Determination of Iodine Adsorption Value of Acetylene Carbon Black
Acetylene carbon black is a special type of carbon black manufactured by the burning of acetylene gas in abnormally oxygen-deficient atmosphere. Carbon black can be used as a reinforcing filler for rubber, plastics and other products. The quality of carbon black is determined by its particle size, structure, surface area and other factors. The iodine adsorption value of acetylene carbon black is one of the indicators to measure the quality of carbon black, and is also an important basis for quality control of products such as tires and rubber hoses.
GB/T3781.7-93 specifies the determination method of iodine adsorption value of acetylene carbon black. The determination method is based on potassium iodate solution as the iodine source and iodine adsorption cotton as a filter and impurity filter. The iodine adsorption value of the acetylene carbon black sample is titrated with the sodium thiosulfate titration after being processed by the sample treatment and test equipment.
1 Sample Preparation
The sample size of acetylene carbon black sample should be no less than 20 g. Amalgamator can be used for grinding, and the sample should be stored in a sealed container and kept in a dry place away from moisture or light.
2 Apparatus
2.1 Amalgamator;
2.2 Residual chlorine ion-selective electrode;
2.3 Residual chlorine solution;
2.4 Potassium iodate solution;
2.5 Iodine adsorption cotton;
2.6 Burette;
2.7 Magnetic stirrer;
2.8 Distilled water;
2.9 Neutral carbon test albumin;
2.10 Beaker;
2.11 Dropper.
3 Reagents
3.1 Potassium iodate solution, c(KIO3)=0.001mol/L;
3.2 Distilled water;
3.3 Residual chlorine solution, c(Cl2)=25mg/L;
3.4 Neutral carbon test albumin, c(C)=10g/L.
4 Determination Method
4.1 Sample treatment: weigh 1.0g of the sample, use 240mL of distilled water and add 0.5mL of residual chlorine solution and 0.03g of neutral carbon test albumin, mix and filter, if the filter solution is still turbid, add 0.03g of neutral carbon albumin, mix and filter;
4.2 Titration: Add 1.25mL of potassium iodate solution to the sample solution, and titrate with 0.01 mol/L of sodium thiosulfate titration until the purple red color reaches the standard. Record the titration amount V(n)mL;
4.3 Calculation: Calculate the iodine adsorption value Vd of acetylene carbon black according to formula (1).
Vd=V(n)×0.001（1）
Where:
Vd – Iodine adsorption value of Acetylene Carbon Black,
V(n) – Titration amount of 0.001 mol/L sodium thiosulfate.
5 Expression of Results
Calculate the average of the results of not less than 3 determinations and express the results to the nearest 0.001, unit g/100g.
6 Precision
The relative standard deviation is not more than 1.0%.
