ABSTRACT
Ultra-high molecular weight polyethylene (UHMWPE) powder was irradiated with air plasma prior to dissolving, quenching, and gel casting. Then, the dried gel cast film was ultradrawn, and its mechanical and surface properties were investigated using a tensile test, dynamic contact angle measurements and an adhesion test. By the plasma pre-treatment, hydrophilic functional groups were introduced onto the UHMWPE powder surface, which migrated into the bulk during gel casting and drying. However, they were relocated onto the surface of the gel cast film by subsequent immersing and ultra-drawing in boiling water. Because of the hydrophilic nature of the surface of the ultra-drawn gel cast film, its adhesion strength was found to increase without sacrificing its mechanical high performance. Silver was vapor deposited onto the UHMWPE film. The adhesion strength between the silver layer and the plasma pre-treated film was superior to that to the untreated film. Further, the luster of the deposited silver surface was excellent because of the surface smoothness of plasma pre-treated film. On the contrary, the plasma post-treatment after ultradrawing caused worse luster to the film because the film surface was roughened. The plasma pretreatment of the powder and its drawing in boiling water were found to be quite useful for the improvement of adhesion properties of ultra-drawn UHMWPE.
