Surface Functionalization of Polyethylene Granules by Treatment with Low-Pressure Air Plasma
Loading...
Date
2019-05-25
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
Polyethylene granules of diameter 2 mm were treated with a low-pressure weakly ionized
air plasma created in a metallic chamber by a pulsed microwave discharge of pulse duration
180 µs and duty cycle 70%. Optical emission spectroscopy showed rich bands of neutral nitrogen
molecules and weak O-atom transitions, but the emission from N atoms was below the detection
limit. The density of O atoms in the plasma above the samples was measured with a cobalt catalytic
probe and exhibited a broad peak at the pressure of 80 Pa, where it was about 2.3 × 1021 m−3
.
The samples were characterized by X-ray photoelectron spectroscopy. Survey spectra showed oxygen
on the surface, while the nitrogen concentration remained below the detection limit for all conditions.
The high-resolution C1s peaks revealed formation of various functional groups rather independently
from treatment parameters. The results were explained by extensive dissociation of oxygen molecules
in the gaseous plasma and negligible flux of N atoms on the polymer surface.
Description
Subject(s)
polyethylene granules, low-pressure MW air plasma, optical emission spectroscopy, XPS, laser cobalt catalytic probe