Cold plasma effect on short glass fibre reinforced composites adhesion properties

The low surface energy and poor wetting properties of polymers make it necessary to modify prior to achieve adhesive bonding. This work is focused on the creation of wettable glass fibre reinforced epoxy and polyester composites, thus improving their adhesion performance. The key to evaluate this parameter as a function of the treatment with an atmospheric pressure plasma torch (APPT) device is the surface energy value. The chemical and morphological effects of APPT on the substrates are characterised by infrared and X-ray photoelectron spectroscopy, while etching of APPT is studied by scanning electron and atomic force microscopy. Benefits of APPT on the composites adhesive behaviour are evaluated through mechanical pull-off tests. Experimental results show an improvement in polarity and Lewis base behaviour of the surfaces as well as the creation of a rougher topography, which would be greatly helpful in the bonding process.