Fast and quantitative compositional analysis of hybrid cellulose-based regenerated fibers using thermogravimetric analysis and chemometrics

Fabrication of a novel magnetic nanostructure based on cellulose-gellan gum hydrogel, embedded with MgAl LDH as an efficient catalyst for the synthesis of polyhydroquinoline derivatives

Nanocatalysts play a vital role in chemical reactions, energy conservation, and pollution control. They significantly contribute to organic synthesis by using natural polymers as nanoparticle substrates in nanocatalysts. Natural hydrogels made from polysaccharide and/or protein sources may be used to accomplish this. Recent research has focused on using layered double-hydroxides (LDHs) in composites having catalytic properties. Magnetic features of the catalyst allow its extraction from the environment using a magnet after the reaction, improving product efficiency. This work developed a catalyst for producing physiologically relevant polyhydroquinoline derivatives using a novel magnetic nanocomposite containing natural cellulose-gellan gum hydrogel and MgAl LDH. The Cell-GG hydrogel/MgAl LDH/Fe3O4 nanocomposite showed over 90 % efficiency in one-pot production of polyhydroquinoline derivatives by asymmetric Hantzsch condensation. Dimedone, ammonium acetate, ethyl acetoacetate, and different substituted aldehydes were employed in successive processes to create polyhydroquinoline derivatives. High product efficiency, quick reaction time, room temperature functioning, and easy separation with a magnet suggest a potent catalyst. Interestingly, the catalyst retains 80 % of its original capability after four cycles. Additionally, the Cell-GG hydrogel/MgAl LDH/Fe3O4 nanocomposite was analyzed using several methods, including FT-IR, FE-SEM, EDX, XRD, VSM and TGA, to obtain insight into its chemical and physical characteristics.

Progress, Challenge and Perspective of Fabricating Cellulose

Cellulose as the most abundant biopolymers on Earth, presents appealing performance in mechanical properties, thermal management, and versatile functionalization. The development of fabrication methods closely relates to enrich its functionality and reduce manufacture cost. However, cellulose is hard to be dissolved by most common solvents or melt due to its recalcitrant property. Herein, the recent progress of fabricating cellulose is summarized. First, the unique hierarchical structure of cellulose is fully investigated and the resulted processability is highlighted in directions of down to nanocellulose, dissolution, and thermoplastic processing. Then, the reported fabrication methods are summarized in three aspects: (1) self-assembly from nano/micro cellulose suspensions, especially the self-assembly of cellulose nanocrystals; (2) dissolution-regeneration-drying, covering spinning and solvent infusion processing; and (3) thermoplastic processing, focusing on analysis of the setup and the morphology changes of the prepared products. In each aspect, the flowchart of the fabrication process, the behind mechanism, fabricated products, and effects of processing parameters are explored. Finally, this review provides a perspective on the further direction of fabricating cellulose, especially the challenges toward mass production of cellulose. This article is protected by copyright. All rights reserved.