CHARACTERIZATION OF PLASMAS AND PLASMA TREATED POLYMERIC MATERIAL SURFACES FOR ADHESION IMPROVEMENT

摘要

Polymeric materials are widely used in a variety of applications, but adhesion to these materials is often difficult because of their low surface energy and poor chemical reactivity. Therefore improving the adhesion to polymeric materials is of considerable importance in assembly of mechanical structures and composite materials. Plasma treatment, which can be operated at room temperature, is attractive for this purpose because they avoid the use of solvents and toxic chemicals, and only the surface is efficiently treated while the bulk properties remain unchanged. With the aim of adhesion improvement, glassy carbon plates, carbon fibres and glass fibre reinforced polyester (GFRP) plates were treated using atmospheric pressure plasmas chosen from a dielectric barrier discharge (DBD) and gliding arcs. Optical emission spectroscopy (OES) of the plasma indicates that oxygen or nitrogen containing radicals were generated, suggesting that they could react at the exposed surfaces during the treatment. Surface characterization using contact angle measurement and x-ray photoelectron spectroscopy (XPS) indicates that after plasma treatment the polar component of surface energy increased and oxygen-containing polar functional groups were effectively introduced onto the surfaces. Raman spectroscopic observation of glassy carbon plates suggests that the defect density, hardness, and density at the surfaces increased with the treatment. Atomic force microscopy indicates that surface roughness tends to increase after the treatment. These characterizations were used for understanding of surface modification effect for observed adhesion improvement.