ASTM D6954-04
(Guide)Standard Guide for Exposing and Testing Plastics that Degrade in the Environment by a Combination of Oxidation and Biodegradation
Standard Guide for Exposing and Testing Plastics that Degrade in the Environment by a Combination of Oxidation and Biodegradation
SIGNIFICANCE AND USE
This guide is a sequential assembly of extant but unconnected standard tests and practices for the oxidation and biodegradation of plastics, which will permit the comparison and ranking of the overall rate of environmental degradation of plastics that require thermal or photooxidation to initiate degradation. Each degradation stage is independently evaluated to allow a combined evaluation of a polymer’s environmental performance under a controlled laboratory setting. This enables a laboratory assessment of its disposal performance in, soil, compost, landfill, and water and for use in agricultural products such as mulch film without detriment to that particular environment.
Note 5—For determining biodegradation rates under composting conditions, Specification D 6400 is to be used, including test methods and conditions as specified.
The correlation of results from this guide to actual disposal environments (for example, agricultural mulch films, composting, or landfill applications) has not been determined, and as such, the results should be used only for comparative and ranking purposes.
The results of laboratory exposure cannot be directly extrapolated to estimate absolute rate of deterioration by the environment because the acceleration factor is material dependent and can be significantly different for each material and for different formulations of the same material. However, exposure of a similar material of known outdoor performance, a control, at the same time as the test specimens allows comparison of the durability relative to that of the control under the test conditions.
SCOPE
1.1 This guide provides a framework or road map to compare and rank the controlled laboratory rates of degradation and degree of physical property losses of polymers by thermal and photooxidation processes as well as the biodegradation and ecological impacts in defined applications and disposal environments after degradation. Disposal environments range from exposure in soil, landfill, and compost in which thermal oxidation may occur and land cover and agricultural use in which photooxidation may also occur.
1.2 In this guide, established ASTM International standards are used in three tiers for accelerating and measuring the loss in properties and molecular weight by both thermal and photooxidation processes and other abiotic processes (Tier 1), measuring biodegradation (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 degradation likely to occur in a chosen application and disposal environment. The conditions should include a range of humidity or water concentrations based on the application and disposal environment in mind. The measured rate of degradation at typical oxidation temperatures is required to compare and rank the polymers being evaluated in that chosen application to reach a molecular weight that constitutes a demonstrable biodegradable residue (using ASTM International biometer tests for CO2 evolution appropriate to the chosen environment). By way of example, accelerated oxidation data must be obtained at temperatures and humidity ranges typical in that chosen application and disposal environment, for example, in soil (20 to 30°C), landfill (20 to 35°C), and composting facilities (30 to 65°C). For applications in soils, local temperatures and humidity ranges must be considered as they vary widely with geography. At least one temperature must be reasonably close to the end use or disposal temperature, but under no circumstances should this be more than 20°C away from the removed that temperature. It must also be established that the polymer does not undergo a phase change, such as glass transition temperature (Tg) within the temperature range of testing.
1.4 The residues resulting from the oxidations are then exposed to appropriate disposal or use environmen...
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Designation: D6954 − 04
StandardGuide for
Exposing and Testing Plastics that Degrade in the
Environment by a Combination of Oxidation and
1
Biodegradation
This standard is issued under the fixed designation D6954; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope must be considered as they vary widely with geography. At
least one temperature must be reasonably close to the end use
1.1 This guide provides a framework or road map to
or disposal temperature, but under no circumstances should
compare and rank the controlled laboratory rates of degrada-
this be more than 20°C away from the removed that tempera-
tion and degree of physical property losses of polymers by
ture. It must also be established that the polymer does not
thermal and photooxidation processes as well as the biodegra-
undergo a phase change, such as glass transition temperature
dation and ecological impacts in defined applications and
(Tg) within the temperature range of testing.
disposal environments after degradation. Disposal environ-
ments range from exposure in soil, landfill, and compost in
1.4 The residues resulting from the oxidations are then
which thermal oxidation may occur and land cover and exposed to appropriate disposal or use environments in stan-
agricultural use in which photooxidation may also occur.
dard biometric test methods to measure the rate and degree of
biodegradation (Tier 2).
1.2 In this guide, establishedASTM International standards
are used in three tiers for accelerating and measuring the loss
1.5 The data generated under Tier 1 evaluation and the
in properties and molecular weight by both thermal and determined time for the biodegradation in the chosen environ-
photooxidation processes and other abiotic processes (Tier 1),
ment (Tier 2) allow ranking relative to other polymers evalu-
measuring biodegradation (Tier 2), and assessing ecological ated under similar environmental conditions with this guide.
impact of the products from these processes (Tier 3).
The degree and time for biodegradation should be consistent
with ASTM International methods, and any residues from the
1.3 TheTier 1 conditions selected for thermal oxidation and
intermediate oxidation stage and from biodegradation must be
photooxidation accelerate the degradation likely to occur in a
showntobeenvironmentallybenignandnotpersistent(Tier3).
chosen application and disposal environment. The conditions
NOTE 1—The intended use of this guide is for comparison and ranking
should include a range of humidity or water concentrations
of data to aid in the design and development and the reduction of
based on the application and disposal environment in mind.
environmental impacts of polymers that require no more than 24 months
The measured rate of degradation at typical oxidation tempera-
to oxidize and biodegrade in the intended use and disposal options and
tures is required to compare and rank the polymers being create no harmful or persistent residues under the appropriate disposal
conditions (for example, two seasons of crop-growing conditions in soil).
evaluated in that chosen application to reach a molecular
weight that constitutes a demonstrable biodegradable residue
1.6 Itiscautionedthattheresultsofanylaboratoryexposure
(using ASTM International biometer tests for CO evolution
in this guide cannot be directly extrapolated to actual disposal
2
appropriate to the chosen environment). By way of example,
environments; confirmation to real world exposure is ulti-
accelerated oxidation data must be obtained at temperatures
mately required as with all ASTM International standards.
and humidity ranges typical in that chosen application and
1.7 The values stated in SI units are to be regarded as
disposalenvironment,forexample,insoil(20to30°C),landfill
standard.
(20 to 35°C), and composting facilities (30 to 65°C). For
NOTE2—ThereisnoISOstandardthatistheequivalentofthisstandard
applications in soils, local temperatures and humidity ranges
guide. Note this changed all subsequent Note numbers.
1.8 This standard does not purport to address all of the
1
This guide is under the jurisdiction of ASTM Committee D20 on Plastics and
safety concerns, if any, associated with its use. It is the
is the direct responsibility of Subcommittee D20.96 on Biodegradable Plastics and
responsibility of the user of this standard to establish appro-
Biobased Products.
priate safety and health practices and determine the applica-
Current edition approved May 1, 2004. Published May 2004. DOI: 10.1520/
bility of regulatory requirements prior to use.
D6954-04.
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