Effect of Low-Temperature Plasma Treatment on Surface Properties of LDPE Film

Abstract

Low-density polyethylene (LDPE) film was treated by low-temperature plasma. Scanning electronic microscope, electronic universal testing machine, contact angle/interfacial tension measuring instrument were used to analyze the surface morphology, surface contact angle, bonding strength and performance of LDPE film before and after they were treated by low-temperature plasma. The results show that air ambience is more appropriate than N2, CO2 for treatment. Specifically, plasma treatment in air ambience, under conditions of 44 W (power), 30 s (duration) and 60 Pa (vacuum degree), can decline static contact angle of LDPE film from 101° to 13.5°. The transiency of plasma-treated LDPE film is so obvious that storage time of longer than one hour will result in a contact angle up to 74° and loss of plasma treatment effect (timeliness). Therefore, the reversible plasma-treated LDPE film should be processed immediately.