1、Designation: D3012 07D3012 13Standard Test Method forThermal-Oxidative Stability of Polypropylene Using aSpecimen Rotator Within an Oven1This standard is issued under the fixed designation D3012; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、of revision, the year of last 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 test method provides a means for estimating the resistance of polypropylene, in molded
3、form, to accelerated aging byheat in the presence of air using a forced draft oven.1.2 The stability determined by this test method is not directly related to the suitability of the material for use when differentenvironmental conditions prevail and shall not be used to predict performance.NOTE 1The
4、 specified thermal levels in this test method are considered sufficiently severe to cause failure of commercial grades of heat-stablepolypropylene within a reasonable period of time. If desired, lower temperatures can be applied to estimate the performance of polypropylene with lowerheat stabilities
5、.1.3 The values stated in SI units are to be regarded as the standard. The values in bracketsparentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establi
6、sh appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.NOTE 2This test method and ISO 45771983 are technically similar but different in preparation of test specimens, thickness of test specimen,measurement of the number of air flow changes in
7、 the ovens, and the number of air changes per hour required.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD3641 Practice for Injection Molding Test Specimens of Thermoplastic Molding and Extrusion MaterialsD4101 Spe
8、cification for Polypropylene Injection and Extrusion MaterialsD5374 Test Methods for Forced-Convection Laboratory Ovens for Evaluation of Electrical InsulationE77 Test Method for Inspection and Verification of ThermometersE220 Test Method for Calibration of Thermocouples By Comparison TechniquesE608
9、 Specification for Mineral-Insulated, Metal-Sheathed Base Metal ThermocouplesE644 Test Methods for Testing Industrial Resistance ThermometersE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1137/E1137M Specification for Industrial Platinum Resistance
10、ThermometersE2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids2.2 ISO Standard:3ISO 45771983 PlasticsPolypropylene and Propylene CopolymersDetermination of Thermal Oxidative Stability inAir-Oven MethodISO 1873 PlasticsPolypropylene and Propylene-Copolymer The
11、rmoplastics:Part 1: DesignationPart 2: Determination of Properties1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.Current edition approved March 1, 2007April 1, 2013. Published March 200
12、7April 2013. Originally approved in 1972. Last previous edition approved in 20042007 asD3012 - 04.D3012 - 07. DOI: 10.1520/D3012-07.10.1520/D3012-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standa
13、rdsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an i
14、ndication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to b
15、e considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 DefinitionsThe definitions of plastics used in this test method are
16、in accordance with Terminology D883 unless otherwiseindicated.4. Summary of Test Method4.1 Aging is accelerated by exposing the specimens to an elevated temperature in a forced draft oven equipped with a biaxialor uniaxial rotating specimen holder.4.2 Visual examination is used to determine the time
17、 to failure. The time to failure of the material is taken as the number ofdays after which the specimen shows localized crazing, crumbling, or discoloration, or a combination thereof.5. Significance and Use5.1 Under the severe conditions of this test method, the specimens undergo degradation at a ra
18、te that is dependent upon thethermal endurance of the polypropylene material under examination.5.2 The thermal level of this test method is considered sufficiently severe to cause failure of commercial grades of heat-stablepolypropylene within a reasonable period of time. If desired, lower temperatu
19、res can be applied to estimate the performance ofpolypropylene materials with lower heat stability.5.3 The technique of specimen rotation described in this test method provides an estimate of the life-temperature relationshipof polypropylene. If this test method is conducted at different temperature
20、s on the same material, a more reliable estimate of thelife-temperature relationship of polypropylene is determined. This test method can be conducted at several temperatures and thedata interpreted through use of the Arrhenius relation, by plotting the logarithms of times to failure against the rec
21、iprocals of thetemperatures in kelvins (K). Temperatures in the range from 100 to 150C, with intervals of 10C, are suggested for this purpose.5.4 The stability as determined under the prescribed test method is not directly related to the suitability of the compound fora use where different condition
22、s prevail.5.5 The specimen rotation technique of thermal aging increases the probability that all specimens will be exposed similarly andthat the effect of temperature gradients in an oven will be minimized.6. Apparatus6.1 Oven, mechanical convection type for controlled circulation of air, with adju
23、stable air intake and exhaust facilities, anddesigned for air velocities around 1000 6 250 1000 mm/s 197(197 6 49 ft/min.ft/min).46.1.1 The oven shall be equipped with a temperature-control system designed to maintain the test temperature range from 1506 1C 302(302 6 1.8F1.8F) and a device to preven
24、t temperature override. With the oven adjusted to the nominal testtemperature of 150C, the override shall be set at 154C 309F.(309F). A bimetallic-strip temperature switch has been foundsatisfactory.6.2 Oven Temperature Measurement System, consisting of a thermocouple, thermometer, or resistance the
25、rmometer as thesensor, together with its associated conditions and readout instrumentation covering at least the temperature range from 0 to 200C32(32 to 372F.372F).6.2.1 The thermometer must cover the range in one-degree subdivisions. It must be tested for bulb stability and standardized,in accorda
26、nce with Test Method E77.6.2.2 The secondary standard shall be ASTM Thermometer S67C03 of Specification E2251.6.2.3 Thermocouples shall comply with the requirements of Specification E608 and shall be calibrated in accordance withMethod E220.6.2.4 Resistance thermometers shall comply with the require
27、ments ofTest Methods E644 and Specification E1137/E1137M, andbe calibrated in accordance with NIST Special Publication 250-22.5,66.3 Molding Press, designed to operate at 200 6 5C 3926 9F.(3926 9F).6.4 Injection Molding Unit, meeting the requirements of Practice D3641.6.5 Mold:6.5.1 Compression Mold
28、, comprised of the following:6.5.1.1 Compression Molding Chase, having a blanked-out area of suitable size (Note 3) and capable of producing a plaque 1.006 0.05 mm 0.039(0.039 6 0.002 in.in.) thick.NOTE 3A 152.4 by 152.4-mm 6(6 by 6-in.6-in.) blanked-out section has been found satisfactory.4 A Preci
29、sion Scientific Freas Model 835 B, or Blue M POM-206C-1, or equivalent, can be used.5 Mangum, B. W., “Platinum Resistance Thermometer Calibration,” NBS Special Publication 250-22 (1987).6 Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 3460, Gaithersburg, M
30、D 20899-3460.D3012 1326.5.1.2 Backing Plates, large enough to cover this chase and strong enough to resist warping or distortion, under the moldingconditions. Polished steel plates, 3 mm 0.1 in.(0.1 in.) thick, are satisfactory.6.5.2 Injection Mold, designed using the guidelines specified in Practic
31、e D3641. The mold shall be capable of producing eithera plaque having a thickness of 1.00 6 0.05 mm 0.039(0.039 6 0.002 in.in.) from which 50 by 10 by 1.00-mm 2 (2 by 0.4 by0.039-in.0.039-in.) specimens maycan be die cut, or mold a standard test specimen, 50 by 10 by 1.00 mm.6.6 Parting SheetsFluoro
32、polymer, polyester, or other film that will not affect the long-term thermal stability of polypropylene,0.05 to 0.20 mm 0.002(0.002 to 0.008 in.in.) thick. The film must be free of wrinkles and foreign matter, such as lubricants andoils.6.7 Cutting Die, to produce 50 by 10-mm 2(2 by 0.4-in.0.4-in.)
33、specimens from either a compression-molded orinjection-molded plaque. The die must be sharp and free of nicks.6.8 Specimen HolderThe specimen holder maycan be biaxially rotated or uniaxially rotated provided that the test specimensare in a stream of air having a relative velocity about 1000 mm/s 197
34、 ft/min.(197 ft/min). Illustrations of suitable apparatus forbiaxially and uniaxially rotated specimen holders are shown in Figs. 1 and 2, respectively. Biaxial rotation increases the probabilitythat all specimens will be exposed similarly. In the case of dispute, the use of biaxial rotation shall b
35、e the reference method.6.8.1 Biaxially Rotated Specimen Holder (see Fig. 1)7. The frequency of rotation about the horizontal and vertical axes shallbe 1 to 3 min1.6.8.2 Uniaxially Rotated Specimen Holder (see Fig. 2). The drum peripheral velocity shall be such that the air stream impingeson the flat
36、 section of the test specimens at about 1 m/s.6.9 Air Velocity Meter, nondirectional resistance wire type for measuring the air velocity in the oven.6.10 Anemometer, with a circular vane, for determining the frequency of air changes in the oven. The anemometer shall bepositioned directly in front of
37、 the oven outlet. Based on the design of the outlet and the anemometer, every effort shall be madeto position the anemometers electronics in a way as to minimize the degree of exposure to the heated air exiting the oven.6.11 Metal Clips, lined with fluorocarbon film or other materials that have no a
38、dverse effect on the oxidative thermal stabilityof polypropylene.7. Specimen Preparation7.1 The test specimens shall be cut from either a compressionmolded plaque or injection-molded plaque prepared fromgranules or other homogeneous molding material. Plaques shall be prepared as follows:7.2 Compress
39、ion Molding:7.2.1 Adjust the temperature of the platens to 200 6 5C 392(392 6 9F.9F).7 Standard Scientific Supply Company, Model CS191, or equivalent, can be used.FIG. 1 Biaxial Ferris-Wheel-Type RotatorD3012 1337.2.2 Place a smooth, clean parting sheet on a backing plate and center the chase on it.
40、 Put enough of the sample into the cavityto fill it completely when molded. A slight excess of material is desirable. Cover the loaded chase first with a clean parting sheetand then a backing plate. Finally, put the assembled mold on the lower platen and close the press carefully until both platens
41、arein contact with the assembly. When the material has melted, apply sufficient pressure to form a void-free plaque in the 1.00 6 0.5mm 0.039(0.039 6 0.002 in.in.) thick and record this pressure. Leave the polypropylene in the heated press under pressure for3 to 4 min at 200 6 5C 392(392 6 9F.9F). F
42、lash cool the mold assembly by transferring to a water-cooled press or by waterquenching.7.3 Injection Molding:7.3.1 Plaques or test specimens shall be injection-molded in accordance with the requirements of Specification D4101.7.4 Prepare a minimum of five specimens per material sample by die-cutti
43、ng specimens from the plaque or directly molding thestandard test specimen. The standard specimen shall be 10 mm wide, 50 mm long, and 1.00 6 0.05 mm thick. Edges shall besmoothed, if necessary, to remove imperfections introduced by cutting.7.5 Test specimens prepared directly by injection molding w
44、ithout die cutting or specimens cut from polypropylene productscan be used as agreed upon between the interested parties. In all cases the referee method will be based on compression moldeddie cut specimens.NOTE 4Failure test times for compression-molded and injection-molded specimens may vary are n
45、ot necessarily comparable due to the skin surfaceeffect and the distinctness or sharpness of the specimen edge.7.6 Specimens of other thicknesses can be used as agreed upon between the interested parties.7.7 In cases of dispute, the referee specimens shall be die-cut only from compression-molded spe
46、cimens, unless the testspecimen is otherwise agreed upon.7.8 In handling the plaques and cut specimens, use clean gloves or tongs to prevent contamination of the test specimens.FIG. 2 Uniaxially Rotated Specimen HolderDrum RotatorD3012 1348. Conditioning8.1 Condition the test specimens in accordance
47、 with Specification D4101. When unsure of the material formulation, conditionthe test specimen at 23 6 2C 73.4(73.4 6 3.6F3.6F) and 50 6 5 % 10 % relative humidity for not less than 40 h prior totest in accordance with Procedure A of Practice D618. In cases of disagreement, the tolerances shall be 6
48、1C 61.8F(61.8F)and 62 %65 % relative humidity.9. Oven Parameters9.1 Unless otherwise specified, the oven temperature shall be 150C 302F(302F) and shall not vary more than 61C,measured at a single location within the oven, or more than 61.5C throughout the oven.9.1.1 To monitor temperature, the oven
49、temperature measurement sensor should be conveniently located about 80 mm 3 in.(3in.) from the top liner of the oven, in the vicinity of the exhaust port.9.2 In the event that the average time to failure at 150C is less than seven days, the test report shall indicate “less than sevendays at 150C” and the test shall be repeated at an oven temperature of 140 6 1C, and, if necessary, at lower temperatures atintervals of 10C until time to failure of seven days is achieved.NOTE 5If it is pr
