(703c) Cellulose Acetate-Laponite® RD Nanocomposites: An Investigation of Model Materials for Advanced Organic-Inorganic Membranes

Membranes offer attractive alternatives to traditional thermally-driven separations. Polymeric materials offer attractive, low-cost processing; however, more selective and productive membranes would provide new application opportunities. Multi-component membranes utilizing organic and inorganic materials offer opportunities to achieve these goals.

Hybrid membranes incorporating traditional zeolite materials, with unit aspect ratios, limit options to create thin selective layers. Recent studies have considered high aspect ratio sieving materials (i.e. flakes or platelets) with significantly higher aspect ratio (L/D above 10) rather than traditional zeolites. These higher aspect ratios increase the tortuous path of permeation for rejected species, so a low volume fraction of platelet materials can be used to produce high performance membranes.

Incorporating nanoplatelet materials requires a high degree of exfoliation and complete particle dispersion to achieve optimal transport properties. Unfortunately, traditional melt-blended nanocomposite techniques are not directly applicable because high performance membranes are produced from solution. Our work focuses on addressing the challenges of preparing a composite mixture for membrane formation using non-thermal methods.

We have chosen cellulose acetate as the organic matrix because it is well-studied and industrially relevant as a material for gas separations membranes. Laponite® RD was chosen as the inorganic filler because its geometry (D < 1μm) is favorable for the transition to the production of asymmetric hollow fiber membranes. In this presentation we will discuss our non-thermal technique for producing composite solutions for membrane/barrier applications. Furthermore, we will discuss the transport properties of the dense-film membranes produced from these solutions and compare these results with common transport models.