Polyethylene powder is treated in an atmospheric pressure circulating fluidized bed plasma reactor, in which powder particles pass the afterglow of 64 discharge channels multiple times. Contact angle drops with increasing treatment time and powder gradually becomes wettable with liquids of higher surface tensions. X‐ray photoelectron spectroscopy is used to prove particle surface functionalization induced by the afterglow process. Two different channel arrangements and geometries are studied and the influence of applied voltage and frequency on activation efficiency is investigated. Minimal surface aging is observed when samples are stored in air. However, when dispersed in water, particles maintain the engineered wettability.

The flowability of micropowders can be improved by depositing a non‐continuous coating on the micropowder surface, which reduces the interparticle van der Waals forces causing cohesion of the native powder. Such a coating can be achieved via a plasma enhanced chemical vapor deposition in a tubular, inductively‐coupled RF glow‐discharge‐plasma reactor fed by plasma‐polymerizable gases. Here we systematically study the influence of user‐set plasma parameters of feed gas flow rate and plasma power on the resulting powder flowability. We find a quasi‐Arrhenius relation between flowability factor and energy delivered per mass of monomer W/FM. These findings demonstrate that flowability measurements can be used to study the plasma polymerization processes and as a metric to assess surface coatings of powders that are otherwise difficult to characterize by standard metrologies.

No abstract

No abstract