GB/T 37632-2019 English PDF (GBT37632-2019)

This Standard specifies the test method for determination of titanium dioxide content in man-made fibers by spectrophotometry. This Standard is applicable to the man-made fibers; thereof, the functional man-made fibers can use it as a reference.

GB/T 37632-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.060.20
W 50
Man-Made Fiber -
Test Method for Titanium Dioxide Content
ISSUED ON: JUNE 04, 2019
IMPLEMENTED ON: JANUARY 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Principle ... 4
5 Reagents ... 5
6 Apparatus ... 5
7 Specimen Requirements ... 5
8 Preparation of Working Curve ... 6
9 Determination of Specimen ... 7
10 Result Expression ... 8
11 Test Report ... 9
Appendix A (Normative) Man-Made Fibre - Ashing Method ... 10
Man-Made Fiber –
Test Method for Titanium Dioxide Content
Warning – Personnel using this Standard shall have hands-on experience
working in the formal laboratory. This Standard does not address all possible safety issues. The users shall assume the responsibility to take appropriate safety and health measures, and ensure compliance with the relevant national regulations.
1 Scope
This Standard specifies the test method for determination of titanium dioxide content in man-made fibers by spectrophotometry.
This Standard is applicable to the man-made fibers; thereof, the functional man-made fibers can use it as a reference.
2 Normative References
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this document.
GB/T 4146 (all parts) Textiles – Man-Made Fibers
GB/T 6503-2017 Man-Made Fibers – Test Method of Moisture Regain
GB/T 6682 Water for Analytical Laboratory Use – Specification and Test Methods 3 Terms and Definitions
The terms and definitions given in GB/T 4146 are applicable to this document. 4 Principle
Under the heating condition, add concentrated sulfuric acid and appropriate amount of hydrogen peroxide to the specimen to digest. The titanium in the presence of specified in GB/T 6503-2017.
8 Preparation of Working Curve
8.1 Preparation of titanium standard solution 1mg/mL
8.1.1 Add 166.8mg of titanium dioxide (5.2) equivalent to 100mg of titanium, 5g~7g of ammonium sulfate (5.4), and 10mL of concentrated sulfuric acid (5.3) into 100mL beaker; slowly heat in a ventilated case till fully dissolved. Cool off the solution naturally to the room temperature.
8.1.2 Pre-add about 30mL of water into the 100mL volumetric flask. Carefully pour the solution into the volumetric flask. After cooling off slightly, rinse the inner wall of the beaker twice with water; pour the eluent into the volumetric flask also. 8.1.3 Add water for several times; shake horizontally and evenly. After cooling off to the room temperature, dilute to the scale; shake evenly; pay attention to releasing the air from the flask during shaking evenly.
NOTE: Protective equipment such as chemical protective glasses and acid-proof gloves needs to be worn during the operation.
8.2 Preparation of standard colorimetric solutions
8.2.1 Pipette 0mL (reagent blank solution), 0.2mL, 0.4mL, 0.6mL, 0.8mL, 1.0mL of titanium standard solution by a graduated pipette; inject them into 100mL volumetric flask, respectively.
8.2.2 Add 50mL of water and 20mL of sulfuric acid solution (5.6), respectively to the above volumetric flask. After mixing evenly, separately add 10mL of 3% hydrogen peroxide solution (5.7).
8.2.3 Add water for several times; shake horizontally and evenly. After cooling off to the room temperature, dilute to the scale; shake evenly; pay attention to releasing the air from the flask during shaking evenly.
8.3 Determination of absorbance for standard colorimetric solutions
Within 1h, use a 3cm or other suitable size cuvette, at the wavelength of 410nm; take the reagent blank solution as the reference solution; adjust the absorbance of the instrument into zero; then measure the absorbance of the standard colorimetric solutions.
8.4 Draw working curve
8.4.1 Draw the working curve by taking the mass of the titanium in the standard 9.3 Determination of the absorbance of the test solution
9.3.1 Within 1h; use a 3cm or other suitable cuvette at the wavelength of 410nm; take reagent blank solution as the reference solution; adjust the absorbance of the instrument into zero; then measure the absorbance of the test solution. 9.3.2 The measured absorbance of the test solution shall be between 0.2 and 0.8. Otherwise, the concentration of the test solution needs to be adjusted. For instance, if the absorbance is too low, the weight of the specimen can be increased appropriately; if the absorbance is too high, the test solution can be diluted to n times appropriately. 9.3.3 According to the measured absorbance of the test solution, check the mass of titanium in the test solution from the working curve.
10 Result Expression
10.1 According to the ratio between molar mass of titanium dioxide and molar mass of titanium, convert the content of titanium dioxide; calculate as per the Formula (1): Where:
w – content of titanium dioxide, in %;
m0 – mass of titanium in the test solution checked from the working curve, in mg; 1.67 - ratio between molar mass of titanium dioxide and molar mass of titanium; m – mass of dried specimen, in mg;
n – dilution factor of test solution, when it is not diluted, n=1.
The measured results shall be expressed by the average value of two parallel tests, retaining 3 significant figures after the decimal point.
10.2 In the same laboratory, the same operator uses the same equipment to take the same test method against the same test object within short time, and take the two independent tests; the absolute difference between the two test results shall be no greater than the 10% arithmetic mean value of the two test results; and the conditions that is greater than 10% arithmetic mean value of the two test results shall be on the premise of not exceeding 5%.
Appendix A
(Normative)
Man-Made Fibre - Ashing Method
A.1 Principle
After the man-made fiber is sufficiently carbonized, it is burned at a high temperature; then obtain the white ash without black spots. Repeatedly burning, cooling, drying and weighing the ash till it is constant weight.
A.2 Apparatus and materials
A.2.1 Balance, the minimum scale value of 0.1mg.
A.2.2 Porcelain crucible, 50mL or 100mL.
A.2.3 Electric furnace, direct-heating type, anti-fire.
A.2.4 Muffle furnace, temperature range of 650°C~1000°C; the temperature control accuracy of ±10°C.
A.2.5 Dryer, desiccant: color-changing silica gel.
A.2.6 Others, crucible tongs.
A.3 Test procedure
A.3.1 Weighing specimen
Accurately weight the dried specimen, accurate to 0.1mg. Take 500mg of semi-dull fiber; and 100mg of full-dull fiber.
A.3.2 Crucible with constant weight
Place the porcelain crucible into the muffle furnace at the temperature of (750±10) °C and burn for 60min. Use the crucible tongs to move the furnace mouth, cool off to the 200°C or so; then take out.
After cooling off the porcelain crucible for 5min the air, move to the dryer. Cool off for more than 3min; weigh the mass of the crucible, accurate to 0.1mg.
Repeat the procedures of burning (30min each time), cooling, and weighing till the difference of two weights after burning is no greater than 0.5mg. Take the final weighing mass as the constant weight of the crucible.