GB/T 2677.10-1995 Determination of holocellulose content in papermaking raw materials

This standard specifies the method for determining the content of holocellulose in papermaking raw materials. This standard is applicable to various wood and non-wood plant fiber raw materials. GB/T 2677.10-1995 Determination of holocellulose content in papermaking raw materials GB/T2677.10-1995 Standard download decompression password: www.bzxz.net

GB/T 2677.10—1995
The technical content of this standard is basically the same as that of the previous version, and only editorial changes have been made to the text. This standard will replace GB2677.10--81 from the date of its entry into force. This standard is proposed by the China Light Industry Federation.
This standard is under the jurisdiction of the National Technical Committee for Paper Standardization. The drafting unit of this standard is China Pulp and Paper Industry Research Institute. The main drafters of this standard are Chen Qizhao and Zhu. This standard was first issued in 1981.
1 Scope
National Standard of the People's Republic of China
Fibrous raw material--Determination of holocellulose
Fibrous raw material--Determination of holocellulose This standard specifies the method for determining the holocellulose content of papermaking raw materials. This standard is applicable to various wood and non-wood plant fiber raw materials. 2 Reference standards
GB/T 2677.10-1995
Replaces GB 2677.10-81
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T2677.1—93 Sampling of samples for analysis of papermaking raw materials GB/T 2677.2—93bZxz.net
Determination of moisture content of papermaking raw materials
GB/T 2677.3—93
Determination of ash content of papermaking raw materials
GB/T 2677. 6--94
Determination of organic solvent extract content of papermaking raw materials 3 Definition and principle
3.1 Holocellulose refers to the total amount of all hemicellulose and cellulose retained after the removal of lignin from plant fiber raw materials. 3.2 The determination method is to treat the sample from which the resin has been extracted with sodium chlorite at a pH of 4 to 5 to remove the contained lignin, and quantitatively determine the amount of residue (i.e., holocellulose).
4 Instruments
4.1 Temperature-controlled constant temperature water bath.
4.2 Soxhlet extractor: 150mL or 250mL. 4.3 Holocellulose tester, including: a 250mL conical flask and a 25mL conical flask, see Figure 1. Approved by the State Administration of Technical Supervision on July 6, 1995 and implemented on April 1, 1996
4.41G2 glass filter.
4.5 Vacuum pump or water pump.
4.6. Filter flask: 1000mL.
5 Reagents
GB/T 2677.10---1995
Figure 1 Holocellulose tester
5.12:1 Benzene-alcohol mixture: Mix 2 volumes of benzene and 1 volume of 95% ethanol and shake well. 5.2 Sodium chlorite (content known): CP grade or above. 5.3 Glacial acetic acid (GB676-90): AR grade. 6 Sampling and treatment
Sampling and treatment shall be carried out in accordance with the provisions of GB/T2677.1. 7 Test steps
7.1 Extraction of resin
Accurately weigh 2g of sample, weigh to 0.0001g, wrap the sample with qualitative filter paper and tie it with cotton thread, extract it with benzene alcohol in accordance with GB/T2677.6, and weigh another sample to determine the moisture content in accordance with GB/T2677.2, and finally air-dry the sample package. 7.2 Determination of holocellulose
Open the air-dried filter paper package, transfer all the samples into the 250mL conical flask of the holocellulose analyzer (Figure 1), add 65ml of distilled water, 0.5mL of glacial acetic acid (5.3), and 0.6g of sodium chlorite (5.2) (calculated as 100%), shake well, cover with a 25mL conical flask, and heat in a 75℃ constant temperature water bath for 1h. During the heating process, the conical flask should be rotated and shaken frequently. After 1 hour, the solution does not need to be cooled. Then add 0.5mL of glacial acetic acid and 0.6g of sodium chlorite, shake well, and continue to heat in a 75℃ water bath for 1 hour. Repeat this process (based on past experience, it is generally repeated four times for wood fiber raw materials and three times for non-wood fiber raw materials). Until the sample turns white and the lignin content is 2% to 4%. Take out the conical flask from the water bath and put it in an ice water bath to cool. Use a 1G2 glass filter with constant weight to filter by suction (the vacuum degree must be well controlled and not too large), wash repeatedly with distilled water until the filtrate does not react acidically, and finally wash it with ketone 3 times, absorb the filtrate and remove the filter, and wash the outside of the filter with distilled water, and place it in a 105±2℃ oven to dry until constant weight. If it is non-wood raw material, the ash content in holocellulose must be determined according to GB/T2677.3. 222
Result calculation
GB/T2677.10-1995
The content of holocellulose X in wood raw materials is calculated according to formula (1): Xi =㎡l × 100
Wherein; X, — the content of holocellulose in wood raw materials, %; m — the content of holocellulose after drying, g,
m. — the mass of the absolutely dry sample, g.
The content of holocellulose X in non-wood raw materials is calculated according to formula (2): mi = m2 × 100
Wherein: X2 — the content of holocellulose in non-wood raw materials, %; — the mass of the absolutely dry sample, 8,
— the content of holocellulose after drying, g;
— the ash content in holocellulose, g.
Carry out two determinations at the same time, and take the arithmetic mean as the determination result, accurate to the second decimal place. The error between the calculated values ​​of the two determinations should not exceed 0.4%.
Test report
The test report should include the following contents:
This national standard number;
Relevant description of the sample;
Test results and necessary explanations;
Any abnormal phenomenon observed during the test; Any operation that is not specified in this national standard or the referenced standards and may affect the results. 223
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