(437f) Additive Manufacturing of Mechanically Adaptive Polymer / Nanocellulose Composites

Bortner, M. J., Virginia Polytechnic Institute and State University
Foster, E. J., Virginia Tech
Fallon, J., Virginia Polytechnic Institute and State University
This research highlights materials development and additive manufacturing (AM) of mechanically adaptive polymer composites in filament extrusion processes. Here we specifically focus on the impact of processing on mechanical modulus change upon exposure to water/moisture. A mechanically adaptive composite comprising thermoplastic polyurethane with 10 wt% cellulose nanocrystals is analyzed following 1) filament production from a masterbatch and 2) subsequent AM of functional parts. The interplay between thermal history and shear induced particle orientation are investigated to highlight the magnitude of dynamic modulus change upon moisture exposure, impact of geometry on moisture diffusion kinetics, and reversibility of the adaptation process. Further, we investigate the response of functionally graded AM produced parts to understand the ability to adapt geometry based on stress mismatch.