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PEEK polymer and the high-performance compounds based on PEEK polymer exhibit outstanding flexural performance over a wide temperature range. Due to the viscoelasticity of these materials, evaluations were performed using a defined strain rate three point bending test (standards ISO R178 and ASTM D790) with the results plotted versus temperature in Figures 4 and 5.
Figure 4 - Flexural Strength Versus Temperature for PEEK Polymer Materials
Figure 5 - Flexural Modulus Versus Temperature for PEEK Polymer Materials
Flexural strength has been defined as the maximum stress sustained by the test specimen during bending, and flexural modulus as the ratio of stress to strain difference at pre-defined strain values.
The data plotted in Figures 4 and 5 define the exceptional temperature range over which PEEK polymer can be used as a structural material. However, flexural strength measurements made above 392°F (200°C) are subject to error as the yield point of these materials is at greater than the 5% strain specified in the test standard. Above this value, a linear stress to strain relationship cannot be assumed for the calculation of flexural properties.
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