Storage of cellulose solution can be practically ineluctable before it is manufactured into various regenerated products (e.g., fibers, films), especially in the case of industrial production. Therefore, it is necessary to evaluate the effect of storage time and temperature on the dissolved state of cellulose in the interested TBAH-based solvents (including TBAH/H2O, TBAH/H2O/DMSO, TBAH/H2O/Urea), as well as on the mechanical property of the relevant regenerated products (films were prepared in this work for the evaluation). The dissolved state of cellulose in these solvents along with storage has been analyzed with the polarized light microscope photographs and Stormer viscosity. Focus on the interested TBAH/H2O/DMSO solvent, the effect of storage time and temperature on the solution viscosity, and degree of polymerization of cellulose have been discussed. Critical storage time for different storing temperature has been determined, after where significant cellulose degradation happens. A series of regenerated cellulose films with storage time ranging from 0 to 200 h have been prepared. The optimal storage time and strengthening mechanism for cellulose films regenerated from the solution of cellulose/TBAH/H2O/DMSO have been discussed. This work can provide reference about storage time and temperature of cellulose/TBAH/H2O/DMSO, especially for the production of pilot-scale, etc.
Bamboo is a kind of renewable natural polymer resource. Using bamboo biomass without a component isolation process can be a sustainable route for the preparation of an ecofriendly biomass film. Inspired by the natural structure of plant biomass, we designed to introduce a bionic interaction, being akin to the role of hemicellulose in natural biomass, for connecting the cellulose and lignin components using tannic acid-modified cellulose nanocrystals (TA@CNCs) as the bridging molecules. In order to make up for the size difference between the cellulosic molecules and lignin particles, cellulose nanocrystals (CNCs) served as the carriers of TA. Core−shell hybrids of TA@CNCs were prepared and added into the solution of bamboo powder dissolved in a tetrabutylammonium hydroxide/dimethyl sulfoxide aqueous solvent (TBAH/H 2 O/DMSO) followed by gelation in air and regeneration in water to prepare the bamboo-derived biomass films with high strength. The results showed that the tensile strength of the as-prepared films was effectively improved from 55.4 to 127.2 MPa by adding 5 wt % TA@CNCs. Structural analyses indicated that TA@CNCs serve as an excellent modifier for the enhancement of cellulose−lignin interfaces by rationally reconstructing the biomimetic hydrogen-bonded system.
Capturing and detecting Fe3+ ions in aqueous solution is of great significance in biological systems as well as the water treatment industry. Herein, pyrene-modified cellulose nanocrystal (CNC-1-Pyr) acting as a fluorescent probe was prepared by a one-step esterification reaction, which shows geometry relaxation under UV-light excitation. Experiments and density functional theory-based simulations revealed that the structural geometry relaxation is controlled by the electron excitation and fluorescence emission. The S1 state of CNC-1-Pyr provides a conformation match for coordination with Fe3+ under the excitation of UV light, facilitating the detecting and capturing of Fe3+ efficiently.
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