Surface modification of polyethylene powder using plasma reactor with fluidized bed

Abstract

Abstract The fluidization technique was applied for the surface modification of powder by plasma, and whether the technique was a practically useful one in the surface modification of powder or not was discussed. Polyethylene powder was used as a specimen to be modified. The oxygen plasma treatment of the polyethylene powder in the fluidized state showed a capability that the surface of the powder was changed from hydrophobic to hydrophilic. The contact angle of water for the treated powder surface was 51°C, which was estimated from the dynamic wicking data. The hydrophilic surface modification of the polyethylene powders in the fluidized bed required the operation of the plasma treatment for at least 3 h. The requirement of the plasma operation for long time rises mainly from large surface area of the powder. The oxygen plasma treatment led to the formation of oxygen functionalities including C  O and C(O)O groups at the outermost layer of the powder. The concentration of the CO and C(O)O functionalities reached 10 and 6% of the total carbon elements being in the XPS sampling depth, respectively. From these results we conclude that the fluidization technique is a useful manner in the surface modification of powder by plasma.