Characterization and exposure of polyetheretherketone (PEEK) to fluid environments

The sorption and desorption behaviour in fluids is described for polyetheretherketone (PEEK) films of different crystallinity. Water, Skydrol, and methylene chloride were used as fluid environments at two temperatures, and the weight gain of the films as a function of time was recorded. Density, thermomechanical, and dynamic mechanical measurements were made for the films before and after the fluid exposure. The results confirmed the general solvent resistance of PEEK. However, exposure to methylene chloride produced two significant effects: plasticization and additional crystallization for incompletely crystallized films. Exposure to different fluids was shown to suppress the exhibited thermomechanical transitions of these films. For the incompletely and fully crystallized films a comparison was made for crystallinity values obtained by the differential scanning calorimetric and density gradient techniques. Finally,dynamic mechanical and sorption in methylene chloride data obtained for PEEK reinforced with continuous carbon fibres are provided for comparison to the neat polymer results.