Surface Charges Control the Structure and Properties of Layered Nanocomposite of Cellulose Nanofibrils and Clay Platelets

Abstract

The interfacial bonding and structure at the nanoscale in the polymer–clay nanocomposites are essential for obtaining desirable material and structure properties. Layered nanocomposite films of cellulose nanofibrils (CNFs)/montmorillonite (MTM) were prepared from the water suspensions of either CNFs bearing quaternary ammonium cations (Q-CNF) or CNFs bearing carboxylate groups (TO-CNF) with MTM nanoplatelets carrying net surface negative charges by using vacuum filtration followed by compressive drying. The effect of the ionic interaction between cationic or anionic charged CNFs and MTM nanoplatelets on the structure, mechanical properties, and flame retardant performance of the TO-CNF/MTM and Q-CNF/MTM nanocomposite films were studied and compared. The MTM nanoplatelets were well dispersed in the network of TO-CNFs in the form of nanoscale tactoids with the MTM content in the range of 5–70 wt %, while an intercalated structure was observed in the Q-CNF/MTM nanocomposites. The resulting TO-CNF/MTM nanocomposite films had a better flame retardant performance as compared to the Q-CNF/MTM films with the same MTM content. In addition, the effective modulus of MTM for the TO-CNF/MTM nanocomposites was as high as 129.9 GPa, 3.5 times higher than that for Q-CNF/MTM (37.1 GPa). On the other hand, the Q-CNF/MTM nanocomposites showed a synergistic enhancement in the modulus and tensile strength together with strain-to-failure and demonstrated a much better toughness as compared to the TO-CNF/MTM nanocomposites.

Composite Films of Nanofibrillated Cellulose with Sepiolite: Effect of Preparation Strategy

“…Additionally, the mixture of charged CNF (TEMPO CNF) with clay minerals can result in a better dispersion state of the mineral and allow a good entanglement of the mineral and CNF [2]. A similar trend was observed in works dealing with films of TEMPO-oxidized CNF and montmorillonite, a planar clay mineral: an increase in tensile strength with the increment of clay content in the nanocomposite up to 10% [23]. The values reported for the tensile strength and Young's modulus were higher than those obtained in the present work, but it is important to note that this kind of layered clay minerals can be easily exfoliated and form exfoliated nanocomposites with good mechanical properties.…”

Assembling Lipoic Acid and Nanoclay into Nacre-Mimetic Nanocomposites

“…In fact, in an organic/inorganic composite, the mechanical performance depends not only on the nature of the components but also on the morphological structure and the interfacial adhesion. They are very critical, in particular in a nacre-like composite with a high fraction of inorganic content. , As indicated by XRD results, tactoids are found in the composites with NH 4 + and K + , which can be one of the reasons for the higher modulus and poorer ductility of the materials . On the other hand, the strength of interfacial adhesion can be related to the hydration of the cations .…”

“…51,62 As indicated by XRD results, tactoids are found in the composites with NH 4 + and K + , which can be one of the reasons for the higher modulus and poorer ductility of the materials. 63 On the other hand, the strength of interfacial adhesion can be related to the hydration of the cations. 51 A weaker hydration of the cation allows water molecules to displace more easily from the clay/ polymer interface by polymers, leading to more polymer adsorption and thereby stronger interfacial adhesion.…”

Chemistry and Nanotechnology‐Oriented Strategies toward Nanocellulose for Human Water Treatment

“…They not only represent a unique biomaterial with significant abundance and sustainable production, but also permit the pursuit of novel applications in a diverse range of fields which can be ascribed to their inherently attractive chemical functionalities and physical attributes. [15][16][17][18][19] There is an urgent need for new approaches to attain complete removal of a broad spectrum of contaminants in a single treatment phase. The main goal of this review is to present new opportunities and approaches by using chemistry and nanotechnology of nanocellulose and nanocellulose derived nanocomposites to enhance the efficiency and affordability of water treatment and wastewater reuse.…”

“…They not only represent a unique biomaterial with significant abundance and sustainable production, but also permit the pursuit of novel applications in a diverse range of fields which can be ascribed to their inherently attractive chemical functionalities and physical attributes. [ 15–19 ]…”