Self-assembled Montmorillonite clay-poly vinyl alcohol nanocomposite as a safe and efficient gas barrier

Abstract

Fabrication of polymer nanocomposite usually requires an extensive high shear mixing and substantial energy input. However, it has been demonstrated that polyvinylpyrrolidone (PVP) and Montmorillonite clay nanoparticles (MMT), will spontaneously form a highly ordered nanocomposite film when applied to a surface utilizing an inkjet printing technique. The as-synthesized nanocomposite prepared by this technique exhibits high barrier properties for oxygen gas. This self-assembly of MMT nanosheets inside the polymer matrix appears to be driven by entropic forces. In this work, an efficient gas barrier based on MMT and polyvinyl alcohol (PVOH) nanocomposite is reported. By adding MMT clay to our PVOH polymer, we solve the problem of sensitivity to humidity observed in pure PVOH films. PVOH is a well-known polymer that exhibits excellent gas barrier properties. However, PVOH is very sensitive to humidity and it must be protected by polymer overcoats such as polypropylene to exclude water. PVOH-MMT nanocomposite prepared in this work solves this problem without the need for polymer overcoating for protection. PVOH and MMT are spontaneously self-assembled into a nanocomposite film that exhibits extremely high oxygen barrier, high transparency, and low sensitivity to humidity which can largely be attributed to constrained polymer effects.