ASTM_D_1387_-_89_2019.pdf

Designation:D138789(Reapproved 2019)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 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 saponi-fication number of synthetic waxes and natural waxes.1.2 This 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 to 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 asstandard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.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 hydroxide 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 control 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 orequivalent 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 6.6 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.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 July 1,2019.Published July 2019.Originally approvedin 1955.Last previous edition approved in 2012 as D1387 89(2012).DOI:10.1520/D1387-89R19.2For 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,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 7.2 Add 40 mL of xylene and a few boiling chips to theflask.Dissolve by heating on the hot plate to the boiling pointof xylene.As soon as the wax dissolves,remove from the hotplate 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 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 thepink color does not reappear on heating.Saponified waxesusually require two repetitions of heating and additionaltitration until the pink color does no