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Method of determination of chitosan in textile fiber content
Source : Hismer Add Time : 2015/09/02 PV:

introduction

Chitosan fiber is currently the only positively charged animal regenerated fiber, has good permeability, moisture, and the physical properties of the adsorption sweat. When it with the human body skin contact with the skin cells has the good affinity, no immunogenicity, and can make the skin of the bacteriolysis enzyme hyperplasia (1.5 ~ 2 times, improve human immunity, promote the skin tender and smooth. It is widely applied in medical field, textile and other industrial fields. But at the moment, with the function of the preparation of chitosan fiber textiles has not an accurate determination of the effective composition content of chitosan. Therefore, how to determination of chitosan in textile fiber content is a problem to solve, also is our country regulation containing chitosan fiber textile products quality supervision department of a bottleneck restriction, urgent need to solve.

L the theory basis for

Colloid titration method is a kind of polyelectrolyte charged groups in aqueous solution of capacity analysis. Chitosan dissolve in the dilute acid, the amino acid molecules or a combination of 1 H + and bring a positive charge, the formation of polyelectrolyte with positive charge. Encountered in the polyelectrolyte in aqueous solution with the opposite charge of polyelectrolyte, takes place in certain stoichiometric relation between each other electricity neutralization reaction, formation of neutral association, eventually forming precipitation. Using chemical structure, molecular weight and concentration of a known the charged polyelectrolyte to determine the number of charged groups of chitosan, which is colloid titration method, the theoretical basis of the determination of the amino content of chitosan using visual method to determine drop point end point. Methods of anionic polyelectrolyte poly potassium sulfate (PotassiumPolyvinylSulfate, PVSK) as the titrant, blue organic dye with positive charge toluidine blue as indicator. Using toluidine blue (1 bluidineblue, T.B) as the indicator because it positively charged, in acidic solution with shell.

2 experimental method

(1) take a constant weight and not more than 2 g textiles under test, remember to w. Place it in the conical flask, join l % 100 ml of acetic acid solution dissolve chitosan in textile fiber under test, set aside;

It is in the process of the dissolution, the best mixing textiles under 4 hours, then let stand for 0.5 hours, allowing for the chitosan fiber in textile fully dissolved in acetic acid solution.

(2) 2.1 in the solution (w3) 5 g into another conical flask, add 50 ml deionized water, add 2-3 drops of toluidine blue indicator, set aside;

(3) put the magnetic rotor 2.2 sheng to be described with the solution in the conical flask, then described taper bottle placed on the magnetic stirrer; Edge stirring handing polyethylene potassium sulfate titration droplets into the solution changed from blue to purple, and in the 20 s do not fade and flocculent precipitate, namely as the titration end point, read polyethylene potassium sulfate standard solution titration volume v1: in drip into the PE in the process of potassium sulfate standard solution, titration speed best control in o. 03 ml/s, if titration speed too fast, often there will be a temporary phenomenon of titration end point.

(4) and 2.2 the same amount of deionized water, according to the same method as above blank titration, read polyethylene potassium sulfate standard solution titration volume V2.

(5) press type calculation of chitosan fiber content in textiles:

WI=C×f×(Vl—V2)×0.001×161.15×100/W3

W2=C×f×(V1一V2)×0.001×203.19x1001W3×(1一D•D)/D•D

g=(W1+W2)/W×100%

C - polyethylene potassium sulfate standard solution of the concentration of content quality, 0.0025 mol/L

f- English: factor, the coefficient of polyethylene potassium sulfate standard solution

W1 - chitosan fibers in the object under test to take off the fiber weight of acetyl, g

W2 - chitosan fibers in the object under test does not remove the fiber weight of acetyl and g

V1-2.3 polyethylene potassium sulfate titrant titer, ml,

V2 -- 2.4 polyethylene potassium sulfate titrant titer, ml,

W3-2.2 according to the solution of weight, 5 g

W a grams of the object under test, g

161.15 - chitosan in the relative molecular mass of a sugar unit

203.19 - of chitin in the relative molecular mass of a sugar unit

D•D-Degree of chitosan (fiber)

G - the content of chitosan in textile fiber, %

Three experimental section

(1) take constant weight chitosan fiber/new styles of viscose/cotton is 10/30/60 textile lg under test, the proportion of the ingredients in the degree of chitosan fiber (d. D) is 93%, according to the above test method for experiment. Measured V1 = 11.23 ml; V2 = 0.15 ml; Into the formula: 2.5 g = 9.88%, the error is 9.88%.

(2) take a constant weight of chitosan/cotton fiber is the ratio of 15/85 0.6 g of textiles under test, its content in the degree of chitosan fiber (d. D) is 93%, according to the above test method for experiment. Measured V1 = 10.30 ml; V2 = o. 15 ml; Into the formula: 2.5 g = 15.07%, the error is 15.07%.

4 conclusion

Through the above experiment can see, using simple experimental apparatus, sensitive and convenient operation steps show titration end point, accurate to calculate the result of the experiment. The causes of errors and the result error is very small, mainly include: (1) the irregularity problems existing in the blended fabric; (2) with differences between visual error cause the titration end point of the person; (3) as a result of human visual error while reading instrument calibration.

(the author: zhoujia village, Hu Guangmin, shandong huaxing textile group co., LTD.)

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