ASTM_D_1693_-_15.pdf

Designation:D169315Standard Test Method forEnvironmental Stress-Cracking of Ethylene Plastics1This standard is issued under the fixed designation D1693;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 U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the sus-ceptibility of ethylene plastics,as defined in TerminologyD883,to environmental stress-cracking when subjected to theconditions herein specified.Under certain conditions of stressand in the presence of environments such as soaps,wettingagents,oils,or detergents,ethylene plastics may exhibitmechanical failure by cracking.1.2 The values stated in SI units are to be regarded asstandard.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.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1204 Test Method for Linear Dimensional Changes ofNonrigid Thermoplastic Sheeting or Film at ElevatedTemperatureD1248 Specification for Polyethylene Plastics ExtrusionMaterials for Wire and CableD3350 Specification for Polyethylene Plastics Pipe and Fit-tings MaterialsD4703 Practice for Compression Molding ThermoplasticMaterials into Test Specimens,Plaques,or SheetsD4976 Specification for Polyethylene Plastics Molding andExtrusion MaterialsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ASTM Adjuncts:Apparatus Drawings and Blueprints33.Terminology3.1 Definitions:3.1.1 stress-crack,nan external or internal rupture in aplastic caused by tensile stresses less than its short-timemechanical strength.3.1.1.1 DiscussionThe development of such cracks isfrequently accelerated by the environment to which the plasticis exposed.The stresses which cause cracking may be presentinternally or externally,or may be a combination of thesestresses.The appearance of a network of fine cracks is calledcrazing.3.1.2 stress-crack failure,nfor purposes of this testmethod,any crack visible to an observer with normal eyesightshall be interpreted as a failure of the entire specimen(1).4Extension of the controlled imperfection shall not be construedas a failure.The appearance of more than one crack in a singlespecimen shall be construed as a single failure.3.1.2.1 DiscussionCracks generally develop at the con-trolled imperfection and run to the outer edge of the specimenapproximately at right angles to it(2).The cracks need notextend completely through the specimen to constitute failure.Cracks sometimes develop under the polymer surface,mani-festing themselves as depressions on the surface.The timewhen this occurs should be noted,and if the depression laterdevelops into a crack,the time of dimpling should be consid-ered as the failure time.4.Summary of Test Method4.1 Bent specimens of the plastic,each having a controlledimperfection on one surface,are exposed to the action of asurface-active agent.The proportion of the total number ofspecimens that crack in a given time is observed.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materi-als.Current edition approved May 1,2015.Published June 2015.Originallyapproved in 1959.Last previous edition approved in 2013 as D1693-13.DOI:10.1520/D1693-15.2For 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.3Detail drawings of the apparatus are available from ASTM Headquarters.Request ADJD169301,ADJD169302,ADJD169303,and ADJD169304.4The boldface numbers in parentheses refer to the list of references at the end ofthis test method.*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 5.Significance and Use5.1 This test method may be used for routine inspectionpurposes by subjecting a required number of specimens to thetest conditions for a specified time and noting the number thatfail.The cracking obtained with the test reagent is indicative ofwhat may be expected from a wide variety of surface-activeagents,soaps,and organic substances that are not absorbedappreciably by the polymer.5.2 Environmental stress-cracking is a property that