1、Designation: D 618 08Standard Practice forConditioning Plastics for Testing1This standard is issued under the fixed designation D 618; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthes
2、es indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 In general, the physical and electrical properties ofplastics are influe
3、nced by temperature and relative humidity ina manner that materially affects test results. In order to makereliable comparisons between different materials and betweendifferent laboratories, it is necessary to standardize the humid-ity conditions, as well as the temperature, to which specimensof the
4、se materials are subjected prior to and during testing. Thispractice defines procedures for conditioning plastics (althoughnot necessarily to equilibrium) prior to testing, and the condi-tions under which they shall be tested.1.2 For some materials, it is possible that a material speci-fication exis
5、ts that requires the use of this practice, but withsome procedural modifications. The material specificationtakes precedence over this practice. Refer to the materialspecification before using this practice. Table 1 in Classifica-tion D 4000 lists the ASTM material specifications thatcurrently exist
6、.1.3 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 determine the applica-bility of regulatory limitations prior to use.NOTE 1This sta
7、ndard and ISO 291 address the same subject matter,but differ in technical content. ISO 291 describes only two temperatureand humidity conditions for conditioning or testing, or both.2. Referenced Documents2.1 ASTM Standards:2D 709 Specification for Laminated Thermosetting MaterialsD 756 Practice for
8、 Determination of Weight and ShapeChanges of Plastics Under Accelerated Service Condi-tions3D 4000 Classification System for Specifying Plastic Mate-rialsD 5032 Practice for Maintaining Constant Relative Humid-ity by Means of Aqueous Glycerin SolutionsE 104 Practice for Maintaining Constant Relative
9、 Humidityby Means of Aqueous Solutions2.2 ISO Standard:ISO 291 PlasticsStandard Atmospheres for Conditioningand Testing43. Terminology3.1 Definitions:3.1.1 room temperaturea temperature in the range from20 to 30C (68 to 86F).3.1.2 standard laboratory atmospherean atmosphere hav-ing a temperature of
10、23C (73.4F) and a relative humidity of50 % with standard tolerances as specified in Section 8 shall bethe standard laboratory atmosphere.3.1.3 standard laboratory temperaturea temperature of23C (73.4F) with standard tolerance as specified in Section 7shall be the standard laboratory temperature.4. S
11、ignificance and Use4.1 Conditioning of specimens is typically conducted: (1)for the purpose of bringing the material into equilibrium withnormal or average room conditions, (2) simply to obtainreproducible results, regardless of previous history of expo-sure, or (3) to subject the material to abnorm
12、al conditions oftemperature or humidity in order to predict its service behavior.4.2 The conditioning procedures prescribed in this practiceare designed to obtain reproducible results and have thepotential to give physical values somewhat higher or somewhatlower than values under equilibrium at norm
13、al conditions,depending upon the particular material and test. Depending onthe thickness, type of material and its previous history, it ispossible that it would take 20 to 100 days or more to ensuresubstantial equilibrium under normal conditions of humidity1This practice is under the jurisdiction of
14、ASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.50 on Durability of Plastics.Current edition approved Nov. 1, 2008. Published November 2008. Originallyapproved in 1941. Last previous edition approved in 2005 as D 618 - 05.2For referenced ASTM standards, visit the A
15、STM 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.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New Y
16、ork, NY 10036, http:/www.ansi.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.and temperature. Consequently, conditioning for reproducibil-ity must of necessity be
17、 used for general purchase specifica-tions and product control tests.5. Sampling5.1 Sampling shall be in accordance with the ASTM testmethods for the specific properties to be determined.6. Test Specimens6.1 The numbers and types of test specimens shall be inaccordance with the ASTM test methods for
18、 the specificproperties to be determined.7. Requirements for Conditioning Atmospheres7.1 When data are to be obtained for comparison purposesat a specific temperature, select the test temperature andassociated tolerance from Table 1.7.1.1 Unless otherwise specified, tolerance for temperatureshall be
19、 as given in Table 1.7.1.2 When a tolerance of 61C (61.8F) is required, itshall be specified and shall be reported.7.1.3 The position for measurement of temperature andrelative humidity measurementmeasurements shall be madeas close as possible to the center of the room or chamber.7.1.3.1 It is possi
20、ble that the temperature and relativehumidity measured are not representative of a conditionelsewhere in an enclosure or room because of local effects ordeficiency in circulation of air. If required, additional measure-ments shall be made throughout the area to show compliance tothe temperature and
21、relative humidity conditions specified.7.2 Relative Humidity:7.2.1 When tolerance for temperature is 62C, the tolerancefor relative humidity shall be 610 %.7.2.2 When tolerance for temperature is 61C, the tolerancefor relative humidity shall be 65%.NOTE 2Annex B of ISO 291 provides background inform
22、ation on thecalculation of tolerance for relative humidity based on the allowedfluctuation in set point temperature.8. Designations for Conditioning8.1 Designation for Conditioning Prior to Test:8.1.1 Designate conditioning of test specimens as follows:8.1.1.1 A number indicating in hours the durati
23、on of theconditioning,8.1.1.2 A number indicating in degrees Celsius the condi-tioning temperature, or8.1.1.3 A number indicating relative humidity, wheneverrelative humidity is controlled, or a word to indicate immersionin a liquid.8.1.2 The numbers shall be separated from each other byslant marks.
24、 A sequence of conditions shall be denoted by useof a plus ( + ) sign between successive conditions. “Des” shallbe used to indicate desiccation over anhydrous calcium chlo-ride. Temperature and relative humidity tolerances shall be inaccordance with Section 7, unless otherwise specified.NOTE 3Exampl
25、es:Condition 96/23/50Condition 96 h at 23C and 50 % relative humidity.Condition 48/50/waterCondition 48 h at 50C in water.Condition 48/50 + 96/23/50Condition 48 h at 50C; then condition 96 hat 23C and 50 % relative humidity.Condition 48/50 + DesCondition 48 h at 50C followed by desiccation.8.2 Desig
26、nation for Test Condition:8.2.1 Designate test conditions as follows:8.2.1.1 A capital letter “T” following the prior conditioningdesignation and separated therefrom by a colon.8.2.1.2 A number indicating in degrees Celsius the testtemperature;8.2.1.3 A number indicating the relative humidity in the
27、 testwhenever relative humidity is controlled.8.2.2 The numbers shall be separated from each other by aslant mark, and from the “T” by a dash. Temperature andrelative humidity tolerances shall be in accordance withSection 7, unless otherwise specified.NOTE 4Examples:Condition 24/180: T180Condition 2
28、4 h at 180C: Test at 180C.Condition 96/35/90: T3590Condition 96 h at 35C and 90 %relative humidity: Test at 35C and 90 % relative humidity.9. Standard Procedures for Conditioning Prior to Test9.1 Procedure ACondition 40/23/50 for specimens 7 mm(0.25 in.) or under in thickness, 88/23/50 for specimens
29、 over 7mmCondition test specimens 7 mm or under in thickness inthe standard laboratory atmosphere for a minimum of 40 himmediately prior to testing. Treat test specimens over 7 mm inthickness as above, except that the minimum time shall be88 h. Provide adequate air circulation on all sides of the te
30、stspecimens by placing them in suitable racks, hanging themTABLE 1 Test Temperatures and TolerancesTestTemperatures, C (F)ATolerance,plus or minus, C (F)70 (94) 2.0 (3.6)55 (67) 2.0 (3.6)40 (40) 2.0 (3.6)25 (13) 2.0 (3.6)0 (32) 2.0 (3.6)23 (73)B2.0 (3.6)35 (95) 2.0 (3.6)50 (122) 2.0 (3.6)70 (158) 2.
31、0 (3.6)90 (194) 2.0 (3.6)105 (221) 2.0 (3.6)120 (248) 2.0 (3.6)130 (266) 2.0 (3.6)155 (311) 2.0 (3.6)180 (356) 2.0 (3.6)200 (392) 3.0 (5.4)225 (437) 3.0 (5.4)250 (482) 3.0 (5.4)275 (527) 3.0 (5.4)300 (572) 3.0 (5.4)325 (617) 4.0 (7.2)350 (662) 5.0 (9.0)400 (752) 6.0 (10.8)450 (842) 8.0 (14.4)500 (93
32、2) 10.0 (18.0)600 (1112) 12.0 (21.6)AThe test temperature is the temperature at which the chamber or room iscontrolled. The tolerance is the maximum allowable variation of the temperatureindicated by the temperature output device during equilibrium conditions. If theindicated temperature is outside
33、the limit defined by the test temperature plus orminus the tolerance, immediately implement procedures to correct the problem.BStandard Laboratory Temperature.D618082from metal clips or laying them on wide-mesh, wire screenframes with at least 25 mm (1 in.) between the screen and thesurface of the b
34、ench.NOTE 5Procedure A is generally satisfactory and is recommendedunless other methods are specified. Note that Procedure A of PracticeD 618 differs from Condition A of Specification D 709 and of the MilitarySpecifications MIL-P designation in that Condition A means “as received,no special conditio
35、ning.”NOTE 6If for any particular material or test, a specific longer time ofconditioning is required, the time shall be agreed upon by the interestedparties. It is acceptable to use shorter conditioning times for thinspecimens provided equilibrium is substantially obtained.9.2 Procedure BCondition
36、48/50 + DesConditionspecimens for a period of 48 h in a circulating-air oven at atemperature of 50 6 2C (122 6 3.6F). Remove the speci-mens from the oven and cool to the room temperature in adesiccator over anhydrous calcium chloride for a period of atleast 5 h for specimens 7 mm (0.25 in.) or under
37、 in thickness,and at least 15 h for specimens over 7 mm in thickness,immediately prior to testing.NOTE 7Procedure B is commonly used for the purpose of obtainingreproducible test results on the thermosetting materials by means of ashort-time conditioning period, or where the specific effects of mode
38、ratedrying are to be determined. The use of other enclosures, desiccants, ordesiccating techniques that produce and maintain an atmosphere equiva-lent to that over anhydrous calcium chloride is acceptable. Note thatProcedure B of Practice D 618 is the same as Condition E-48/50 ofSpecifications D 709
39、 and of the Military Specifications MIL-P designa-tion.9.3 Procedure CCondition 96/35/90Condition speci-mens for a period of 96 h in an atmosphere of 90 % relativehumidity at a temperature of 35C (95F). The tolerances forthis procedure shall be as follows:Time, h 62Temperature, C (F) 61 (1.8)Humidit
40、y, % 62NOTE 8Procedure C is recommended wherever the specific effects ofexposure to severe atmospheric moisture are to be determined.NOTE 9It has been found that, for certain tests and materials, morereliable data are obtained in enclosures with circulating air rather than stillair. In such cases us
41、e enclosures with circulating air.9.4 Procedure DCondition 24/23/waterConditionspecimens by immersion in distilled water for 24 612 hat236 1C (73.4 6 1.8F).9.5 Procedure ECondition 48/50/water + 1/23/waterCondition specimens by immersion in distilled water for 48 612 hat506 1C (122 6 1.8F), and cool
42、 them by immersionin a sufficient quantity of distilled water to reduce the tempera-ture to 23C (73.4F) within 1 h.NOTE 10Procedures D and E have been found useful in ASTMelectrical and mechanical tests, and are used extensively in MilitarySpecifications MIL-P designation.9.6 Procedure FCondition /2
43、3/96 (time as specified inapplicable materials specification)Condition specimens in anatmosphere of 96 6 1 % relative humidity at a temperature of23 6 1C (73.4 6 1.8F) for a period of time as specified in theapplicable materials specification.NOTE 11Constant relative humidity can be obtained only by
44、 carefultemperature control. Procedures for maintaining close tolerances aredescribed in Practice E 104. When use of acid or salt solutions has adeleterious effect on materials being tested, use glycerin solutions inaccordance with Practice D 5032 to control relative humidity.NOTE 12A considerable n
45、umber of other procedures that might beconsidered as functional are outlined in Practice D 756.NOTE 13It has been found that, for certain tests and materials, morereliable data are obtained in enclosures with circulating air rather than stillair. In such cases enclosures with circulating air should
46、be used.10. Tests at Normal Temperatures10.1 Unless otherwise specified, test materials conditionedin the standard laboratory atmosphere in the same atmosphere.10.2 Unless otherwise specified, test materials conditionedin accordance with Procedure B at room temperature condi-tions. Start the test as
47、 soon as possible, but do not allow morethan12 h to elapse between removal of the specimens from thedesiccator and the start of the tests.10.3 Unless otherwise specified, test materials conditionedin accordance with Procedures C and F in the same atmo-sphere.10.4 Unless otherwise specified, wipe mat
48、erials conditionedin accordance with Procedures D and E immediately with adamp cloth, then with a dry cloth, and test them at roomtemperature. Specimens should only be removed from thewater as the tests are ready to be conducted. Start the testsimmediately and complete them as soon as possible.11. T
49、ests at Other Standard Test Temperatures11.1 When tests are desired at standard test temperaturesprescribed in Section 7, transfer materials to the test conditionswithin12 h, preferably immediately, after completion of thepreconditioning (in accordance with Procedure A or B). Holdthe specimens at the test temperature for no more than 5 h priorto test, and in no case for less than the time required to ensurethermal equilibrium.NOTE 14Specific materials, specimen geometries, or physical condi-tionin
