1、Designation: F2778 09Standard Test Method forMeasurement of Percent Crystallinity ofPolyetheretherketone (PEEK) Polymers by Means ofSpecular Reflectance Fourier Transform InfraredSpectroscopy (R-FTIR)1This standard is issued under the fixed designation F2778; the number immediately following the des
2、ignation indicates the year oforiginal adoption or, in the case 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. Scope1.1 This test method describes th
3、e collection of absorptionspectra of polyetheretherketone (PEEK) polymer in filled andunfilled grades, as supplied by a vendor, and the subsequentcalculation of the percent crystallinity. The material is evalu-ated by infrared spectroscopy. The intensity (height) of theabsorbance peaks is related to
4、 the amount of crystalline regionspresent in the material.1.2 This test method can be used for PEEK consolidatedforms, such as injection molded parts, as long as the samplesare optically flat and smooth.1.3 The applicability of the infrared method to industrialand medical grade PEEK materials has be
5、en demonstrated byscientific studies.2, 3Percentage of crystallinity is related toR-FTIR measurement by calibration through wide-angle x-rayscattering (WAXS) crystallinity measurements.2, 3It is antici-pated that this test method, involving the peak heights near1305 cm-1and 1280 cm-1, will be evalua
6、ted in an Interlabora-tory Study (ILS) conducted according to Test Method E691.1.4 This test method does not suggest a desired range ofcrystallinity for specific applications.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1
7、.6 This standard may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine
8、the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 crystallinity index (CI), nthe ra
9、tio of the heightbetween the absorption peaks 1305 cm-1and 1280 cm-1.4. Significance and Use4.1 Mechanical properties of PEEK, such as stiffness oryield strength, are influenced by the level of crystallinity.5Thereported crystallinity index determined by this test method hasbeen correlated with perc
10、ent crystallinity in PEEK by wide-angle X-ray scattering (WAXS) experiments.2, 34.2 This test method may be useful for both processdevelopment, process control, product development, and re-search.5. Interferences5.1 Samples must be smooth and optically flat over the areaof investigation, typical of
11、injection-molded specimens. Theymust be sufficiently thick (for example, 1 to 2 mm) such thatthere is no detectable back surface reflected radiation.5.2 Samples must be sized appropriately to be accommo-dated in the FTIR apparatus.1This test method is under the jurisdiction of ASTM Committee F04 on
12、Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Methods.Current edition approved Nov. 15, 2009. Published December 2009. DOI:10.1520/F277809.2Chalmers J. M., Everall, N. J., Hewitson, K., Chesters, M. A., Pearson, M.,Grady,A., Kuzicka
13、, B., “Fourier Transform Infrared Microscopy: SomeAdvances inTechniques for Characterisation and Structure-Property Elucidations of IndustrialMaterial,” The Analyst, Vol 23, 1998, pp. 579586.3Jaekel, D. J., Medel, F. J., Kurtz, S. M., “Validation of Crystallinity Measure-ments of Medical Grade PEEK
14、Using Specular Reflectance FTIR-microscopy,”Society of Plastics Engineers Annual Technical Conference 2009, Chicago 2009,Manuscript ID ANTEC-0248-2009.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStan
15、dards volume information, refer to the standards Document Summary page onthe ASTM website.5Kurtz, S. M., Devine, J. N., “PEEK biomaterials in trauma, orthopedic, andspinal implants,” Biomaterials , Vol 28, No. 32, 2007, pp. 48454869.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
16、West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Infrared Spectrometer:6.1.1 An infrared spectrometer capable of recording a re-flection absorption spectrum over the range of 500 cm-1to1500 cm-1is necessary.6.1.1.1 A minimum scan resolution of 4 cm-1shall be used.6.1.1.2 Aminimum aper
17、ture of 360 3 360 m shall be used.6.1.1.3 A minimum of 100 scans shall be collected perspectrum.6.1.2 Software capable of using the Kramers-Kronig trans-form algorithm to derive the absorbance spectra.6.2 Specimen HolderEquipment capable of accuratelypositioning the sample under the orifice and allo
18、wing thesample to be in focus.6.3 Samples Preparation EquipmentEquipment capableof producing optically flat and optically thick samples.7. Preparation of Apparatus7.1 Prior to testing, the FTIR dewer chamber should befilled with liquid nitrogen until peak-to-peak signal in trans-mission mode is over
19、 10.8. Calibration and Standardization8.1 Validation and calibration should be conducted weeklyby running a validation check of the infrared spectrometerbased on manufacturers instructions.8.2 A background scan should be conducted at the start oftesting and every 30 min thereafter for the duration o
20、f testingwhile using the same scanning settings as the test parametersdictate. The background scan should be taken from a com-pletely reflective surface.9. Procedure9.1 Check settings to ensure you are in reflectance mode,collecting at 100 scans per spectrum with a resolution of4cm-1, an aperture of
21、 360 3 360 m, and the spectrometer isset to use a Kramers-Kronig transform algorithm.9.2 Place and secure the sample in the holder so that itappears level and flat.9.3 Through the microscope, focus the view on the surfaceof the sample.9.4 Samples can continue to be tested as long as a newbackground
22、is collected every 30 min.10. Calculation or Interpretation of Results10.1 Crystallinity Index (CI):10.1.1 Open a spectrum data file, and restrict the absorptionband range to 900 cm-1and 1400 cm-1.10.1.2 Perform an automatic baseline correct of this spec-trum range.10.1.2.1 Determine a reference bas
23、eline for the heightmeasurements from the zero value absorbance points on thespectrum as shown in Fig. 1. The first point for the baseline isthe lowest absorbance value point between the spectra bands,1340 to 1375 cm-1, and the second point is lowest absorbancevalue point between 1000 cm-1and 1080 c
24、m-1.10.1.3 Calculate the heights of the peaks near1305 cm-1(HA) and 1280 cm-1(HB) as shown in Fig. 1.10.1.3.1 HA is the peak height corresponding to carbonyllinkages, while HB is primarily influenced by the diphenylether groups of the PEEK molecular chain. The bands influ-enced by the diphenyl ether
25、 groups (HB) are invariant to theFIG. 1 Representative Spectrum of Unfilled, Medical Grade PEEK and Example of Crystallinity Index CalculationF2778 092level of crystallinity, whereas the absorption peak correspond-ing to carbonyl linkages (HA) increases with the level ofcrystallinity.610.1.4 CI shal
26、l be calculated by dividing the calculatedheight HA (peak height at 1305 cm-1) by the calculated heightHB (peak height at 1280 cm-1)(Fig. 1):CI 5 HA/HB (1)10.2 Percent Crystallinity:10.2.1 Based on published data,3the CI is related to thepercent crystallinity.10.2.1.1 Crystallinity Correlation:%Crys
27、tallinity 5CI 0.7281.5493 100 (2)10.2.1.2 Eq 2 was derived from CI measurements in speci-mens with known crystallinity from WAXS (Fig. 2).11. Report11.1 Report the following information:11.1.1 Description of the raw material, preparation methods,or treatment protocols. This should include any inform
28、ation onfiller material, annealing procedures, or processing (injectionmolding, extruding, etc.).11.1.2 Material used for background collection.11.1.3 Description of instrument and software packageused.11.1.4 The heights of the peaks near 1305 cm-1and1280cm-1, as well as the subsequent Crystallinity
29、 Index calcu-lated by Eq 1.11.1.5 The percent crystallinity calculated by Eq 2.12. Precision and Bias12.1 A round robin study will be conducted on PEEKsamples to determine a precision and bias statement.13. Keywords13.1 crystallinity; Fourier transmission infrared spectros-copy (FTIR); polyetherethe
30、rketone (PEEK); specular reflec-tance6Nguyen, H. X., and Ishida, H., “Molecular Analysis of the Melting Behavior ofPoly(Aryl-Ether-Ether-Ketone),” Polymer, Vol 27, No. 9, 1986, pp. 14001405.FIG. 2 FTIR and WAXS Calibration Curves Defining the Relationship Between CI and Percent Crystallinity for Fil
31、led and Unfilled Gradesof PEEK (Adapted from Jaekel2)F2778 093ASTM 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
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