GB/T 5473-1985 Determination of free ammonia in phenolic molding products GB/T5473-1985 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Detection of free ammonia in phenolic mouldings
Phenol -- formaldehyde mouldings ---Detection of free ammonia
This standard is equivalent to the international standard ISO172--1978 "Plastics-1 Scope
-Phenol-formaldehyde mouldings-
UDC 678.632: 678
067: 543.813
GB5473-85
-Detection of free ammonia".
This standard specifies a qualitative method for detecting free ammonia or other volatile alkalis in phenolic mouldings by placing a test paper in the gas emitted from a powder sample. It can also be applied when no free ammonia is required. 2 Principle
Use a wide range of test paper to detect the alkaline gas emitted from a powder sample in a sealed flask. 3 Apparatus
3.1 Instrument for powdering the molded product. 3.2 Day: Sensitivity 0.01 g. bzxz.net
3.3 Ground-mouth glass flask with stopper: Capacity 50 ml. 3.4 Standard test paper: pH 1-14°.
4 Preparation of the sample
Powder a representative sample of the molded product by filing, milling, grinding, turning or drilling. Be careful not to overheat the material. The prepared sample should be tested immediately.
5 Procedure
Weigh about 1 g of the sample (see Chapter 4) and immediately place it in the flask (3.3). Quickly stopper the flask and place a strip of standard test paper (3.4) moistened with distilled water between the stopper and the flask, with one end of the test paper extending into the flask. Be careful not to let the test paper touch the sample.
After 30 minutes, check the color change of the test paper and make a record. 6. Results
If the test paper does not change color, report that the molded product does not contain free ammonia or other volatile bases. If the test paper changes color, it indicates the presence of alkaline gas, report that the molded product contains free ammonia or other volatile bases. 7. Test report
The test report should include the following items:
a. Indicate that it is in accordance with this national standard;
Instructions for use: 1) ISO172-1978 stipulates that pH test paper is a universal test paper with a pH range of 1.0 to 11.0. This standard uses domestically produced universal test paper with a pH range of 1 to 14.
Issued by the National Bureau of Standards on October 17, 1985
Industry information is available for free
Implemented on July 1, 1986
Full details of the sample to be identified,
GB5473-85
The method used to make the molded product into powder, whether there is free ammonia or other volatile base;
Test date.
Additional remarks:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China and is under the jurisdiction of the Chemical Method Branch of the National Technical Committee for Plastic Standardization. This standard was drafted by Shanghai Plastic Factory. The main drafters of this standard are Ban Yichu and Wang Zhaoliang. 598
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