1、Designation:D695404(Reapproved 2013)Standard Guide forExposing and Testing Plastics that Degrade in theEnvironment by a Combination of Oxidation andBiodegradation1This standard is issued under the fixed designation D6954;the number immediately following the designation indicates the year oforiginal
2、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.1.Scope1.1 This guide provides a framework or road map tocompare and rank the controll
3、ed laboratory rates of degrada-tion and degree of physical property losses of polymers bythermal and photooxidation processes as well as the biodegra-dation and ecological impacts in defined applications anddisposal environments after degradation.Disposal environ-ments range from exposure in soil,la
4、ndfill,and compost inwhich thermal oxidation may occur and land cover andagricultural use in which photooxidation may also occur.1.2 In this guide,established ASTM International standardsare used in three tiers for accelerating and measuring the lossin properties and molecular weight by both thermal
5、 andphotooxidation processes and other abiotic processes(Tier 1),measuring biodegradation(Tier 2),and assessing ecologicalimpact of the products from these processes(Tier 3).1.3 The Tier 1 conditions selected for thermal oxidation andphotooxidation accelerate the degradation likely to occur in achos
6、en application and disposal environment.The conditionsshould include a range of humidity or water concentrationsbased on the application and disposal environment in mind.The measured rate of degradation at typical oxidation tempera-tures is required to compare and rank the polymers beingevaluated in
7、 that chosen application to reach a molecularweight that constitutes a demonstrable biodegradable residue(using ASTM International biometer tests for CO2evolutionappropriate to the chosen environment).By way of example,accelerated oxidation data must be obtained at temperaturesand humidity ranges ty
8、pical in that chosen application anddisposal environment,for example,in soil(20 to 30C),landfill(20 to 35C),and composting facilities(30 to 65C).Forapplications in soils,local temperatures and humidity rangesmust be considered as they vary widely with geography.Atleast one temperature must be reason
9、ably close to the end useor disposal temperature,but under no circumstances shouldthis be more than 20C away from the removed that tempera-ture.It must also be established that the polymer does notundergo a phase change,such as glass transition temperature(Tg)within the temperature range of testing.
10、1.4 The residues resulting from the oxidations are thenexposed to appropriate disposal or use environments in stan-dard biometric test methods to measure the rate and degree ofbiodegradation(Tier 2).1.5 The data generated under Tier 1 evaluation and thedetermined time for the biodegradation in the c
11、hosen environ-ment(Tier 2)allow ranking relative to other polymers evalu-ated under similar environmental conditions with this guide.The degree and time for biodegradation should be consistentwith ASTM International methods,and any residues from theintermediate oxidation stage and from biodegradatio
12、n must beshown to be environmentally benign and not persistent(Tier 3).NOTE1The intended use of this guide is for comparison and rankingof data to aid in the design and development and the reduction ofenvironmental impacts of polymers that require no more than 24 monthsto oxidize and biodegrade in t
13、he intended use and disposal options andcreate no harmful or persistent residues under the appropriate disposalconditions(for example,two seasons of crop-growing conditions in soil).1.6 It is cautioned that the results of any laboratory exposurein this guide cannot be directly extrapolated to actual
14、 disposalenvironments;confirmation to real world exposure is ulti-mately required as with all ASTM International standards.1.7 The values stated in SI units are to be regarded asstandard.NOTE2There is no ISO standard that is the equivalent of this standardguide.Note this changed all subsequent Note
15、numbers.1.8 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is the1This guide is under the jurisdiction of ASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.96 on Environmentally DegradablePlastics and Biobased Pr
16、oducts.Current edition approved Jan.1,2013.Published January 2013.Originallyapproved in 2004.Last previous edition approved in 2004 as D6954-04.DOI:10.1520/D6954-04R13.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use.2.Referenced Documents2.1 ASTM Standards:2D883 Term
