Preparation and Barrier Properties of Nanocellulose / Layered Double Hydroxide Composite Film

Abstract

Cellulose nanofibrils (CNFs) were oxidized by the TEMPO oxidation system from bleached kraft eucalyptus pulp, and layered double hydroxides (LDHs) were prepared via the hydrothermal method. MgAl-CO3-LDHs/CNFs composite films with different LDH ratios were prepared via a filtering/evaporation technique that endowed the nanocomposites with barrier and strengthening properties. The MgAl-CO3-LDHs could uniformly disperse in the CNFs matrix with an improved reciprocal adhesion, and the surface result was smooth and continuous. The basic structure of the membrane did not change, but the thermodynamic properties and the water vapor barrier property improved. This composite membrane can be widely used in food, pharmaceutical, and chemical packaging industries as a gas-liquid barrier material. Keywords INTRODUCTIONCellulose nanofibrils (CNFs) film was peeled off from CNFs water suspension. This type of film exhibits environmental friendliness, high transparency, high mechanical performance, and enhanced gas barrier properties. With these multifunctional combinations, these nanocomposites have wide application prospects in the encapsulation of drugs, tissue engineering, or outdoor load-bearing applications. The transparency of the CNFs film was achieved by air-drying, which simultaneously improved the tensile strength and oxygen barrier properties. Because hydrogen bonding in cellulosic nanoparticles forms a dense percolating network, and the penetration of molecules is difficult in the crystalline domains of cellulose microfibrils, these composite films have been suggested for use as barrier films (Fukuzumi 2009;Belbekhouche et al. 2011). Due to the high hydrophilicity of nanocellulose, the fiber network of CNFs membrane material is loose, and the mechanical properties decrease when wet (Lavoine et al. 2012). To improve the barrier properties of CNFs based film materials, chemically modified CNFs were used, and lamellar substances were also added to extend the path of small molecules in the CNFs infiltration. Talc platelets (Liimatainen et al. 2013) and montmorillonite platelets (Wu et al. 2012) were used to increase gas barrier properties of the CNFs film. Compared with other typical platelet-like inorganic materials, the aspect ratio of layered double hydroxides (LDHs) nanosheets can be easily adjusted during the synthesis process. As an important nanoscale material, LDHs have a hydrophobic nature and layered structures, which make the movement of gas and water molecules become complex and difficult. LDHs improve the gas barrier properties of CNF films, as illustrated in Fig. 1 (Qian et al. 2015).LDHs were prepared via a hydrothermal method, and CNFs were prepared by TEMPO oxidation / homogenization (Saito et al. 2007). The MgAl-CO3-LDHs were PEER-REVIEWED BRIEF COMMUNICATION bioresources.com Wang et al. (2018). "Nanocellulose composite," BioResources 13(1), 1055-1064. 1056 incorporated into the CNFs via a filtering/evaporation technique, which strengthened the nanocomposites. The MgAl-CO3-LDHs dispersed uniformly int...

The State-of-the-Art Functionalized Nanomaterials for Carbon Dioxide Separation Membrane

“…While the development of membrane technology was initially centered around water treatment processes such as microfiltration (MF), ultrafiltration (UF) and reverse osmosis (RO), the interest on this technology soon expanded to various applications such as gas purification, energy storage, power generation, pharmaceutic and health care [19][20][21][22][23]. The preference towards membrane technology is largely driven by the simplicity of membrane processes which involve few moving parts and have low labor and maintenance requirements [24,25].…”