Transparent montmorillonite/cellulose nanofibril nanocomposite films: the influence of exfoliation degree and interfacial interaction

Abstract

To obtain high performance of nanocomposite lms made of cellulose nano brils (CNFs) and montmorillonites (MMTs), highly ordered nanostructures and abundant interfacial interactions are of extreme importance, especially for CNF lm with high MMT content. Here, we tend to unveil the in uence of exfoliation degree of MMTs and their interfacial interactions with CNFs on the properties of ensuing nanocomposite lms. Monolayer MMTs prefer to form highly ordered nanostructure during water evaporation induced self-assembly. The obtained nanocomposite lm with 30 wt% monolayer MMTs exhibits a tensile strength of 132 MPa, a total light transmittance of 90.2% (550nm), and water vapor transmission rate (WVTR) of 41.5 g•mm/m2•day, better than the lm made of original bulk MMTs and CNFs (30 MPa strength, 60% transparency, and 78.7 g•mm/m2•day WVTR). Moreover, the physical properties (153 MPa strength and 20.9 g•mm/m2•day WVTR) of nanocomposite lm can be further enhanced by constructing ionic interactions between the monolayer MMT and CNF using 0.5 wt% cationic polyethylenimine (PEI). However, as the amount of PEI continues to increase, its performance will be deteriorated dramatically because of the disordered orientation of monolayer MMTs. This work could provide an insight into the fabrication of high performance MMT/CNF nanocomposite lm for advanced applications.

Cellulose Nanofibril/Talc Composite Films with Excellent Barrier Properties by Alternate Hierarchical Method

“…The cross sections were obtained by immersing the films in liquid nitrogen and breaking them with tweezers. In the cross sections of pure TOCN, TOCN/talc-20, pure MCNF, and MCNF/talc-20 films, alternate hierarchical structures formed by talc platelets and CNFs were observed in the vertical direction, which reduced the passage of gases, such as oxygen and water vapor through the film . The energy-dispersive X-ray analysis (EDS) element mappings of MCNF/talc-20 and TOCN/talc-20 films are shown in Figure m,n, demonstrating that the talc platelets (element Si and Mg) were uniformly distributed in the CNF films.…”

“…In the cross sections of pure TOCN, TOCN/talc-20, pure MCNF, and MCNF/talc-20 films, alternate hierarchical structures formed by talc platelets and CNFs were observed in the vertical direction, which reduced the passage of gases, such as oxygen and water vapor through the film. 27 The energy-dispersive Xray analysis (EDS) element mappings of MCNF/talc-20 and TOCN/talc-20 films are shown in Figure 3m,n, demonstrating that the talc platelets (element Si and Mg) were uniformly distributed in the CNF films. However, some gaps appeared between the layers in TOCN/talc-40 and MCNF/talc-40 due to the insufficient dispersion of some talc platelets, which might affect some properties of the films.…”

Reducing Water Exchange by Polyacrylic Acid Based Water‐Vapor‐Resistant Membrane in Zinc/Air Battery

“…As known, water molecules form a hydrogen bond network in liquid water, but when water exists in a gaseous state, it is shown that water exists in the form of water molecule clusters, and the number of water molecules in the clusters is related to the temperature and humidity of the environment, generally between several to dozens [13] . To suppress the transmission of water vapor, functional layers can be prepared from differrent organic/inorganic materials, such as graphene oxide, [14] PVA/ alkyl ketene dimer/nanoclay, [15] poly(styrene‐b‐2‐vinylpyridine)‐MgO, [16] PVA‐lignin nanomicelle [17] and cellulose nanofibrils‐montmorillonites, [18] which leads to the increase of the water vapor resistance to a certain extent.…”