This standard specifies a method for determining the water extract content of papermaking raw materials. This standard is applicable to wood and non-wood fiber raw materials. GB/T 2677.4-1993 Determination of water extract content of papermaking raw materials GB/T2677.4-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of water solubility of papermaking raw materials
Fibrous raw material-Determination of water solubility
1 Subject content and scope of application
This standard specifies a method for determining the water solubility of papermaking raw materials. This standard is applicable to wood and non-wood fiber raw materials. 2 Reference standards
GB2677.1 Sampling of samples for analysis of papermaking raw materials Determination of water content of papermaking raw materials
GB 2677.2
3 Principle
GB/T 2677. 4-- 93
Replaces GB2677.4-81
The determination method is to treat the sample with water, and then dry the residue after extraction to determine the content of the extract. 4 Water
The water used in the analysis should be distilled water or deionized water. 5 Instruments
General laboratory instruments.
5.2 Constant temperature water bath (temperature range: room temperature ~ 100℃ adjustable). 5.3 A constant temperature device that can adjust the temperature to 23±2℃. 5.4 30 mL glass filter (1G2). wwW.bzxz.Net
5.5 Constant temperature oven.
5.6 500mL and 300mL conical flasks. Condenser.
6 Sample collection and preparation
Sample collection and preparation shall be carried out in accordance with the provisions of GB2677.1. Prepare an air-dried sample of not less than 20g, and the sample shall be fine enough to pass through a 40-mesh sieve but not a 60-mesh sieve. 7 Determination of cold water extract content
7.1 Test steps
Accurately weigh 1.9~~2.1g (weighed to 0.0001g) of sample (simultaneously weigh another sample to determine the water content according to GB2677.2), transfer it into a 500mL conical flask, add 300mL of distilled water, place it in a temperature-adjustable constant temperature device, and maintain the temperature at 23±2℃. Cover and place it for 48h, and shake it frequently. Filter it through a 1G2 glass filter that has been constant weight by pouring method, wash the residue and conical flask with distilled water and wash all the residue in the flask into the filter, continue washing until the washing liquid is colorless, and then wash it 2~3 more times. Drain the filtrate, wash the outside of the filter with distilled water, move it into an oven, and dry it at 105 ± 2°C until the mass is constant. 7.2 Calculation of results
Cold water extract content (%), calculated according to formula (1): xi (%) =
Where: m, absolute dry mass of the sample before extraction, g; m2 - absolute dry mass of the sample after extraction, g. 8 Determination of hot water extract content
8.1 Test steps
m - mz
Accurately weigh 1.9-2.1g (weighed to 0.0001g) of sample (simultaneously weigh another sample to determine the water content according to GB2677.2), transfer it into a 300mL conical flask, add 200mL of hot distilled water at 95-100℃, install a reflux condenser or air condenser, place it in a boiling water bath (the water bath level must be higher than the liquid level in the conical flask containing the sample), heat for 3h, and shake it frequently. Filter through a 1G2 glass filter with constant weight by pouring method, wash the residue and conical flask with hot distilled water, and wash all the residue in the conical flask into the filter. Continue washing until the washing liquid is colorless, wash 2-3 more times, absorb the filtrate, wash the outside of the filter with distilled water, transfer it into an oven, and dry it at 105±2℃ until the mass is constant. 8.2 Calculation of results
Two determinations of water extract should be carried out at the same time. The arithmetic mean is taken as the determination result, which is required to be rounded to one decimal place. The deviation between the calculated values ​​of the two determinations should not exceed 0.2%. The content of hot water extract 2 (%) is calculated according to formula (2): 2 (%) = m2m × 100
Where: m--the absolute dry mass of the sample before extraction, g, m3--the absolute dry mass of the sample after extraction, m. 9 Test report
The test report should include the following items:
the number of this national standard,
the data, location and reference materials of the test; b.
the method used (specify whether it is cold water or hot water extraction); c.
all the information required for complete identification of the sample; d.
the operation not in accordance with the provisions of the standard and other factors that may affect the test results. (2)
Additional Notes:
GB/T2677.4—93
This standard was proposed by the Ministry of Light Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Paper Industry. This standard was drafted by the Paper Industry Scientific Research Institute of the Ministry of Light Industry. This standard refers to the American standard TAPPIT207om-88 "Determination of water extracts in wood and pulp". This standard was first issued in 1981.
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