Partial Amorphization of Cellulose through Zinc Chloride Treatment: A Facile and Sustainable Pathway to Functional Cellulose Nanofibers with Flame-Retardant and Catalytic Properties

Abstract

This work established an energy-saving and straightforward treatment of cellulosic pulp to obtain functional cellulose nanofibers equipping them at the same time with catalytic activity and flame-retardant properties. For this purpose, dried cellulose pulp was mixed with a recyclable swelling agent, ZnCl 2 hydrate, at room temperature. The mild treatment affected the crystal structure through a partial amorphization, yielding a mix of native cellulose I and regenerated cellulose II. This treatment tremendously facilitated the fibrillation into a cellulose nanofiber (CNF) network. In comparison to fibrillated cellulose from nontreated pulp, the ZnCl 2 -treated counterpart featured higher viscosity, film transparency, better mechanical properties, and higher heat stability. Films produced from these nanofibers showed flame-retardant properties without any further modification. The ZnCl 2 −CNF showed also high reactivity in fiber surface acetylation and allowed a fast and efficient reaction while using very mild conditions. All in all, we propose a simple and resource-efficient cellulose treatment to obtain a nanostructured cellulose. These nanofibrils are decorated with ZnCl 2 which imposes flame-retardant properties and confined catalytic activity at the fibril surface.

Role of Combined Na2HPO4 and ZnCl2 in the Unprecedented Catalysis of the Sequential Pretreatment of Sustainable Agricultural and Agro-Industrial Wastes in Boosting Bioethanol Production

“…To explore the influence of the pretreatment on the surface morphology and the physical features changes of CS and TP after pretreatment with Z and NZ, SEM analysis was investigated, and is presented in Generally, the improvement in the produced glucose after pretreatment may be related to the low lignin content, which implies exposure of a higher number of active sites and the 1-beta glucoside bonds of the cellulose to the enzymes [26]. These results correspond with those found in the literature [27].…”

Deconstruction and Reassembly of Renewable Polymers and Biocolloids into Next Generation Structured Materials

“…Cellulose fibers, of 90% purity or higher, are referred to as dissolving-grade pulp, the starting material for the production of soluble cellulose ethers or esters, 27 but also used as precursor for functional biocolloids. 163 , 204 , 205 …”

Fire-Safe Polymer Composites: Flame-Retardant Effect of Nanofillers

“…In general, bromine- or chlorine-containing compounds are used for several halogen-based flame retardants [ 91 , 92 , 93 , 94 ]. Particularly, bromine compounds with high bromine content and low-energy carbon–bromine covalent bonds are widely used as flame retardants in both thermoplastics and thermosets.…”