Cellulose is an abundant green polymer, which can be obtained in a variety of
nanoscale structures broadly grouped as nano/microfibrils (CNF/MFC), bacterial
celluloses (BC) or nano/microcrystals (CNC/CMC). There is increasing interest of
nanocelluloses by the research and industrial communities due to increasing
available materials (facilities than can produce ton per day), impressive
strength properties, low density, renewability and biodegradability. However,
one problem is the lack of knowledge on the nanomechanical properties of
cellulose nanofibrils, which creates barriers for the scientists and producers
to optimize and predict behavior of the final product.
In this research, the behavior of thin filmed (t≤100 μm)
cellulose nanofibrils’, located on aluminum pin stubs, under nano
compression loads were investigated using an Asylum Research MFP-3D Atomic Force
Microscope equipped with a nanoindenter. Unloading curves were analyzed using
Oliver-Pharr. As a result of 58 successful nanoindents, the average modulus
value was estimated as 16.6 GPa with the reduced modulus value of 18.2 GPa. The
CNF Modulus values varied between 12.4 GPa – 22.8 GPa with 16.9%
coefficient of variation (COV) while the reduced modulus ranged from 13.7 GPa to
24.9 GPa with a 16.2 % COV.
This research provides practical knowledge for producers of nanocellulose,
researchers and applications developers who focus on nanocellulose reinforced
composite materials.