Physical and mechanical properties of surface modified poly ethylene terephthalate films through low pressure plasma and ultra-violet light

The present work focussed on the effect of UV light radiation and Direct current glow Discharge Plasma (DC) on Polyethylene Terephthalate (PET) surface for food packaging applications. The PET was treated by three different plasma such as air, argon, and oxygen with a treatment time of 5–25 min and pressure kept as 3 Pa. The PET film was exposed by UV radiation using the wavelength between 200–400 nm UV light Lamp with a treatment time of 5–25 min. And also we measured the electron temperature (Te) and electron density (Ne) of the three different plasmas by Single Langmuir probe method. The surface properties of UV light radiated and plasma treated PET films were characterized by static contact angle, x-ray diffraction, Optical analysis (UV–vis), ATR-FTIR, Structural analysis (AFM)) and the results were compared. We observed that the bulk properties of the treated materials remained unchanged. This was confirmed by x-ray diffraction results. The new polar functional groups were also detected on the treated films by FTIR spectrum analysis. The surface roughness was calculated from AFM analysis for both untreated and treated PET films. The oxygen plasma treated sample showed higher roughness, which indicated that a large amount of oxygen containing polar groups appeared on the surface of the PET film. The obtained results reveal that the plasma treated PET films were more effective than the Ultra-violet (UV) light radiated film.