Plasma treatment is used to modify and improve the surface conditions of various materials. The use of plasma technology on plastic and composite substrates enables these heat-sensitive materials to be successfully coated with ultraviolet (UV) curable powder coatings. Plasma treatment of a part raises its surface energy and removes contaminants. The increase in surface energy enhances the level of surface wetting, which correlates to improved coating adhesion. There are various conditions and processing variables that can be manipulated to increase the effectiveness of plasma treatment of a material surface. A study was conducted on six plastic and composite substrates. The effectiveness of plasma treatment was first determined from the change in surface energy. In general, the surface energy of all samples increased from 30 -48 dyne/cm to 64 -70+ dyne/cm. To further study the effectiveness of plasma treatment, the treated plastics and composites were finished with a UV cured powder coating. UV cured powder coatings use less heat energy and cure faster than conventional powder coatings and do not degrade or deform heat-sensitive substrates. After cure, coating adhesion to the substrate was measured and evaluated. Consistent with the increase in surface energy, improved adhesion was noted on all the test samples.
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