GB/T 9872-1988 Determination of Bromine and Chlorine Contents in Rubbers and Rubber Products by Oxygen Burning
1 Introduction
GB/T 9872-1988 [1] is a standard specifying a test method to determine the bromine and chlorine contents in rubbers and rubber products by oxygen burning, which was issued by the Standardization Administration of the Peoples Republic of China on December 20, 1988. It is the basis for quality inspection and acceptance of rubber and rubber products.
2 Application Scope
This standard specifies a test method to determine the total bromine and chlorine contents of unsaturated natural rubber, butadiene rubber, nitrile rubber, styrene-butadiene rubber and chloroprene rubber by oxygen burning.
3 Principle
This test method is based on the principle that bromine and chlorine are easily oxidized in an oxygen atmosphere at high temperature, and their oxidation products are weighed.
4 Reagents
All test reagents must be analytical grade or retail grade reagents that are qualified in the application scope.
4.1 Oxygen: Dry free oxygen, purity ≥ 99.5%.
4.2 Phosphorus pentoxide: Phosphorus pentoxide containing no more than 0.05% of impurities.
4.3 Potassium Persulfate: Potassium Persulfate containing no more than 0.005% of impurities.
5 Apparatus
5.1 Burner: Composed of ceramic furnace and oxygen burner, size and product type should be selected in accordance with the requirements of this standard.
5.2 Balance: Used to measure up to 0.1 mg, with an error of not more than 0.5 mg.
6 Test Procedures
6.1 Sample Preparation
The rubber sample should be taken according to a certain weighting formula. The sample should be chopped into small pieces, dried on filter paper, andmilled in accordance with the requirements of this standard to a size of 1.0 to 2.0 mm.
6.2 Oxygen Burning
Put a weighed sample of rubbers into the crucible. Ignite until smoke is almost visible and then pour a small amount of oxygen onto the sample for about 10 minutes of oxygen burning. Then reduce the oxygen flow, wait for the temperature to drop to 600°C and protect from the wind. When the ash appears to be light yellow, stop the burning andput the sample ash into a crucible.
6.3 Bromine and Chlorine Determination
Weigh 0.4 to 0.6 g of the sample onto a dish and add 0.15 g of potassium persulfate, 0.15 g of phosphorus pentoxide and 0.5 g of silica gel, and heat on a steam bath until the color of the P2O5 turns yellow. Cool it to room temperature and weigh to the nearest 0.1 mg, and then calculate the result according to the equations in this standard.
7 Report
Report the mass fraction of bromine and chlorine in the rubber sample according to this standard.
8 Precision
The reproducibility of the test results (RSD) should not be greater than 5%.
9 Reference
[1] GB/T 9872-1988 Determination of Bromine and Chlorine Contents in Rubbers and Rubber Products by Oxygen Burning
