1、Designation: D926 08 (Reapproved 2013)D926 17Standard Test Method forRubber PropertyPlasticity and Recovery (Parallel PlateMethod)1This standard is issued under the fixed designation D926; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test meth
3、od covers the determination of plasticity and recovery of unvulcanized rubber by means of the parallel plateplastometer. Uncompounded, compounded, and reclaim rubber may be tested.NOTE 1ISO 2007 and Test Method D3194 use a principle similar to this test method although the apparatus, test conditions
4、 and procedure aredifferent.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 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
5、 this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished
6、in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3194 Test Method for Rubber From Natural SourcesPlasticity Retention
7、Index (PRI)D3767 Practice for RubberMeasurement of DimensionsD4483 Practice for Evaluating Precision for Test Method Standards in the Rubber and Carbon Black Manufacturing IndustriesE145 Specification for Gravity-Convection and Forced-Ventilation Ovens2.2 ISO Standard:3ISO 2007 Rubber UnvulcanizedDe
8、termination of PlasticityRapid Plastimeter Method3. Summary of Test Method3.1 Plasticity:3.1.1 A specimen of specific volume and height is tested at room temperature or heated to a specified test temperature for 15min and then subjected to a compressive force of 49 N for a specified time.3.1.2 At th
9、e end of this time, the height of the specimen is measured, and the plasticity number is calculated.3.2 RecoveryThere are two recovery procedures.3.2.1 Procedure AThe test specimen is removed from the plastometer immediately after the determination of plasticity andallowed to cool and recover some o
10、f its original height for 1 min. The height is measured again and the recovery is calculated.3.2.2 Procedure BThe test specimen is compressed to a height of 5 mm for 30 s and then allowed to recover at the testtemperature for 5 min. The height is measured again and the recovery is calculated.1 This
11、test method is under the jurisdiction of ASTM committee D11 on Rubber and Rubber-like Materials and is the direct responsibility of Subcommittee D11.12 inProcessability Tests.Current edition approved Nov. 1, 2013Oct. 1, 2017. Published January 2014November 2017. Originally approved in 1956. Last pre
12、vious edition approved in 20082013as D926 08.D926 08 (2013). DOI: 10.1520/D0926-08R13.10.1520/D0926-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards
13、Document Summary page on the ASTM website.3 Available from American National Standards Institute, 25 West 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 indication of what changes have been made to the pre
14、vious 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 be considered the official document.Copyright ASTM I
15、nternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 The plasticity number and the recovery of the test specimen are related to the flow properties and the elastic properties,respectively, and may be useful in predicting process
16、ing characteristics, such as ease of forming and extrusion characteristics.4.1.1 In this test method, plasticity is measured in an inverse manner, as noted by the final height of the specimen. Thus, highplasticity rubbers (high degree of flow during test) are indicated by a low plasticity number.5.
17、Apparatus5.1 The essential features of the parallel plate plastometer, illustrated in Fig. 1, are as follows:5.1.1 Two metal plates, not less than 10 mm in thickness and 40 mm in diameter, shall be mounted on a suitable frame so thatone plate moves with respect to the other, and so that the two plat
18、es are parallel within 0.017 rad (1) at all times.5.1.2 The apparatus shall be so designed that a specimen between the parallel plates is subjected to a force of 49 6 0.5 N,including the effect of the spring in the dial gauge during test.5.1.3 A digital or dial indicator gauge calibrated in hundredt
19、hs of a millimetre (0.01 mm) shall be mounted on the apparatusin such a manner that the distance between the plates can be determined at all times.5.1.4 When required, the apparatus shall be operated in any oven, as described in Specification E145, that is capable ofcontaining the plastometer.5.1.5
20、A separate dimensional measurement gauge is required for performing recovery measurements. The apparatus andmethodology described in Practice D3767, Procedure A, shall be employed when performing these measurements.5.2 Test SurfacesFilms or material with low coefficients of friction shall be used to
21、 prevent sticking of the test specimen tothe plates. The most commonly used test surface is polyester film. Other films such as cellophane or nylon may be used. The testsurface film shall have a thickness of 0.25 6 0.005 mm.NOTE 2The test surface used can affect the plasticity number. Even different
22、 grades of the same type of film can cause different results. Whencomparing results, the same test surface must be used.6. Sampling6.1 Samples may be taken from raw rubber or unvulcanized rubber compounds undergoing processing operations.FIG. 1 One Type of Parallel Plate PlastometerD926 1727. Test S
23、pecimens7.1 The specimen shall be a right cylinder 2.00 6 0.02 cm3 in volume and be free from air pockets. (A cylinder 16 mm indiameter and 10 mm in height is appropriate.) The specimen may be prepared from either a solid piece or plied sheets ofunvulcanized rubber approximately 1.5 mm in thickness,
24、 care being taken to exclude air pockets in the sheet. The specimens maybe cut from the sheet either by means of two mating dies conforming to Fig. 2, which produce cylinders of the correct volume,or a rotating die having an internal diameter of approximately 16 mm. If a rotating die is used, the he
25、ight of the cylinder shall beadjusted until the volume is 2.00 6 0.02 cm3. If the density is known, weighing may be used to adjust to the correct volume. Ifnecessary, the specimen shall be placed in a suitable holder so that it is not appreciably deformed before testing.8. Test Conditions8.1 The pla
26、sticity and recovery values obtained for a given sample will depend largely upon the manner in which the testspecimen is prepared. It is therefore imperative that when comparisons are made between similar materials, the test specimenpreparation should be in accordance with some rigidly specified met
27、hod. This is necessary because the plasticity and recovery maybe affected by the amount of mechanical working and the conditions under which such work is done. This effect is not constantfor all materials. The time interval between test specimen preparation and testing is important and should be the
28、 same for testspecimens between which comparisons are to be made.8.2 The test temperature shall be 23 25 6 5C (room temperature), or 40, 70, 85, or 100C 100 6 2C unless anothertemperature is agreed upon. The most frequently used temperature is 23C.25C. When comparing test results, the sametemperatur
29、e conditions shall be used.8.3 Readings may be taken at any desired interval following the application of the load. The most frequently used intervals arebetween 3 and 10 min.9. Plasticity Procedure9.1 Set the indicator to read zero with two thicknesses of the test surface between the plates. Condit
30、ion the plastometer at thetest temperature until temperature equilibrium is achieved.9.2 Place the test specimen between the two test surfaces to prevent sticking of the test specimen to the plates.9.3 If required, condition the test specimen at the test temperature for 15 6 0.5 min.9.4 Quickly plac
31、e the test specimen between the two parallel plates, lower the mass, and at the end of the required time interval,read the thickness gauge to hundredths of a millimetre. Record the height of the specimen in millimetres as h1.9.5 Calculate plasticity, P, as follows:P 5100h1 (1)10. Recovery Procedures
32、10.1 Recovery values may be determined by the procedure described in either 10.2 or 10.3, but the results will differ.10.2 Procedure A:10.2.1 After determining the plasticity as described in Section 9, immediately remove the test specimen from the plastometerand allow it to cool exactly 1 min at 23
33、6 2C. Then measure the height of the specimen with the two test surfaces using the dialmicrometer gauge specified in 5.1.5. Record this reading as h2.10.2.2 Calculate recovery, RA, as follows:FIG. 2 Die for Forming Test SpecimenD926 173RA5100 h22h1! (2)10.3 Procedure B:10.3.1 Follow the procedure de
34、scribed in Section 9 for determining plasticity, except that the test specimen shall be compressedto a height of 5 mm for 30 s. This may be done by placing three spacers 5.00 6 0.01 mm in thickness on two thicknesses of testsurface at suitable positions between the plates to ensure parallelism and p
35、revent misalignment of the plates.10.3.2 At the end of the compression period, remove the specimen from between the plates and permit it to recover for 5 minat the test temperature.10.3.3 At the end of the 5-min recovery period, measure the height of the specimen with the micrometer gauge specified
36、in5.1.5. Record as h3.10.3.4 Calculate recovery, RB, as follows:RB5100 h325! (3)11. Report11.1 Report the following information:11.1.1 Sample Identification:11.1.1.1 A full description of the sample and its origin,11.1.1.2 Compound details, where appropriate,11.1.1.3 Preparation method of the test p
37、iece (plied or solid), and11.1.1.4 Time between preparation and test.11.1.2 Test Conditions:11.1.2.1 Test surface used,11.1.2.2 Test temperature,11.1.2.3 Time, in minutes, the force was applied to the test piece,11.1.2.4 Recovery time, in minutes, and11.1.2.5 Date of the test.11.1.3 Test Results:11.
38、1.3.1 Plasticity number, P, and11.1.3.2 Recovery number, RA or RB.12. Precision and Bias12.1 These precision and bias statements have been prepared in accordance with Practice D4483. Please refer to Practice D4483for terminology and other testing and statistical concept explanations.12.2 The Type 1
39、precision was determined from an interlaboratory study of three compounds that were mixed in one laboratory.Four laboratories prepared samples and tested each compound.12.3 A “test result” for this plasticity and recovery testing represents one measurement with a parallel plate plastometer.12.4 Tabl
40、e 1 lists the precision data. AType 1 precision, as defined in Practice D4483, includes as components of variation, thespecimen preparation and testing operation within each laboratory, but not the mixing or compound preparation components ofvariation.12.5 The precision of this test method may be ex
41、pressed in the format of the following statements which use an “appropriatevalue” of r,R, (r), or (R), that is, that value to be used in decisions about test results (obtained with the test method). Theappropriate value is that value of r or R associated with a mean level in Table 1 closest to the m
42、ean level under consideration (atany given time, for any given material) in routine testing operations.TABLE 1 Type 1 PrecisionTest Test Tem-perature, C Rangeof ValuesA Within LaboratoryB Between LaboratoryBSr r (r)B SR R (R)CPlasticity 70 415755 22.7 64.2 11.0 64.2 181.7 31.1Plasticity 100 350630 1
43、7.7 50.1 10.2 25.5 72.2 14.7Recovery 70 50250 28.6 80.9 54.0 55.7 157.6 105.0Recovery 100 30190 15.8 44.7 40.6 21.0 59.4 54.0A Units = mm 100.B Sr = repeatability standard deviation, in measurement units.r = repeatability in measurement units.(r) = repeatability (relative) percent.SR = reproducibili
44、ty standard deviation, in measurement units.R = reproducibility in measurement units.(R) = reproducibility (relative) percent.C Midpoint of range used to calculate (r) and (R).D926 17412.6 RepeatabilityThe repeatability, r, of this test method has been established as the appropriate value tabulated
45、in Table 1.Two single test results, obtained under normal test method procedures, that differ by more than this tabulated r (for any given level)must be considered as derived from different or non-identical sample populations.12.7 ReproducibilityThe reproducibility, R, of this test method has been e
46、stablished as the appropriate value tabulated in Table1. Two single test results obtained in two different laboratories, under normal test method procedures, that differ by more than thetabulated R (for any given level) must be considered to have come from different or non-identical sample populatio
47、ns.12.8 Repeatability and reproducibility expressed as a percent of the mean level, (r) and (R), have equivalent applicationstatements as above for r and R. For the (r) and (R) statements, the difference in the two single test results is expressed as a percentof the arithmetic mean of the two test r
48、esults.12.9 BiasIn test method terminology, bias is the difference between an average test value and the reference (or true) testproperty value. Reference values do not exist for this test method since the values of plasticity and recovery are exclusively definedby the test method. Bias, therefore,
49、cannot be determined.13. Keywords13.1 elastic properties; flow properties; parallel plate plastometer; plasticity; plasticity and recovery; plastometer; WilliamsplastometerASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any
