ASTM D914-2012 Standard Test Methods for Ethylcellulose《乙基纤维素的标准试验方法》.pdf

1、Designation: D914 12Standard Test Methods forEthylcellulose1This standard is issued under the fixed designation D914; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the

2、year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These test methods cover the testing of ethylcellulose.1.2 The test procedures appear in t

3、he following order:SectionsMoisture 4 to 6Sulfated Ash 7 to 11Chlorides (as Sodium Chloride) 12 to 16Ethoxyl Content 20 to 24Viscosity 25 to 391.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.4 WarningMercury has been designat

4、ed by EPA andmany state agencies as a hazardous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury-containing products. See the applicable product

5、 Ma-terial Safety Data Sheet (MSDS) for details and EPAs website(http:/www.epa.gov/mercury/faq.htm) for additional informa-tion. Users should be aware that selling mercury or mercury-containing products, or both, in your state may be prohibited bystate law.1.5 This standard may involve hazardous mat

6、erials,operations, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations

7、prior to use.2. Referenced Documents2.1 ASTM Standards:2D362 Specification for Industrial Grade Toluene (Withdrawn1989)3D446 Specifications and Operating Instructions for GlassCapillary Kinematic ViscometersD841 Specification for Nitration Grade TolueneD4794 Test Method for Determination of Ethoxyl

8、or Hy-droxyethoxyl Substitution in Cellulose Ether Products byGas ChromatographyE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids3. Purity of Reagents and Materials3.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, all of the

9、 reagents used shallconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society, where suchspecifications are available.4Where such specifications havenot been established, reagents of the best grade available shallbe used. References to water shall be under

10、stood to meandistilled water.MOISTURE4. Scope4.1 This test method covers the determination of the volatilecontent of ethylcellulose.5. Significance and Use5.1 The results of this test are used for calculating the totalsolids in the sample and, by common usage, all materialsvolatile at this test temp

11、erature are designated as moisture.5.2 Moisture analysis (along with sulfated ash) is used tocalculate the amount of active polymer in the material and shallbe considered when determining the amount of ethylcellulosein various functions.1These test methods are under the jurisdiction of ASTM Committe

12、e D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D01.36 on Cellulose and Cellulose Derivatives.Current edition approved July 1, 2012. Published September 2012. Originallyapproved in 1947. Last previous edition approved in 2006 as D914 0

13、0 (2006).DOI: 10.1520/D0914-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of

14、this historical standard is referenced onwww.astm.org.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd.,

15、 Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus6.1 Oven, gravity convection, capable

16、 of maintaining atemperature of 105 6 3C.6.2 Weighing Bottles.6.3 Analytical Balance.7. Procedure7.1 Weigh accurately 2 to5gofthesample to the nearest0.001 g into a tared dish (fitted with a lid) and dry for2hinanoven at 100 to 105C. Remove the dish from the oven, coverwith a lid, cool in a desiccat

17、or, and weigh.8. Calculation8.1 Calculate the percent moisture, M as follows:M 5 A/B! 3100 (1)where:A = mass loss on heating, g, andB = sample used, g.9. Precision and Bias9.1 PrecisionStatistical analysis of intralaboratory (re-peatability) test results indicates a precision of 65 % at the95 % conf

18、idence level.9.2 BiasNo statement of bias can be made as no suitablereference material is available as a standard.SULFATED ASH10. Scope10.1 This test method covers the determination of theresidue on ignition of ethylcellulose after a specimen has beentreated with sulfuric acid.11. Significance and U

19、se11.1 This test method (along with moisture) is used tocalculate the active polymer in the material. It shall be usedwhen testing ethylcellulose in United States government regu-lated applications. Excessive ash may also affect solutionclarity and film properties.12. Apparatus12.1 Muffle Furnace.12

20、.2 Crucibles, either porcelain, 30mL high, form cracked,platinum.13. Reagent13.1 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).14. Procedure14.1 Ignite a crucible for 10 to 15 min at 800 6 25C, coolin a desiccator, and weigh to the nearest 0.001 g.14.2 Weigh about5gofsample to the near

21、est 0.001 g(previously dried for3hat105C) into the crucible. Burn offthe bulk of the carbonaceous material directly over a flame.After cooling, add 1 mL of H2SO4in such a way as to moistenthe entire ash; then cautiously heat with the burner to densewhite fumes. Ignite in a muffle furnace at 800 6 25

22、C until allsigns of carbon are gone. Cool in a desiccator and reweigh tothe nearest 0.001 g.15. Calculation15.1 Calculate the percent ash (as sulfate), C, as follows:C 5 A/B! 3100 (2)where:A = ash, g, andB = sample used, g.16. Precision and Bias16.1 PrecisionStatistical analysis of interlaboratory (

23、re-producibility) test results indicates a precision of 610 % at the95 % confidence level.16.2 BiasNo statement of bias can be made as no suitablereference material is available as a standard.CHLORIDES (as Sodium Chloride)17. Scope17.1 This test method covers the determination of thechloride content

24、 of ethylcellulose.18. Significance and Use18.1 Sodium chloride is a major by-product of the ethylcel-lulose manufacturing process. This test is a measure of thepurity of ethylcellulose. Chlorides may also affect solutionproperties.19. Apparatus19.1 Titration pH Meter.19.2 Mercury-Mercurous Sulfate

25、Reference ElectrodeTheelectrode uses a potassium sulfate electrolyte to avoid chloridecontamination from a chloride electrolyte.19.3 Silver-Silver Chloride ElectrodeThe electrode iscoated with silver chloride periodically. Prepare the electrodeby polishing with fine steel wool, briefly soaking it in

26、 5 %potassium cyanide solution, and rinsing it with water. Coat theelectrode with silver chloride by electrodeposition from 0.1 Npotassium chloride solution using a 3-V dry cell and a platinumwire electrode. Connect the silver electrode to the positive poleof the battery and electrolyze for 20 s; th

27、en reverse theconnections for 5 s. Repeat these operations twice, and finally,chloridize the silver electrode for 20 s at the positive terminal.Store the silver electrode in 0.1 N potassium chloride solution.Rinse the electrode with water and wipe it with a soft tissuebefore each titration.19.4 Salt

28、 Bridge for Reference ElectrodeFig. 1 shows oneconfiguration in use. Exact dimensions are not important. Thesalt bridge is used to keep the reference electrode fromplugging with the ethylcellulose slurry.19.5 Air-Driven Stirrer.D914 12220. Reagents20.1 Ethanol (95 volume %), undenatured or specially

29、denatured conforming to Formula 2B of the U.S. Bureau ofInternal Revenue.20.2 Ethanol-Distilled Water Solvent Mixture (80 + 20)Mix 800 g of 2B ethanol with 200 g of water. Add 7.5 g ofaerosol OT 100 % surface-active agent per 3000 g of ethanol-water mixture.20.3 Potassium Nitrate (KNO3) Solution (sa

30、turated) for saltbridge (Fig. 1).20.4 Silver Nitrate, Standard Solution (0.02 N)Dissolve3.4 g of silver nitrate (AgNO3) in water, dilute to 1 L withwater in a volumetric flask, and mix. Weigh exactly 0.5845 g ofdry, primary standard sodium chloride (NaCl), dissolve in 25mL of water, and dilute to 1

31、L with water in a volumetric flask.Add 10 mL of H2SO4(1 + 16) to each aliquot before titrating.Titrate aliquots of this solution potentiometrically with theAgNO3solution. Calculate the normality, N, of the AgNO3solution as follows:N 5 A/B! 30.01 (3)where:A = 0.01 N NaCl solution added, mL, andB = Ag

32、NO3solution required for the titration, mL.20.5 Sulfuric Acid (1 + 16)Add 1 volume of concentratedsulfuric acid (H2SO4, sp gr 1.84) slowly with stirring into 16volumes of water.20.6 Toluene, meeting the requirements of SpecificationD362.20.7 Toluene-Ethanol Solvent Mixture (90 + 10)Mix 900g of tolue

33、ne with 100 g of ethanol.21. Procedure21.1 Weigh accurately 10 g of sample to the nearest 0.001 g(previously dried for2hat100to105C) and transfer to a600-mL beaker containing 200 mL of the toluene-ethanolsolvent mixture. Stir with an air-driven stirrer until solution iscomplete.21.2 Add 200 mL of th

34、e ethanol-water mixture and agitatefor 5 min to form a uniform emulsion. Immerse the electrodesin the emulsion using an air-driven stirrer for mixing. Add 10mL of H2SO4(1 + 16) and agitate for 3 to 4 min to allow thesystem to reach equilibrium.21.3 Titrate slowly with the 0.02 N AgNO3solution. Makei

35、ntermittent additions of 0.1 mL. It is advisable to allow longerperiods of time between additions of titrant as the end point isapproached to avoid passing the equivalence point. Run ablank by the same procedure.22. Calculation22.1 Calculate parts per million of chlorides as NaCl, C,asfollows:C 5 VN

36、 30.05845!/W# 31 000 000 (4)where:V = AgNO3solution, mL,N = normality of AgNO3solution,W = sample used, g, and0.05845 = milliequivalent mass of NaCl.23. Precision and Bias23.1 PrecisionStatistical analysis of interlaboratory (re-producibility) test results indicates a precision of 65 % at the95 % co

37、nfidence level.23.2 BiasNo statement of bias can be made as no suitablereference material is available as a standard.ETHOXYL CONTENT24. Scope24.1 This test method covers the determination of theethoxyl content of ethylcellulose.24.2 For an alternative method see Test Method D4794.25. Significance an

38、d Use25.1 This test method determines the amount of substituentgroups added to the cellulose backbone. The level can greatlyaffect solution properties, rheology, solubility parameters, andfilm properties.26. Apparatus26.1 Distillation Apparatus, as illustrated in Fig. 2, consist-ing of a boiling fla

39、sk with a side arm for admission of carbondioxide (CO2) or nitrogen, an air condenser with a trap, and areceiver.in.mm1320.8183.25167.9389.51212.77822.2112383766152FIG. 1 Salt Bridge and Reference Electrode for Chloride Determi-nationD914 12326.2 Oil Bath, equipped with a heating device, preferablye

40、lectrical, so that the bath can be maintained at 145 to 150C.27. Reagents27.1 Bromine SolutionDissolve 5 mL of bromine in 145mL of the potassium acetate (KC2H3O2) solution. Prepare thebromine solution fresh daily in a hood to remove brominevapors.27.2 Carbon DioxidePass the CO2through a bubblecounte

41、r and a dry trap, and then through a pressure regulatorconsisting of a glass tee whose vertical arm extends almost tothe bottom of a 254-mm (10-in.) column of water. A screwclamp shall be attached to the thin-walled rubber tubingconnecting the horizontal arm of the tee with the boiling flask.This ar

42、rangement permits regulation of the flow of gas andallows any excess gas to escape. Nitrogen may be used in placeof CO2.27.3 Formic Acid (90 %).27.4 Gelatin CapsulesGelatin capsules of a suitable sizeto hold from 50 to 60 mg of the dried sample will be required.27.5 Hydriodic Acid (sp gr 1.70)5Hydri

43、odic acid (HI)forms with water a constant-boiling mixture (boiling point 126to 127C) that contains 57 % HI. The concentration of HI in thereagent used should be not less than 56.5 %. The blankdetermination, which is affected primarily by free iodine in thereagent, should require no more than 0.5 mL

44、of 0.1 N sodiumthiosulfate (Na2S2O3) standard solution. If necessary, the acidmay be purified by adding to it a small amount of redphosphorus and boiling for 20 to 30 min in a hood whilepassing a stream of CO2into the liquid. Distillation is thencarried out behind a safety-glass shield in a hood, us

45、ing anall-glass apparatus with a slow stream of CO2running throughthe receiver. Under some conditions, the poisonous gas phos-phine (PH3) is formed during distillation, and this may unitewith molecular iodine to form phosphorus triiodide (PI3) whichmay explode on contact with air. It is, therefore,

46、advisable tokeep the current of CO2going after the distillation is ended anduntil the apparatus has cooled; this will prevent air from beingsucked into the apparatus. Put the purified HI in small, brown,glass-stoppered bottles, previously swept out with CO2, andseal the stoppers with molten paraffin

47、. Store in a dark place. Tominimize decomposition of HI due to contact with air, run CO2into the bottle while withdrawing portions of the acid for use.27.6 Phosphorus Slurry (0.06 g/100 mL)Add about 0.06 gof red phosphorus to 100 mLof water. Shake well before using.27.7 Potassium Acetate Solution (1

48、00 g/L)Dissolve 100 gof anhydrous potassium acetate (KC2H3O2) crystal in 1 L of asolution containing 900 mL of glacial acetic acid and 100 mLof acetic anhydride.27.8 Potassium Iodide (KI).27.9 Sodium Acetate Solution (220 g/L)Dissolve 220 g ofanhydrous sodium acetate in water and dilute to 1 L.27.10

49、 Sodium Thiosulfate, Standard Solution (0.1 N)Dissolve 25 g of sodium thiosulfate (Na2S2O35H2O) in 200mL of water and dilute to 1 L. Use freshly boiled and cooledwater. It is preferable to allow the solution to stand for a fewdays before standardization. Standardize the solution against0.1000 N potassium dichromate (K2Cr2O7) solution preparedby dissolving exactly 4.9037 g of K2Cr2O7(National Instituteof Standards and Technology Standard Sample No. 136) inwater and diluting to 1 L in a volumetric flask. By means of aburet, measure accu