A Study on Thermal and Nanomechanical Performance of Cellulose Nanomaterials (CNs)

Abstract

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.

Green esterification: A new approach to improve thermal and mechanical properties of poly(lactic acid) composites reinforced by cellulose nanocrystals

“…The first peak was related decomposition of the negatively charged sulfate groups on CNCs and the second peak can be related to depolymerization of cellulose in competition with dehydration. These observations are corroborated by another study on cellulose nanomaterials treated with sulfuric acid . Table presents thermal characteristics of PLA and nanocomposites obtained from TGA and DTG curves.…”

“…These observations are corroborated by another study on cellulose nanomaterials treated with sulfuric acid. 27,36,37 Table II presents thermal characteristics of PLA and nanocomposites obtained from TGA and DTG curves.…”

Comparison of tension wood and normal wood for oxidative nanofibrillation and network characteristics

“…The reduced bonding can thus be attributed to the presence of larger nanofibrils in the TW networks. Moduli between 12.4 and 15.1 GPa have been reported for other CNF networks from similar cellulosic materials (Yildirim and Shaler 2017), and values of 4.7-8.8 GPa have been reported for cellulose nanocrystal films with a hardness of 0.3-0.5 GPa (Wu et al 2013). These ranges are similar to those of the networks observed in this study.…”

Isolation of Cellulose Nanofibers from Oryza sativa Residues via TEMPO Mediated Oxidation

“…Lower thermal stability has been reported to be linked to increased crystallinity, fibril and particle sizes as highly crystalline and small particle size materials have a higher heat transfer ability due to increased surface area. Moreover, smaller particle sizes increase the number of end chains which in turn decompose at lower temperatures yielding higher amount of char while the presence of inorganic salts and acids has been known to act as flame retardants during pyrolysis thereby increasing char yield (Nascimento et al 2016;Yildirim and Shaler 2017).…”