1、Designation: D 926 04Standard Test Method forRubber PropertyPlasticity and Recovery (Parallel PlateMethod)1This standard is issued under the fixed designation D 926; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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. Scope1.1 This test method covers the determination
3、 of plasticityand recovery of unvulcanized rubber by means of the parallelplate plastometer. Uncompounded, compounded, and reclaimrubber may be tested.NOTE 1ISO 2007 and D 3194 use a principle similar to this testmethod although the apparatus, test conditions, and procedure are differ-ent.1.2 The va
4、lues stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.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 safet
5、y and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 3194 Test Method for Rubber From Natural SourcesPlasticity Retention Index (PRI)D 3767 Practice for Rubber-Measurement of DimensionsD 4483 Practice for Determin
6、ing Precision for Test MethodStandards in the Rubber and Carbon Black IndustriesE 145 Specification for Gravity-Convection and Forced-Ventilation Ovens2.2 ISO Standard:32007 Rubber UnvulcanizedDetermination of PlasticityRapid Plastimeter Method3. Summary of Test Method3.1 Plasticity:3.1.1 A specimen
7、 of specific volume and height is tested atroom temperature or heated to a specified test temperature for15 min and then subjected to a compressive force of 49 N fora specified time.3.1.2 At the end of this time, the height of the specimen ismeasured, and the plasticity number is calculated.3.2 Reco
8、veryThere are two recovery procedures.3.2.1 Procedure AThe test specimen is removed from theplastometer immediately after the determination of plasticityand allowed to cool and recover some of its original height for1 min. The height is measured again and the recovery iscalculated.3.2.2 Procedure BT
9、he test specimen is compressed to aheight of 5 mm for 30 s and then allowed to recover at the testtemperature for 5 min. The height is measured again and therecovery is calculated.4. Significance and Use4.1 The plasticity number and the recovery of the testspecimen are related to the flow properties
10、 and the elasticproperties, respectively, and may be useful in predictingprocessing characteristics, such as ease of forming and extru-sion characteristics.4.1.1 In this test method, plasticity is measured in an inversemanner, as noted by the final height of the specimen. Thus,high plasticity rubber
11、s (high degree of flow during test) areindicated by a low plasticity number.5. 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 thicknessand 40 mm in diameter, shall be mounted on a suitable fra
12、meso that one plate moves with respect to the other, and so that thetwo plates are parallel within 0.017 rad (1) at all times.5.1.2 The apparatus shall be so designed that a specimenbetween the parallel plates is subjected to a force of 49 6 0.5N, including the effect of the spring in the dial gage
13、during test.1This test method is under the jurisdiction of ASTM committee D11 on Rubberand is the direct responsibility of Subcommittee D11.12 in Processability Tests.Current edition approved June 1, 2004. Published June 2004. Originallyapproved in 1956. Last previous edition approved in 2002 as D 9
14、26 02.2For 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.3Available from American National Standards Institute,
15、25 West 43rd St., 4thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.3 A digital or dial indicator gage calibrated in hun-dredths of a millimetre (0.01 mm) shall be mounted on theapparatus in such a mann
16、er that the distance between the platescan be determined at all times.5.1.4 When required, the apparatus shall be operated in anyoven, as described in Specification E 145, that is capable ofcontaining the plastometer.5.1.5 A separate dimensional measurement gage is requiredfor performing recovery me
17、asurements. The apparatus andmethodology described in Practice D 3767, Procedure A, shallbe employed when performing these measurements.5.2 Test SurfacesFilms or material with low coefficientsof friction to prevent sticking of the test specimen to the plates.The most commonly used test surface is po
18、lyester film.4NOTE 2The test surface used can affect the plasticity number. Evendifferent grades of the same type of polyester film can cause differentresults. When comparing results, the same test surface must be used.6. Sampling6.1 Samples may be taken from raw rubber or unvulcanizedrubber compoun
19、ds undergoing processing operations.7. Test Specimens7.1 The specimen shall be a right cylinder 2.00 6 0.02 cm3in volume and be free from air pockets. (A cylinder 16 mm indiameter and 10 mm in height is appropriate.) The specimenmay be prepared from either a solid piece or plied sheets ofunvulcanize
20、d rubber approximately 1.5 mm in thickness, carebeing taken to exclude air pockets in the sheet. The specimensmay be cut from the sheet either by means of two mating diesconforming to Fig. 2, which produce cylinders of the correctvolume, or a rotating die having an internal diameter ofapproximately
21、16 mm. If a rotating die is used, the height of thecylinder shall be adjusted until the volume is 2.00 6 0.02 cm3.If the density is known, weighing may be used to adjust to thecorrect volume. If necessary, the specimen shall be placed in asuitable holder so that it is not appreciably deformed before
22、testing.8. Test Conditions8.1 The plasticity and recovery values obtained for a givensample will depend largely upon the manner in which the testspecimen is prepared. It is therefore imperative that whencomparisons are made between similar materials, the testspecimen preparation should be in accorda
23、nce with somerigidly specified method. This is necessary because the plas-ticity and recovery may be affected by the amount of mechani-cal working and the conditions under which such work is done.This effect is not constant for all materials. The time intervalbetween test specimen preparation and te
24、sting is important andshould be the same for test specimens between which com-parisons are to be made.8.2 The test temperature shall be 23 (room temperature), 40,70, 85, or 100C unless another temperature is agreed upon.The most frequently used temperature is 23C.8.3 Readings may be taken at any des
25、ired interval followingthe application of the load. The most frequently used intervalsare between 3 and 10 min.9. Plasticity Procedure9.1 Set the indicator to read zero with two thicknesses of thetest surface between the plates. Condition the plastometer atthe test temperature until temperature equi
26、librium is achieved.9.2 Place the test specimen between the two test surfaces toprevent sticking of the test specimen to the plates.9.3 If required, condition the test specimen at the testtemperature for 15 6 0.5 min.9.4 Quickly place the test specimen between the two paral-lel plates, lower the mas
27、s, and at the end of the required time4Mylar 300A polyester film has been found satisfactory for this purpose.FIG. 1 One Type of Parallel Plate PlastometerFIG. 2 Die for Forming Test SpecimenD926042interval, read the thickness gage to hundredths of a millimetre.Record the height of the specimen in m
28、illimetres as h1.9.5 Calculate plasticity, P, as follows:P 5 100h1(1)10. Recovery Procedures10.1 Recovery values may be determined by the proceduredescribed 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 inSection 9, immediat
29、ely remove the test specimen from theplastometer and allow it to cool exactly 1 min at 23 6 2C.Then measure the height of the specimen with the two testsurfaces using the dial micrometer gage specified in 5.1.5.Record this reading as h2.10.2.2 Calculate recovery, RA, as follows:RA5 100 h22 h1! (2)10
30、.3 Procedure B:10.3.1 Follow the procedure described in Section 9 fordetermining plasticity, except that the test specimen shall becompressed to a height of 5 mm for 30 s. This may be done byplacing three spacers 5.00 6 0.01 mm in thickness on twothicknesses of test surface at suitable positions bet
31、ween theplates to ensure parallelism and prevent misalignment of theplates.10.3.2 At the end of the compression period, remove thespecimen from between the plates and permit it to recover for5 min at the test temperature.10.3.3 At the end of the 5-min recovery period, measure theheight of the specim
32、en with the micrometer gage specified in5.1.5. Record as h3.10.3.4 Calculate recovery, RB, as follows:RB5 100 h32 5! (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,1
33、1.1.1.3 Preparation method of the test piece (plied orsolid), 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 testpiece,11.1.2.4 Recovery time, in minutes, and11.1.2.5 Da
34、te of the test.11.1.3 Test Results:11.1.3.1 Plasticity number, P, and11.1.3.2 Recovery number, RAor RB.12. Precision and Bias12.1 These precision and bias statements have been pre-pared in accordance with Practice D 4483. Please refer toPractice D 4483 for terminology and other testing and statisti-
35、cal concept explanations.12.2 The Type 1 precision was determined from an inter-laboratory study of three compounds that were mixed in onelaboratory. Four laboratories prepared samples and tested eachcompound.12.3 A “test result” for this plasticity and recovery testingrepresents one measurement wit
36、h a parallel plate plastometer.12.4 Table 1 lists the precision data. A Type 1 precision, asdefined in Practice D 4483, includes as components of varia-tion, the specimen preparation and testing operation withineach laboratory, but not the mixing or compound preparationcomponents of variation.12.5 T
37、he precision of this test method may be expressed inthe format of the following statements which use an “appro-priate value” of r, R,(r), or (R), that is, that value to be used indecisions about test results (obtained with the test method).The appropriate value is that value of r or R associated wit
38、h amean level in Table 1 closest to the mean level underconsideration (at any given time, for any given material) inroutine testing operations.12.6 RepeatabilityThe repeatability, r, of this test methodhas been established as the appropriate value tabulated in Table1. Two single test results, obtain
39、ed under normal test methodprocedures, that differ by more than this tabulated r (for anygiven level) must be considered as derived from different ornon-identical sample populations.12.7 ReproducibilityThe reproducibility, R, of this testmethod has been established as the appropriate value tabulated
40、in Table 1. Two single test results obtained in two differentlaboratories, under normal test method procedures, that differby more than the tabulated R (for any given level) must beconsidered to have come from different or non-identical samplepopulations.12.8 Repeatability and reproducibility expres
41、sed as a per-cent 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 apercent of the arithmetic mean of the two test results.12.9 BiasIn test method terminology, bias
42、 is the differ-ence between an average test value and the reference (or true)test property value. Reference values do not exist for this testmethod since the values of plasticity and recovery are exclu-sively defined by the test method. Bias, therefore, cannot bedetermined.13. Keywords13.1 elastic p
43、roperties; flow properties; parallel plate plas-tometer; plasticity; plasticity and recovery; plastometer; Will-iams plastometerD926043ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this stand
44、ard 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 time by the responsible technical committee and must be reviewed every five years andi
45、f not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, wh
46、ich you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
47、United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Type 1 PrecisionTestTest Tem-perature,
48、 CRangeof ValuesAWithin LaboratoryBBetween LaboratoryBSrr (r)BSRR (R)CPlasticity 70 415755 22.7 64.2 11.0 64.2 181.7 31.1Plasticity 100 350630 17.7 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 54.0AUnits = mm 3 100.BSr= repeatab
49、ility standard deviation, in measurement units.r = repeatability in measurement units.(r) = repeatability (relative) percent.SR= reproducibility standard deviation, in measurement units.R = reproducibility in measurement units.(R) = reproducibility (relative) percent.CMidpoint of range used to calculate (r) and (R).D926044
