GB/T 4497-1984 Vulcanized rubber - Determination of total sulfur content - Oxygen bottle combustion method

This standard is a method for determining the total sulfur content in vulcanized rubber using an oxygen combustion bottle. This method is applicable to the determination of total sulfur in the following vulcanized rubbers (excluding sulfur in barium sulfate). Natural rubber; styrene-butadiene rubber; butadiene rubber; chloroprene rubber; isoprene rubber; butyl rubber; triethylene propylene rubber; nitrile rubber; hard rubber; and rubber compounds of the above rubbers. This method is unreliable for samples containing lead compounds (usually too low). Antimony, barium, magnesium, and calcium salts interfere. GB/T 4497-1984 Determination of total sulfur content of vulcanized rubber - Oxygen bottle combustion method GB/T4497-1984 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of total sulphur content in vulcanized rubber
Oxygen combustion flask method
Vulcanized rubber-Determination of total sulphurcontent-Oxygen combustion flask methodScope of application
UDC 678.44: 543
273:546.22
GB4497—84
This standard is a method for determining the total sulphur content in vulcanized rubber using an oxygen combustion flask. This method is applicable to the determination of total sulphur in the following vulcanized rubbers (excluding the sulphur in barium sulfate). Natural rubber;
styrene-butadiene rubber;
cis rubber;
chloroprene rubber;
isoprene rubber:
basic rubber;
ethylene-propylene-diene rubber;
nitrile rubber,
hard rubber;
and the rubbers mixed with the above rubbers.
This method is not reliable for samples with lead compounds (usually too low). Antimony, barium, magnesium, and calcium salts have 2 Test method www.bzxz.net
The sample is burned in oxygen with platinum wire as catalyst, and the carbon, hydrogen and sulfur of hydrocarbon compounds are oxidized. The sulfur oxides are absorbed by hydrogen peroxide solution and converted into sulfuric acid. The needle reagent is used as an indicator and titrated with chlorinated solution. 2.2 Reagents
Analytical reagents and distilled water or water of equivalent purity should be used during the analysis. 2.2.130° Hydrogen peroxide (HG3—1082-77). 2.2.2 Anhydrous (GB 678-78).
2.2.3 95° (GB 679-80)
2.2.4 Reagent (sodium 2-naphthene-3,6-disulfonate). 2.2.5 Barium chloride (BaCl2·2H2O) (GB 652-65). 2.2.6 Anhydrous p-aminobenzenesulfonic acid (HG3-992-76), 2.2.7 Hydrochloric acid (GB 622-77).
2.2.8 Potassium nitrate (GB 647-77).
2.3 Preparation and calibration of solutions
2.3.1 Hydrogen peroxide absorption solution: dilute 1 volume of 30% chlorine peroxide with water to 30 volumes. Issued by the National Bureau of Standards on June 17, 1984
Implemented on May 1, 1985
GB 4497 -84
Needle reagent solution: 0.2%, dissolve 0.2g reagent in 100ml water. 2.3.2
2.3.3 Hydrochloric acid solution: 2mol/l.
Potassium nitrate solution: 0.4%, dissolve 0.4g potassium nitrate in 100ml water. 2.3.4
Barium chloride standard solution, 0.02mol/1.
2.3.5.1 Preparation: Weigh 5g barium chloride and dissolve it in 1L water. 2.3.5.2 Calibration: Weigh 0.01g p-aminobenzenesulfonic acid, accurate to 0.00001g, and proceed according to 2.6. 2.3.5.3 Calculation: The concentration of barium chloride standard solution (mol/1) is calculated according to formula (1): 18.51 ×m
(V -Vo)× 3.206
Formula: 18.51-
-Sulfur content of p-aminobenzenesulfonic acid, %,
Mass of p-aminobenzenesulfonic acid, name,
-Volume of barium chloride solution consumed by titrating p-aminobenzenesulfonic acid, ml;-Volume of barium chloride solution consumed by blank, ml. 2.4 Strong acid cation exchange resin
After the resin is qualified after treatment, it needs to be regenerated after about 10 uses. (1)
Regeneration method: Pass 10ml of 2mol/l hydrochloric acid solution through the resin layer at a rate of 2 to 3 drops per second, and then wash the resin layer with water at a relatively fast speed until there is no chlorine ion. 2.5 Instrument
2.5.1 Platinum wire: The diameter is about 1 mm. 2.5.2 Oxygen combustion flask: It is a 500ml flask. Weld a piece of platinum wire with a spiral lower end to the center of the ground mouth stopper of the flask (see Figure 1). Alternatively, the oxygen combustion bottle shown in Appendix A (reference) can be used. 2.5.3 Microburette: Capacity 5-10 ml, scale 0.01 ml. 2.5.4 Cation exchange column: Take a glass tube with a piston at the lower end, with an inner diameter of about 10 mm and a length of about 250 mm. Fill the bottom with glass fiber about 10 mm thick. Fill the tube with a treated cation exchange resin about 170 mm high. 2.5.5 Oxygen storage cylinder.
2.5.6 Ash-free filter paper: Soak the filter paper with 0.4% potassium nitrate solution and dry it, and cut it into a flag shape (see Figure 2). 2.5.7 Analysis day and a half: The graduation value is 0.00001 g. Figure 1 Oxygen combustion bottle
2.6 Operation steps
GB 4497--84
Figure 2 Shape of sample paper
Weigh 0.02-0.04g sample (accurate to 0.00001g), wrap it with filter paper, and clamp it in the spiral platinum wire. Add 10ml hydrogen peroxide absorption solution into the bottle. Connect the oxygen storage cylinder and pass oxygen for at least 30s. When the bottle is full of oxygen, ignite the end of the filter paper, quickly disconnect the oxygen system, plug the bottle, press it tightly with your hand, and seal the bottle mouth with a little water. After burning, let it stand for 2h. There should be no black ash residue in the bottle. If there is 1 disturbed cation in the absorption liquid, pass this liquid through the cation exchange column. The outflow rate of the solution is preferably 2-3 drops per second. Wash the bottle with 20ml of water 3 times. The washing liquid should pass through the exchange column and be collected in the same container with the solution. Add a certain amount of ethanol (anhydrous or 95% ethanol) to make the alcohol content in the solution 70-90%. Add 3 drops of needle reagent and titrate with sodium chloride standard solution until the solution changes from yellow to a steady pink. This is the end point. Perform a blank test under the same conditions.
2.7 Safety measures
2.7.1 The sample weighed each time shall not exceed 0.04g. 2.7.2 The combustion should be carried out in a safety cover, and the oxygen combustion bottle can be removed from the safety cover only when the flame is extinguished. 2.8 Expression of results
The total sulfur percentage is calculated according to formula (2):
(V,-Vo) ×C × 0.03206
Wherein:
C—concentration of fluoride standard solution, moll
V—volume of barium chloride standard solution consumed by the sample, mlVo; volume of chlorinated iodine standard solution consumed by the sample, mlm--—mass of the sample, g;
0.03206—mass of sulfur per millimole, g. 2.9 Precision
*Interfering cations refer to calcium, magnesium, zinc, strontium, chlorine, etc., and a small amount of zinc oxide in the formula does not interfere with the determination. 632
GB4497-84
The two measurement results obtained by the same operator must conform to the following table: The total sulfur content of the test sample must conform to the following table: GB 4497--84
Appendix A
Reference oxygen combustion bottle
(reference)
A.1 The total sulfur content of vulcanized rubber can also be determined by the apparatus shown in Figures A1 and A2. Bayonet oxygen
-IS024/29 connector
One wire
One fuse
One sample fire rack
1 liter flask
Figure A1 Oxygen combustion bottle
Sample clamp
GB4497-84
IS024/29 connector
0.53 tinned copper wire
Each 1 platinum wire
$0.45 platinum wire
Figure A2 Combustion element of oxygen combustion bottle
Additional instructions:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China and is under the jurisdiction of the Rubber Industry Research and Design Institute of the Ministry of Chemical Industry. This standard was drafted by the Rubber Industry Research and Design Institute of the Ministry of Chemical Industry. The main drafters of this standard are Wu Peizhi and Dai Meiying. This standard is entrusted to the Rubber Industry Research and Design Institute of the Ministry of Chemical Industry for interpretation. 635
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