Cross-linking by activated species of inert gases

Surface cross-linking can be achieved by the so-called CASING process (cross-linking by activated species of inert gases), in which an inert gas is activated, for example, by microwaves (He- - He ), and then allowed to react with the surface of the polymer ... 

CASING Cross-linking by activated species of inert gases... 

Treatment of certain polymeric surfaces with excited inert gases greatly improves the bond strength of adhesive joints prepared from these materials. With this technique, called plasma treatment, a low-pressure inert gas is activated by an electrode-less radio-frequency discharge or microwave excitation to produce metastable species which react with the polymeric surface. The type of plasma gas can be selected to initiate a wide assortment of chemical reactions. In the case of polyethylene, plasma treatment produces a strong, wettable, cross-linked skin. Commercial instruments are available that can treat polymeric materials in this manner. Table 7.10 presents bond strength of various plastic joints pretreated with activated gas and bonded with an epoxy adhesive. 

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