB/T2910.1 - 2009, textile quantitative chemical analysis, first parts: General rules of test [S].

[3]GB/T2910.2 - 2009, textile quantitative chemical analysis, second parts: three component fiber mixture [S].

[4]GB/T2910.4 – 2009, textile quantitative chemical analysis, fourth parts: mixture of certain protein fibers and some other fibers (hypochlorite) [S].