Studies on the reprocessability of poly(ether ether ketone) (PEEK)

• PEEK was reprocessed five times by regrinding and injection moulding.
• First regrind and virgin PEEK were blended in varying proportions.
• The tensile properties of PEEK were maintained through three regrind cycles.
• Regrind PEEK had no significant effect on the tensile properties of virgin PEEK.
• Regrinding and blending had no significant effect on PEEK crystallinity.

Whilst demonstrating desirable mechanical properties, corrosion resistance and the ability to retain structural integrity over extended temperatures, PEEK (poly(ether ether ketone)) remains expensive, restricting broader usage. The reuse and recyclability characteristics of PEEK are therefore commercially important, where the most prevalent manufacturing process for PEEK is injection moulding. This study comments on the reprocessability of PEEK specifically applied to the injection moulding process, comparing the effect of repeated reuse on mechanical properties. Recycled PEEK retains its tensile properties through at least three moulding and regrinding cycles. XRD and DSC measurements confirmed that reused PEEK shows no degradation in crystallinity.