ASTM D5272-08(2021)
(Practice)Standard Practice for Outdoor Exposure Testing of Photodegradable Plastics
Standard Practice for Outdoor Exposure Testing of Photodegradable Plastics
SIGNIFICANCE AND USE
4.1 When discarded as litter, articles made using photodegradable plastics are subject to attack by daylight (particularly solar-ultraviolet radiation), oxygen, heat, and water. The 5° exposure angle used in this practice represents typical conditions for degradation experienced by litter.
4.2 This practice requires characterization of the duration of exposure in terms of solar-ultraviolet radiation. Solar-ultraviolet radiation varies considerably as a function of location and time of year. This can cause dramatic differences in the time required to produce a specified level of degradation in a polymer. Daro4 has shown that when the same lot of polyethylene containing an iron-salt prodegradant is exposed at various times of the year in a single location, the time required to produce an average of two chain scissions per molecule varied by over 130 %. Daro, and Zerlaut and Anderson5 have shown that this variability can be significantly reduced when total solar or solar-ultraviolet radiation, or both, is used to characterize the exposure increments.
4.3 In addition to variations in level of daylight and solar-ultraviolet radiation, there are significant differences in temperature, and moisture stresses between different locations, and between different years, or periods within a single year, at a single location. Because of this variability, results from this test cannot be used to predict the absolute rate at which photodegradable plastics degrade. Results from this test can be used to compare relative rates of degradation for materials exposed at the same time in the same location. Results from multiple exposures of a common lot of material (during different seasons over several years) at different sites can be used to compare the relative rates at which a particular photodegradable plastic will degrade in each location.
Note 2: An inherent limitation in solar-radiation measurements is that they do not reflect the effects of variations in temperature and moi...
SCOPE
1.1 This practice defines test conditions applicable when Practices D1435 and G7/G7M are employed for the outdoor exposure testing of photodegradable plastics.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1: There is no known ISO equivalent to this standard.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D5272 − 08 (Reapproved 2021)
Standard Practice for
Outdoor Exposure Testing of Photodegradable Plastics
This standard is issued under the fixed designation D5272; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope G169Guide for Application of Basic Statistical Methods to
Weathering Tests
1.1 This practice defines test conditions applicable when
G183Practice for Field Use of Pyranometers, Pyrheliom-
Practices D1435 and G7/G7M are employed for the outdoor
eters and UV Radiometers
exposure testing of photodegradable plastics.
1.2 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 The terminology given in Terminology E772 and Ter-
responsibility of the user of this standard to establish appro-
minology D883 is applicable to this practice.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4. Significance and Use
NOTE 1—There is no known ISO equivalent to this standard.
4.1 When discarded as litter, articles made using photode-
gradable plastics are subject to attack by daylight (particularly
1.3 This international standard was developed in accor-
dance with internationally recognized principles on standard- solar-ultraviolet radiation), oxygen, heat, and water. The 5°
exposure angle used in this practice represents typical condi-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- tions for degradation experienced by litter.
mendations issued by the World Trade Organization Technical
4.2 Thispracticerequirescharacterizationofthedurationof
Barriers to Trade (TBT) Committee.
exposure in terms of solar-ultraviolet radiation. Solar-
ultraviolet radiation varies considerably as a function of
2. Referenced Documents
location and time of year. This can cause dramatic differences
2.1 ASTM Standards: inthetimerequiredtoproduceaspecifiedlevelofdegradation
D882Test Method for Tensile Properties of Thin Plastic
in a polymer. Daro has shown that when the same lot of
Sheeting
polyethylenecontaininganiron-saltprodegradantisexposedat
D883Terminology Relating to Plastics
various times of the year in a single location, the time required
D1435Practice for Outdoor Weathering of Plastics
to produce an average of two chain scissions per molecule
D3593Test Method for Molecular WeightAverages/ Distri-
varied by over 130%. Daro, and Zerlaut and Anderson have
bution of Certain Polymers by Liquid Size-Exclusion
shown that this variability can be significantly reduced when
Chromatography (Gel Permeation Chromatography GPC)
total solar or solar-ultraviolet radiation, or both, is used to
Using Universal Calibration (Withdrawn 1993)
characterize the exposure increments.
D3826Practice for Determining Degradation End Point in
4.3 In addition to variations in level of daylight and solar-
DegradablePolyethyleneandPolypropyleneUsingaTen-
ultraviolet radiation, there are significant differences in
sile Test
temperature, and moisture stresses between different locations,
E772Terminology of Solar Energy Conversion
and between different years, or periods within a single year, at
G7/G7MPractice for Natural Weathering of Materials
a single location. Because of this variability, results from this
test cannot be used to predict the absolute rate at which
photodegradableplasticsdegrade.Resultsfromthistestcanbe
ThispracticeisunderthejurisdictionofASTMCommitteeD20onPlasticsand
used to compare relative rates of degradation for materials
is the direct responsibility of Subcommittee D20.50 on Durability of Plastics.
exposed at the same time in the same location. Results from
Current edition approved Dec. 1, 2021. Published December 2021. Originally
approved in 1992. Last previous edition approved in 2013 as D5272-08(2013).
DOI: 10.1520/D5272-08R21.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Daro,A.,etal,“DegradationofPolymerBlendsIV,NaturalWeatheringofLow
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM DensityandLinearLowDensityPolyethylene,”EuropeanPolymerJournal,Vol26,
Standards volume information, refer to the standard’s Document Summary page on No. 1, 1990, pp. 47–52.
the ASTM website. Zerlaut, G. L., and Anderson, T. A., “Ultraviolet Radiation as a Timing
The last approved version of this historical standard is referenced on TechniqueforOutdoorWeatheringofMaterials,”SocietyofAutomotiveEngineers,
www.astm.org. SAE Technical Paper Number 850348 , 1985.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5272 − 08 (2021)
multiple exposures of a common lot of material (during 5.2.1 Exposure Rack A—Positionable mounting bars used
different seasons over several years) at different sites can be for attaching specimens shall be arrayed over a regular mesh
used to compare the relative rates at which a particular
expanded-metal (aluminum or stainless steel) sheet backing.
photodegradable plastic will degrade in each location.
Use 16–18 gage metal with approximately 0.5-in. openings. It
isrecommendedthatthesurfaceareaoftheexpandedmetalbe
NOTE 2—An inherent limitation in solar-radiation measurements is that
60to70%open.Useanoncorrodingmaterialforthemounting
they do not reflect the effects of variations in temperature and moisture
exposure, which often can be as important as solar radiation. The same
bars. 6061T6 aluminum or untreated wood are typical materi-
solar-ultraviolet radiation increment will not necessarily give the same
als used for the mounting bars. Fig. 1 is a top view showing
changes in properties of the test specimen in different exposure sites.
typical rack construction.
Results from this practice must be regarded as giving only a general
indication of the degree of degradability and should always be considered 5.2.2 Exposure Rack B—Unpainted exterior-grade plywood
in terms of characteristics of the exposure site as well.
forms the rack surface to which specimens are directly at-
4.4 Where measurement of total solar-ultraviolet radiation tached. Replace the plywood when there is any evidence of
is not possible, exposure duration can be determined by the delamination or fiber separation which could produce sharp
numberofdays,weeks,ormonthsexposed.Whenthispractice edges and damage exposed specimens. Medium-density over-
isused,areferencematerialwhosedegradationpropertieshave
lay (MDO) or high-density overlay (HDO) plywood are
been well established must be exposed at the same time as the
satisfactory substrates and will require less frequent replace-
other materials being tested. The reference material used must
ment than plywood with no overlay.
be agreed upon by all interested parties.The time to produce a
NOTE 4—There is less air circulation around the specimens when Rack
specified level of degradation for each material in this simul-
Bexposuresareused.DegradationratesfromexposuresusingRackBwill
taneousexposureisthencompared.Itisalsoagoodpracticeto
be somewhat faster than those using Rack A because specimen tempera-
usereferencematerialswhenexposurelengthisdeterminedby
tures will be higher. Comparisons between materials should only be made
total solar or solar UV radiant exposure.
with exposures conducted at the same time and using the same rack type.
NOTE 3—Areference material can be a single lot of material which has
5.3 Solar Radiometers:
shown consistent results after a number of exposures. It is not necessary
5.3.1 Ultraviolet Radiometer—Unless otherwise specified,
that the composition or properties of the reference material be character-
use a total UV radiometer that measures ultraviolet radiation
ized and certified by a recognized standards agency or group.
from 295 to 385 mm. Operate the radiometer in accordance
5. Apparatus
with Practice G183. Narrow band radiometers (for example,
5.1 Use exposure racks constructed i
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