Liquid ammonia treatment of (cationic) nanofibrillated cellulose/vermiculite composites

Abstract

Liquid ammonia was used to treat films of nanofibrillated cellulose (NFC), trimethylammonium-modified NFC (TMA-NFC), and their composites with vermiculite. Crystal structure, mechanical properties, water vapor permeation and water vapor adsorption of the resulting materials were investigated. Upon treatment, the crystal structure of (TMA-)NFC both in presence and absence of vermiculite changed from cellulose I to III. With the exception of TMA-NFC/vermiculite composites, pronounced effects on the addressed mechanical properties arose after exposure of the materials to ammonia. Furthermore, treatment of composite films with ammonia led to a distinct decrease in water vapor permeation. Remarkably, TMA-NFC/vermiculite composites films show the best water vapor barrier properties, high-

Nanocellulose-montmorillonite composites of low water vapour permeability

“…Although significant studies on cellulose-clay composites exist, only nine investigations aimed at reducing WVP. Various nanocellulose-nanoclay composites were made with surfactant [46], nanofibrillated cellulose surface modification [39,47,48], and poly(vinyl alcohol) and poly(acrylic acid) polymer addition [18]. Similar cellulose nanofibre-clay composites, but made from a different methodology, reported WVP of 1,800,000 g μm/ m 2 day kPa [49]; WVP for nanofibrillated cellulose-vermiculite composite is 60.5 g μm/m 2 day kPa [3], bacterial cellulose with unmodified MMT composite, 53.3 g μm/m 2 day kPa [50] and the lowest WVP value reported for cellulose nanofibrils-mineral MMT composite made by solvent casting is 16.4 g μm/m 2 day kPa [45].…”

Characterization of Water Vapor Sorption Performance and Heat Storage of MIL-101 (Cr) Complex MgCl2, LiCl/LaCl3 System for Adsorptive Thermal Conversion

“…Because water is easily available and harmless, more adsorption heat pump systems choose water vapor as the adsorbate material. The commonly used adsorbents are mainly various porous materials, such as zeolite, expanded vermiculite, kaolin, diatomite, microporous aluminum phosphate, and so on. They physically adsorb with water at lower temperatures and release heat, while they store heat by dehydration and heat absorption at higher temperatures …”