Surface treatment of polypropylene by corona discharge and flame

The surface properties of the treated films were found to be related to the normalized energy (E), which can be determined ft-om the net power and the film velocity [2]  

These radicals react rapidly with atmospheric oxygen [2]  

These reactions make possible crosslinking and functionalization of the polymer surface with and without chain scission. The decomposition of the hydroperoxide groups produce oxygen functional groups on the surface, including C—OH, C=0 and COOH. 

Important variables for flame treatment are the air-to-gas ratio, air and gas flow rates, the distance between the tip of the flame and the object to be treated, the nature of the gas and the treatment time. The effect of these variables for flame treatment of polypropylene was studied by Sutherland et al. [4]. Oxidation at the polymer surface caused by flame treatment could be attributed to the high flame temperature (1000-2000°C) or reactions with many excited species in the flame. Flame treatment of polypropylene was studied by Garbassi et al. [5] using XPS and secondary ion mass spectrometry. XFS analyses revealed that oxygen functional groups such as OH, C=0, CC30R and COOH were detected on flame-treated polypropylene surfaces. Garbassi et al. [5] 

After the formation of the hydroxyl group, the oxidation proceeds with the formation of formyl and carboxyl groups. 

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Surface treatment of polypropylene by corona discharge and flame... 

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