Study of the synthetic silica functionalization effect on wettability of oxidized polypropylene film by plasma discharge

Abstract

AbstractThis work describes the effect of functionalized silica, treated with organosilane (γ‐methacryloxypropyltrimethoxysilane), on the wettability loss of polypropylene (PP) film when exposed to surface oxidization treatment by atmospheric air plasma. The observed wettability loss results from the spontaneous process within the polymer matrix, which reduces surface energy, causing oxidized polymer molecules to move toward the bulk of the film. The effect of silica's functionalization on the initial wettability of oxidized PP film and its loss on storage time is measured by contact angle. Elemental analysis of the modified silica, employing acid catalytic processes, reveals the highest functionalization yield. Silicon nuclear magnetic resonance shows that the post‐condensation process negatively affects structures formed by the organosilane, eliminating three‐dimensional bonds and reverting it to its original and hydrolyzed state. The solvent extraction process and elemental analysis confirm that the concentration of organosilane in the chemically bonded layer, which was around 9 wt%, is not influenced by the post‐condensation treatment. Notably, silica functionalized with the highest concentration of organosilane has significantly improved initial wettability when oxidative treatment occurs within a shorter residence time (30 s), which achieved a contact angle of 53.8° against 59.1° for the film with untreated silica. However, the wettability loss rate of the materials remains unaffected by the presence of functionalized silica.