1、Designation:D134894(Reapproved 2008)Standard Test Methods forMoisture in Cellulose1This standard is issued under the fixed designation D1348;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 parent
2、heses 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 U.S.Department of Defense.1.Scope1.1 These test methods cover the determination of moisturein cellulose usi
3、ng two oven-drying procedures and one KarlFischer procedure.1.2 The test procedures appear in the following order:SectionsTest Method ASpecimen Weighed in Oven4 10Test Method BSpecimen Weighed Outside of Oven11 17Test Method CKarl Fischer Method18 251.3 The values stated in SI units are to be regard
4、ed as thestandard.The values given in parentheses are for informationonly.1.4 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 th
5、e applica-bility of regulatory limitations prior to use.2.Significance and Use2.1 These test methods determine the amount of moisturecontained in a cellulose sample which determines the amountof bone dry cellulose present in a sample.The actual amount ofcellulose in a sample is an essential entity w
6、hen using celluloseas a starting material for the production of cellulose deriva-tives.3.Sampling3.1 Cellulose in a variety of forms is sampled for moisture,and no single set of directions can be given that is applicableto all types of cellulose material.The following generalconsiderations should be
7、 borne in mind.3.1.1 Cellulose,either in compact form,such as wood,sheeted pulp or paper,baled cotton or baled staple rayon,or inloose form such as sawdust or chips,may have an appreciablydifferent moisture content in sections lying relatively closetogether.In order to secure representative samples,
8、therefore,abulk sample should be made up of small portions taken fromvarious parts of the lot and having the proper proportion ofedge and center material.3.1.2 Except for those samples taken in an atmosphere withwhich the sample is in equilibrium,the moisture content of thesample will begin to chang
9、e immediately after it is removedfrom its original surroundings.This change can be reduced bytaking extra layers of sheeted material and discarding a fewlayers from the top and bottom before weighing,folding,orrolling the sample to reduce the exposed area,and by placingsmall samples in cans or bottl
10、es and protecting larger samplesby wrapping in rubber sheets,moistureproof cellophane,orother protective wrappings.These means do not providecontinuous protection,and the test samples should be weighedas soon as possible.3.1.3 When possible,bulk samples should be taken.Thesesamples should weigh from
11、 100 to 300 g(3.5 to 10.5 oz),thelarger samples being taken when the moisture content is low orvariable.Following the initial weighing,the bulk samplesshould be cut up or torn into small pieces and then mixed andallowed to stand overnight or longer in a sealed container toobtain moisture equilibrium
12、 before weighing out test speci-mens;or the sample may be allowed to come to approximateequilibrium with the laboratory air and reweighed to determinemoisture change before weighing test specimens.The latterprocedure is recommended since it permits routine weighing ofsamples without the use of speci
13、al weighing bottles or boxes,and a series of accumulated samples can be weighed simulta-neously.Predrying is very desirable on samples with a highmoisture content(more than 5%above equilibrium value).When samples have been predried,calculate the moisture lost,as follows:R 5M 2 A/A#3100(1)where:R=moi
14、sture,air-dry sample basis,%,M=original mass of the sample,g,and1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.36 on Cellulose and Cellulose Derivatives.Current edition
15、approved June 1,2008.Published June 2008.Originallyapproved in 1954.Last previous edition approved in 2003 as D1348 94(2003).DOI:10.1520/D1348-94R08.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 A=air-dry mass of sample,g.3.1.4 The appa
16、rent moisture subsequently observed whentesting a predried sample must be calculated on the basis of theoriginal sample mass in order to get the original moisturecontent.Calculate the original mass of the air-dried sample asfollows:Original sample mass,g 5A 31001R!#/100(2)NOTE1ExampleIf 1000 g(35 oz)of bulk(wet)sample on exposureto air lose 200 g(7 oz)of water,the apparent moisture content is 20%andequivalent regain is 25%.If an 8-g(0.28-oz)specimen of the air-drymaterial is taken for drying in
