SURFACE-TREATMENT OF POLYETHERETHERKETONE (PEEK) COMPOSITES BY PLASMAACTIVATION

Carbon-fiber-reinforced PEEK composites (APC 2, ICI pie) were plasma t reated for adhesive bonding. This was done in a microwave plasma in ar gon or oxygen. An epoxy-based film adhesive (AF 191, 3M) was employed for adhesive bonding (1 h curing at 175 degrees C, 30 N/cm(2)). Both p lasma treatments resulted in a high level of lap shear strength (Ar: > 40 MPa, 25 degrees C). The environmental behaviour (42 d, 70 degrees C hot water) of the adhesively bonded composites has also shown that go od bonds could be obtained. Regarding the stability of the freshly-tre ated surfaces against exposure to the surrounding atmosphere only a sm all decrease in lap shear strength was observed. After storage for 4 w eeks in air the strength was still almost 85% of that when the bonding was done directly after the treatment. ESCA measurements revealed an increase in carbon-oxygen groups by the plasma treatment and a strong cleavage of the PEEK chemical structure.