INVESTIGATION OF THE PERFORMANCE OF A BARREL ATMOSPHERIC PLASMA SYSTEM FOR THE TREATMENT OF SILICONE PARTICLES

This study reports on the use of a novel atmospheric plasma source for both the activation and coating of silicone polymer particles. The research involved the manufacture of the silicone from its resin, extrusion of the... [ view full abstract ]

This study reports on the use of a novel atmospheric plasma source for both the activation and coating of silicone polymer particles. The research involved the manufacture of the silicone from its resin, extrusion of the polymer, followed by thermal curing and then automated blade cutting to obtain the required particle size (diameter of 5 mm). The plasma treatments were carried out using a barrel reactor. In this the plasma was generated using both helium and helium / oxygen gas mixtures. The effect of plasma treatment time, operating voltage and gas flow rate, on the water contact angle of the treated polymer were investigated. The modified silicone particles were analysed using SEM (morphology), water contact angle (wettability), FTIR and XPS (functional chemistry). Using a helium plasma only, the contact angle of the silicone polymer decreased from 145° to 71° after treatment for 2 hours. In contrast addition of oxygen to the helium plasma decreased the contact angle of the silicone particles to less than 5° after 2 minutes of treatment. The use of the barrel reactor for depositing a fluorocarbon coating onto the silicone particles was also investigated. The (Perfluoro–1–Decene) precursor was introduced into the helium plasma and coatings deposited at flow rates in the range 5 to 9 μl/min. The retention of the chemical functionality of the precursor in the plasma polymerised coating was demonstrated using both XPS and FTIR analysis. This study thus successfully demonstrated the success of the barrel reactor for the activation and coating of polymer particles.