1、Designation:D211510Standard Practice forOven Heat Stability of Poly(Vinyl Chloride)Compositions1This standard is issued under the fixed designation D2115;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A num
2、ber 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.Scope*1.1 This practice lists procedures for determining the rela-tive
3、 thermal stability of sheet or molded poly(vinyl chloride)compounds as indicated by discoloration due to exposure to anelevated temperature at controlled oven conditions.1.2 A specimen preparation technique using a two-roll millis provided for compositions that are not in molded or sheetedform.1.3 T
4、his practice is not intended for use in purchasingspecifications because the conditions of processing plasticcompounds vary widely,and the degree of correlation of dataobtained by this practice to process exposure has not beendetermined.However,despite this limitation,this practice doesyield data of
5、 value in judging the comparative service qualityof poly(vinyl chloride)compositions.1.4 The values stated in SI units are to be regarded as thestandard.The values in parentheses are given for informationonly.1.5 This standard does not purport to address all of thesafety concerns,if any,associated w
6、ith 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.NOTE1This standard is similar in content,but not technicallyequivalent to ISO 3051990.2.Referenced Documents2
7、.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-tics2.2 ISO Standard:ISO3051990 PlasticsDetermination of Thermal Stabilityof Poly(Vinyl Chloride),Related Chlorine-ContainingPolymers and Copolymers and Their CompoundsDiscoloration Method
8、33.Terminology3.1 GeneralDefinitions are in accordance with Terminol-ogy D883 and abbreviations with Terminology D1600,unlessotherwise indicated.4.Significance and Use4.1 Poly(vinyl chloride)compositions degrade by discolor-ation on prolonged exposure to heat.The degree of discolor-ation is related
9、to the condition of exposure,such as length ofperiod and temperature.When the conditions of exposure arefixed and controlled,then the relative resistance to discolor-ation due to heat of two or more compositions is able to bedetermined.The precision of heat stability testing is alsodependent on the
10、thickness of the specimens and the history ofheat exposure prior to testing.This practice allows for controlor the reporting of these variables.4.2 This practice is particularly applicable for determininggross differences in the heat stabilities of poly(vinyl chloride)compositions that are detectabl
11、e as a color change.It is notintended to measure absolute thermal stability.Although theobserved color changes may be evidence of degradation,molecular degradation phenomena such as chain-scission orcross-linking may not be identifiable.NOTE2While discoloration caused by exposure to elevated tempera
12、-ture is commonly regarded as evidence of degradation in poly(vinylchloride)compositions,it must be borne in mind that some vinylcompositions may undergo substantial change in color without appre-ciable loss of mechanical strength,chemical resistance,etc.,whereasothers may resist change in color yet
13、 undergo substantial change in otherproperties.Therefore,resistance to discoloration should not be taken assole evidence of thermal stability.It is recommended that this test besupplemented by others such as tensile strength and elongation,impactstrength,and deflection temperature under load(for rig
14、id compositions),Durometer hardness(for nonrigid compositions),and dilute solution1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.Current edition approved Aug.1,2010.Published September 2010.O
15、riginallyapproved in 1962.Last previous edition approved in 2004 as D2115-04.DOI:10.1520/D2115-10.2For 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
16、Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 viscosity,and that the test results before and after oven exposure becompared to determine the degree of degradation which has beenproduced in each of the properties measured.4.3 This practic
