Study On Quantitative Analysis Method Of Wool / Mulberry Silk / 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: 0.0002 g; constant temperature oven; drier; glass sand core crucible; Soxhlet extractor; grinder triangular flask with glass plug: Volume 250 mL; electrothermal constant temperature water bath pot; vacuum pump filter.

Petroleum ether: distillation range 40 ~ 60 ~ C; distilled water; sodium hypochlorite solution (sodium hypochlorite solution calibration, so that its concentration in the range of 0.9 mol/L~1.1 mol/L); dilute acetic acid solution; dilute ammonia solution.

1.3 sample pretreatment

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

After pretreatment, three kinds of fibers were blended into different proportions to form blended samples.

2 experiment

2.1 test principle

According to GB/T 2910.2 - 2009

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 100 mL 75% sulfuric acid solution. After full oscillation and wetting, it was placed in a certain temperature water bath. The flask was vigorously vibrated every 10 min, 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) dissolution of wool and wool by sodium hypochlorite method

According to GB/T 2910.4 - 2009, textile quantitative chemical analysis fourth part: some protein fiber mixture with some other fibers (hypochlorite method), using sodium hypochlorite solution to dissolve wool and mulberry silk.

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

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 is dried, cooled and weighed.

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

The fiber is 25 C, 3035 C, 40 C, 45 C.

Wool insoluble d=0.968 insoluble d=0.974 insoluble d=0.987 insoluble d=0.992 insoluble d=1.030

Some undissolved part of mulberry silk is not dissolved, but not dissolved or dissolved.

Cotton is dissolved, dissolved, dissolved, dissolved, dissolved.

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

2) three component test results

According to the above test conditions and GB/T 2910.4 - 2009, the fiber content of two blended samples was detected. The results are shown in Table 2.

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

The net dry content of each component of the sample blended sample is determined by the actual net dry content.

Wool mulberry silk cotton sheep Mao Sang silk cotton

No. 1 sample 38.8 30 30 31.2 38.5 30.4 31.1

No. 2 sample 19.4 30.1 30.1 50.5 19.2 30.5 50.3

Note: in the calculation of net dry percentage, the D value of wool fiber is 0.99, the D value of cotton fiber is 1.01, and the result obtained is the average value of 3 parallel samples.

According to the results of Table 2, the measured values of fiber content of each component are closer to the actual value. Therefore, the method can detect more accurately the components of wool / mulberry silk / cotton blended samples.

4.2 conclusion

According to GB/T 2910.2 - 2009, GB/T 2910.4 - 2009 and the sulfuric acid method established by himself, 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.