ASTM_D_3790_-_79_2012.pdf

Designation:D379079(Reapproved 2012)Standard Test Method forVolatile Matter(Moisture)of Leather by Oven Drying1This standard is issued under the fixed designation D3790;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.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method covers the determination of volatilematter(moisture)in all types of leather.1.2 The values stated in SI units are 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 and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D2813 Practice for Sampling Leather for Physical andChemical TestsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)33.Summary of Test Method3.1 The ground leather specimen is heated in a mechanical-convection oven for 16 h at 100C,placed in a desiccator,cooled,and reweighed.The loss in weight represents thevolatile matter.4.Significance and Use4.1 The result obtained by this test is normally considered tobe the moisture content of the leather sample.This result isused to correct all other chemical tests to a moisture-free basis.4.2 Materials that are volatile under these conditions,otherthan water,may be present in the leather,although their amountin any normal leather would be expected to be a very smallpercentage of the total volatile matter.4.3 Under the conditions of this test,certain materials inleather,such as protein fiber and chromium tanning salts,mayretain moisture.Other materials,such as tannins and oils,maybe oxidized.Both of these effects produce negative errors inthe moisture determination.4.4 The amount of volatile matter(moisture)released by agiven leather varies with(a)degree of grinding of the sample,(b)weight of sample taken,(c)temperature and time of theoven drying,(d)shape of the weighing container,and(e)typeof oven(gravity versus mechanical convection)used.4.5 Because of the above unknown errors,the result of thistest is a purely arbitrary value for the moisture content of thesample.It is,therefore,essential that the method be followedexactly in order to obtain reproducible results among labora-tories.This is particularly true if other chemical analytical testsbeing performed on the same sample are reported on themoisture-free basis.5.Apparatus5.1 Weighing Bottle4,glass,low-form,cylindrical with aground-glass stopper of standard taper.The bottle shall have 706 5 mm inside diameter,and 33 6 3 mm overall height.5.2 Oven,mechanical-convection draft capable of setting at100C,with a thermoregulator system capable of holding oventemperature within 6 2C of set point.Athermometer accurateto 60.2C should be used to check and monitor the oven setpoint.5.3 Balance,capable of weighing up to 100 g with anaccuracy of 60.001 g.5.4 Desiccator,any convenient form or size,using anynormal desiccating agent such as calcium sulfate,calciumchloride,or silica gel.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.06 on Chemical Analysis.Current edition approved April 1,2012.Published April 2012.Originallyapproved in 1979.Last previous edition approved in 2006 as D3790-79(2006)1.DOI:10.1520/D3790-79R12.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4Weighing bottles that have been found to be satisfactory are the Kimble GlassCo.No.15166 and 15165 with 71/15 standard-taper caps and are available frommost laboratory supply houses.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.Sampling6.1 The leather shall be sampled in accordance with PracticeD2813.7.Procedure7.1 Insert the empty weighing bottle inside the invertedstoppered cap and place on a shelf in the oven at 100 6 2C for1 h or more.If the stopper has a handle then the stopper maybe placed on the shelf in the oven near the empty weighingbottle.7.2 Remove and place in a desiccator for at least 2 h to cool.7.3 Weigh and record to the nearest 60.001 g.7.4 Use the ground leather sample as specified in PracticeD2813 and transfer 5 6 1 g of ground leather into thepreviously weighed weighing bottle