1、Designation: D 7389 07Standard Test Method forAcid Number (Empirical) of Maleic Anhydride (MAH) GraftedWaxes1This standard is issued under the fixed designation D 7389; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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. Thenumber is obtai
3、ned 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 hydrolysis of acid anhyd
4、ride that can occur duringstorage of the wax.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regula
5、tory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1386 Test Method for Acid Number (Empirical) of Syn-thetic and Natural WaxesE 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis3. Terminology3.1 Definitions:3.1
6、.1 acid number or acid valuethe number of milligramsof potassium hydroxide necessary to neutralize1gofthesample.4. Significance and Use4.1 This test method is used to determine the free acidcontent of MAH-grafted waxes. The potential hydrolysis of theanhydride functionality of this wax in storage ma
7、kes themunsuitable for determining free acid content by Test MethodD 1386. Free acid content is a significant quality control test,and is a determinant of the utility 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 an
8、d Materials6.1 Purity of ReagentsReagent-grade chemicals orequivalent, as specified in Practice E 200, shall be used in alltests.6.2 Ethanolic Potassium Hydroxide, Standard Solution (0.1N)Dissolve 6.6 g of potassium hydroxide in 5.6 g of distilledwater. Dilute with USSD3A denatured ethanol or 95 % e
9、thanolto 1000 mL. Standardize with 0.1 N hydrochloric acid.6.3 Phenolphthalein Indicator Solution (10 g/litre)Dissolve1gofphenolphthalein in 100 mL of USSD3A,denatured 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 18019
10、0C. 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 sample at 180190C for 4 h. Determination of the acidnumber is made immediately after dehydration. Over heatingor holding the sample for m
11、ore 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 nearest0.001 g, to a 250-mL acid-value flask. Add 40 mL of xylene.Heat the mixture on a hot plate or water bath to dissolve thesample. Occasion
12、al swirling may be necessary.8.2 Add 3 to 5 drops of phenolphthalein indicator solutionand titrate the hot solution to the first persistent 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
13、 during titration, reheat the sample. The1This 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, 2007. Published October 2007.2For referenced ASTM standards, visit the ASTM w
14、ebsite, 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United S
15、tates.titration should be carried out as quickly as possible. Recordthe number of millilitres of standard 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 3 56.1!/Bwhere:A = millilitr
16、es of alkali solution required for titration of thesample,N = normality of the alkali solution, andB = grams of sample used.10. Precision and Bias10.1 PrecisionDuplicate results by the same operatorshall not be considered suspect unless the results are greaterthan a standard deviation of 0.8.10.2 Bi
17、asThis test method has no bias because the valuesproduced are defined only in terms of this test method.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 pat
18、ent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly 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
19、 at any time by the responsible technical committee and must be reviewed every five years andif not revised, 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 comm
20、ents will receive careful consideration at a meeting of theresponsible technical committee, which you may 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 copyrighte
21、d by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. 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).D7389072
