(655e) Reverse Dialysis to Concentrate Cellulose and Chitin Nanomaterials and Their Polymer Composite Gels
AIChE Annual Meeting
Thursday, November 19, 2020 - 9:00am to 9:15am
In this work, we will show the potential of reverse dialysis as an effective and controllable method to concentrate cellulose and chitin nanomaterials and their PVA composite gels. Water is removed by dialyzing suspensions of the nanomaterials against a concentrated polymer solution. Although this method has been proposed before to concentrate nanocellulose, prior studies did not provide much detail. We first investigated the water removal kinetics at different PEG concentrations to understand the dialysis process and were able to concentrate CNC and TEMPO-CNF to at least twice the concentration of the existing commercially available slurry products. Rheological characterization of the samples dialyzed to various concentrations will be shown. Secondly, in addition to concentrating pure cellulose and chitin nanomaterials, we also use reverse dialysis to obtain high loadings of well-dispersed nanomaterials in polymer composite gels. The TEMPO-CNF/PVA composite gels were prepared in suspension at low concentration to ensure full dispersion, followed by water removal via reverse dialysis to form the gel. We will show that the composite gels prepared by this method are homogeneously dispersed at high loadings of polymers and nanomaterials, which cannot be easily achieved by directly mixing concentrated solutions of pure components. We used the new procedures to make PVA composite gels that contain TEMPO-CNF of different fibril sizes in order to study the effect of nanomaterials morphology. The reverse dialysis method enables quick processing of the materials, and samples can be retrieved with little loss. The method also increases the processing range of the cellulose and chitin nanomaterials, which can help to expand applications of these sustainable nanomaterials.