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This paper evaluates the use of an air based atmospheric pressure plasma jet for the activation of carbon fibre epoxy composites. In addition the performance of the jet in the removal of a 5-8 nm thick layer of FreKote 710-NC from the composite surface prior to heat-cured epoxy adhesive bonding was also investigated. The plasma treated composites were examined using thermal infra-red imaging, WCA, profilometry and SEM. A reflectance-IR technique was used to monitor the removal of FreKote as well as changes in the functional chemistry of the plasma treated composite surface. The optimised plasma pre-treatment conditions were identified which help to maximise composite-to-composite adhesive bond strength based on LST. This involved a treatment at a 14 mm nozzle to composite distance and scan rate of 30 mm/s. The air plasma process was bench marked against a manual methanol solvent wipe process, for the removal of FreKote. Both the plasma and the solvent wipe treatments yielded similar composite to composite bond strengths, demonstrating that both were successful in the removal of the FreKote. A comparison was also made between the plasma treated composite and a composite which had been grit blasted using 50 µm aluminium oxide grit. A 7% enhancement in lap-shear strength was achieved with the plasma treatment compared to grit blasting. [ABSTRACT FROM AUTHOR]

Atmospheric pressure plasma systems are routinely used to treat the surfaces of thermally sensitive materials. There are wide ranges of commercial plasma jet systems available, and for the end user, it can be difficult to directly compare the power outputs of these sources. This paper evaluates the use of a thermal imaging technique in order to provide a semiquantitative evaluation of energy output from plasma jets. The evaluation involved a comparison of the thermal energy transfer obtained from three commercially available atmospheric pressure plasma jet systems: 1) PlasmaTreat’s Openair; 2) Dow Corning’s PlasmaStream; and 3) SurFx’s Atomflo. [ABSTRACT FROM PUBLISHER]