TAPPI T 212-02

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T 212 om-02

TENTATIVE STANDARD – 1933

OFFICIAL STANDARD – 1934

REVISED – 1976

OFFICIAL TEST METHOD – 1983

REVISED – 1988

REVISED – 1993

REVISED – 1998

REVISED – 2002

2002 TAPPI

The information and data contained in this document were prepared

by a technical committee of the Association. The committee and the

Association assume no liability or responsibility in connection with

the use of such information or data, including but not limited to any

liability under patent, copyright, or trade secret laws. The user is

responsible for determining that this document is the most recent

edition published.

Approved by the Standard Specific Interest Group for this Test Method

TAPPI

CAUTION:

This Test Method may include safety precautions which are believed to be appropriate at the time of publication of the method. The intent of these

is to alert the user of the method to safety issues related to such use. The user is responsible for determining that the safety precautions are complete

and are appropriate to their use of the method, and for ensuring that suitable safety practices have not changed since publication of the method. This

method may require the use, disposal, or both, of chemicals which may present serious health hazards to humans. Procedures for the handling of

such substances are set forth on Material Safety Data Sheets which must be developed by all manufacturers and importers of potentially hazardous

chemicals and maintained by all distributors of potentially hazardous chemicals. Prior to the use of this method, the user must determine whether

any of the chemicals to be used or disposed of are potentially hazardous and, if so, must follow strictly the procedures specified by both the

manufacturer, as well as local, state, and federal authorities for safe use and disposal of these chemicals.

One percent sodium hydroxide solubility of wood and

pulp

1. Scope

This method for determination of 1% sodium hydroxide solubility can be applied to wood and to unbleached and

bleached pulp.

2. Summary

Wood or pulp is extracted with hot 1% sodium hydroxide solution for 1 h. The loss in weight is determined and

calculated as percent solubility.

3. Significance

3.1 Hot alkali solution extracts low-molecular-weight carbohydrates consisting mainly of hemicellulose and

degraded cellulose in wood and pulp.

3.2 The solubility of wood could indicate the degree of a fungus decay or of degradation by heat, light,

oxidation, etc. As the wood decays or degrades, the percentage of the alkali-soluble material increases (1, 2).

3.3 The solubility of pulp indicates an extent of cellulose degradation during pulping and bleaching processes

and has been related to strength and other properties of pulp (3).

T 212 om-02 One percent sodium hydroxide solubility of wood and pulp / 2

4. Apparatus1

4.1 Pulp dispersion apparatus (as in Fig. 1 or a similar apparatus), consisting of a variable speed motor and a

stainless steel stirrer with a shell. The speed of the motor and the angle of the blades should be adjusted so that no air is

drawn into the pulp suspension during stirring.

4.2 Water bath, designed so that the temperature of the material during treatment is uniformly maintained at

97° to 100°C. The type of bath recommended is one that has a cover with holes of such a size that the beakers used may

be placed inside the bath and supported in position by their flared rims.

4.3 Beakers, tall form, 200 mL.

4.4 Filtering crucibles, 30 mL, medium porosity (nominal maximum pore size 10-15µm). Dry before use in

an oven at 105° ± 3°C for 60 min, cool in a desiccator, and weigh.

4.5 Filtering flasks, 1000 mL.

4.6 Other equipment: graduated cylinder, 100 mL; watch glasses; stirring rods; thermometer, vacuum source.

5. Reagents

5.1 Sodium hydroxide solution, 1.0% ± 0.1% NaOH (0.25N). Dissolve 10.0 g of solid NaOH in water and

dilute to 1000 mL. Determine normality of the solution by titration with a standard acid according to TAPPI T 610

“Preparation of Indicators and Analytical Reagents and Standardization of Volumetric Solutions” and adjust to 0.25 ±

0.025N.

5.2 Acetic acid, 10%. Dilute 100 mL of glacial CH3COOH with water to 1000 mL.

1Names of suppliers of testing equipment and materials for this method may be found on the Test Equipment Suppliers list in the

bound set of TAPPI Test Methods, or may be available from the TAPPI Quality and Standards Department.

3 / One percent sodium hydroxide solubility of wood and pulp T 212 om-02

6. Safety precautions

Sodium hydroxide is a strong caustic. Solutions of sodium hydroxide are corrosive and damaging to human skin. Great

care should be taken when handling the sodium hydroxide solution in this method.

7. Sampling

7.1 For wood, obtain a sample and prepare wood meal in accordance with TAPPI T 257 “Sampling and

Preparing Wood for Analysis.”

CAUTION: Do not extract wood meal with organic solvents or water prior to the testing.

7.2 For pulp, obtain a sample equivalent to about 10 g oven-dry in accordance with a predetermined sampling

procedure.

7.2.1 If the sample is taken from a pulp sheet, split it in layers and tear by hand into small pieces about 10 mm

across. Do not cut or shred the pulp by mechanical devices.

7.2.2 If the sample is a slush pulp, filter it on a Büchner funnel and press between blotters to remove water.

Tear the pulp into small pieces and dry thoroughly in air or in an oven at a temperature not higher than 60°C.

8. Test specimens

8.1 Allow the sample to come to moisture equilibrium in the atmosphere near the balance; then weigh out

two test specimens of 2.0 ± 0.1 g to the nearest 1.0 mg. Place the test specimens in 200-mL tall-form beakers.

8.2 At the same time weigh a specimen for moisture determination, in accordance with TAPPI T 264

“Preparation of Wood for Chemical Analysis,” TAPPI T 210 “Sampling and Testing Wood Pulp Shipments for

Moisture,” or TAPPI T 550 “Determination of Equilibrium Moisture in Pulp, Paper, and Paperboard for Chemical

Analysis.”

9. Procedure

9.1 To the wood meal, add 100 ± 1 mL of 1% NaOH solution and stir with a glass rod.

9.2 To the pulp add 75 mL of 1% NaOH solution and stir with the pulp dispersion apparatus until the pulp is

dispersed. Raise the stirrer and remove the adhered pulp fibers with a glass rod. Rinse with 25 mL of the NaOH reagent,

adding it to the beaker so that 100 ± 1 mL of the reagent are added to the pulp.

NOTE 1: Some pulps could be dispersed readily by stirring and macerating with a glass rod; however, complete dispersion is essential, and

too low a solubility value will be obtained if the pulp dispersion is not complete.

9.3 Cover the beaker with a watch glass and place in a water bath maintained at 97° to 100°C for a period of

60 min. Keep the water in the bath boiling and its level above that of the alkali solution in the beaker.

9.4 Stir the pulp with a rod for about 5 s at 10, 15, and 25 min after placing in the bath.

9.5 At the end of 60 min transfer the material to a tared filtering crucible and wash with 100 mL of hot water.

Then add 25 mL of 10% acetic acid and allow to soak for 1 min before removal. Repeat this step with a second 25-mL

portion of 10% acetic acid. Wash the material finally with hot water until acid free.

9.6 Dry the crucible and contents in an oven at 105° ± 3°C to a constant weight, cool in a desiccator, and

weigh.

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摘要：

TAPPI T 212-02 是一项由美国纸浆与造纸工业技术协会（TAPPI）发布的标准测试方法，专门用于测定纸浆在冷碱（氢氧化钠溶液）中的溶解度。该方法通过将纸浆样品在特定温度下与碱液反应，经称重计算溶解部分的比例，从而评估纸浆中纤维的降解程度、纤维素含量以及工艺处理对纤维结构的影响。该标准广泛应用于纸浆质量检测、造纸工艺优化以及原材料分析，帮助工程师和研究人员判断纸浆的纯度、老化程度及最终的纸张性能，是纸浆与纤维分析领域的重要参考依据。

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