Figure 1 illustrates the flow of common surface preparation processes. The best way to improve adhesive bonding is to improve surface polarity and the stability of the surface chemistry. For any surface preparation method, the treatment must not damage the region below the surface, or else the point of failure will simply be moved slightly away from the bond line without imparting any real advantage. Surface preparation process flow. Surface Preparation of Polymers.
Corona treatment is a quick and inexpensive method for improving surface energy on plastics.
This process involves the atmospheric generation of ozone in an electrical discharge, which induces oxidation of the surface. Because corona treatment can be quixotic in its effect, an alternative is oxygen plasma treatment, which requires a closed chamber but leads to more reliable oxidation. Strong plasma treatment can damage subsurface layers, so it is essential to use correct power and exposure times. Flame treatment is effective and inexpensive but requires good process control to prevent scorching. Strong oxidizing acids, such as chromic acid, can also be used to oxidize a substrate surface, though acid oxidation carries the drawback of hazardous material handling and waste.