Plasma treatment ambient pressure

Figure 30.5 The effects of input power (A) 8 W, (B) 30 W, (C) 63 W, and system pressure (1) 25mtorr, (2) 50mtorr, (3) lOOmtorr, on Wilhelmy force loops of O2 plasma-treated LDPE oxygen flow rate and plasma treatment time were fixed at 10 seem and 0.2 min, respectively, dark-colored force loops were taken just after samples were removed from the reactor, and gray-colored force loops were taken two weeks later after equilibrating with ambient air.

Other Methods Examples for other methods include co-casting of a hydrophobic and a hydrophilic polymer that contains amine, imine, hydroxyl, or carboxyl groups [61,89] surface modification by oxidation with ozone or by exposure to an electron or ion-beam ultrasonic etching and UV or laser irradiation [90-92]. A variety of functional groups have been also introduced onto the membrane surfaces by applying the gas discharge techniques (plasma treatment) operated at low or ambient pressure [93,94]. 

A variety of functional groups have been also introduced onto the membrane surfaces by applying the gas discharge techniques (plasma treatment) operated at low or ambient pressure [113,114],... 

Operating at ambient pressure allows industry to move from batch to continuous processing and also facilitates much simpler equipment designs with reduced maintenance requirements due to the lack of vacuum pumps, seals, etc. Besides activation and functionalization of surfaces, the APP technology also involves different coating processes. Recent advances in this technology have included the development of aerosol-assisted plasma deposition techniques. A schematic view of an aerosol-assisted DBD treatment of foils is shown in Fig. 20.30. 

A number of chemical and physical surface treatments have been developed for polymeric materials in recent years. Due to the disadvantage of chemical treatments, physical surface treatments are preferred to modify the surface of polymeric materials (Petrie 2006). Plasma surface treatment is often the preferred way to treat the surfaces as it offers more stable and longer-lasting surface-energy enhancement than any other treatments (Rotheiser 1999). However, conventional plasma treatment also has shortcomings. It requires a low pressure (partial vacuum), and thus the parts must be processed in a vacuum chamber, restricting the part size. Atmospheric-pressure plasma has been developed to operate at near ambient temperature and atmospheric pressure, eliminating the expensive vacuum systems. 

It is frequent that low wettability surfaces influence badly the production line of the goods. It is desirable to introduce surface treatment processes to low wettability materials such as thermoplastics. For instance, short wavelength UV irradiation with low pressure mercury lamps and ambient pressure plasma irradiation are popular for the purpose. Even shot-term irradiation can improve the wettability of surface very much and the bond strength increases, as shown in O Fig. 41.9. 

Methods such as corona treatment have not been very common for three-dimensional moldings in Europe due to the difficulties to control parameters like distance of the corona electrode to the surface to be treated. However, simply shaped parts like side protection moldings have been effectively tteated prior to coating using the corona discharge method. A variation of the improved method is known as Ambient Pressure Plasma (Plasma Gun) (13). Ultraviolet (UV) primers have been used in France and Italy combining the adhesion effect of adhesion promoters with the attack of free radicals formed under UV irradiation to the polymer (14). 

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