1、BS ISO 5351:2010ICS 85.040NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPulps Determinationof limiting viscositynumber in cupri-ethylenediamine (CED)solutionThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 3
2、1 March2010 BSI 2010ISBN 978 0 580 64651 5Amendments/corrigenda issued since publicationDate CommentsBS ISO 5351:2010National forewordThis British Standard is the UK implementation of ISO 5351:2010. Itsupersedes BS ISO 5351:2004 which is withdrawn.The UK participation in its preparation was entruste
3、d to TechnicalCommittee PAI/11, Methods of test for paper, board and pulps.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct ap
4、plication.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS ISO 5351:2010Reference numberISO 5351:2010(E)ISO 2010INTERNATIONAL STANDARD ISO5351Second edition2010-02-15Pulps Determination of limiting viscosity number in cupri-ethylenediamine (CED) solution Ptes Dtermi
5、nation de lindice de viscosit limite laide dune solution de cupri-thylnediamine (CED) BS ISO 5351:2010ISO 5351:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefa
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10、ww.iso.org Published in Switzerland ii ISO 2010 All rights reservedBS ISO 5351:2010ISO 5351:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Normative references1 3 Terms and definitions .1 4 Principle2 5 Reagents and materials 3 6 Apparatus and materials.3
11、 7 Calibration of viscometers .5 8 Sampling and preparation of sample 6 9 Procedure.6 9.1 Choice of mass concentration of solution6 9.2 Weighing of test portion .7 9.3 Preparation of test solution7 9.4 Determination of efflux time.7 10 Calculation .7 10.1 Viscosity ratio 7 10.2 Limiting viscosity nu
12、mber8 10.3 Expression of results8 11 Precision.8 11.1 General check using reference pulp .8 11.2 Repeatability 8 11.3 Reproducibility 9 12 Test report9 Annex A (normative) Preparation and analysis of the cupri-ethylenediamine (CED) solution 10 Annex B (normative) Values of corresponding to different
13、 values of the viscosity ratio ratio(/0).15 Annex C (informative) Calculation of degree of polymerization 18 Bibliography19 BS ISO 5351:2010ISO 5351:2010(E) iv ISO 2010 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standard
14、s bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organiz
15、ations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in
16、the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % o
17、f the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 5351 was prepared by Technical Committee ISO/TC 6, Paper, boa
18、rd and pulps, Subcommittee SC 5, Test methods and quality specifications for pulps. This second edition cancels and replaces the first edition (ISO 5351:2004), Subclause 6.1.1, Clauses 8 and 9 and Annex A of which have been technically revised. BS ISO 5351:2010ISO 5351:2010(E) ISO 2010 All rights re
19、served vIntroduction The viscosity (or dynamic viscosity), symbol , of a fluid is defined by the Newtonian equation = (1) where is the shear stress; is the viscosity; is the velocity gradient dv/dz (v being the velocity of one plane relative to the other, and z the co-ordinate perpendicular to the t
20、wo planes). In non-Newtonian behaviour, which is normally the case with polymer solutions of high molecular mass such as cellulose, the ratio of the shear stress to the velocity gradient varies with the shear stress. The data required for evaluation of the limiting viscosity number of pulp in dilute
21、 solutions are derived by means of a capillary-tube viscometer (for terms and definitions, see Clause 3). The results of these measurements are seriously affected by the shear rate. The mass concentration of the pulp is therefore chosen so that, if multiplied by the limiting viscosity number , it gi
22、ves a product equal to 3,0 0,4, corresponding to a viscosity ratio /0equal to 6 to 10. The determination is then carried out at a reproducible shear rate G of (200 30) s1; this involves the employment of two viscometers, one for the calibration and one for the measurement of the viscosity of the pul
23、p. The viscosity of a pulp in cupri-ethylenediamine (CED) solution gives an indication of the average degree of polymerization (DP) of the cellulose (see Annex C). Such a measurement therefore gives a relative indication of the degree of degradation (decrease in cellulose molecular mass) resulting f
24、rom the pulping and/or bleaching process. Care must be taken in drawing conclusions regarding the strength properties of the pulp strictly from viscosity measurement, unless previous investigation has identified the relationship. A direct relationship between pulp strength and viscosity has not been
25、 found. BS ISO 5351:2010BS ISO 5351:2010INTERNATIONAL STANDARD ISO 5351:2010(E) ISO 2010 All rights reserved 1Pulps Determination of limiting viscosity number in cupri-ethylenediamine (CED) solution 1 Scope This International Standard specifies a method which yields a number that is an estimate of t
26、he limiting viscosity number of pulp in a dilute cupri-ethylenediamine (CED) solution. This International Standard is primarily applicable to CED-soluble samples of bleached chemical pulps, but can also be applied to any kind of pulp that dissolves completely in CED solution. NOTE 1 The results can
27、be used to estimate the extent of cellulose degradation caused by cooking or bleaching. Results obtained with samples containing appreciable amounts of substances other than cellulose must be interpreted with caution, however. NOTE 2 In the strictest sense, viscosity measurement procedures are appli
28、cable only to the polysaccharide fraction of the sample. This notwithstanding, viscosity measurement can usually be used to obtain a result on unbleached pulps having lignin contents of up to 4 %, because most of these pulps can be successfully dissolved in CED. However, the simple fact that an unbl
29、eached pulp can be dissolved in CED does not mean that the results are valid. In summary, viscosity results for pulps containing more than 0,5 % of lignin are not acceptable for technical specification purposes. 2 Normative references The following referenced documents are indispensable for the appl
30、ication of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 638, Paper, board and pulps Determination of dry matter content Oven-drying method ISO 7213, Pulps Sampling fo
31、r testing 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 shear rate G velocity gradient of a fluid layer, parallel to the direction of flow, at the periphery of the capillary, defined by the equation 3f4VGrt=(2) where V is the volume between
32、 two arbitrary calibration marks on the viscometer, in millilitres; r is the radius of the capillary tube, in centimetres; tfis the efflux time of the fluid, in seconds. BS ISO 5351:2010ISO 5351:2010(E) 2 ISO 2010 All rights reserved3.2 viscosity ratio relative viscosity (deprecated) ratioratio of t
33、he viscosities and 0of the polymer solution of stated concentration and of the solvent, respectively, at the same temperature ratio0= (3) NOTE Viscosity ratio is dimensionless. 3.3 viscosity relative increment viscosity ratio (3.2) minus one 0001 = (4) NOTE Viscosity relative increment is dimensionl
34、ess. 3.4 viscosity number VN ratio of the viscosity relative increment (3.3) to the mass concentration of polymer , expressed in grams per millilitre, in the solution 00 (5) NOTE Viscosity number is measured in millilitres per gram. 3.5 limiting viscosity number limiting value of the viscosity numbe
35、r (3.4) at infinite dilution 000lim=(6) NOTE 1 Limiting viscosity number is measured in millilitres per gram. NOTE 2 In the literature, the term intrinsic viscosity is often used and is equal to the limiting viscosity number. There is no general conversion factor between the limiting viscosity numbe
36、r in ml/g and other viscosities, determined by other methods and expressed in millipascal seconds (mPas) (see 7 in the Bibliography). 4 Principle Measurement of the times of efflux of the diluted solvent and the pulp solution through a capillary-tube viscometer at a specified mass concentration at 2
37、5 C. Calculation by Martins formula (see 9 in the Bibliography) of the limiting viscosity number from these measurements, and from the known mass concentration of the solution. BS ISO 5351:2010ISO 5351:2010(E) ISO 2010 All rights reserved 35 Reagents and materials Use only chemicals of recognized an
38、alytical grade and only distilled or deionized water. 5.1 Cupri-ethylenediamine (CED) solution, c(CED) = (1,00 0,02) mol/l, saturated with copper(ll) hydroxide, for convenience referred to as CED solution. The solution contains 1,0 mol/l of copper, and 2,0 mol/l of ethylenediamine. It is commerciall
39、y available, or may be prepared and analysed as described in Annex A. WARNING Because of the presence of allergens, avoid contact of the skin with CED and ethylenediamine solutions. Ethylenediamine is volatile and repeated exposure may lead to severe respiratory allergic reactions with subsequent se
40、nsitization. Cupri-ethylenediamine solutions should not be pipetted by mouth. CED solution is also environmentally harmful, and it is recommended to use a suitable destruction procedure before disposal. 5.2 Glycerol, solution in water, c(C3H8O3) = 65 % (by mass), having a viscosity of about 10 mPas.
41、 5.3 Nitric acid (HNO3), dilute solution for cleaning the copper wire (6.4). 5.4 Acetone (CH3COCH3), analytical reagent grade. WARNING Acetone is inflammable. Keep away from open fire. Do not use a gas heater. Follow pertinent safety regulations. 5.5 Sulfuric-acid-based cleaning solution, designed f
42、or the washing of laboratory glassware. 5.6 Reagents, for calibration of capillary-tube viscometers equipped with an automatic time-recording device. As specified in the manufacturers instructions. 6 Apparatus and materials Ordinary laboratory apparatus and the following. 6.1 Capillary-tube viscomet
43、ers (6.1.1 and 6.1.2), each with a water jacket, connected to the constant-temperature bath (6.3). Two different viscometers are required because of the great difference between the viscosities of the test solution and the solvent. Suitable viscometers are shown in Figure 1. NOTE Viscometers without
44、 a water jacket can be used if measurement is made while the viscometer is immersed in the constant-temperature bath. Capillary-tube viscometers equipped with an automatic time-recording device may be used, provided they comply with this International Standard and give similar results. Clean the vis
45、cometers by rinsing with water and acetone (5.4). If any residual material remains after cleaning, clean again with a sulfuric-acid-based cleaning solution (5.5) designed for use with laboratory glassware. Soak particularly dirty tubes overnight or longer in this cleaning solution to remove all trac
46、es of contaminants. After cleaning, drain all cleaning solution from the tube, rinse well with water and acetone and dry. 6.1.1 Capillary-tube viscometer for calibration purposes, having a capillary tube with a diameter of (0,58 0,02) mm and, in other respects, the dimensions given in Figure 1a). NO
47、TE The efflux time of the viscometer for distilled or deionized water will be about 60 s. 6.1.2 Capillary-tube viscometer for determination of limiting viscosity number at constant shear rate, having a capillary tube with a diameter of (0,80 0,05) mm and, in other respects, the dimensions given in F
48、igure 1b). BS ISO 5351:2010ISO 5351:2010(E) 4 ISO 2010 All rights reservedNOTE 1 Efflux time is about 100 s for a solution of /0= 8,4 at a shear rate (3.1) of (200 30) s1. NOTE 2 Solutions of polymers of high relative molecular mass are usually non-Newtonian. Their viscosity decreases as the shear r
49、ate (or in the present case the flow rate) increases. To avoid this complication, this International Standard specifies that the viscosity be determined at a shear rate of (200 30) s1. The dimensions of the viscometer see Figure 1b) are such that, for a solution of viscosity 10 mPas, the efflux time is about 90 s and the maximum shear rate (3.1) is then within the range (200 30) s1. Dimensions in millimetr
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