ANSI T 230 OM-2013 Viscosity of pulp (capillary viscometer method).pdf

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1、TAPPI/ANSI T 230 om-13 SUGGESTED METHOD 1946 OFFICIAL STANDARD 1976 OFFICIAL TEST METHOD 1982 REVISED 1989 REVISED 1994 REVISED 1999 REVISED 2004 REVISED 2008 REVISED 2013 2013 TAPPI The information and data contained in this document were prepared by a technical committee of the Association. The co

2、mmittee 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 pu

3、blished. 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

4、 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 chem

5、icals 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 hazard

6、ous 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 a

7、nd disposal of these chemicals. Viscosity of pulp (capillary viscometer method) 1. Scope This method describes a procedure for determining the viscosity of 0.5% cellulose solutions, using 0.5M cupriethylenediamine (CED) as a solvent and a capillary viscometer. Measurements may be made on bleached co

8、tton and wood pulps. Conventional kraft pulps with up to 4% lignin, as defined by TAPPI T 222 “Acid-Insoluble Lignin in Wood and Pulp” can also be analyzed. The applicability of this procedure to extended delignification pulps has not been determined. 2. Summary 2.1 This procedure describes the tech

9、niques for dissolving the pulp and measuring of the viscosity of the pulp solution. The procedure gives two alternative techniques for dissolving the pulp sample. This first technique involves mechanical shaking of the sample-solvent mixture in a closed bottle containing glass beads. The second tech

10、nique involves stirring the sample and solvent in an open tube with a copper rod. A survey of users and an interlaboratory test program indicated an equal preference for the two techniques. 2.2 The second technique, which involves stirring the sample and solvent in an open tube, has the potential fo

11、r oxidation of the cupriethylenediamine solution. If this occurs the method will give erroneous results. Caution should be taken to minimize the potential oxidation by continuous flooding of the open end of the dissolving tube with nitrogen. 3. Significance 3.1 The solution viscosity of a pulp gives

12、 an indication of the average degree of polymerization of the cellulose. Such a test therefore gives a relative indication of the degradation (decrease in cellulose molecular weight) resulting from the pulping and/or bleaching process. 3.2 Caution should be exercised in drawing conclusions about pul

13、p strength properties strictly from viscosity results unless previous investigation has identified the relationship. T 230 om-13 Viscosity of pulp (capillary viscometer method) / 2 4. Apparatus 4.1 General. 4.1.1 Cylinder of nitrogen gas, purity 99.998%, fitted with a pressure reducing valve to give

14、 14 to 21 kPa (2 to 3 psi) pressure. 4.1.2 Constant temperature bath, capable of being maintained at 25.0 0.1C and equipped with clamps to support the viscometers in the thermostating fluid. 4.1.3 Viscometer, capillary type, size chosen according to expected viscosity range in compliance with the ch

15、aracteristics for oil calibrations shown in Table 1. In order to avoid correction for the kinetic energy effect, choose a viscometer with an efflux time of over 100 s, but less than 800 s. Viscometer calibration is given in Appendix A. 4.1.4 Stopwatch or electric timer, readable to 0.1 s. 4.1.5 Bure

16、t, 25 mL, automatic gravity fill, all openings sealed to air; for solvent. 4.1.6 Buret or pipet, 25 mL; for water. 4.1.7 Bchner funnels, for forming slush pulps into pads. 4.1.8 Glass filter, coarse, small diameter; and vacuum flask. Table 1. Characteristics for oil calibrations Size Viscosity range

17、, number mPas (cP) 50 0.83.2 100 311 150 727 200 1976 300 48190 4.1.9 Vacuum, source and tubing 4.1.10 Drying oven, 105 2C 4.2 Bottle technique. 4.2.1 Dissolving bottles, 118-mL (4-oz) flat medicine bottles with plastic screw cap and polyethylene liner or rubber septa caps. 4.2.2 Glass beads, approx

18、imately 6 mm diameter. 4.2.3 Mechanical shaker, such as Burrell wrist action shaker. 4.3 Copper stirring rod technique. 4.3.1 Dissolving tube, round flat-bottom glass tube, 19 mm (3/4 in.) inside diameter and 150 mm (6 in.) high (see Fig. 1), such as A.O.C.S. color comparison tubes, Kimbel #45290, o

19、r equivalent. 4.3.2 Copper stirring rod, made from 3.2-mm (1/8-in.) diameter electrolytic copper rod (No. 8 B the results should check within 2.0%. Poor repeatability can result from incomplete dissolution of the pulp, inadequate temperature control, a dirty viscometer, or impurities in the nitrogen

20、 gas. NOTE 4: The viscometer size is selected to give efflux times of over 100 s, but less than 800 s. In practice, efflux times greater than 350 s should be avoided as reproducible results will be difficult to obtain. To adjust the efflux time, change the size of the viscometer accordingly. 8.5 Vis

21、cometer cleaning. Drain the CED solution from the viscometer immediately after the viscosity determination is complete. Rinse the tube well with water to remove all traces of the CED solution. Clean each tube with a sulfuric acid based cleaning solution designed for use with laboratory glassware. So

22、ak especially dirty tubes for 24 hours or more to remove all traces of contaminants. Drain all cleaning solution from the tube and rinse well with deionized or distilled water. Viscometer tubes may be dried in two ways, by using a forced air oven or by rinsing with acetone with air drying. With eith

23、er drying method, traces of moisture or condensation should not be visible in tube after drying. 8.5.1 To dry a viscometer in a forced air oven, place the viscometer in an oven set at 105 2C. Allow the viscometer tube(s) to remain in the air oven just until all traces of moisture are removed. 8.5.2

24、To dry a viscometer with acetone, rinse the tube well with reagent grade acetone, drain, and allow the tube to air dry. NOTE 5: CED solution is highly alkaline and will etch the interior of the viscometer tubes over a period of time. This will change the calibration constant. For this reason, do not

25、 allow the CED solution to remain in the tube after the viscosity determination is complete. Drain all CED solution from the tube and rinse it with water to remove all traces of CED solution immediately after the determination is complete. 9. Calculation Calculate the viscosity, V, of the pulp solut

26、ion from the formula: V = Ctd where V = viscosity of cupriethylenediamine solution at 25.0C, mPas (cP) C = viscometer constant found by calibration t = average efflux time, s d = density of the pulp solution, g/cm3(= 1.052) 10. Report Report the average result of two determinations in mPas to three

27、significant figures, and identify it as the cupriethylenediamine (CED) viscosity of the 0.5% pulp solution by the capillary viscometer method. 11. Precision 11.1 The values of repeatability and reproducibility provided below have been calculated for test results, each of which is an average of two t

28、est determinations. The values are based on data obtained in an interlaboratory test program with 18 participants using six materials. Table 3 gives a statistical summary of the data. The footnote to Table 3 lists a description of the materials tested. 11.2 Repeatability (within a laboratory) = 4.0%

29、. The range of average repeatability for all materials in the study was between 1.8 to 6.1% (0.109 to 2.63 mPas) with the % repeatability increasing as the grand mean increases. 11.3 Reproducibility (between laboratories) = 19%. The range of average reproducibility for all materials in the study was

30、 between 9.6 to 27.2% (0.58 to 11.0 mPas). 11.4 The repeatability and reproducibility are in accordance with the definitions of these terms in TAPPI T 1200 “Interlaboratory Evaluation of Test Methods to Determine TAPPI Repeatability and Reproducibility.” T 230 om-13 Viscosity of pulp (capillary visc

31、ometer method) / 6 Table 3. Statistical summary of data. Sample* Statistical parameter A B C D E F Grand mean, mPas 6.04 11.18 43.2 15.8 19.6 22.6 Repeatability, mPas 0.109 0.327 2.63 0.60 0.95 1.02 Repeatability, % 1.8 2.9 6.1 3.8 4.8 4.5 Reproducibility, mPas 0.58 1.38 11.0 3.19 3.65 6.15 Reproduc

32、ibility, % 9.6 12.3 25.4 20.1 18.6 27.2 *A = sulfite - cellophane grade; B = prehydrolyzed kraft; C = cotton linters; D = kraft bleached pine; E = kraft semi-bleached pine; F = sulfite paper grade. 12. Keywords Pulp, Viscosity, Capillarity, Cuene, Cellulose 13. Additional information 13.1 Effective

33、date of issue: April 30, 2013. 13.2 The 1999 revision includes a change in the requirements for check results for the viscosity measurement. Section 8.4.2 was changed from a “check within 0.25” to “a check within 2.0%.” This change permits the use of this method on extended lignification pulps which

34、 have a wider range of times. The results with other chemical pulps are not significantly affected. 13.3 The falling ball viscometer method, as described in Useful Method 247 “Falling Ball Measurement of Cupriethylenediamine Disperse Viscosity of Pulp,” may be applied as a control procedure, althoug

35、h this is a less reliable procedure. Four laboratories used the falling ball viscometer method in the interlaboratory program and the results showed a repeatability of 10% and a reproducibility of 38%. 13.4 Related methods: PAPTAC G.24, “Cupriethylenediamine Viscosity of Pulp,” Pulp and Paper Techni

36、cal Association of Canada, Montreal, Canada; SCAN-C 15-16, “Viscosity of Cellulose in Cupriethylenediamine Solution (CED),” Scandinavian Pulp, Paper and Board Testing Committee, Stockholm, Sweden; ISO Standard 5351/1; ASTM D 446-93, “Standard Specifications and Operating Instructions for Glass Capil

37、lary Kinematic Viscometer.” 13.5 The 1966 edition of this method included provisions for delignifying unbleached pulps as a means to extend the scope of the method. Chlorite delignification does attack cellulose and when used in conjunction with this procedure may result in lower viscosity measureme

38、nts. If delignification is used, the results should be considered only as approximations. It has been noted that pulps above 35 to 40 kappa number should be delignified with a mild treatment of sodium chlorite or chlorine dioxide to obtain meaningful results. A mild treatment will minimize cellulose

39、 degradation. 13.6 It has been observed that oxygen pulping and oxygen or ozone bleaching of pulps produces viscosity/strength relationships different from traditionally bleached sulfite and kraft pulps. 13.7 Technical changes in this 2008 edition include updating safety precautions and adding a dry

40、ing oven to 4.1.10. The change in the 2013 edition was a modification of 8.4.1 to include an alternative method to fill the viscometer, allowing the viscometers to be filled to the appropriate mark using a precision pipette. Reference Sihtola, H., Kyrklund, B., Laamanen, L., Palenius, I., “Compariso

41、n and Conversion of Viscosity and DP-Values Determined By Different Methods,” Paperi ja Puu 45:225 (1963). Appendix A. Calibration of viscometers 7 / Viscosity of pulp (capillary viscometer method) T 230 om-13 A.1 The calibration constant, C, for each viscometer is determined by the use of standard

42、viscosity oils of known viscosity and density at 25.0 0.1C. Depending on the viscometer size and viscosity range in Table 1, select the appropriate standard oil from Table 2. A.2 Fill the viscometer by immersing its small diameter leg into the oil and drawing the liquid into the instrument by applyi

43、ng suction to the other end. Draw the liquid level to the second etch mark. Remove the tube from the solution, wipe the outside clean and return the instrument to a vertical position within 1 of vertical. Place the viscometer in the constant temperature bath at 25.0 0.1C and allow at least 5 min for

44、 the vessel to reach the temperature. NOTE 6: The initial temperature of the solution will affect the time needed for the solution to reach the equilibrium temperature in the bath. Use a kinematic thermometer to verify that the time is adequate for the solution to reach the equilibrium temperature.

45、A.3 Draw the solution up into the measuring leg of the viscometer with a suction bulb, then allow the oil to drain back into the reservoir to wet the inner surface of the measuring vessel. Determine the efflux time by drawing the liquid above the upper mark and measuring the time required for the me

46、niscus to pass between the reference lines. Make duplicate measurements; these should check within 0.2 s. Failure to obtain the required repeatability is indicative of a dirty viscometer or inadequate temperature control. A.4 The viscometer constant, C, is calculated from the formula: C = V/td where

47、 V = viscosity of standard oil, mPas d = density of standard oil, g/cm3at 25C t = efflux time, s Appendix B. Preparation of 1M cupriethylenediamine B.1 Preparation of Cu(OH)2. B.1.1 Dissolve 250 g of reagent grade copper sulfate (CuSO45H2O) in approximately 2000 mL of hot distilled water. Heat to bo

48、iling and add reagent grade NH4OH slowly with vigorous agitation until the solution is faintly alkaline to pH (about 115 mL of NH4OH are required). Let the precipitate settle, and wash by decantation with 1000-mL portions of distilled water, four times with hot water and twice with cold. Then add su

49、fficient cold water to make the volume of the slurry 1500 mL; cool below 20C (preferably below 10C), and add slowly 850 mL of cold 20% NaOH solution with vigorous stirring. Wash the precipitated Cu(OH)2with distilled water by decantation until the washings are colorless to phenolphthalein indicator and give no precipitation of sulfate upon addition of BaCl2solution. B.1.2 Cupric hydroxide purchased from chemical reagent suppliers may be used provided it is free from ammonia, chlorides, sulfates, and nitrates, and retains its blue