Atmospheric plasma thermoplastics

There can be reinforcements added to polymeric matrices such as cellulosic fibers, and fillers such as titanium dioxide incorporated into roll thermoplastics, to improve performance properties or reduce cost bases. These host matrices can include polypropylene, polyethylene, polystyrene, polyamide, and PVC to name a few. In these circumstances, the addition of dispersants and/or coupling agents is needed to attract the more highly polar fibers and fillers to the less polar polymer matrix. These added constituents will form a level of presence (depending upon their inclusion ratio relative to the bulk) at the composite surface which must be considered relative to atmospheric plasma chemistry prescription. 

Paintable interior automotive components include hard trim parts, instrument panel skins, door panels, and airbag covers. Exterior components include bumper fascias, body side cladding, rocker panels, and vent grilles. The preferred substrate for these components has been thermoplastic polyolefins (TPOs), a material with low flexural modulus and low surface energy. It is considerably difficult to promote paint adhesion to TPOs without the use of predominantly oxidative surface treatment techniques, such as flame or atmospheric plasmas, or a chemical adhesion promoter, to prepare the surface to accept and wet-out paint. 

Conventionally, this type of coating is applied by plasma at a temperature of about 2()0°C, which has limited its application of surfaces such as metals and ceramics. The CVD technology, however, enhanced by a plasma source operated only intermittently (PECVD), can function at around 50-8()°C. Combined with plasma washing in a specific atmospheric gas, it has been possible to coat thermoplastic materials with much lower softening points. 

Moritzer E, Budde C, Leister C. Effect of atmospheric pressure plasma pre-treatment and aging conditions on the surface of thermoplastics. Weld World 2014 1-10. 

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