engleski

Modification of ink-jet paper by oxygen-plasma treatment

A study on oxygen plasma treatment of ink-jet paper is presented. Paper was exposed to a weakly ionized, highly dissociated oxygen plasma with an electron temperature of 5 eV, a positive-ion density of 8x1015 m-3 and a density of neutral oxygen atoms of 5x1021 m-3. Optical emission spectroscopy (OES) was applied as a method for detection of the reaction products during the plasma treatment of the paper. OES spectra between 250 nm and 1000 nm were measured continuously during the plasma treatment. The wettability of the samples before and after the plasma treatment was determined by measuring the contact angle of a water drop. The appearance of the surface-functional groups was determined by using a high-resolution XPS, while changes in the surface morphology were monitored with SEM. Already after 1 second of the plasma treatment the surface, which was originally hydrophobic, changed to hydrophilic, what was indicated by a high absorption rate of a water drop into the paper. The OES showed rapid increase of the CO and OH bands for the first few seconds of the plasma treatment, followed by a slow decrease during next 40 s. The intensity of the O atom line showed reversed behaviour. The XPS analyses showed a gradual increase of oxygen-rich functional groups on the surface, while SEM analyses did not show significant modification of the morphology during the first 10 s of the plasma treatment. The results were explained by degradation of the AKD sizing agent during the first few seconds of the oxygen plasma treatment.

paper; cellulose; oxygen plasma; surface activation; functionalization; XPS; OES; SEM; AKD

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