(137b) High Shear Capillary Rheometry of Cellulose Nanomaterials for Industrial Relevant Processing

Nanocellulosics, which are typically found in the form of Cellulose nanocrystals (CNCs) and Cellulose Nanofibrils (CNFs) provide promise as both filler and reinforcement materials. The biological origin of CNCs promises a biorenewable resource combined with potential expedited degradation times compared to traditional plastic species. Meanwhile, the surface functional groups on CNCs promise networking capabilities via hydrogen bonding. While much research is currently investigating the possible uses of this material, they offer limited aid if they are not scalable to industrial processing techniques. Common processing techniques such as injection molding subject materials to strain rates upwards of 10,000 s^-1. The resulting stresses have the potential to cause alignment in the crystals, providing exploitable anisotropy in any injected product. In this work, we investigate the effect of these strain rates and subsequent shear stresses on CNCs and CNFs over multiple concentrations up to 12.1 wt% in water. Both capillary and extensional rheometry have been deployed to characterize the potential degradation and relaxation characteristics of these materials after exposure to high strain rates. Furthermore, we investigate the potential to apply Williams-Landel-Ferry (WLF) like shift factors for time-temperature superposition as well as time-concentration superposition.