CORONA DISCHARGE TREATMENT OF POLYOLEFINS

The effects of corona discharge treatment on polyethylene and polyprop ylene homopolymers have been studied. X-ray photoelectron spectroscopy was used to determine surface compositions which were related to surf ace free energy estimates from contact angle measurements. Changes in composition and surface free energy were measured as a function of tre atment level. The work of adhesion was seen to increase with oxygen in corporation. The increase was not linear and this is attributed to an increase in the degree of sub-surface to near-surface oxidation at int ense treatment levels. Aging of samples followed by XPS and contact an gle measurement showed that surface wettability is reduced whereas a s light increase in surface oxygen was found. This phenomenon was attrib uted to the reorientation/migration of functional groups. Morphologica l examination by scanning electron microscopy indicated no surface rou ghening at any power level.