Polymer/Nanoclay Nanocomposites for Paper Barrier Coating, 2006 International Conference on Nanotechnology

Improving barrier properties of paper containers using nanocomposites has been an active research area recently. In this study, Montmorrilonite and Saponite were used as the nanoclay sources, and polystyrene-butadiene copolymer latex and polyacrylate aqueous dispersions were used as the coating polymers to form the Polymer/Clay Hybrid Nanocomposite (PCHN). The effects of different treatments on the dispersion stability and the nanoclay addition on the improvement of barrier properties were studied. The nanoclay properties and their interactions with the polymer matrix were correlated. Results show that the as-intercalated nanoclay can be fully exfoliated by a simple mechanical mixing in aqueous solution in the presence of dispersion agents Tween-85 and polyacrylic acids (Mw ~ 5 k to 15 k Dalton). The coating layer of exfoliated polymer/clay nanocomposites could significantly improve paper barrier properties. However, the barrier properties of the coating layer are intimately dependent on the mixing conditions, coating process, surface morphology, and the agglomerate formation of the exfoliated clay in the polymer matrix. The study explored a pathway toward practical application of nanoclay with polymer dispersions in paper coating in a cost effective and environmentally friendly way. A brief economic estimation reveals that the PCHN can effectively reduce the paper coating cost to a reasonable level.