1、Designation: D 4440 08Standard Test Method forPlastics: Dynamic Mechanical Properties Melt Rheology1This standard is issued under the fixed designation D 4440; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. 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 outlines the use of dynamic mechanicalinstrumentation in determining and reporting the rheologicalproperties of
3、 thermoplastic resins and other types of moltenpolymers. It may be used as a method for determining thecomplex viscosity and other significant viscoelastic character-istics of such materials as a function of frequency, strainamplitude, temperature, and time. Such properties may beinfluenced by fille
4、rs and other additives.1.2 It incorporates a laboratory test method for determiningthe relevant rheological properties of a polymer melt subjectedto various oscillatory deformations on an instrument of the typecommonly referred to as a mechanical or dynamic spectrom-eter.1.3 This test method is inte
5、nded to provide a means ofdetermining the rheological properties of molten polymers,such as thermoplastics and thermoplastic elastomers over arange of temperatures by nonresonant, forced-vibration tech-niques. Plots of modulus, viscosity, and tan delta as a functionof dynamic oscillation (frequency)
6、, strain amplitude, tempera-ture, and time are indicative of the viscoelastic properties of amolten polymer.1.4 This test method is valid for a wide range of frequencies,typically from 0.01 to 100 Hz.1.5 This test method is intended for homogenous andheterogeneous molten polymeric systems and compos
7、ite for-mulations containing chemical additives, including fillers,reinforcements, stabilizers, plasticizers, flame retardants, im-pact modifiers, processing aids, and other important chemicaladditives often incorporated into a polymeric system forspecific functional properties, and which could affe
8、ct theprocessability and functional performance. These polymericmaterial systems have molten viscosities typically less than 106Pas (107poise).1.6 Apparent discrepancies may arise in results obtainedunder differing experimental conditions. Without changing theobserved data, reporting in full (as des
9、cribed in this testmethod) the conditions under which the data was obtained mayenable apparent differences observed in another study to bereconciled.1.7 Test data obtained by this test method are relevant andappropriate for use in engineering design.1.8 The values stated in SI units are to be regard
10、ed as thestandard. The values given in parentheses are for informationonly.1.9 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 determin
11、e the applica-bility of regulatory limitations prior to use.NOTE 1This test method is equivalent to ISO 6721, Part 10.2. Referenced Documents2.1 ASTM Standards:2D 4000 Classification System for Specifying Plastic Mate-rialsD 4065 Practice for Plastics: Dynamic Mechanical Proper-ties: Determination a
12、nd Report of ProceduresD 4092 Terminology for Plastics: Dynamic MechanicalPropertiesE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:3ISO 6721, Part 10 Plastics Determination of DynamicMechanical Properties, Part 10, Complex Shear Visc
13、osityUsing a Parallel-Plate Oscillatory Rheometer3. Terminology3.1 Definitions: Definitions are in accordance with Termi-nology Standard D 4092.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Propertie
14、s.Current edition approved Aug. 1, 2008. Published September 2008. Originallyapproved in 1984. Last previous edition approved in 2007 as D 4440 - 07.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda
15、rds volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM Int
16、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 A known amount of thermoplastic polymer (moltenpowder or pellet, or solid preform disk) is placed in mechanicaloscillation at a fixed or varying frequency at isothermalconditi
17、ons or over a linear temperature increase or a time-temperature relation simulating a processing condition. Storage(elastic) modulus, G8 or loss (viscous) modulus, G88, or both,or the corresponding dynamic viscosity functions n8 =g88/wand n88 =g8/w, of the polymeric material specimen are mea-sured i
18、n shear as a function of frequency, strain, temperature,or time.5. Significance and Use5.1 This test method provides a simple means of character-izing the important rheological properties and viscosity ofthermoplastic polymers using very small amounts of material(approximately 25 to 50 mm in diamete
19、r by 1 to 3 mm inthickness . approximately 3 to 5 g). Data may be used forquality control, research and development, and establishmentof optimum processing conditions.5.2 Dynamic mechanical testing provides a sensitivemethod for determining molten polymer properties by measur-ing the elastic and los
20、s moduli as a function of frequency,strain, temperature, or time. Plots of viscosity, storage, and lossmoduli, and tan delta as a function of the aforementionedprocess parameters provide graphical representation indicativeof molecular weight, molecular weight distribution, effects ofchain branching,
21、 and melt-processability for specified condi-tions.5.3 Values obtained in this test method can be used to assessthe following:5.3.1 Complex viscosity of the polymer melt as a functionof dynamic oscillation,5.3.2 Processing viscosity, minimum as well as changes inviscosity as a function of experiment
22、al parameters,5.3.3 Effects of processing treatment,5.3.4 Relative polymer behavioral properties, including vis-cosity and damping, and5.3.5 Effects of formulation additives that might affectprocessability or performance.5.4 Before proceeding with this test method, referenceshould be made to the spe
23、cification of the material being tested.Any test specimen preparation, conditioning, dimensions, ortesting parameters, or combination thereof, covered in therelevant ASTM materials specification shall take precedenceover those mentioned in the test method. If there are norelevant ASTM material speci
24、fications, then the default condi-tions apply.6. Interferences6.1 Since small quantities of polymer are used, it is essentialthat the specimens be homogeneous and representative.6.2 Toxic or corrosive effluents, or both, may be releasedwhen heating the polymer specimen to its molten state andcould b
25、e harmful to personnel or to the instrumentation.6.3 Entrapped air/gas may affect the results obtained usingpowder or pellet-type samples.7. Apparatus7.1 The function of the apparatus is to hold a moltenpolymer of known volume and dimensions so that the materialacts as the elastic and dissipative el
26、ement in a mechanicallydriven oscillatory system, as outlined in Practice D 4065.These instruments operate in one or more of the followingmodes for measuring rheological behavior in dynamic oscilla-tory shear: (1) forced constant amplitude, fixed frequency, (2)forced constant amplitude, varying freq
27、uency, and (3) forcedvarying amplitude, fixed frequency.7.2 The apparatus shall consist of the following:7.2.1 Test FixturesA choice of either polished cone andplate (having a known cone angle) or parallel plates havingeither smooth, polished, or serrated surfaces. Variations of thistooling, such as
28、 bottom plates with concentric overflow rims,can be used as necessary.7.2.2 Oscillatory Deformation (Strain)A device for ap-plying a continuous oscillatory deformation (strain) to thespecimen.7.2.3 DetectorsA device or devices for determining de-pendent and independent experimental parameters, such
29、asforce (stress or strain), frequency, and temperature. Tempera-ture should be measurable with a precision of 61C, frequencyto 61 %, strain to 61 %, and force to 61%.7.2.4 Temperature Controller and OvenA device for con-trolling the specimen temperature, either by heating (in steps orramps), cooling
30、 (in steps or ramps), or maintaining a constantspecimen environment, or a combination thereof. Fig. 1 illus-trates several time-temperature profiles. A temperature pro-grammer should be sufficiently stable to permit measurementof sample temperature to 1C.7.3 Nitrogen, or other gas supply for purging
31、 purposes, ifappropriate.8. Test Specimens8.1 The molten polymer composition should be both homo-geneous and representative.8.2 Due to various geometries that might be used fordynamic mechanical characterization of molten polymericsystems, size is not fixed by this test method; however, sampleFIG. 1
32、 Rheological Properties of a Polymer MeltD4440082geometry (diameter and thickness) should be reported for anyseries of comparisons.8.3 Serrated tooling might be used for materials exhibitinginterfacial slippage due to high modulus (as when approachinga solidified state).9. Calibration9.1 Calibrate t
33、he instrument using procedures recommendedby the manufacturer.10. Procedure10.1 Lower the upper test fixture so that it is just touchingthe bottom fixture. Zero the gap indicator dial.10.2 If a dynamic temperature sweep (linear heating rate orramp temperature scan) is required for the specimen, then
34、 thegap setting must be corrected for the thermal expansion of thesupport fixtures during testing.10.2.1 Determine the thermal expansion of the fixtures atthe temperature sweep conditions to be used during testing.Record the gap-setting reading at the time and temperaturecorresponding to computer ca
35、lculation of the viscoelasticproperties, while maintaining a fixed normal force between thetest fixtures.10.2.2 Plot the gap-separation reading, due to thermal ex-pansion of the fixtures, as a function of temperature.10.2.3 Adjust the upper test fixture during the test in orderto maintain a fixed sa
36、mple thickness, if necessary.10.3 Apply an adequate amount of polymer material ontothe test fixture. Be certain that there is sufficient material tocover the bottom plate uniformly.10.4 Bring down the upper test fixture so that it is touchingthe polymeric material.10.4.1 A gap setting from 1 to 3 mm
37、 is a good operatingrange for parallel plate geometry. This gap setting is arbitraryand dependent on the type of material being characterized. Agap setting of 0.5 mm would be a minimum. However, whenlarge platens and low-viscosity materials are being used, therecommended minimum gap setting is 0.25
38、mm.10.4.2 Cone and plate experiments should be conducted atan isothermal temperature. Any change in the temperaturesetting will require adjustment of the gap at the new tempera-ture.10.4.3 Remove excess material flush to the test fixturesusing a razor blade, spatula, knife, or hot soldering iron, as
39、appropriate.10.5 Isothermal Evaluations at Elevated Temperature:10.5.1 In cases where the specimen can be introduceddirectly into the test chamber at elevated temperatures, preheatand stabilize the chamber to the desired temperature prior tointroducing the test specimen.10.5.2 Ramped or Simulated Pr
40、ocess Program HeatingFor materials that are to be characterized starting at a lowtemperature, and controlled for either a linear ramp or step-and-hold function, the material should be applied to the testtooling and the test chamber closed and heated at the desiredrate. Temperature should be monitore
41、d during this heat-up.Thermal gradients of 3 to 5C/min are recommended formeasuring the rheological properties. For both isothermal andsimulated processing conditions, measurements should bediscontinued when the polymeric composition exhibits dete-rioration, degradation, or decomposition since the d
42、egradationof the polymer will affect the test results.10.6 Maximum strain amplitude should be within the linearviscoelastic range of the material. Automated strain sweepsmay be conducted to determine the strain sensitivity of thepolymeric material. This is especially helpful for characteriz-ing the
43、effects of fillers and for monitoring crystallization as themolten polymer slowly cools down.10.7 Duplicate measurements are recommended.11. Calculation11.1 The following equations listed in Practice D 4065 areused to calculate the important rheological properties measuredin forced, nonresonant dyna
44、mic oscillation:11.1.1 Storage (elastic) modulus, G8,11.1.2 Loss (viscous) modulus, G88,11.1.3 Tan delta, d,11.1.4 Complex modulus, G*,11.1.5 Complex viscosity, h*, and11.1.6 Dynamic viscosity, n8,n88.11.2 Plot the moduli, tan delta, and viscosity as a function ofeither frequency, strain amplitude,
45、temperature, or time, asrequired.An example of typical data representation is shown inFig. 1.12. Report12.1 Report the following information:12.1.1 Complete identification and description of the mate-rial tested including the name, stock or code number, datemade, form, source, etc., if available.12.
46、1.2 Description of the instrument used for the test.12.1.3 Dimensions of the sample geometry and type oftooling.12.1.4 Description of the calibration procedure.12.1.5 Identification of the sample atmosphere by gas com-position, purity, and rate used, if appropriate.12.1.6 Details of conditioning the
47、 specimen prior to test.12.1.7 The temperature used in the analysis, the thermalgradient if any, and the time for the specimen to reachequilibrium.12.1.8 Table of data and results, including the moduli,complex viscosity, and tan delta as a function of the dynamicoscillation (frequency), percent stra
48、in, temperature, or time, asappropriate.12.1.9 Number of specimens tested.12.1.10 A plot of the rheological behavior versus experi-mentally controlled independent variable(s) for multiple stud-ies.12.1.11 Frequency of test or frequency range.12.1.12 Strain amplitude or range.12.1.13 Date of test.13.
49、 Precision and Bias413.1 Table 1 is based on a round robin conducted in 2007 inaccordance with Practice E 691, involving five materials tested4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D201246.D4440083by eight laboratories. For each material, all the samples wereprepared at one source, but the individual specimens wereprepared at the laboratories that tested them. Each test resultwas the average of three individual determinations. Eachlaboratory obtained three test results for each material.(War
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