Alternatives to Drying and to Low-Solids Processing of Cellulose Nanomaterials

摘要

The removal of water from cellulose nanomaterial suspensions remains one of the greatest challenges for their processing and application. Existing drying strategies are often costly, have low throughput and tend to undesirably alter the morphology of the nanomaterials. often resulting in materials that are no longer nanoscale. Here some alternative strategies to producing, processing and incorporating cellulose nanomaterials into composites will be discussed. One such strategy is to "wet compound" cellulose nanomaterials into composites by directly introducing cellulose nanomaterial suspensions directly with polymers and driving the water out as the materials are mixed. Depending on the polymer system, wet compounding can provide additional benefits, including the reduction of melt and processing temperatures. Other strategies include hydrolyzing pulps at high solids under high shear rates, potentially enabling the handling of fibrillated pulps with relatively low water content. High solids hydrolysis and fiber deconstruction can be facilitated by tailored biochemistry, including the use of thermophilic enzyme formulations. Some examples from these strategies will be provided along with a discussion of their limitations and remaining challenges.