Wettability and Adhesion of Polyethylene Powder Treated with Non-Equilibrium Various Gaseous Plasma in Semi-Industrial Equipment

Plasma treatment of polyethylene powder was carried out in low-pressure gaseous plasma sustained in a semi-industrial reactor powered with a microwave source, in which it was specifically worked with the residual atmosphere. Timed applications of plasma-treated powder in air atmosphere were carried out to study their influence on the adhesion. Based on wettability and adhesion, a treatment time of 5 min was selected for the study of other working gases (nitrogen, oxygen, hydrogen, argon and a mixture of nitrogen and hydrogen). The measurements of wettability showed the highest adhesion increase for nitrogen. The highest increase of adhesion and of surface oxygen contain shown by oxygen treatment. By contrast, treatment with hydrogen resulted in increased roughness of the sintered surface of the powder. The selection of appropriate working gases which are not standard in industrial processes enables one to atypically regulate the adhesion or wettability.