1、Designation: D 5870 95 (Reapproved 2003)Standard Practice forCalculating Property Retention Index of Plastics1This standard is issued under the fixed designation D 5870; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers procedures for the calculation of aproperty retention index (PRI) of thermoplastic and thermosetp
3、lastics after exposure to thermal aging, natural or artificialaccelerated weathering, or chemical exposures.1.2 This practice is not intended to establish a fixed proce-dure for conducting the exposure test, but it is intended toprovide a set of specific procedures used to calculate theretention ind
4、ex of a characteristic property of the material afterit has been exposed. Selection of the specific exposure testconditions depends on the material being tested and theproperty being measured. It is up to the user to determinewhich exposure test conditions are most relevant to the specificmaterial a
5、nd the service condition being used. The exposuretest used must be conducted in accordance with conditionsdescribed in specific exposure standards.1.3 This practice does not describe procedures for samplingthe materials to be tested. These procedures are described in thestandards and specifications
6、applicable to the material beingevaluated.1.4 The procedure used to calculate the PRI depends onwhether the test used to characterize the materials beingexposed is destructive or nondestructive. The PRI can be usefulin describing short-term mechanical, electrical, and otherproperties of plastics at
7、specified temperatures after the mate-rials have been subjected to an exposure test.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and
8、 determine the applica-bility of regulatory limitations prior to use.NOTE 1There is no similar or equivalent ISO standard. ISO DIS11248 is significantly different since it pertains only to thermosettingresins.2. Referenced Documents2.1 ASTM Standards:D 543 Test Method for Resistance of Plastics to C
9、hemicalReagents2D 618 Practice for Conditioning Plastics for Testing2D 883 Terminology Relating to Plastics2D 1435 Practice for Outdoor Weathering of Plastics2D 1499 Practice for Filtered Open-Flame (Carbon-Arc) Ex-posures of Plastics2D 1898 Practice for Sampling of Plastics2D 2565 Practice for Oper
10、ating Xenon Arc-Type Light Ex-posure Apparatus With and Without Water for Exposure ofPlastics3D 3045 Practice for Heat Aging of Plastics Without Load3D 4329 Practice for Operating Light- and Water-ExposureApparatus (Fluorescent UV-Condensation Type) for Expo-sure of Plastics4D 4364 Practice for Perf
11、orming Accelerated OutdoorWeathering of Plastics Using Concentrated Natural Sun-light4D 4459 Practice for Operating an Accelerated LightfastnessXenon-Arc-Type (Water Cooled) Light-Exposure Appara-tus for the Exposure of Plastics for Indoor Applications4D 4674 Test Method for Accelerated Testing for
12、ColorStability of Plastics Exposed to Indoor Fluorescent Light-ing and Window-Filtered Daylight4D 6360 Practice for Enclosed Carbon-Arc Exposures ofPlastics4G 113 Terminology Relating to Natural and ArtificialWeathering Test of Nonmetallic Materials52.2 ISO Standards:6ISO 291 PlasticsStandard Atmosp
13、heres for Conditioningand TestingISO 877 PlasticsMethods of Exposure to Direct Weath-ering, to Weathering Using Glass Filtered Daylight, and toIntensified Weathering by Daylight Using Fresnel MirrorsISO 4892 PlasticsMethods of Exposure to LaboratoryLight Sources Part 1: General Guidance, Part 2: Xen
14、on1This practice is under the jurisdiction of ASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved May 10, 2003. Published June 2003. Originallyapproved in 1995. Last previous edition approved in 1995 as D 5870 - 95.2
15、Annual Book of ASTM Standards, Vol 08.01.3Annual Book of ASTM Standards, Vol 08.02.4Annual Book of ASTM Standards, Vol 08.03.5Annual Book of ASTM Standards, Vol 14.02.6Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM Internatio
16、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Arc Exposures, Part 3: Fluorescent UV Exposures, andPart 4: Filtered Open Flame Carbon Arc ExposuresISO DIS 11248 PlasticsThermosetting Molding Materi-als, Evaluation of Short-Term Performance at ElevatedTempera
17、tures3. Terminology3.1 Definitions: The terminology given in TerminologiesD 883 and G 113 is applicable to this practice.4. Significance and Use4.1 The property retention index (PRI) determined by thispractice is intended primarily to provide relative durabilityperformance information on materials f
18、or design engineers. Itis up to the user to ensure that appropriate sampling proceduresare used for the selection of specimens to be exposed so thatthe PRI data obtained is actually representative of the materialbeing evaluated.4.2 The PRI obtained depends on the material being tested,property being
19、 evaluated, and exposure condition used. A PRIobtained for one property will probably not be the same as thePRI for a different property of the same material, even if thesame exposure test is used.4.3 Plastics exposed to a combination of environmental andthermal treatments may undergo a change in fu
20、nctional perfor-mance. Any laboratory-accelerated aging procedure, especiallythose that use only a single stress, may not realistically indicatethe changes a plastic may undergo in actual use conditions.This practice provides a means for expressing the changes inproperties as a function of time expo
21、sed in a wide variety oftests. The PRI data obtained is best used for comparing theperformance of materials subjected to the same exposure testsimultaneously.4.3.1 Both laboratory-accelerated and outdoor exposuretesting can be highly variable, and the PRI data will beinfluenced by this variability.
22、For example, PRI data fromoutdoor exposures can vary depending on the exposure loca-tion and the time of year when the exposure is conducted.Variability in laboratory-accelerated exposure tests can resultin large differences in PRI data from two laboratories runningsupposedly identical tests. PRI da
23、ta obtained from exposure tolaboratory-accelerated tests cannot be used to predict the PRIfor exposure to natural weathering or actual use conditionsunless there is a sufficient amount of data from both types ofexposure to allow valid statistical comparisons.4.4 A number of different exposure techni
24、ques can be usedto provide information on the effects of environmental stressessuch as light, heat, and water on plastics (see Practices D 1435,D 1499, D 2565, D 4329, D 4364, and D 4459; Test MethodD 4674; and ISO 4892 and 877). When it is desirable toevaluate the effects of heat alone, exposures s
25、hould be con-ducted in accordance with Practice D 3045. When it is desir-able to evaluate the effects of chemical exposures, the expo-sures should be conducted in accordance with Test MethodD 543.4.5 There are a number of factors influencing the physicalproperties and the retention of these properti
26、es after exposure.In addition to a complete description of the exposure testconditions used, the following information shall be included inany report referencing this practice: (1) complete description ofthe material tested, including the type, source, manufacturerscode number, form, and previous hi
27、story; (2) methods ofpreparation for the material and individual test specimens; (3)procedure used for specimen conditioning prior to and afterexposure; (4) complete description of the environment inwhich the physical properties were determined (for example,temperature and relative humidity); (5) co
28、mplete description ofthe procedure used to determine the physical properties tested,including the rate at which specimens were tested, if appli-cable; (6) if applicable, void content of the specimens testedand the method used to measure void content.NOTE 2It is not the intent of this practice to req
29、uire users to divulgeproprietary information regarding composition. To avoid divulging pro-prietary information, generic descriptions may be used to provide infor-mation on material composition.4.6 When destructive tests are used to determine a physicalor chemical change, or both, which occurs as a
30、result ofexposure, the amount of change is expressed as a function ofthe value obtained for the material tested at a specified testenvironment (for example, temperature and humidity). Theexposed and reference specimens are measured at the sametime in the specified test environment.4.7 When nondestru
31、ctive tests are used to determine aphysical or chemical change, or both, which occurs as a resultof exposure, the amount of change is expressed as a function ofthe value obtained on the specimens prior to exposure. Prop-erty measurement tests on the specimens before and afterexposure shall be conduc
32、ted at the same conditions (forexample, temperature and humidity).4.8 The property or properties to be measured may bespecified in an ASTM, ISO, or other appropriate standard forthe material being tested, or by any prior agreement betweeninterested parties. If the method used to measure the property
33、being evaluated is not described in an ASTM, ISO, or otherappropriate standard, a description of the test method shall beincluded in the report of test results.4.9 It is realized that a material cannot be tested withoutspecifying the method of preparation. To have any meaning incomparative testing,
34、specimens of each material being evalu-ated by these test procedures should be prepared or moldedfrom the same lot under identical processing conditions andrandomized prior to testing at the conditions desired. It must berealized that lot-to-lot variation in the material may causeadditional variabil
35、ity in results.NOTE 3For those plastics with a Tg greater than ambient, the slowcollapse of free volume, with attendant significant changes in mechanicalproperties such as fatigue resistance, impact resistance, yield stress, andvapor transmission, etc. will be accelerated at elevated temperatures be
36、lowthe Tg but will be reversed at temperatures above the Tg. Therefore,incubation at elevated temperatures in the Tg range may be erraticallysusceptible to oven fluctuation effects.4.10 The results depend on which side of the test specimenis exposed with some tests. In bending tests, for example,dif
37、ferent results are obtained in accordance with whether theexposed surface or the unexposed surface of the test specimenis placed under tension. Care must be taken to ensure that allspecimens being exposed have the same orientation in the testD 5870 95 (2003)2fixture used to hold the specimens during
38、 exposure. In addition,the results also depend on the orientation of test specimensduring the procedure used to measure the property beingmonitored. This is especially true with impact tests. During theprocedure used to measure the characteristic property, caremust be taken to ensure that all specim
39、ens are oriented thesame way in the test fixture.4.11 Before proceeding with this practice, reference shouldbe made to the specification of the material being tested. Anytest specimen preparation, conditioning, or dimensions, orsome combination thereof, and testing parameters covered inthe materials
40、 specification shall take precedence over thosementioned in this practice. The default conditions described inthis practice apply if there are no material specifications.5. Apparatus5.1 The apparatus used for exposure and measurement ofthe property desired will depend on the particular exposureused
41、and property being measured. Refer to the appropriateASTM or ISO standards for requirements on the apparatusneeded.6. Sampling6.1 Sampling of materials for testing is covered underapplicable standards or specifications for the material beingtested.6.2 It is important to select samples for testing th
42、at arerepresentative of the material being evaluated. Procedures forsampling plastics are described in Practice D 1898.7. Test Specimens7.1 The test specimens shall be in accordance with theappropriate test method used for the properties being mea-sured.7.2 All test specimens shall be prepared in ac
43、cordance withthe pertinent material standards and other relevant ASTMstandards.7.3 Annealing of thermoplastic materials and post-curing ofthermosetting materials has a significant effect on manyproperties. To minimize errors caused by these effects, anneal-ing and post-curing shall be conducted accu
44、rately in accor-dance with pertinent material standards or, if not available, inaccordance with the material manufacturers recommenda-tions. The conditions used for any annealing or post curing ofspecimens shall be reported.7.4 The number of specimens tested shall be in accordancewith the test metho
45、d for the particular properties being mea-sured. Large numbers of test specimens should be used in casesof extreme variability, in which the standard deviation of testresults is more than 20 % of the mean value. If the test methodused does not require a specific number of test specimens, aminimum of
46、 five replicate specimens of each material shall beused.8. Procedure8.1 Exposure of Test Specimens8.1.1 When determining the PRI for materials exposed tonatural weathering, conduct exposures in accordance withPractice D 1435.8.1.2 When the PRI for exposure to concentrated naturalsunlight is to be de
47、termined, conduct exposures in accordancewith Practice D 4364.8.1.3 When the PRI for exposure to laboratory light sourcesis to be determined, conduct exposures in accordance with oneof the following ASTM standards:(1) Practice D 1499 for exposures to filtered open-flamecarbon-arc light sources;(2) P
48、ractice D 2565 for exposures to xenon-arc lightsources;(3) Practice D 4329 for exposure to fluorescent ultraviolet(UV) light sources; and(4) Practice D 6360 for exposures to enclosed carbon-arclight sources;(5) Procedures for exposure to these and other types oflight sources are also described in AS
49、TM or ISO standardsapplicable to specific types of materials; these can also be usedwhen mutually agreed upon by all interested parties.8.1.4 When the PRI for exposure to heat onermined, con-duct exposures in accordance with Practice D 3045. Exposuresused to determine the PRI will typically be conducted at one ortwo temperatures. The procedures covered in Practice D 3045,which describe the calculation of a time to fail, would not beused for tests to determine the PRI.8.1.5 When the PRI for chemical exposure is to be deter-mined, conduct exposures in accordance with Test MethodD
