Radio frequency oxygen plasma

It was found that alkali and silane treatments also increased the tensile and flexural strength of PLA/ramie composites, exhibiting that alkali treatment (5 wt%, 3h) is more effective than silane treatment (APS and GPS, 24h) [145]. Oxygen plasma treatment of jute fibers improved the tensile and flexural properties of jute/HDPE composites, showing that radio frequency (RE) plasma treatment was more effective than low frequency (LE) plasma treatment up to 60 W [139]. Oligomeric siloxane treatment after alkali treatment of jute fibers resulted in an additional increase in both tensile and flexural strengths of JEP and JUP composites, compared with either alkali or silane treatment alone, resulting from the increase of fiber-matrix adhesion by surface treatment, as mentioned earlier [53]. 

Poljraer surfaces can be easily modified with microwave or radio-frequency-energized glow discharge techniques. The polymer surface cross-links or oxidizes, depending on the nature of the plasma atmosphere. Oxidizing (oxygen) and nonoxidizing (helium) plasmas can have a wide variety of effects on polymer surface wettability characteristics (92). 

Low temperature ashing with radio frequency induced oxygen plasma ... 

Charles C, Garcia P, Grolleau B and Turban G 1992 Mass spectrometric study of tetraethoxysilane and tetraethoxysilane oxygen plasmas in a diode type radio-frequency reactor J. Vac. Scl. Technol A 10 1407-13... 

Much research has been focused on reducing oxide and hydroxide formation in plasmas. Oxide formation depends on such experimental variables as injector flowrate, radio-frequency power, sampler skimmer spacing, sample orifice size, plasma gas contposition, oxygen elimination, and solvent removal efficiencies. All of these variables can be adjusted to address specific oxide and hydroxide overlap problems. 

Plasma oxidation versus photo oxidation of polystyrene, Polym. Commun. 32, 217 (1991) A.F. Whitaker and B.Z. Jang, The mass loss mechanisms of polymers in a radio frequency induced atomic oxygen environment, J. Appl. Polym. Sci. 48, 1341 (1993). 

Particulate matter in a measured volume of air can be collected on a cellulose-acetate-membrane filter (e.g., Millipore ). The filter is dry ashed in a low-temperature asher. (This device uses oxygen radicals in a radio-frequency plasma for ashing at below 100°C, thus minimizing losses due to volatility of the test element and retention on crucible walls.) The ash is taken up in dilute HCl and aspirated directly, or the filter can be digested with a mixture of nitric and perchloric acids. For beryllium determination, a nitrous oxide-acetylene flame is used. Results are reported as Mg/m of air. 

Figure 1 shows the apparatus used for the plasma treatment of PS and PC. The plasma treatment was cairied out at a pressure of 65 Pa (0.5 ton) using a rotary pump with flowing oxygen or nitrogen gas. The plasma was generated by the application of radio frequency (R.F.) electric field of 13.56 MHz and 100 W to the outer R.F. coil for 60 sec. 

It is worthwhile to note that the ORR activity on carbon-based electrode surface is strongly dependent on the pretreatment such as polishing, dipping a carbon electrode into chromic acid, exposing to radio frequency plasma in oxygen atmosphere, and... 

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