1、T 212 om-12 TENTATIVE STANDARD 1933 OFFICIAL STANDARD 1934 REVISED 1976 OFFICIAL TEST METHOD 1983 REVISED 1988 REVISED 1993 REVISED 1998 REVISED 2002 REAFFIRMED 2007 REVISED 2012 2012 TAPPI The information and data contained in this document were prepared by a technical committee of the Association.
2、 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 edi
3、tion 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
4、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,
5、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
6、 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 saf
7、e 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 solut
8、ion 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
9、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 stre
10、ngth and other properties of pulp (3). 4. Apparatus4.1 Pulp dispersion apparatus (as in Fig. 1 or a similar apparatus), consisting of a variable speed motor and a T 212 om-12 One percent sodium hydroxide solubility of wood and pulp / 2 stainless steel stirrer with a shell. The speed of the motor and
11、 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 100C. The type of bath recommended is one that has a cover with holes of su
12、ch 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 10-15m). Dry before use in an oven at 105 3C for 60 min, cool in a desiccator, and
13、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
14、 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. 6. Safety precautions Sodium h
15、ydroxide 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. 3 / One percent sodium hydroxide solubility of wood and pulp T 212 om-12 7. Sampling 7.1 For wood, obtain a sam
16、ple 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 proc
17、edure. 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 Bchner funnel and press between blotters to remove water. Tear the
18、pulp into small pieces and dry thoroughly in air or in an oven at a temperature not higher than 60C. 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 specime
19、ns 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
20、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 a
21、dhered 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
22、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 100C 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 th
23、e 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 seco
24、nd 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 3C to a constant weight, cool in a desiccator, and weigh. 10. Calculation Calculate the percent solubility (S) as follows: S = (A - B)/A 100 where A = ov
25、en-dry weight of the test specimen before extraction, g B = oven-dry weight of the test specimen after extraction, g 11. Report Report 1% sodium hydroxide solubility as an average of two determinations to the nearest 0.1%. T 212 om-12 One percent sodium hydroxide solubility of wood and pulp / 4 12.
26、Precision 12.1 Repeatability: wood, 0.45%; pulp, 0.36%. 12.2 Reproducibility: wood, 1.96%; pulp, 2.04%. 12.3 Comparability: not known. 12.4 Repeatability and reproducibility values were obtained from an interlaboratory study conducted by nine laboratories on four wood and four bleached pulp samples
27、and are stated in accordance TAPPI T 1200 “Interlaboratory Evaluation of Test Methods to Determine TAPPI Repeatability and Reproducibility.” Solubility of wood samples in 1% NaOH ranged from 11.2 to 17.0%; that of pulp samples, from 2.6 to 7.6%. 13. Keywords Sodium hydroxide, Solubility, Wood, Pulp,
28、 Carbohydrates, Hemicellulose, Cellulose, Caustic solubles 14. Additional information 14.1 Effective date of issue: April 24, 2012. 14.2 Related methods: PAPTAC G.6 and 7, “One Percent Caustic Soda Solubility of Wood and Pulp,” Canadian Pulp and Paper Association, Montreal, Canada. Literature cited
29、1. Morgan, H. W., “Wood Evaluation for Soda Pulp Manufacture,” Paper Trade J. 92 (15): 51 (1931). 2. Procter, A. R., and Chow, W. M., “A Chip Quality Index for Rot,” Pulp Paper Mag. Can. 74 (7): 97 (1973). 3. Anderson, O. E., “Some Causes for Non-Uniformity in Sulfite Pulp Manufacture,” Paper Trade J. 104 (6): 42 (1937). Your comments and suggestions on this procedure are earnestly requested and should be sent to the TAPPI Standards Department. g
