1、Designation:D127891a(Reapproved 2015)Standard Test Methods forRubber from Natural SourcesChemical Analysis1This standard is issued under the fixed designation D1278;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last rev
2、ision.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 These test methods cover the sampling and chemicalanalysis of solid natural rubber in the forms supplied to therubber industry.1.2
3、The analytical procedures appear in the following order:SectionsSampling5Volatile Matter6 8Dirt9 13Ash14 17Copper(Referee Colorimetric Method)18 22Copper(Alternative Colorimetric Method)23 27Copper(Alternative Flame Atomic Absorption Method)28Manganese(Colorimetric Method)29 33Manganese(Alternative
4、Flame Atomic Absorption Method)34Iron(Colorimetric Method)35 39Acetone Extract40 41Rubber Hydrocarbon42 43Nitrogen44 451.3 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information only.1.4 This standard does not purport to address all of thesafety
5、 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:2D297 Test Methods for Rubber ProductsC
6、hemical Analy-sisD1193 Specification for Reagent WaterD1485 Practice for Rubber from Natural SourcesSampling and Sample PreparationD3533 Test Method for RubberNitrogen Content(With-drawn 2006)3D4004 Test Methods for RubberDetermination of MetalContent by Flame Atomic Absorption(AAS)AnalysisD4483 Pra
7、ctice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE131 Terminology Relating to Molecular Spectroscopy3.Significance and Use3.1 These test methods are intended for quality contr
8、olacceptance of natural rubber and may be used for refereepurposes.4.Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American
9、 Chemical Society,where such specifications are available.4Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently higher purity to permit its use without lessening theaccuracy of the determination.4.2 Purity of WaterUnless otherwise indicated,referencesto water s
10、hall be understood to mean reagent water conformingto Specification D1193.5.Sampling5.1 A lot of natural rubber shall be sampled,the sampleprepared for test,and the acceptability of the lot determinedfrom tests on the sample in accordance with Test MethodsD1485.1These test methods are under the juri
11、sdiction of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.22 on NaturalRubber.Current edition approved Sept.1,2015.Published December 2015.Originallyapproved in 1953.Last previous edition approved in 2011 as D1278 91a(2011).DOI:10.1520/D1278-91AR15.2For referenced
12、 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.o
13、rg.4Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For Suggestions on the testing of reagents notlisted by the American Chemical Society,see Annual Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand Na
14、tional 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 States1 VOLATILE MATTER6.Procedure6.1 Weigh a 10 to 12-g specimen of homogenized rubber tothe nearest 1 mg and then dry it in a
15、circulating-air oven at 1006 5C to constant mass.If it is suspected that volatilehydrocarbon oils are present,they should be determined byheating the rubber in a circulating-air oven at 160 6 5C toconstant weight.The drying is facilitated by cutting the rubberinto 25-mm strips having a maximum width
16、 and thickness of2.5 by 1.25 mm or by passing it through a laboratory mill witha clearance between rolls set at 0.5 6 0.1 mm(0.020 6 0.004in.).Keep the dried specimen in a covered weighing vessel orin a desiccator after its removal from the oven until it is readyto be weighed.7.Calculation7.1 Calculate the percentage of volatile matter as follows:V 51 2B 3D!/A 3C!#3100(1)where:V=percentage of volatile matter,A=mass of piece taken from bale,B=mass of piece after homogenizing,C=mass of specimen be
