Polymer Nanocomposite Films

Polymer nanocomposites using low weight loadings of a platelet filler can improve the polymer's material properties. Less than 10wt% platelets in a nanocomposite can lead to remarkably different properties due to the amplified polymer-platelet interfacial area. The thermal, mechanical and gas barrier properties are improved, all while maintaining the optical clarity.

In this study, the solution blending method was used to make polyvinyl alcohol (PVOH) films loaded with exfoliated montmorillonite (MMT) clay. The optical and gas barrier properties of these films were tested to determine their possible use in various applications including food packaging.

UV-Vis spectroscopy results indicated that appropriate “cleaning” of MMT solutions is important to maintain the optical clarity of the films. Loading of “clean” MMT in PVOH at less than 10wt% does not affect light transmission in the visible region. However, MMT does absorb or scatter UV light which may prevent polymer degradation in sunlight. The oxygen barrier of MMT/PVOH films was not as high as predicted by recent theoretical models. We used AFM to measure the films' surface roughness which might play some role. Other factors, including polymer crystallinity and platelet orientation, will need to be investigated further to determine their role in gas barrier performance.