1、Designation: D1439 03 (Reapproved 2008)1D1439 15Standard Test Methods forSodium Carboxymethylcellulose1This standard is issued under the fixed designation D1439; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1 NOTEEditorial changes were made in Sections 11, 12, 15.5, and 31.1 in June 2008.1. Scope Scope*1.1 These test methods cover the testing o
3、f sodium carboxymethylcellulose.1.2 The test procedures appear in the following order:SectionsMoisture 4 9Moisture 4 9Degree of Etherification:Degree of Etherification:Test Method AAcid Wash 10 17Test Method AAcid Wash 10 17Test Method BNonaqueous Titration 10, 12, 18 23Test Method BNonaqueous Titra
4、tion 10, 12, 18 23Viscosity 24 30Viscosity 24 29Purity 31 38Purity 30 37Sodium Glycolate 39 47Sodium Glycolate 38 46Sodium Chloride 48 55Sodium Chloride 47 54Density 56 62Density 55 611.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for inform
5、ation only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For s
6、pecific hazard statements, see 15.1 and 20.2. Referenced Documents2.1 ASTM Standards:2D1347 Test Methods for Methylcellulose (Withdrawn 2003)3E1 Specification for ASTM Liquid-in-Glass Thermometers3. Purity of Reagents3.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated,
7、 it is intended that all reagents shall conformto the specifications of the Committee on Analytical Reagents of the American Chemical Society,4, where such specifications areavailable. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permi
8、t its usewithout lessening the accuracy of the determination.1 These test methods are under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and are the direct responsibility ofSubcommittee D01.36 on Cellulose and Cellulose Derivatives.Current edition
9、 approved June 1, 2008Dec. 1, 2015. Published June 2008January 2016. Originally approved in 1956. Last previous edition approved in 20032008 asD1439 03.D1439 03 (2008)1. DOI: 10.1520/D1439-03R08E01.10.1520/D1439-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM C
10、ustomer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.4 Reagent Chemicals, American Chemical Society Specification
11、s, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention,
12、Inc. (USPC), Rockville, MD.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends t
13、hat users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
14、 Conshohocken, PA 19428-2959. United States13.2 Unless otherwise indicated, references to water shall be understood to mean distilled water.MOISTURE4. Scope4.1 This test method covers the determination of the volatile content of sodium carboxymethylcellulose.4.2 The results of this test are used for
15、 calculating the total solids in the sample; and, by common usage, all materials volatileat this test temperature are designated as moisture.5. Significance and Use5.1 Moisture analysis (along with purity) is used to calculate the amount of active polymer in the material and must beconsidered when d
16、etermining the amount of sodium carboxymethylcellulose to use in various formulations.6. Apparatus6.1 OvenGravity convection oven, capable of maintaining a temperature of 105 6 3C.6.2 Weighing Bottles, low-form, 50-mm inside diameter by 30-mm height, or equivalent.6.3 Analytical Balance.7. Procedure
17、7.1 Weigh 3 to 5 g of the sample to the nearest 0.001 g in a tared and covered weighing bottle.7.2 Place the bottle in an oven at 105C for 2 h with the cover removed. Cool the bottle in a desiccator, replace the cover, andweigh.7.3 Replace the sample in the oven for 30 min, cool, and reweigh.7.4 Con
18、tinue this procedure to a mass loss of not more than 5 mg for 30 min drying time.8. Calculation8.1 Calculate the percent moisture, M, as follows:M 5A/B! 3100 (1)where:A = mass loss on heating, g, andB = sample used, g.9. Precision and Bias9.1 PrecisionStatistical analysis of interlaboratory reproduc
19、ibility test results on samples containing 2 to 10 % moistureindicates a precision of 60.2 % absolute at the 95 % confidence level.9.2 BiasNo justifiable statement can be made on the bias of the procedure for measuring moisture because no suitablereference material exists.DEGREE OF ETHERIFICATION10.
20、 Scope10.1 These test methods cover the determination of the degree of etherification (D.E.) of sodium carboxymethylcellulose.10.2 Two test methods are included as follows:10.2.1 Test Method A (Acid Wash), for crude grades of sodium carboxymethylcellulose with degrees of etherification up to 0.85.Ab
21、ove 0.85 degree of etherification, slightly low results may be obtained.10.2.2 Test Method B (Nonaqueous Titration), for purified grades of sodium carboxymethylcellulose of all degrees ofetherification. It is not applicable to the crude grades.11. Significance and Use11.1 These test methods determin
22、e the amount of substituent groups added to the cellulose backbone. The level can greatlyaffect solution properties, rheology, viscosity, hygroscopicity, salt tolerance, and many other properties of the polymer.Test Method AAcid Wash12. Summary of Test Method12.1 The water-soluble sodium carboxymeth
23、ylcellulose is converted to the insoluble acid form, purified by washing, dried, andthen a weighed sample is reconverted to the sodium salt with a measured excess of sodium hydroxide.D1439 15213. Apparatus13.1 Stirrer, air-driven.13.2 Buchner Funnel, 75-mm, fitted with a 70-mm fine-texture, heavy-du
24、ty filter paper.A60-mm medium-porosity, fritted glassfunnel may also be used.13.3 Drying Oven, maintained at 105C.14. Reagents14.1 Diphenylamine ReagentDissolve 0.5 g of diphenylamine in 120 mL of sulfuric acid (H2SO4, 9 + 2). The reagent shouldbe essentially water-white. It will give a deep blue co
25、loration with traces of nitrate or other oxidizing agents.14.2 Ethyl Alcohol (95 volume %)Denatured ethyl alcohol conforming to either Formula 2B, 3A, or 30 of the U. S. Bureauof Internal Revenue.14.3 Ethyl Alcohol (80 % by volume)Dilute 840 mL of Formula 2B, 3A, or 30 denatured alcohol to 1 L with
26、water.14.4 Hydrochloric Acid, Standard (HCl, 0.3 to 0.5 N).14.5 Methanol, anhydrous.14.6 Nitric Acid (sp gr 1.42)Concentrated nitric acid (HNO3).14.7 Sodium Hydroxide, Standard Solution(0.3 to 0.5 N)Prepare and standardize a 0.3 to 0.5 N solution of sodium hydroxide(NaOH).14.8 Sulfuric Acid (9 + 2)C
27、arefully mix 9 volumes H2SO4 with 2 volumes of water.15. Procedure15.1 Weigh approximately 4 g of the sample into a 250-mLbeaker and add 75 mLof ethyl alcohol (95 %). Stir the mixture withan airdriven stirrer until a good slurry is obtained. Add 5 mL of HNO3, while agitating, and continue agitation
28、for 1 to 2 min.Heat the slurry and boil for 5 min. (WarningExercise care to avoid fire.) Remove the heat and continue agitation for 10 to 15min.15.2 Decant the supernatant liquid through the filter and transfer the precipitate to the filter with 50 to 100 mL of ethyl alcohol(95 %). Wash the precipit
29、ate with ethyl alcohol (80 %) that has been heated to 60C, until all of the acid has been removed.15.3 Test for the removal of acid and salts (ash) by mixing a drop of the acid carboxymethylcellulose slurry from the filter witha drop of diphenylamine reagent on a white spot plate. A blue color indic
30、ates the presence of nitrate and the necessity for furtherwashing. If the first drop of reagent does not produce a blue color, further drops should be added until an excess of reagent is knownto be present, noting the color after each drop. Four to six washings will usually suffice to give a negativ
31、e test for nitrate.15.4 Finally, wash the precipitate with a small amount of anhydrous methanol and draw air through it until the alcohol iscompletely removed. Transfer the precipitate to a glass or aluminum weighing dish provided with a cover. Heat the uncovered dishon a steam bath until the odor o
32、f alcohol can no longer be detected (in order to avoid fires due to methanol fumes in the oven),then dry the dish and contents, uncovered for 3 h at 105C. Place the cover on the dish and cool to room temperature in a desiccator.15.5 The sulfate ash content of the sample at this point should be less
33、than 0.5 % when determined on 0.5 g of the sample bythe procedure given in the Ash as Sulfate section of Test Methods D1347. If the ash content is greater than 0.5 %, rewash thesample with ethyl alcohol (80 %). If necessary, repeat the procedure described in 15.1 15.4.15.6 Weigh, to the nearest 0.01
34、 g, about 1 to 1.5 g of the dried acid carboxymethylcellulose (depending on the normality of theacid and base to be used) into a 500-mL Erlenmeyer flask. Add 100 mL of water and 25.00 mL of 0.3 to 0.5 N NaOH solution,while stirring. Heat the solution to boiling, and boil for 15 to 30 min.15.7 Titrat
35、e the excess NaOH, while the solution is hot, with the 0.3 to 0.5 N HCl to a phenolphthalein end point.16. Calculation16.1 Calculate the degree of etherification, G, as follows:A 5BC2DE!/F (2)G 50.162A/120.0584A! (3)where:A = milliequivalents of acid consumed per gram of sample,B = NaOH solution add
36、ed, mL,C = normality of the NaOH solution,D = HCl required for titration of the excess NaOH, mL,D1439 153E = normality of the HCl,F = acid carboxymethylcellulose used, g,162 = gram molecular mass of the anhydroglucose unit of cellulose, and58 = net increase in molecular mass of anhydroglucose unit f
37、or each carboxymethyl group substituted.17. Precision and Bias17.1 PrecisionStatistical analysis of intralaboratory (repeatability) test results indicates a precision of 60.04 D.E. units at the95 % confidence level.17.2 BiasNo justifiable statement can be made on the bias of the procedure for measur
38、ing degree of etherification because nosuitable reference material exists.Test Method BNonaqueous Titration18. Summary of Test Methods18.1 This measurement is based upon a nonaqueous acid-base titration. The sample is refluxed with glacial acetic acid, and theresulting sodium acetate is titrated wit
39、h a standard solution of perchloric acid in dioxane, to a potentiometric end point. Impuritiescontaining alkaline sodium will also be titrated under these conditions. Sodium chloride does not interfere.19. Apparatus19.1 pH Meter, equipped with a standard glass electrode and a calomel electrode modif
40、ied as follows:19.1.1 Discard the aqueous potassium chloride solution, then rinse and fill with the calomel electrode solution as described in20.2.19.1.2 Add a few crystals of potassium chloride and silver chloride or silver oxide to the electrode.19.2 Buret, micro, 10-mL capacity.20. Reagents20.1 A
41、cetic Acid, glacial.20.2 Calomel Electrode SolutionAdd 2 g of potassium chloride (KCl) and 2 g of silver chloride (AgCl) or silver oxide (Ag2O)to 100 mL of methanol and shake thoroughly to saturate. Use the supernatant liquid.20.3 1,4-Dioxane.20.4 Perchloric Acid (0.1 N)Add 9 mL of concentrated perc
42、hloric acid (HClO4, 70 % to 1 L of dioxane, with stirring(WarningThe solution of perchloric acid in dioxane should never be heated or allowed to evaporate.). Store in an amber glassbottle. Any slight discoloration that appears on standing may be disregarded.20.4.1 Standardize the solution as follows
43、: Dry potassium acid phthalate for 2 h at 120C. Weigh 2.5 g to the nearest 0.0001g into a 250-mLvolumetric flask.Add glacial acetic acid, shake to dissolve, and then make up to volume and mix thoroughly. Pipet10 mL into a 100-mL beaker and add 50 mL of acetic acid. Place on a magnetic stirrer and in
44、sert the electrodes of the pH meter.Add nearly the required amount of HClO4 from a buret, then decrease the increments to 0.05 mL as the end point is approached.Record the millilitres of titrant versus millivolts, and continue the titration a few millilitres beyond the end point. Plot the titrationc
45、urve and read the volume of titrant at the inflection point. Calculate the normality, N, as follows:N 5A 31031000!/B 3204.223250! (4)where:A = potassium acid phthalate used, g,B = HClO4 added, mL,204.22 = gram molecular mass of potassium acid phthalate,10 = potassium acid phthalate solution added, m
46、L, and250 = glacial acetic acid used to dissolve potassium acid phthalate, mL.20.5 Potassium Acid Phthalate, primary standard, National Institute of Standards and Technology Standard Sample No. 84.21. Procedure21.1 Weigh 0.2 g of the sample, to the nearest 0.0001 g, into a 250-mL Erlenmeyer flask wi
47、th ground-glass joint. Add 75 mLof acetic acid, connect to a water-cooled condenser, and reflux gently on a hot plate for 2 h.21.2 Cool, and transfer the solution to a 250-mL beaker with the aid of 50 mL of acetic acid. Place on the magnetic stirrer andtitrate to a potentiometric end point with 0.1
48、N HClO4 in accordance with 20.4.D1439 15422. Calculation22.1 Calculate the degree of etherification, H, as follows (Note 1):M 5AN3100!/G 31002B! (5)H 50.162 M/1.00020.080 M! (6)where:M = milliequivalents of acid consumed per gram of sample,A = HClO4 added, mL,N = normality of HClO4,G = sample used,
49、g,B = percent moisture, determined on a separate sample, in accordance with Sections 4 7,162 = gram molecular mass of an anhydroglucose unit of cellulose, and80 = net increase in molecular mass of an anhydroglucose unit for each sodium carboxymethyl group added.NOTE 1The result calculated in accordance with Section 18 includes the alkaline sodium from sodium glycolate; however, if the latter is less than0.5 %, the interference is negligible.23. Precision and Bias23.1 PrecisionStatistical analys
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