1、Designation: D6954 04 (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 oforigi
2、nal 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 t
3、he controlled 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 exposur
4、e in soil, landfill, 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
5、by both thermal 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 likel
6、y to occur in achosen 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 polyme
7、rs beingevaluated in 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 temperaturesa
8、nd humidity ranges typical 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
9、one temperature must be reasonably 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
10、 the temperature range of testing.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 t
11、ime for the biodegradation in the chosen 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
12、oxidation stage and from biodegradation must beshown to be environmentally benign and not persistent (Tier 3).NOTE 1The 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
13、 24 monthsto oxidize and biodegrade in the 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
14、 cannot be directly extrapolated to actual 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.NOTE 2There is no ISO standard that is the equivalent of this standard
15、guide. Note this changed all subsequent Note 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 En
16、vironmentally DegradablePlastics and Biobased Products.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 Consh
17、ohocken, PA 19428-2959. United States1responsibility 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 Terminology Relating to PlasticsD3826 Pract
18、ice for Determining Degradation End Point inDegradable Polyethylene and Polypropylene Using a Ten-sile TestD3987 Practice for Shake Extraction of Solid Waste withWaterD5071 Practice for Exposure of Photodegradable Plastics ina Xenon Arc ApparatusD5208 Practice for Fluorescent Ultraviolet (UV) Exposu
19、reof Photodegradable PlasticsD5272 Practice for Outdoor Exposure Testing of Photode-gradable PlasticsD5338 Test Method for Determining Aerobic Biodegrada-tion of Plastic Materials Under Controlled CompostingConditions, Incorporating Thermophilic TemperaturesD5510 Practice for Heat Aging of Oxidative
20、ly DegradablePlastics (Withdrawn 2010)3D5526 Test Method for Determining Anaerobic Biodegrada-tion of Plastic Materials Under Accelerated Landfill Con-ditionsD5951 Practice for Preparing Residual Solids Obtained Af-ter Biodegradability Standard Methods for Plastics inSolid Waste for Toxicity and Com
21、post Quality Testing(Withdrawn 2011)3D5988 Test Method for Determining Aerobic Biodegrada-tion of Plastic Materials in SoilD6002 Guide for Assessing the Compostability of Environ-mentally Degradable Plastics (Withdrawn 2011)3D6400 Specification for Labeling of Plastics Designed to beAerobically Comp
22、osted in Municipal or Industrial Facili-tiesE1440 Guide for Acute Toxicity Test with the Rotifer Bra-chionus2.2 Other Standards:EPA TITLE 40 CFA 40CFR62, 40CFR50-189, 40CFR260-299, 40CFR300-399, 700-799, and 49CFR100-1804OECD Guideline 207 Earthworm, Acute Toxicity Tests5OECD Guideline 208 Terrestri
23、al Plants, Growth Test5ORCA Guidelines for the Evaluation of Feedstock forSource Separated Biowaste Composting and Biogasifica-tion63. Terminology3.1 Definitions:3.1.1 Definitions of most terms applicable to this guideappear in Terminology D883 and Guide D6002.3.2 Definitions of Terms Specific to Th
24、is Standard:3.2.1 environmental degradation of a plastic, nabiotic orbiotic degradation process or both that occurs in a givenenvironment and includes photodegradation, oxidation,hydrolysis, and biodegradation. Living organisms effect bioticdegradation processes and abiotic degradation processes are
25、nonbiological in nature.3.2.1.1 DiscussionTerm not defined in TerminologyD883.3.2.2 gels, ncross-linked polymer structures insoluble insolvents that do not break the primary or cross-linking bonds inthe polymer. Cross-links created during oxobiodegradadationof polymers are chemical bonds created by
26、the degradationprocess, mostly carbon-carbon bonds, and thus extremelyresistant to solvent degradation.73.2.3 oxidation, nprocess promoted thermally or by irra-diation in the presence of oxygen.4. Summary of Guide4.1 This guide may be used to compare and rank the rateand degree of thermal oxidative
27、degradation of a plasticmaterial relatively to a molecular weight range that can beestablished as biodegradable in a chosen environment.Subsequently, the biodegradation of these degraded polymersin diverse environments such as soil, compost, landfill, andwater may be compared and ranked using standa
28、rd biometrictest methods and measuring carbon dioxide evolution.NOTE 3If composting is the designated disposal route, SpecificationD6400 is the only ultimate and definitive applicable specification formeasuring biodegradation or compostability. Oxidation followed bybiodegradation under the condition
29、s found in this guide does not conferthe designation “compostable” or any connotation that the applications areacceptable for composting in a commercial or municipal compostingfacility.4.2 This guide uses a tiered criteria-based approach toassess the consecutive oxidation and biodegradability of pla
30、sticproducts and ecological impacts in defined applications. This isshown schematically in Section 6. Each tier in this guideincludes objectives and a summary that presents test methods,method principles, test duration, and interpretation of results.4.3 The tiered approach is chosen in the laborator
31、y forconvenient separation of oxidative degradation,biodegradation, and ecological impact stages even though inthe real world all three are likely to be concurrent rather thanconsecutive.4.4 Tiered Methodology:4.4.1 Tier 1 measures the rate and extent of molecularweight loss resulting from oxidation
32、 that is indicative of lossesin physical properties from oxidation. Tier 1 requires eitheraccelerated testing or long-term testing over a range of relative2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM
33、Standards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from United States Environmental Protection Association (EPA),Ariel Rios Bldg., 1200 Pennsylvania Ave., NW, Was
34、hington, DC 20460.5Available from OECD, 2 rue Andre Pascal, F-75775 Paris Cedex 16, France.6Available from ORCA, Avenue E. Mounier 83, Box 1, Brussels, BelgiumB-1200.7Vollmert, B., Polymer Chemistry, Springer-Verlag, New York, 1973, p. 27, alsopp. 543- 561.D6954 04 (2013)2humidity or amount of moist
35、ure. Accelerated testing must beperformed under conditions and temperatures that are accept-ably typical of the specific application and disposal environ-ments under consideration. Practices D5208, D5510, andD5071 may be used to specify the oxidative conditions andPractice D3826 may be used to defin
36、e the point of embrittle-ment.NOTE 4For measuring the extent of disintegration/fragmentation, asieve test is required. In this tier, the fragments are subjected to molecularweight analysis and a total mass balance is obtained in the process.Exposure temperatures may range from 20 to 70C in the prese
37、nce of airand specified moisture or water levels for selected periods of time.At leastone temperature must be reasonably close to the end use or disposaltemperature, but under no circumstances should this be more than 20Caway from that temperature. It must also be established that the polymerdoes no
38、t undergo a phase change, such as glass transition temperature (Tg)within the temperature range of testing. As an alternate degradationprocess, the test samples may be exposed to photooxidation in air as perPractices D5208 or D5071 and the mass change of the plastic recordedafter exposure.4.4.2 Tier
39、 1 accelerated oxidation tests are not indicators ofbiodegradability and should not be used for the purpose ofmeeting the specifications as described in Specification D6400and claiming compostability or biodegradation during com-posting. (If oxidation is thought to be sufficiently rapid in Tier1, su
40、ggesting that composting may be a disposal environment,then Specification D6400 must be done and all the specifica-tions in Section 6 (Detailed Requirements) must be met.4.5 Gel Formation and Consequences During OxidationPhaseDiscussion:4.5.1 Gel formation is a frequent side reaction of theoxidative
41、 degradation of polymers, especially polyolefins. Gelsare cross-linked structures arising from the free radical natureof oxidative degradation. They are insoluble in nonreactivesolvents, that is, solvents that do not break additional bonds.Normally, gels are not available to biodegradation. Some gel
42、sdissolve on further oxidative degradation and become availablefor ultimate biodegradation. However, the prooxidant (catalyst)may be excluded from the gel structure because of solubilitychanges in gel phase. In this case, the gel would become anondegradable or very slowly degradable new fraction wit
43、hinthe polymer. It is important to establish the extent of gel and itsnature or permanence in the polymer residue and report thesefindings.4.5.2 The purpose of Tier 2 is to estimate the biodegrad-ability of all the fragmented products from Tier 1 underlaboratory scale conditions appropriate to the a
44、pplication usingcurrent Test Methods D5988 and D5338. The entire materialfrom the Tier 1 exposure is subjected to biodegradation testing.The percent biodegradation shall be calculated and reported asstated in the above referenced standards. The results from Tier1 and Tier 2 shall be combined and use
45、d for comparison andranking purposes between polymers of interest.4.5.3 Tier 3 involves considerations of the ecological im-pacts in the final disposal medium such as soil, as in allbiodegradation testing methods, which is basically a compari-son of the test medium before and following oxidation and
46、biodegradation.5. Significance and Use5.1 This guide is a sequential assembly of extant butunconnected standard tests and practices for the oxidation andbiodegradation of plastics, which will permit the comparisonand ranking of the overall rate of environmental degradation ofplastics that require th
47、ermal or photooxidation to initiatedegradation. Each degradation stage is independently evalu-ated to allow a combined evaluation of a polymers environ-mental performance under a controlled laboratory setting. Thisenables a laboratory assessment of its disposal performance in,soil, compost, landfill
48、, and water and for use in agriculturalproducts such as mulch film without detriment to that particularenvironment.NOTE 5For determining biodegradation rates under compostingconditions, Specification D6400 is to be used, including test methods andconditions as specified.5.2 The correlation of result
49、s from this guide to actualdisposal environments (for example, agricultural mulch films,composting, or landfill applications) has not been determined,and as such, the results should be used only for comparativeand ranking purposes.5.3 The results of laboratory exposure cannot be directlyextrapolated to estimate absolute rate of deterioration by theenvironment because the acceleration factor is material depen-dent and can be significantly different for each material and fordifferent formulations of the same material. However, exposureof a similar material of known outd
