1、Designation: D4473 08 (Reapproved 2016)Standard Test Method forPlastics: Dynamic Mechanical Properties: Cure Behavior1This standard is issued under the fixed designation D4473; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 method covers th
3、e use of dynamic-mechanical-oscillation instrumentation for gathering and reporting thethermal advancement of cure behavior of thermosetting resin.It may be used for determining the cure properties of bothunsupported resins and resins supported on substrates sub-jected to various oscillatory deforma
4、tions.1.2 This test method is intended to provide a means fordetermining the cure behavior of supported and unsupportedthermosetting resins over a range of temperatures by freevibration as well as resonant and nonresonant forced-vibrationtechniques, in accordance with Practice D4065. Plots ofmodulus
5、, tan delta, and damping index as a function oftime/temperature are indicative of the thermal advancement orcure characteristics of a resin.1.3 This test method is valid for a wide range of frequencies,typically from 0.01 to 100 Hz. However, it is stronglyrecommended that low-frequency test conditio
6、ns, generallybelow 1.5 Hz, be utilized as they generally will result in moredefinitive cure-behavior information.1.4 This test method is intended for resin/substrate compos-ites that have an uncured effective elastic modulus in sheargreater than 0.5 MPa.1.5 Apparent discrepancies may arise in result
7、s obtainedunder differing experimental conditions. These apparent differ-ences from results observed in another study can usually bereconciled, without changing the observed data, by reporting infull (as described in this test method) the conditions underwhich the data were obtained.1.6 Due to possi
8、ble instrumentation compliance, especiallyin the compressive mode, the data generated may indicaterelative and not necessarily absolute property values.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 reg
9、arded as thestandard.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 determine the applica-bility of regulatory limitations prior t
10、o use. Specific precau-tionary statements are given in Note 5.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D4000 Classification System for Specifying Plastic Materi-alsD4065 Practice for Plastics: Dynamic Mechanical Proper-ties: Determination and
11、 Report of ProceduresD4092 Terminology for Plastics: Dynamic MechanicalPropertiesASTM/IEEE SI10 Standard for Use of the InternationalSystem of Units (SI): The Modern Metric System3. Terminology3.1 DefinitionsFor definitions applicable to this testmethod refer to Terminology D4092.4. Summary of Test
12、Method4.1 A known amount of thermosetting liquid resin or resin-impregnated substrate is placed in mechanical oscillation ateither a fixed or natural resonant frequency or by free vibrationand at either isothermal conditions, with a linear temperatureincrease or using a time-temperature relation sim
13、ulating aprocessing condition. The elastic or loss modulus, or both, ofthe composite specimen are measured in shear or compressionas a function of time. The point in time when tan delta ismaximum, and the elastic modulus levels off after an increase,is calculated as the gel time of the resin under t
14、he conditions ofthe test.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved Nov. 1, 2016. Published November 2016. Originallyapproved in 1985. Last previous edition app
15、roved in 2008 as D4473 - 08. DOI:10.1520/D4473-08R16.2For 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.*A Summa
16、ry 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 States1NOTE 2The particular method for measuring the elastic and lossmoduli and tan delta depends upon the individual instruments operat
17、ingprinciples.5. Significance and Use5.1 This test method provides a simple means of character-izing the cure behavior of thermosetting resins using very smallamounts of material (fewer than 3 to 5 g). The data obtainedmay be used for quality control, research and development, andestablishment of op
18、timum processing conditions.5.2 Dynamic mechanical testing provides a sensitivemethod for determining cure characteristics by measuring theelastic and loss moduli as a function of temperature or time, orboth. Plots of cure behavior and tan delta of a material versustime provide graphical representat
19、ion indicative of cure behav-ior under a specified time-temperature profile.5.3 This test method can be used to assess the following:5.3.1 Cure behavior, including rate of cure, gel, and curetime.5.3.2 Processing behavior, as well as changes as a functionof time/temperature.NOTE 3The presence of the
20、 substrate prevents an absolute measure,but allows relative measures of flow behavior during cure.5.3.3 The effects of processing treatment.5.3.4 Relative resin behavioral properties, including curebehavior and damping.5.3.5 The effects of substrate types on cure.NOTE 4Due to the rigidity of a suppo
21、rting braid, the gel time obtainedfrom dynamic mechanical traces will be longer than actual gel time of theunsupported resin measured at the same frequency. This difference will begreater for composites having greater support-to-polymer rigidity ratios.35.3.6 Effects of formulation additives that mi
22、ght affectprocessability or performance.5.4 For many materials, there may be a specification thatrequires the use of this test method, but with some proceduralmodifications that take precedence when adhering to thespecification. Therefore, it is advisable to refer to that materialspecification befor
23、e using this test method. Table 1 of Classi-fication System D4000 lists the ASTM materials standards thatcurrently exist.6. Interferences6.1 Since small quantities of resin are used, it is essentialthat the specimens be representative of the polymeric materialbeing tested.6.2 The result is a respons
24、e of the thermal advancement orcure behavior of the resin in combination with any substrateused to support the resin.7. Apparatus7.1 The function of the apparatus is to hold a neat (unmodi-fied) resin or uncured supported composite formulation orcoated substrate of known volume and dimensions. The m
25、ate-rial acts as the elastic and dissipative element in a mechanicallydriven oscillatory shear or dynamic compression system. Thesedynamic mechanical instruments operate in one or more of thefollowing modes for measuring cure behavior in torsional shearor dynamic compression:7.1.1 Forced, constant a
26、mplitude, fixed frequency,7.1.2 Forced, constant amplitude, resonant oscillation,7.1.3 Freely decaying oscillation.7.2 The apparatus shall consist of the following:7.2.1 Test Fixtures, a choice of the following:7.2.1.1 Polished Cone and Plate (Having a Known ConeAngle)Usually a 25 or 50-mm diameter
27、cone and plate orparallel plates are recommended for neat resins. Variations ofthis tooling, such as bottom plates with concentric overflowrims, may be used as necessary.7.2.1.2 Parallel Plates, having either smooth, polished, orserrated surfaces are recommended for neat resins or prepregshaving les
28、s than 6 % volatiles.7.2.1.3 ClampsA clamping arrangement that permits grip-ping of the composite sample.7.2.2 Oscillatory Deformation (Strain Device)A devicefor applying a continuous oscillatory deformation (strain) tothe specimen. The deformation (strain) may be applied andthen released, as in fre
29、e-vibration devices, or continuouslyapplied, as in forced-vibration devices (see Table 1 of PracticeD4065).7.2.3 DetectorsA device or devices for determining de-pendent and independent experimental parameters, such asforce (stress or strain), frequency, and temperature. Tempera-ture should be measur
30、able with a precision of 61C, frequencyto 61 %, and force to 61%.7.2.4 Temperature Controller and OvenA device for con-trolling the temperature, either by heating (in steps or ramps),cooling (in steps or ramps), maintaining a constant specimenenvironment, or a combination thereof. Fig. 1 illustrates
31、 typical3Hedvat, S., Polymer Engineering and Science, Vol 21, No. 3, February 1981.FIG. 1 Typical Temperature ProfileD4473 08 (2016)2time-temperature profiles. A temperature controller should besufficiently stable to permit measurement of sample tempera-ture to within 1C.7.3 Nitrogen, or other inert
32、 gas supply for purging purposes.8. Test Specimens8.1 The neat resin or the self-supporting composition, orboth, should be representative of the polymeric material beingtested.8.2 Due to the various geometries that might be used fordynamic mechanical curing of thermosetting resins/composites, specim
33、en size is not fixed by this test method.Cure rates may be influenced by specimen thickness, so equalvolumes of material should be used for any series of compari-sons.8.3 For convenience, low-viscosity neat resins can be stud-ied using a supporting substrate.8.4 The substrate on which the resin is s
34、upported is nor-mally in the form of a woven-glass cloth or tape or abraided-glass cord. The substrate should have negligible stiff-ness when compared to the cured resin sample in both aflexural and torsional mode of deformation. Other substratescan be used if their effect on cure mechanisms were of
35、 interest.The composition should be representative of the polymericmaterial being tested.8.4.1 To standardize the pH of the supporting substrates,soak the cloth or braid overnight in distilled water andvacuum-dry. This will avoid any extraneous results with resinsthat are pH-sensitive.9. Calibration
36、9.1 Calibrate the instrument using procedures recommendedby the manufacturer for that specific make and model.10. ProcedureNOTE 5Precaution: Toxic or corrosive effluents, or both, may bereleased when heating the resin specimen to its cured state and could beharmful to personnel or to the instrumenta
37、tion.10.1 Apply the resin or uncured, self-supporting compositeonto the test fixture. In the case of two-part room-temperaturecure resins, mixing should be carried out in less than 1 % of theexpected gel time.10.2 Out-time effects and moisture-effect data must berecorded and reported.10.3 Procedure
38、AUnsupported Resin:10.3.1 Allow the sample to equilibrate to room temperaturein a desiccator. In case of a solid sample, place it in an oven at100C for 5 to 10 min in order to soften. Use a vacuum ovento degas, if necessary. Use 50-mm diameter test plates for lowminimum-viscosity systems and 25-mm d
39、iameter plates forhigher minimum-viscosity materials.10.3.2 For neat resins, be certain that there is sufficientmaterial to cover the bottom plate uniformly.10.3.3 Lower the upper test fixture so that it is touching thematerial to be cured.10.3.3.1 The distance between the two parallel plates should
40、be approximately 0.5 mm. However, when low viscositymaterials are being evaluated using cone and plate test fixtures,the recommended minimum gap setting is equipment-dependent and reference should be made to the manufacturersoperational manual for correct gap setting.10.3.3.2 Cone and plate experime
41、nts should be run only atone temperature. Any changes in the temperature setting willrequire adjusting the gap setting to the manufacturers recom-mended value.10.3.4 Conduct cure characterization of the submitted ma-terial in accordance with the desired time and temperatureparameters recording the a
42、ppropriate property values.10.4 Procedure BSupported Compositions:10.4.1 For self-supporting compositions in prepreg-typeform using cone and plate or parallel plate fixturing, be certainthat there is sufficient material to fill the sample volume on thelower plate completely.10.4.2 Insert the substra
43、te between the plates of the testinstrument. A sample disk (usually 25 mm in diameter) of theself-supporting composition can be die-cut, or several plies ofprepreg can be compressed into a sheet (for example, for 3 minat 77C at 75 atmospheres, 1000 psi) and then a disk die-cut.The orientation of uni
44、directional reinforcements may affectcure behavior and the orientation should be reported in 12.1.4.10.4.3 For three to five plies, the recommended gap settingis 1 to 2 mm. This gap setting is arbitrary and dependent on thetype of material and the number of plies being characterized. Agap setting of
45、 0.5 mm would be minimum. Cone and plate testfixtures are not recommended for supported compositions.10.4.4 For self-supporting substrates where either a baresubstrate is to be impregnated with liquid resin (rectangular orcylindrical form) or where a similar prepreg-type specimenforms a rectangular
46、specimen, clamp the substrate in placeutilizing the instruments grip system.10.4.5 Conduct the cure characterization of the submittedmaterial in accordance with the desired time and temperatureparameters recording the appropriate property values.10.5 Procedure CDynamic Compression:10.5.1 Prepare the
47、 test specimen in accordance with theprocedure described in 10.4.2 and 10.4.3.10.5.2 Compress slightly the specimen disk and monitorand record the preload force by observing the normal forcegage or indicator. Adjust the gap as necessary to accommodateany material expansion or contraction during the
48、thermaladvancement.10.5.3 Conduct the cure characterization of the submittedmaterial in accordance with the desired time and temperatureparameters recording the appropriate property values.10.6 Remove excess material by flushing or trimming thetest fixtures, using a razor blade, spatula, knife, or h
49、ot solderinggun.10.7 Isothermal Curing at Elevated Temperature:10.7.1 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.D4473 08 (2016)310.7.2 Prevent the material from entering a variable tensilestress mode by adjusting the fixture to compensate for thecontraction of the resin during curing.10.7.3 Ramped or Simulated Process Program HeatingFor materials that are to be cured starting at a low temperatureand prog
