1、Designation: D3644 15Standard Test Method forAcid Number of Styrene-Maleic Anhydride Resins1This standard is issued under the fixed designation D3644; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber 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 measurement of the freeacidity present in styrene-maleic anhydride resins.1.2 The values stated in SI units ar
3、e to be regarded asstandard. No other units of measurement are included in thisstandard.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
4、 and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D329 Specification for AcetoneD1193 Specification for Reagent Water3. Terminology3.1 Definitions:3.1.1 acid numberthe number of milligrams of potassiumhydroxide (KOH) required to neutr
5、alize the alkali-reactivegroups in1gofmaterial under the conditions of test.4. Significance and Use4.1 This test method is used to determine the property ofstyrene-maleic anhydride resins functionality. Acid functional-ity determines the utility of resin as well as being a significantquality control
6、 test.4.2 Because some of the anhydride functionality has beenhydrolyzed in the manufacturing process, direct titration withbase will produce erroneous data on the total acid content ofthe fully hydrolyzed resin in use. This test method chargesexcess alkali to hydrolize the anhydride functionality a
7、ndneutralize the resulting acid. The remaining unreacted alkali isthen back titrated with a standardized acid solution and the acidcontent is determined by difference.5. Reagents and Materials5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is i
8、ntended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use w
9、ithout lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D1193.5.3 Acetone, conforming to the requirements described inSpecification D329.5.4 Phenolphthalein Indicator Solu
10、tion (20 g/L)Dissolve10 g of phenolphthalein in 100 mL of acetone.5.5 Sodium Hydroxide, Standard Solution (0.1 N)Dissolve7gofsodium hydroxide (NaOH) in 7 mL of water,and filter the resulting solution through a glass mat in a Goochcrucible with the aid of suction. Do not wash the residue.Dilute two t
11、hirds of the clear filtrate to 1 L with freshly boiledwater. Standardize against National Institute of Standards andTechnology standard sample of acid potassium phthalate No.84, using phenolphthalein as the indicator. Do not adjust theconcentration of the solution, but calculate the normality.5.6 Su
12、lfuric Acid, Standard Solution (0.1 N)Measure out3 mLof concentrated sulfuric acid (H2SO4)(d = 1.84) and pourit slowly, and with constant stirring, into about 100 mL ofwater. Cool to room temperature, mix thoroughly, and dilute to1 L. Standardize against 0.1 N NaOH solution, as prepared in4.5, using
13、 phenolphthalein as the indicator. Do not adjust theconcentration of the solution, but calculate the normality.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, 2015. P
14、ublished October 2015. Originallyapproved in 1983. Last previous edition approved in 2012 as D3644 06(2012).DOI: 10.1520/D3644-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
15、ion, refer to the standards Document Summary page onthe ASTM website.3Reagent 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 LaboratoryChemi
16、cals, BDH Ltd., 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. Procedure6.1 Weigh 0.1 g of the
17、 sample to the nearest 0.0001 g intoa 250-mL Erlenmeyer flask.6.2 Add 150 6 2 mL of acetone to the flask, stopper it, andswirl it until the sample is dissolved. All 0.2 mL of phenol-phthalein indicator solution and titrate with NaOH solution tothe end point, a faint pink color which persists for 30
18、s. Thenadd 2.0 mL of additional NaOH solution, stopper the flask, andallow it to stand for exactly 10 min.NOTE 1If a precipitate forms during the titration, discard the sampleand repeat the test using a smaller sample or a greater volume of acetone,or both. A slight haze can be tolerated and does no
19、t interfere with the test.6.3 Back titrate with 0.1 N H2SO4to the end point, at whichthe sample turns colorless and remains so for 30 s.6.4 Using the same procedure, titrate a blank composed of150 mL of acetone and 5 mL of water.7. Calculation7.1 Calculate the acid number as follows:Blank 5 VBNB! 2
20、VANA!Acid number 5VBNB2 VANA1blank! 356.1CVA= millilitres of H2SO4,NA= normality of H2SO4,VB= millilitres of NaOH solution,NB= normality of NaOH solution, andC = weight of sample.8. Report8.1 Report the acid number of the resin tested, to the nearestwhole number.9. Precision and Bias9.1 PrecisionDup
21、licate results by the same operator shallnot be considered suspect unless they differ by more than astandard deviation of 0.8.9.2 BiasThis test has no bias because the values producedare defined only in terms of this test method.10. Keywords10.1 acid number; free acid; polish; resins; SMA resins;sty
22、rene-maletic anhydrid resin; titrationASTM 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 expressly advised that determination of the validity of any such patent rights, and the r
23、iskof 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 revised, either reapproved or withdrawn. Your comments are invited either for revision of t
24、his 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 may attend. If you feel that your comments have not received a fair hearing you shouldmak
25、e 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 States. Individual reprints (single or multiple copies) of this standard may be obtained b
26、y 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 152
