A study on thermal and nanomechanical performance of cellulose nanomaterials (CNs)

Wood-based cellulose nanomaterials (CNs) (specifically, cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs)) are environmentally sourced low-impact materials with remarkable thermal, mechanical, and physical properties. This uniqueness makes them great candidates for creating nanocomposite materials with a wide range of attributes. Investigating the morphological, thermal, and nanomechanical properties of CNs becomes crucial to intelligent development of novel composite materials. An atomic force microscope equipped with a nanoindenter was used to investigate the compression modulus of CNFs and CNCs using two analytical approaches (denoted as Oliver Pharr (OP) and Fused Silica (FS)). The CNC modulus values (ECNC-FS = 21.1 GPa, ECNC-OP = 28.7 GPa) were statistically larger than those obtained from CNFs (ECNF-FS = 12.4 GPa, ECNF-OP = 15.1 GPa). Additionally, the FS analytical approach provided statistically significant lower estimates. Thermal stability of CNFs and CNCs was investigated using thermogravimetric analysis. Significant differences were found between CNF and CNC onset temperatures (OnsetCNC = 228.2 °C, OnsetCNF = 279.9 °C), decomposition temperatures (DTGACNC = 247.9 °C, DTGACNF = 331.4 °C), and residues (ResidueCNC = 34.4%, ResidueCNF = 22.8%). This research enriches the information on thermal stability and nanomechanical performance of cellulose nanomaterials, and provides increased knowledge on understanding the effect of CNs as a matrix or reinforce in composites.