|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||2018 Technical Division Student Poster Competition
||SPG-9: Hygroscopic Swelling Determination of Cellulose Nanocrystal (CNC) Films by Polarized Light Microscope Digital Image Correlation
||Shikha Shrestha, Jairo Diaz, Siavash Ghanbari , Jeffrey P. Youngblood
|On-Site Speaker (Planned)
The coefficient of hygroscopic swelling (CHS) of self-organized and shear- oriented cellulose nanocrystal (CNC) films was determined by capturing hygroscopic strains, which was produced by isothermal water vapor intake in equilibrium. The characterization of dimensional changes induced by the hygroscopic swelling of the films is enabled by contrast-enhanced microscopy digital image correlation. The distinct microstructure and birefringence of CNC films served in exploring the in-plane swelling at relative humidity values ranging from 0% to 97%. The experimental moisture sorption and kinetic profiles were analyzed by fitting with Guggenheim, Anderson, and deBoer (GAB) and Parallel Exponential Kinetics (PEK) models, respectively. Self-organized CNC films showed isotropic swelling, CHS ~ 0.040 %strain/% C whereas, shear-oriented CNC films exhibited an anisotropic swelling, resulting in CHS ~ 0.02 and ~ 0.30 %strain/%C, parallel and perpendicular to CNC alignment, respectively. Finite element analysis (FEA) predicted moisture diffusion as the predominant mechanism for swelling in CNC films.