1、Designation: D7389 07 (Reapproved 2012)Standard Test Method forAcid Number (Empirical) of Maleic Anhydride (MAH) GraftedWaxes1This standard is issued under the fixed designation D7389; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the acidnumber of maleic anhydride (MAH) grafted waxes. The
3、number is obtained by direct titration of the material andindicates the amount of free acid present.1.2 This test method is applicable to MAH-grafted waxesbecause it uses a special sample preparation step (7.1) that isnot required for other waxes. The special sample preparationreverses the hydrolysi
4、s of acid anhydride that can occur duringstorage of the wax.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther
5、esponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1386 Test Method for Acid Number (Empirical) of Syn-thetic and Natural WaxesE200 Practi
6、ce for Preparation, Standardization, and Storageof Standard and Reagent Solutions for Chemical Analysis3. Terminology3.1 Definitions:3.1.1 acid number or acid valuethe number of milligramsof potassium hydroxide necessary to neutralize1gofthesample.4. Significance and Use4.1 This test method is used
7、to determine the free acidcontent of MAH-grafted waxes. The potential hydrolysis of theanhydride functionality of this wax in storage makes themunsuitable for determining free acid content by Test MethodD1386. Free acid content is a significant quality control test,and is a determinant of the utilit
8、y of the wax.5. Apparatus5.1 Analytical Balance.5.2 Buret, 50-mL, with 0.1-mL graduations.5.3 Flasks, acid value, 250-mL.6. Reagents and Materials6.1 Purity of ReagentsReagent-grade chemicals orequivalent, as specified in Practice E200, shall be used in alltests.6.2 Ethanolic Potassium Hydroxide, St
9、andard Solution (0.1N)Dissolve 6.6 g of potassium hydroxide in 5.6 g of distilledwater. Dilute with USSD3A denatured ethanol or 95 % ethanolto 1000 mL. Standardize with 0.1 N hydrochloric acid.6.3 Phenolphthalein Indicator Solution (10 g/litre)Dissolve1gofphenolphthalein in 100 mL of USSD3A,denature
10、d ethanol or 95 % ethanol.6.4 Xylene.7. Sample Preparation7.1 Melt 20 g of the sample wax in a 250-mL flask or beakerand heat to 180190C. Apply a slight vacuum as the waxmelts and hold at temperature for 10 to 15 min, or as long asbubbles appear in the melt. If a vacuum is not available, holdthe sam
11、ple at 180190C for 4 h. Determination of the acidnumber is made immediately after dehydration. Over heatingor holding the sample for more than 4 h will cause excessdarkening of the wax and making the end point difficult to see(8.2).8. Procedure8.1 Transfer 1 to2gofthesample, weighed to the nearest0.
12、001 g, to a 250-mL acid-value flask. Add 40 mL of xylene.1This test method is under the jurisdiction ofASTM Committee D21 on Polishesand is the direct responsibility of Subcommittee D21.02 on Raw Materials.Current edition approved Oct. 1, 2012. Published October 2012. Originallyapproved in 2007 as D
13、738907. DOI: 10.1520/D7389-07R12.2For 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.Copyright ASTM International
14、, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Heat the mixture on a hot plate or water bath to dissolve thesample. Occasional swirling may be necessary.8.2 Add 3 to 5 drops of phenolphthalein indicator solutionand titrate the hot solution to the first persiste
15、nt pink color. Theend point it taken when the pink color remains for at least 10s. Swirl the flask vigorously during the titration. If precipitationof waxes occurs during titration, reheat the sample. Thetitration should be carried out as quickly as possible. Recordthe number of millilitres of stand
16、ard alkali solution used. Toavoid saponification, do not reheat the solution during thisoperation.9. Calculation9.1 Calculate the acid number as follows:Acid number 5 AN 356.1!/Bwhere:A = millilitres of alkali solution required for titration of thesample,N = normality of the alkali solution, andB =
17、grams of sample used.10. Precision and Bias10.1 PrecisionDuplicate results by the same operator shallnot be considered suspect unless the results are greater than astandard deviation of 0.8.10.2 BiasThis test method has no bias because the valuesproduced are defined only in terms of this test method
18、.11. Keywords11.1 acid anhydride function; acid number; free acid; MAHgrafted waxes; polish; synthetic waxes; titration; waxesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are e
19、xpressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not rev
20、ised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you m
21、ay attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United St
22、ates. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D7389 07 (2012)2
