This standard specifies a direct potentiometric titration method for the determination of inorganic substances, also called inorganic chlorine or "ionic chlorine", in epoxy resins and glycidyl esters. GB/T 4613-1984 Determination of inorganic chlorine in epoxy resins and glycidyl esters GB/T4613-1984 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Epoxide resins anu glycidyl estersDetermination of inorganic chlorineThis standard is equivalent to ISO4573-1978 "Scope of Application of Plastics
Epoxy resins and glycidyl esters
UDC 678.68:543
GB 4613-84
Determination of inorganic chlorine".
This standard specifies a direct potentiometric titration method to determine inorganic matter, also called inorganic chlorine or "ionized chlorine", in epoxy resins and glycidyl esters.
2 Principle
Dissolve the sample in an appropriate solvent and perform potentiometric titration with silver nitrate standard titration solution to determine chloride ions 3 Reagents
In the analysis, only recognized analytically pure reagents and pure water with a resistivity greater than 300 kΩ cm and free of chloride ions are used. 3.1 Glacial acetic acid: density 1.05 g/ml. 3.2 Acetone (methyl ethyl ketone).
Note: When the resin is not completely dissolved in the acetone, other more suitable solvents may be used and stated in the test report. 3.3 Hydrochloric acid: 0.1N solution.
3.4 ​​Potassium chloride: 0.01N solution.
3.5 Silver nitrate: 0.01N standard titration solution (0.002N standard titration solution may be used if necessary). 3.5.1 Preparation
Dissolve 1.70 g of silver nitrate in water and dilute to 1 liter. 3.5.2 Calibration
Weigh 2025 mg of standard sodium nitride (accurate to 0.1 mg) pre-dried at 120°C into a 300 ml conical flask and dissolve in 50 ml of water. Titrate with silver nitrate solution according to 6.3. 3.5.3 Calculation of concentration
The equivalent concentration N is calculated according to formula (1): bzxZ.net
Where: m-the mass of sodium fluoride used, mg m
the volume of silver nitrate consumed in titration, ml: V
58.45-milligram equivalent of sodium chloride.
4 Instruments
(1)
4.1 Microburette: with a capacity of 10 ml, a minimum scale of 0.02 or 0.05 ml, and a capillary tip extending about 120 mm below the piston.
Issued by the National Bureau of Standards on July 30, 1985
Implemented on May 1, 1985
4.2 Magnetic stirrer.
GB 4613-84
4.3 pH-millivoltmeter: with glass electrode, silver electrode and titration stand. 4.4--General laboratory instruments.
5 Preparation of electrodes
Before each titration, wash the glass electrode with solvent, rinse it with water, soak it in hydrochloric acid for at least 10 minutes, and then rinse it with water and solvent. Before each titration, polish the silver electrode with fine sandpaper (such as metallographic sandpaper No. 003) and rinse it with water. Note: ① It is important to follow these instructions to prepare the electrode. Otherwise, the electrode will not respond correctly during titration. If the same product is measured frequently, the electrode can be treated once a day. ② Other types of electrodes and other methods of preparing electrodes may be used if agreed upon by the relevant parties. 6 Operation steps
6.1 In a 250 ml beaker, weigh 3 to 10 grams of sample (accurate to 1 mg) and add 100 ml of acetone. Dissolve the sample at room temperature using a magnetic stirrer.
6.2 Use a pipette to add 1 ml of potassium chloride solution and 25 ml of glacial acetic acid to the sample solution and immediately titrate according to 6.3. 6.3 Place the electrode and the microburette containing the silver nitrate solution in an appropriate position, with the tip of the microburette immersed in the liquid for about 10 mm. Stir throughout the titration process. Carefully add the silver nitrate solution until a constant potential is formed. Record the readings of the microburette and millivoltmeter and quickly draw a graph. When the potential change is very small with each addition of 0.1 ml of silver nitrate solution, continue to add. When the potential change ratio is greater than 10 mV/0.1 ml, use 0.05 ml increments. Add about 0.3 ml after the inflection point and stop titrating.
6.4 Perform a blank test at the same time as the determination, using the same steps and the same reagents, but without adding the sample. 7 Expression of Results
7.1 Record the equivalence point on the graph obtained in 6.3. 7.2 The inorganic chlorine content C expressed in mg/kg (parts per million by mass) is calculated according to formula (2): (V, -V.) × 35.5 × N × 1000
tt: Vo
The volume of silver nitrate solution used in the blank test, ml, the volume of silver nitrate solution used to titrate the sample, ml, the equivalent concentration of the silver nitrate solution calculated according to formula (1); the mass of the sample, g;
35.5--the number of milligrams of chlorine per milligram equivalent. 8 Test report
The test report shall include the following items:
The solvent used, if different from that specified, shall be indicated. Full identification of the test material.
The type of electrode and the preparation method used, if different from that specified, shall be indicated. The test results and the method of expression used.
Additional Notes:
GB4613—84
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China and drafted by the Chemical Method Branch of the National Technical Committee for Plastic Standardization. The main drafters of this standard are Li Boqing, Bao Limin and Wu Rongdong. 700
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