Mechanical properties of PEEK, such as stiffness or yield strength, are influenced by the level of crystallinity. The reported crystallinity index determined by this test method has been correlated with percent crystallinity in PEEK by wide-angle X-ray scattering (WAXS) experiments.

This test method may be useful for both process development, process control, product development, and research.

1.1 This test method describes the collection of absorption spectra of polyetheretherketone (PEEK) polymer in filled and unfilled grades, as supplied by a vendor, and the subsequent calculation of the percent crystallinity. The material is evaluated by infrared spectroscopy. The intensity (height) of the absorbance peaks is related to the amount of crystalline regions present in the material.

1.2 This test method can be used for PEEK consolidated forms, such as injection molded parts, as long as the samples are optically flat and smooth.

1.3 The applicability of the infrared method to industrial and medical grade PEEK materials has been demonstrated by scientific studies. Percentage of crystallinity is related to R-FTIR measurement by calibration through wide-angle x-ray scattering (WAXS) crystallinity measurements. It is anticipated that this test method, involving the peak heights near 1305 cm^-1 and 1280 cm^-1, will be evaluated in an Interlaboratory Study (ILS) conducted according to Test Method E691.

1.4 This test method does not suggest a desired range of crystallinity for specific applications.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.