Comparative Study of Aerogels Obtained from Differently Prepared Nanocellulose Fibers

Abstract

This article describes the fabrication of nanocellulose fibers (NCFs) with different morphologies and surface properties from biomass resources as well as their self-aggregation into lightweight aerogels. By carefully modulating the nanofibrillation process, four types of NCFs could be readily fabricated, including long aggregated nanofiber bundles, long individualized nanofibers with surface C6 -carboxylate groups, short aggregated nanofibers, and short individualized nanofibers with surface sulfate groups. Free-standing lightweight aerogels were obtained from the corresponding aqueous NCF suspensions through freeze-drying. The structure of the aerogels could be controlled by manipulating the type of NCFs and the concentration of their suspensions. A possible mechanism for the self-aggregation of NCFs into two- or three-dimensional aerogel nanostructures was further proposed. Owing to web-like structure, high porosity, and high surface reactivity, the NCF aerogels exhibited high mechanical flexibility and ductility, and excellent properties for water uptake, removal of dye pollutants, and the use as thermal insulation materials. The aerogels also displayed sound-adsorption capability at high frequencies.

Effect of homogenization and ultrasonication on the physical properties of insoluble wheat bran fibres

“…The HIU treatment makes use of the cavitation effect of ultrasound to break down the aggregation of fibres while the axial shear force is weak (Chen et al, 2014), which leads to long cellulose fibres, resulting in larger size. The particle size of the homogenized suspension decreased with the increase in the initial concentration of IDF.…”

Preparation and Characterization of Nanocellulose Fibers from NaOH/Urea Pretreatment of Oil Palm Fibers

“…The term nanocellulose fibers usually refers to fibers within a general size range of 10 nm to 1000 nm, basically consisting of nanocrystalline cellulose, nanofibrillated cellulose, and bacterial cellulose. Due to its excellent properties, such as thermal stability, environmental benefits, optical transparency, and hydroxyl groups on the surfaces, nanocellulose fibers have become a precursor in a variety of new functional biomaterials, including transparent films , aerogels (Chen et al 2014), reinforcing agents (Tibolla et al 2014), and separation membranes (Metreveli et al 2014).…”

Structural Characterization and Modifications of Surface-oxidized Cellulose Nanofiber

“…These unique properties of TOCN _ COOH aerogels are explained in terms of the following three factors; (1) the aerogels consist of TOCN elements with high tensile properties 21), 22) , (2) the TOCN elements in the aerogels form aligned structures owing to the nematic-ordered structures originally present in the aqueous TOCN dispersions 63) , and (3) formation of TOCN agglomerates during drying process can be prevented as much as possible in the aerogels. Although some nanocelluloserelated aerogels have been prepared by various procedures 65) 71) , TOCN _ COOH aerogels prepared in our laboratory are superior to other nanocellulose aerogels in terms of low density and high specific surface area, and optical, mechanical and thermal properties.…”