Michał Kwiatkowski

RF-Powered Atmospheric-Pressure Plasma Jet in Surface Treatment of High-Impact Polystyrene

The application of RF-powered atmospheric-pressure plasma jet (APPJ) for changing the surface properties of rubber-modified styrenic polymers on the example of high-impact polystyrene (HIPS) is investigated. We have utilized a 0-D chemical kinetic model to identify the dominant particle species generated by our device in experimental conditions. Ozone is found to be an important species in the plasma, and in higher concentrations, it can also contribute to oxidative degradation of the specimen. Basic properties of APPJ, such as electrical characteristics and outlet gas temperature measurement results, are presented. Influence of the plasma treatment on HIPS surface wettability is discussed.

Effects of atmospheric pressure plasma jet operating with DBD on Lavatera thuringiaca L. seeds’ germination

The paper presents the results of an experiment on the effect of pre-sowing stimulation of seeds with atmospheric pressure plasma jet operating with dielectric barrier discharge (DBD plasma jet) on the process of germination of Thuringian Mallow (Lavatera thuringiaca L.). Five groups of seeds characterized by a different exposure times (1, 2, 5, 10 and 15 minutes) as well as untreated seeds—control were used. Pre-sowing plasma stimulation of seeds improved germination parameters such as: germination capacity and germination energy for all tested groups relative to control. The highest germination parameters were obtained for seeds stimulated with plasma for the exposure times of 2 and 5 min. The analysis of the contact surface angle indicated the decrease of its’ mean values upon seed stimulation while no statistical effects were observed. Analysis of the SEM scans revealed the increase in seed pattern intensity which could be attributed to removing of the surface parts of cuticle possibly covered with wax upon short time—2 and 5 min plasma treatment. Such a phenomenon can act similarly to mechanical scarification of seeds. Longer exposure of seeds to plasma resulted in affecting the deeper zone of cuticle and damage or fracture of some parts of the cuticle. Lower germination parameters of seeds upon longer exposure times to plasma may indicate mechanical damage of the seeds.