1、Designation:D695418Standard 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 adoption or,in th
2、e 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.Scope*1.1 This guide provides a framework or road map tocompare and rank the controlled laboratory ra
3、tes 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,landfill,and compo
4、st 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 andphotooxidati
5、on 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 achosen application a
6、nd 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 that chosen app
7、lication 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 typical in that ch
8、osen 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 reasonably close to th
9、e 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.1.4 The residues
10、 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 chosen environ-me
11、nt(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 biodegradation must beshown t
12、o 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 the intended use
13、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 disposalenviron
14、ments;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.1.8 This standard does not purport to address all of t
15、hesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dan
16、ce with internationally recognized principles on standard-ization established in the Decision on Principles for 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 Products.Current edition approved March 1,2018.Published March 2018.Originallyapproved in 2004.Last previous edition approved in 2013 as D6954-04(2013).DOI:10.1520/D6954-18.*A Summary of Changes section appe
