1、Designation:D138789(Reapproved 2012)Standard Test Method forSaponification Number(Empirical)of Synthetic and NaturalWaxes1This standard is issued under the fixed designation D1387;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the y
2、ear 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 saponi-fication number of synthetic waxes and natural waxes.1.2 Thi
3、s test method is applicable to Fischer Tropsche,microcrystalline,polyethylene,and Montan Ester waxes.1.3 Certain synthetic waxes,notably copolymers ofethylene,exhibit poor reproducibility when running saponifi-cation values.Reproducibility can be improved if cooking timein 7.2 is extended from 3 h t
4、o 1820 h.1.4 Some oxidized polyethylene and other waxes with amelt temperature above 100C may give poor reproducibility.1.5 Some dark-colored(Gardner Color 14)waxes mayobscure the color change of the indicator,resulting in poorreproducibility.1.6 The values stated in SI units are to be regarded asst
5、andard.No other units of measurement are included in thisstandard.1.7 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 applic
6、a-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E200 Practice for Preparation,Standardization,and Storageof Standard and Reagent Solutions for Chemical Analysis3.Terminology3.1 Definitions:3.1.1 saponification numberthe number of milligrams ofpotassium hydro
7、xide required to hydrolyze 1 g of the sampleand is a measure of the amount of saponifiable matter present.4.Significance and Use4.1 This test method is used to determine the property ofester functionality.Ester functionality determines the utility ofthe wax as well as being a significant quality con
8、trol test.5.Apparatus5.1 Analytical Balance.5.2 Boiling Chips,chemically resistant glass.5.3 Burets,two 50-mL capacity with 0.1-mL graduations.5.4 Erlenmeyer Flasks,250-mL,alkali-resistant.5.5 Hot Plate.5.6 Reflux Condenser.6.Reagents and Materials6.1 Purity of ReagentsReagent-grade chemicals orequi
9、valent as specified in Practice E200 shall be used in alltests.6.2 Hydrochloric Acid Standard(0.5 N).6.3 Phenolphthalein Indicator Solution(10 g/litre)Dissolve 1 g of phenolphthalein in 100 mL of USSD3Adenatured ethanol or 95%ethanol.6.4 Potassium Hydroxide,Alcoholic Solution(6.6 g/litre)Dissolve 6.
10、6 g of potassium hydroxide(KOH)in USSD3Adenatured ethanol or 95%ethanol.Dilute to 1 L with theethanol.6.5 Xylene.7.Procedure7.1 Transfer approximately 1 g of the sample,weighed tothe nearest 0.001 g to a 250-mL Erlenmeyer flask.7.2 Add 40 mL of xylene and a few boiling chips to theflask.Dissolve by
11、heating on the hot plate to the boiling pointof xylene.As soon as the wax dissolves,remove from the hot1This 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 Oc
12、tober 2012.Originallyapproved in 1955.Last previous edition approved in 2007 as D138789(2007).DOI:10.1520/D1387-89R12.2For 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
13、 standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 plate and add 50.0 mL of 0.1 N ethanolic KOH solution fromthe buret.Fit the flask with a reflux condenser and reflux for 3h using the hot
14、plate.7.3 Remove the condenser from the flask,add 5 drops of thephenolphthalein solution and titrate the sample with 0.5 N HCluntil the pink color disappears.Reheat the sample to theboiling point,and if it turns pink,resume titration until thecolor once again disappears.Repeat this procedure until t
15、hepink color does not reappear on heating.Saponified waxesusually require two repetitions of heating and additionaltitration until the pink color does not reappear.8.Calculation8.1 Calculate the saponification number as follows:Saponification number5B 2 A!N 356.1C(1)where:A=millilitres of HCl soluti
16、on required for titration of thesample,B=millilitres of HCl solution required for titration of theblank,C=grams of sample used,andN=normality of the HCl solution.9.Precision and Bias9.1 Precision and bias have been established only forlight-colored waxes melting below 100C.9.1.1 Duplicate results by the same operator shall not beconsidered suspect unless they differ by more than 61.3saponification numbers(95%confidence limits for average).9.1.2 Results reported by two laboratories shall not beco