1、Designation: D 5208 09Standard Practice forFluorescent Ultraviolet (UV) Exposure of PhotodegradablePlastics1This standard is issued under the fixed designation D 5208; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 practice covers the specific procedures applicablefor fluorescent Ultraviolet (UV) exposure of photodegradableplast
3、ics conducted in accordance with Practices G 151 andG 154. This practice also covers the preparation of test speci-mens and the evaluation of test results.NOTE 1Previous versions of this practice referenced fluorescent UVdevices described by Practice G53, which described very specificequipment desig
4、ns. Practice G53has been withdrawn and replaced byPractice G 151, which describes performance criteria for all exposuredevices that use laboratory light sources and by Practice G 154, whichgives requirements for exposing nonmetallic materials in fluorescent UVdevices.1.2 Practice D 4329 covers fluor
5、escent UV exposures ofplastics intended for long term use in outdoor applications.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety problems, if any, associated with
6、its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 2There is no known ISO equivalent to this practice.2. Referenced Documents2.1 ASTM Standards:2D 3826 Practi
7、ce for Determining Degradation End Point inDegradable Polyethylene and Polypropylene Using a Ten-sile TestD 4329 Practice for Fluorescent UV Exposure of PlasticsD 5870 Practice for Calculating Property Retention Indexof PlasticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the P
8、recision of a Test MethodG53 Practice for Operating Light-and Water-Exposure Ap-paratus (Fluorescent UV-Condensation Type) for Exposureof Nonmetallic Materials (Discontinued 2001)3G113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 141 Guide forAddressing Va
9、riability in Exposure Testingof Nonmetallic MaterialsG 147 Practice for Conditioning and Handling of Nonme-tallic Materials for Natural and Artificial Weathering TestsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 154 Practice for Op
10、erating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic MaterialsG 169 Guide forApplication of Basic Statistical Methods toWeathering Tests3. Terminology3.1 The definitions given in Terminology G113are appli-cable to this practice.4. Significance and Use4.1 Materials made from photodegrada
11、ble plastics are in-tended to show relatively rapid deterioration of chemical,physical, and mechanical properties when exposed to light,heat, and water after fulfilling their intended purpose. Thispractice is intended to induce property changes associated withconditions that might be experienced whe
12、n the material isdiscarded as litter, including the effects of sunlight, moisture,and heat. The exposure used in this practice is not intended tosimulate the deterioration caused by localized weather phe-nomena such as atmospheric pollution, biological attack, andsalt water exposure.4.2 CautionsVari
13、ation in results may be expected whenoperating conditions are varied within the accepted limits ofthis practice. Therefore, no reference to the use of this practiceshould be made unless accompanied by a report prepared inaccordance with Section 9 that describes the specific operating1This practice i
14、s under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.96 on Environmentally DegradablePlastics and Biobased Products.Current edition approved Sept. 1, 2009. Published September 2009. Originallyapproved in 1991. Last previous edition approved in
15、 2001 as D 5208 - 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of
16、 this historical standard is referencedon www.astm.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.conditions used. Refer to Practice G 151 for detailed informa-ti
17、on on the caveats applicable to use of results obtained inaccordance with this practice.NOTE 3Additional information on sources of variability and onstrategies for addressing variability in the design, execution and dataanalysis of laboratory accelerated exposure tests is found in Guide G 141.4.3 Ex
18、posure of a similar material of known performance (acontrol) at the same time as the test specimens provides astandard for comparative purposes. Use of a control to rank thestability of test materials greatly improves agreement betweendifferent laboratories.4,5It is recommended that at least threere
19、plicates of each material evaluated be exposed to allow forstatistical evaluation of results.4.4 Test results will depend upon the care that is taken tooperate the equipment in accordance with Practice G 154.Significant factors include regulation of line voltage, tempera-ture of the room in which th
20、e device operates, temperaturecontrol, and condition and age of the lamps.5. Apparatus5.1 Use of fluorescent UV apparatus that conform to therequirements defined in Practices G 151 and G 154 is requiredto conform to this practice.5.2 The spectral power distribution of the fluorescent UVlamp shall co
21、nform to the requirements in Practice G 154 for aUVA 340 lamp.5.3 Test Chamber Location:5.3.1 Locate the apparatus in an area maintained between 18and 27C (65 and 80F). Measure ambient temperature at amaximum distance of 150 mm (6 in.) from the plane door ofthe apparatus. Control of ambient temperat
22、ure is particularlycritical when one apparatus is stacked above another, becausethe heat generated from the lower unit can interfere with theoperation of the units above.5.3.2 Place the apparatus at least 300 mm from walls orother apparatus. Do not place the apparatus near a heat sourcesuch as an ov
23、en.5.3.3 Ventilate the room in which the apparatus is located toremove heat and moisture.6. Test Specimens6.1 The size and shape of specimens to be exposed will bedetermined by the specifications of the particular test methodused to evaluate the effects of the exposure on the specimens;the test meth
24、od shall be determined by the parties concerned.Where practical, it is recommended that specimens be sized tofit specimen holders and racks supplied with the exposureapparatus. Unless supplied with a specific backing as anintegral part of the test, specimens shall be mounted so thatonly the minimum
25、specimen area required for support by theholder shall be covered. This unexposed surface must not beused as part of the test area.6.2 For specimens of insulating materials, such as foams,maximum specimen thickness is 20 mm in order to allow foradequate heat transfer for condensation.6.3 To provide r
26、igidity, attach flexible specimens to abacking panel made of aluminum, 0.635 mm (0.025 mm) thick.Suggested aluminum alloys are 5052, 6061, or 3003.6.4 Seal any holes in specimens larger than two mm and anyopenings larger than one mm around irregularly shaped speci-mens to prevent loss of water vapor
27、. Attach porous specimensto a solid backing such as aluminum that can act as a vaporbarrier.6.5 Unless otherwise specified, expose at least three repli-cate specimens of each test and control material.6.6 Follow the procedures described in Practice G 147 foridentification and conditioning and handli
28、ng of specimens oftest, control, and reference materials prior to, during, and afterexposure.6.7 Do not mask the face of a specimen for the purpose ofshowing on one panel the effects of various exposure times.Misleading results may be obtained by this method, since themasked portion of the specimen
29、is still exposed to temperatureand humidity cycles that, in many cases, will affect results.6.8 Since the thickness of a specimen may markedly affectthe results, thickness of test and control specimens shall bewithin 610 % of the nominal dimensions.NOTE 4This is especially important when mechanical
30、properties arebeing investigated.6.9 Retain a supply of unexposed file specimens of allmaterials tested.6.10 Specimens should not be removed from the exposureapparatus for more than 24 h and then returned for additionaltests, since this may not produce the same results on allmaterials as tests run w
31、ithout this type of interruption. Anyelapsed time should be reported as noted under Section 9.NOTE 5Since the stability of the file specimen may also be time-dependent, users are cautioned that over prolonged exposure periods, orwhere small differences in the order of acceptable limits are anticipat
32、ed,comparison of exposed specimens with the file specimen may not be valid.Instrumental measurements are recommended whenever possible.7. Procedure7.1 When the test and control specimens do not completelyfill the specimen racks, fill all empty spaces with blank panelsto maintain the test conditions
33、within the chamber.7.2 Unless otherwise specified, control irradiance at 0.89 60.02 W/(m2 nm) at 340 nm.NOTE 6In devices without irradiance control operated at 50 6 3Cuninsulated black panel temperature the typical irradiance at 340 nm is0.89 W/(m2 nm). (See Note 1 of Table X2.1 in Practice G 154 fo
34、r a fullexplanation of the current default irradiance.)7.2.1 During equilibrium operation, the allowed deviationfrom the 340 nm set point is 60.02 W/(m2 nm). If theindicated irradiance is outside the tolerance, stop the test andcorrect the problem before continuing.7.3 Unless otherwise specified, pr
35、ogram the device to one ofthe following test cycles.4Fischer, R., “Results of Round Robin Studies of Light- and Water-ExposureStandard Practices,” Accelerated and Outdoor Durability Testing of OrganicMaterials, ASTM STP 1202, Warren D. Ketola and Douglas Grossman, Eds.,American Society for Testing a
36、nd Materials, Philadelphia, 1993.5Ketola, W., and Fischer, R., “Characterization and Use of Reference Materialsin Accelerated Durability Tests,” VAMAS Technical Report No. 30. Available fromNIST, Gaithersburg, MD.D52080927.3.1 Cycle A20 h UV (light only) with uninsulated blackpanel temperature contr
37、olled at 50C.4 h Dark/condensation with uninsulated blackpanel temperature controlled at 40C.Repeat this 24-hour cycle continuously until the desired totalexposure is reached.7.3.2 Cycle B4 h UV (light only) with uninsulated blackpanel temperature controlled at 50C.4 h Dark/condensation with uninsul
38、ated blackpanel temperature controlled at 40C.Repeat this 8-hour cycle continuously until the desired totalexposure is reached.7.3.3 Cycle Ccontinuous UV with uninsulated blackpanel temperature controlled at 50C. Operate continuouslyuntil the desired total exposure is reached.7.3.4 During equilibriu
39、m operation, the maximum allow-able deviation from the uninsulated black panel temperature setpoint is 63C. If the indicated temperature of the uninsulatedblack panel is outside these limits, stop the test and correct theproblem before continuing.NOTE 7The set points and tolerances for 7.2 and Cycle
40、s A, B, and Crepresent an operational control point for equilibrium conditions at asingle location in the cabinet which may not necessarily represent theuniformity of those conditions throughout the cabinet. ASTM CommitteeG03 is working to refine these tolerances and address the uniformity issue.7.3
41、.5 Use Cycle C for materials that will be used for toxicitytesting after exposure. This is essential because cycles that usecondensation may wash away by-products of photochemicaldegradation.7.4 Unless otherwise specified, reposition specimens asfollows in order to minimize any effects from temperat
42、ure orUV light variation. Figure 1 shows a diagram of the specimenrepositioning.7.4.1 Reposition the specimens horizontally at least everythird day by (1) moving the two extreme right hand holders tothe far left of the exposure area, and (2) sliding the remainingholders to the right.7.4.2 Reposition
43、 the specimens vertically so that each speci-men spends the same amount of exposure time in each verticalposition within the specimen holder. For instance, if twospecimens are stacked vertically in each holder, then the topand bottom specimens should switch places halfway throughthe test. If four sp
44、ecimens are stacked vertically, then thespecimens should be repositioned vertically three times duringthe test.7.5 Identification of any control specimen used shall accom-pany the report.8. Periods of Exposure and Evaluation of Test Results8.1 If a standard or specification for general use requires
45、adefinite property level after a specific time or radiant exposurein an exposure test conducted in accordance with this practice,base the specified property level on results from round-robinexperiments run to determine the test reproducibility from theexposure and property measurement procedures. Co
46、nduct theseround-robins in accordance with Practice E 691 and include astatistically representative sample of all laboratories or orga-nizations who would normally conduct the exposure andproperty measurement. The precision and bias section containsresults from such a round-robin.8.1.1 If a standard
47、 or specification for use between two orthree parties requires a definite property level after a specifictime or radiant exposure in an exposure test conducted inaccordance with this practice, base the specified property levelon two independent experiments run in each laboratory todetermine the repr
48、oducibility for the exposure and propertymeasurement process. The reproducibility of the exposure/property measurement process is then used to determine theminimum level of property after the exposure that is mutuallyagreeable to all parties.8.2 When reproducibility in results from an exposure testc
49、onducted in accordance with this practice have not beenestablished through round-robin testing, specify performancerequirements for materials in terms of comparison (ranked) toa control material. The control specimens shall be exposedsimultaneously with the test specimen(s) in the same device.All concerned parties must agree on the specific controlmaterial used.8.2.1 Conduct analysis of variance to determine whetherany differences between test materials and control materials arestatistically significant. Expose replicates of the test specimenand the control speci
