1、Designation: D6954 04 (Reapproved 2013)D6954 18Standard 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
2、 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.1. Scope Scope*1.1 This guide provides a framework or road map to co
3、mpare and rank the controlled laboratory rates of degradation and degreeof physical property losses of polymers by thermal and photooxidation processes as well as the biodegradation and ecologicalimpacts in defined applications and disposal environments after degradation. Disposal environments range
4、 from exposure in soil,landfill, and compost in which thermal oxidation may occur and land cover and agricultural use in which photooxidation may alsooccur.1.2 In this guide, established ASTM International standards are used in three tiers for accelerating and measuring the loss inproperties and mol
5、ecular weight by both thermal and photooxidation processes and other abiotic processes (Tier 1), measuringbiodegradation (Tier 2), and assessing ecological impact of the products from these processes (Tier 3).1.3 The Tier 1 conditions selected for thermal oxidation and photooxidation accelerate the
6、degradation likely to occur in achosen application and disposal environment. The conditions should include a range of humidity or water concentrations based onthe application and disposal environment in mind. The measured rate of degradation at typical oxidation temperatures is requiredto compare an
7、d rank the polymers being evaluated in that chosen application to reach a molecular weight that constitutes ademonstrable biodegradable residue (using ASTM International biometer tests for CO2 evolution appropriate to the chosenenvironment). By way of example, accelerated oxidation data must be obta
8、ined at temperatures and humidity ranges typical in thatchosen application and disposal environment, for example, in soil (20 to 30C), landfill (20 to 35C), and composting facilities (30to 65C). For applications in soils, local temperatures and humidity ranges must be considered as they vary widely
9、with geography.At least one temperature must be reasonably close to the end use or disposal temperature, but under no circumstances should thisbe more than 20C away from the removed that temperature. It must also be established that the polymer does not undergo a phasechange, such as glass transitio
10、n temperature (Tg) within the temperature range of testing.1.4 The residues resulting from the oxidations are then exposed to appropriate disposal or use environments in standardbiometric test methods to measure the rate and degree of biodegradation (Tier 2).1.5 The data generated under Tier 1 evalu
11、ation and the determined time for the biodegradation in the chosen environment (Tier2) allow ranking relative to other polymers evaluated under similar environmental conditions with this guide. The degree and timefor biodegradation should be consistent withASTM International methods, and any residue
12、s from the intermediate oxidation stageand from biodegradation must be shown to be environmentally benign and not persistent (Tier 3).NOTE 1The intended use of this guide is for comparison and ranking of data to aid in the design and development and the reduction of environmentalimpacts of polymers
13、that require no more than 24 months to oxidize and biodegrade in the intended use and disposal options and create no harmful orpersistent residues under the appropriate disposal conditions (for example, two seasons of crop-growing conditions in soil).1.6 It is cautioned that the results of any labor
14、atory exposure in this guide cannot be directly extrapolated to actual disposalenvironments; confirmation to real world exposure is ultimately required as with all ASTM International standards.1.7 The values stated in SI units are to be regarded as standard.NOTE 2There is no ISO standard that is the
15、 equivalent of this standard guide. Note this changed all subsequent Note numbers.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and health
16、environmental practices and determine theapplicability of regulatory requirementslimitations prior to use.1 This guide is under the jurisdiction ofASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.96 on Environmentally Degradable Plasticsand Biobased Products.Curren
17、t edition approved Jan. 1, 2013March 1, 2018. Published January 2013March 2018. Originally approved in 2004. Last previous edition approved in 20042013 asD6954 - 04. 04 (2013). DOI: 10.1520/D6954-04R13.10.1520/D6954-18.This document is not an ASTM standard and is intended only to provide the user of
18、 an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as pub
19、lished by ASTM is to be considered the official document.*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 States11.9 This international standard was developed in accordance with
20、 internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D
21、883 Terminology Relating to PlasticsD3826 Practice for Determining Degradation End Point in Degradable Polyethylene and Polypropylene Using a Tensile TestD3987 Practice for Shake Extraction of Solid Waste with WaterD5071 Practice for Exposure of Photodegradable Plastics in a Xenon Arc ApparatusD5208
22、 Practice for Fluorescent Ultraviolet (UV) Exposure of Photodegradable PlasticsD5272 Practice for Outdoor Exposure Testing of Photodegradable PlasticsD5338 Test Method for Determining Aerobic Biodegradation of Plastic Materials Under Controlled Composting Conditions,Incorporating Thermophilic Temper
23、aturesD5510 Practice for Heat Aging of Oxidatively Degradable Plastics (Withdrawn 2010)3D5526 Test Method for Determining Anaerobic Biodegradation of Plastic Materials Under Accelerated Landfill ConditionsD5951 Practice for Preparing Residual Solids ObtainedAfter Biodegradability Standard Methods fo
24、r Plastics in Solid Waste forToxicity and Compost Quality Testing (Withdrawn 2011)3D5988 Test Method for Determining Aerobic Biodegradation of Plastic Materials in SoilD6002 Guide for Assessing the Compostability of Environmentally Degradable Plastics (Withdrawn 2011)3D6400 Specification for Labelin
25、g of Plastics Designed to be Aerobically Composted in Municipal or Industrial FacilitiesE1440 Guide for Acute Toxicity Test with the Rotifer Brachionus2.2 Other Standards:EPA TITLE 40 CFA 40CFR62, 40CFR50-189, 40CFR260-299, 40CFR300-399, 700-799, and 49CFR100-1804OECD Guideline 207 Earthworm, Acute
26、Toxicity Tests5OECD Guideline 208 Terrestrial Plants, Growth Test5ORCA Guidelines for the Evaluation of Feedstock for Source Separated Biowaste Composting and Biogasification63. Terminology3.1 Definitions:3.1.1 Definitions of most terms applicable to this guide appear in Terminology D883 and Guide D
27、6002.3.2 Definitions of Terms Specific to This Standard:3.2.1 environmental degradation of a plastic, nabiotic or biotic degradation process or both that occurs in a given environmentand includes photodegradation, oxidation, hydrolysis, and biodegradation. Living organisms effect biotic degradation
28、processesand abiotic degradation processes are nonbiological in nature.3.2.1.1 DiscussionTerm not defined in Terminology D883.3.2.2 gels, ncross-linked polymer structures insoluble in solvents that do not break the primary or cross-linking bonds in thepolymer. Cross-links created during oxobiodegrad
29、adation of polymers are chemical bonds created by the degradation process,mostly carbon-carbon bonds, and thus extremely resistant to solvent degradation.63.2.3 oxidation, nprocess promoted thermally or by irradiation in the presence of oxygen.4. Summary of Guide4.1 This guide may be used to compare
30、 and rank the rate and degree of thermal oxidative degradation of a plastic materialrelatively to a molecular weight range that can be established as biodegradable in a chosen environment. Subsequently, thebiodegradation of these degraded polymers in diverse environments such as soil, compost, landf
31、ill, and water may be comparedand ranked using standard biometric test methods and measuring carbon dioxide evolution.NOTE 3If composting is the designated disposal route, Specification D6400 is the only ultimate and definitive applicable specification for measuringbiodegradation or compostability.
32、Oxidation followed by biodegradation under the conditions found in this guide does not confer the designation2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the stan
33、dards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.4 Available from United States Environmental Protection Association (EPA), Ariel Rios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460.5 Available from OECD, 2
34、 rue Andre Pascal, F-75775 Paris Cedex 16, France.6 Vollmert, B., Polymer Chemistry, Springer-Verlag, New York, 1973, p. 27, also pp. 543- 561.D6954 182“compostable” or any connotation that the applications are acceptable for composting in a commercial or municipal composting facility.4.2 This guide
35、 uses a tiered criteria-based approach to assess the consecutive oxidation and biodegradability of plastic productsand ecological impacts in defined applications. This is shown schematically in Section 6. Each tier in this guide includes objectivesand a summary that presents test methods, method pri
36、nciples, test duration, and interpretation of results.4.3 The tiered approach is chosen in the laboratory for convenient separation of oxidative degradation, biodegradation, andecological impact stages even though in the real world all three are likely to be concurrent rather than consecutive.4.4 Ti
37、ered Methodology:4.4.1 Tier 1 measures the rate and extent of molecular weight loss resulting from oxidation that is indicative of losses in physicalproperties from oxidation.Tier 1 requires either accelerated testing or long-term testing over a range of relative humidity or amountof moisture. Accel
38、erated testing must be performed under conditions and temperatures that are acceptably typical of the specificapplication and disposal environments under consideration. Practices D5208, D5510, and D5071 may be used to specify theoxidative conditions and Practice D3826 may be used to define the point
39、 of embrittlement.NOTE 4For measuring the extent of disintegration/fragmentation, a sieve test is required. In this tier, the fragments are subjected to molecular weightanalysis and a total mass balance is obtained in the process. Exposure temperatures may range from 20 to 70C in the presence of air
40、 and specifiedmoisture or water levels for selected periods of time.At least one temperature must be reasonably close to the end use or disposal temperature, but underno circumstances should this be more than 20C away from that temperature. It must also be established that the polymer does not under
41、go a phase change,such as glass transition temperature (Tg) within the temperature range of testing. As an alternate degradation process, the test samples may be exposedto photooxidation in air as per Practices D5208 or D5071 and the mass change of the plastic recorded after exposure.4.4.2 Tier 1 ac
42、celerated oxidation tests are not indicators of biodegradability and should not be used for the purpose of meetingthe specifications as described in Specification D6400 and claiming compostability or biodegradation during composting. (Ifoxidation is thought to be sufficiently rapid inTier 1, suggest
43、ing that composting may be a disposal environment, then SpecificationD6400 must be done and all the specifications in Section 6 (Detailed Requirements) must be met.4.5 Gel Formation and Consequences During Oxidation PhaseDiscussion:4.5.1 Gel formation is a frequent side reaction of the oxidative deg
44、radation of polymers, especially polyolefins. Gels arecross-linked structures arising from the free radical nature of oxidative degradation.They are insoluble in nonreactive solvents, thatis, solvents that do not break additional bonds. Normally, gels are not available to biodegradation. Some gels d
45、issolve on furtheroxidative degradation and become available for ultimate biodegradation. However, the prooxidant (catalyst) may be excluded fromthe gel structure because of solubility changes in gel phase. In this case, the gel would become a nondegradable or very slowlydegradable new fraction with
46、in the polymer. It is important to establish the extent of gel and its nature or permanence in thepolymer residue and report these findings.4.5.2 The purpose of Tier 2 is to estimate the biodegradability of all the fragmented products from Tier 1 under laboratory scaleconditions appropriate to the a
47、pplication using current Test Methods D5988 and D5338. The entire material from the Tier 1exposure is subjected to biodegradation testing. The percent biodegradation shall be calculated and reported as stated in the abovereferenced standards. The results from Tier 1 and Tier 2 shall be combined and
48、used for comparison and ranking purposes betweenpolymers of interest.4.5.3 Tier 3 involves considerations of the ecological impacts in the final disposal medium such as soil, as in all biodegradationtesting methods, which is basically a comparison of the test medium before and following oxidation an
49、d biodegradation.5. Significance and Use5.1 This guide is a sequential assembly of extant but unconnected standard tests and practices for the oxidation andbiodegradation of plastics, which will permit the comparison and ranking of the overall rate of environmental degradation ofplastics that require thermal or photooxidation to initiate degradation. Each degradation stage is independently evaluated to allowa combined evaluation of a polymers environmental performance under a controlled laboratory setting. This enables a laboratoryassessment of its disposal performan
