An integrated wet-spinning system for continuous fabrication of high-strength nanocellulose long filaments.

The continuous production of high-strength nanocellulose long filaments (NCLFs) is critical in natural fiber-reinforced polymer composites. Despite the widespread availability of numerous filament production processes, the cost-effective and continuous fabrication of high-strength NCLFs on a large scale remains an ongoing challenge. Herein, we present an integrated wet-spinning system by incorporating a few previously researched filament production techniques to mass fabricate high-strength continuous NCLFs. The spinning speed is increased to improve NCLF productivity, and the bobbin winder speeds, collector bobbin winder location, and NCLF drying conditions are tuned. At the spinning speed of 510 cm/min, a production rate of 4.99 m/min is achieved, five times higher than the productivity of the former pilot system (0.92 m/min). Moreover, an AC electric field and mechanical stretching are introduced to highlight the versatility of the proposed integrated wet-spinning system, thereby enhancing the mechanical properties of NCLFs.

Molecular Dynamics Study of Cellulose Nanofiber Alignment under an Electric Field.

The alignment of cellulose by an electric field is an interesting subject for cellulose material processing and its applications. This paper reports an atomistic molecular dynamics simulation of the crystalline cellulose nanofiber (CNF) model in varying electric field directions and strengths. GROMACS software was used to study crystalline cellulose 1ß consisting of 18 chains in an aqueous environment at room temperature, and an electric field was applied along the cellulose chain direction and the perpendicular direction with varying field strength. The root-mean-square displacement, radius of gyration, end-to-end length, and hydrogen bond population of the crystalline CNF model were analyzed to determine the effects of the applied electric field on the structure of the CNF model. The results suggest that the nanosecond electric field can induce the orientation of the CNF along the applied electric field direction. The alignment rate and ability to maintain the alignment depend on the electric field strength. Analysis of the radius of gyration, end-to-end length, and bond lengths for intrachain and interchain hydrogen bonds revealed no significant effect on the cellulose structure. Cellulose alignment in an electric field has the potential to broaden the design of electric field-induced processing techniques for cellulose filaments, thin films, and electro-active cellulose composites.

High-strength cellulose nanofiber/graphene oxide hybrid filament made by continuous processing and its humidity monitoring.

Human-made natural-fiber-based filaments are attractive for natural fiber-reinforced polymer (NFRP) composites. However, the composites' moisture distribution is critical, and humidity monitoring in the NFRP composites is essential to secure stability and keep their life span. In this research, high strength and humidity sensing filament was developed by blending cellulose nanofiber (CNF) and graphene oxide (GO), wet-spinning, coagulating, and drying, which can overcome the heterogeneous mechanical properties between embedded-type humidity sensors and NFRP composites. The stabilized synthesis process of the CNF-GO hybrid filament demonstrated the maximum Young's modulus of 23.9 GPa and the maximum tensile strength of 439.4 MPa. Furthermore, the achieved properties were successfully transferred to a continuous fabrication process with an additional stretching process. Furthermore, its humidity sensing behavior is shown by resistivity changes in various temperature and humidity levels. Therefore, this hybrid filament has excellent potential for in-situ humidity monitoring by embedding in smart wearable devices, natural fiber-reinforced polymer composites, and environmental sensing devices.

Cellulose Nanofiber-Based Nanocomposite Films Reinforced with Zinc Oxide Nanorods and Grapefruit Seed Extract.

Here, we report the fabrication and characterization of cellulose nanofiber (CNF)-based nanocomposite films reinforced with zinc oxide nanorods (ZnOs) and grapefruit seed extract (GSE). The CNF is isolated via a combination of chemical and physical methods, and the ZnO is prepared using a simple precipitation method. The ZnO and GSE are used as functional nanofillers to produce a CNF/ZnO/GSE film. Physical (morphology, chemical interactions, optical, mechanical, thermal stability, etc.) and functional (antimicrobial and antioxidant activities) film properties are tested. The incorporation of ZnO and GSE does not impact the crystalline structure, mechanical properties, or thermal stability of the CNF film. Nanocomposite films are highly transparent with improved ultraviolet blocking and vapor barrier properties. Moreover, the films exhibit effective antimicrobial and antioxidant actions. CNF/ZnO/GSE nanocomposite films with better quality and superior functional properties have many possibilities for active food packaging use.

All-biobased transparent-wood: A new approach and its environmental-friendly packaging application.

Transparent-wood (TW) is an emerging research topic that can be applied to biobased products. However, it is necessary to fill pores in TW with natural substances to prepare all-biobased TW. This paper reports an all-biobased TW by infiltrating cellulose nanofiber (CNF) and chitosan (CTS) suspensions into the bleached wood. CNF was isolated by combining the chemical and physical methods, and CTS was dissolved in acetic acid, and they were infiltrated into the pores of the bleached Fir veneer wood using a vacuum jar. The CNF and chitosan effects on the mechanical properties of the TW were studied, and the morphologies, crystallinity index, water contact angle, antioxidant, thermal degradation, and UV-shielding properties were investigated. The prepared TW showed 80 % total transmittance and 30-60 % haze, suitable for solar cell application. The all-biobased TW showed good thermal stability up to 315 °C and excellent UV shielding property for UV-B and UV-C. The antioxidant property of the CTS-TW significantly increased as compared to the original wood. The CNF-TW showed considerable tensile strength and yield strength of more than 200 % improved from the original wood. The potential for environment-friendly packaging applications was demonstrated by making a bag, medicine packaging, and straw for a drink.

Chitosan Nanofiber and Cellulose Nanofiber Blended Composite Applicable for Active Food Packaging.

This paper reports that, by simply blending two heterogeneous polysaccharide nanofibers, namely chitosan nanofiber (ChNF) and cellulose nanofiber (CNF), a ChNF-CNF composite was prepared, which exhibited improved mechanical properties and antioxidant activity. ChNF was isolated using the aqueous counter collision (ACC) method, while CNF was isolated using the combination of TEMPO oxidation and the ACC method, which resulted in smaller size of CNF than that of ChNF. The prepared composite was characterized in terms of morphologies, FT-IR, UV visible, thermal stability, mechanical properties, hygroscopic behaviors, and antioxidant activity. The composite was flexible enough to be bent without cracking. Better UV-light protection was shown at higher content of ChNF in the composite. The high ChNF content showed the highest antioxidant activity in the composite. It is the first time that a simple combination of ChNF-CNF composites fabrication showed good mechanical properties and antioxidant activities. In this study, the reinforcement effect of the composite was addressed. The ChNF-CNF composite is promising for active food packaging application.

Steered Pull Simulation to Determine Nanomechanical Properties of Cellulose Nanofiber.

Cellulose nanofiber (CNF) exhibits excellent mechanical properties, which has been extensively proven through experimental techniques. However, understanding the mechanisms and the inherent structural behavior of cellulose is important in its vastly growing research areas of applications. This study focuses on taking a look into what happens to the atomic molecular interactions of CNF, mainly hydrogen bond, in the presence of external force. This paper investigates the hydrogen bond disparity within CNF structure. To achieve this, molecular dynamics simulations of cellulose I ß nanofibers are carried out in equilibrated conditions in water using GROMACS software in conjunction with OPLS-AA force field. It is noted that the hydrogen bonds within the CNF are disrupted when a pulling force is applied. The simulated Young's modulus of CNF is found to be 161 GPa. A simulated shear within the cellulose chains presents a trend with more hydrogen bond disruptions at higher forces.

Green nanocomposite made with chitin and bamboo nanofibers and its mechanical, thermal and biodegradable properties for food packaging.

This paper reports a green nanocomposite made by simply blending chitin nanofibers and bamboo cellulose nanofibers without chemically dissolving chitin and cellulose raw materials. Good biodegradability and biocompatibility of chitin in conjunction with good mechanical properties of cellulose are beneficial for developing green nanocomposite applicable for food packaging. The bamboo cellulose nanofiber (BACNF) is isolated by using a TEMPO-oxidation followed by an aqueous counter collision (ACC) method. Chitin nanofiber (CTNF) is isolated by using the ACC method. A simple blending is used to prepare the nanocomposite with different CTNF and BACNF concentration. Morphologies, mechanical properties, chemical interactions, thermal properties, water contact angles and biodegradability of the nanocomposite are investigated. The tensile strength and Young's modulus of the prepared nanocomposite increased up to 3 and 1.3 times, respectively as the BACNF concentration increase. The nanocomposite exhibites better thermal stability than the pure BACNF. Furthermore, the nanocomposite is fully biodegradable within a week. Good mechanical, thermal properties as well as biodegradability of the nanocomposite are promising for possible food packaging application.

Epidermal growth factor receptor (EGFR) structure-based bioactive pharmacophore models for identifying next-generation inhibitors against clinically relevant EGFR mutations.

Present work elucidates identification of next generation inhibitors for clinically relevant mutations of epidermal growth factor receptor (EGFR) using structure-based bioactive pharmacophore modeling followed by virtual screening (VS) techniques. Three-dimensional (3D) pharmacophore models of EGFR and its different mutants were generated. This includes seven 3D pharmacophoric points with three different chemical features (descriptors), that is, one hydrogen bond donor, three hydrogen bond acceptors and three aromatic rings. Pharmacophore models were validated using decoy dataset, Receiver operating characteristic plot, and external dataset compounds. The robust, bioactive 3D e-pharmacophore models were then used for VS of four different small compound databases: FDA approved, investigational, anticancer, and bioactive compounds collections of Selleck Chemicals. CUDC101 a multitargeted kinase inhibitor showed highest binding free energy and 3D pharmacophore fit value than the well known EGFR inhibitors, Gefitinib and Erlotinib. Further, we obtained ML167 as the second best hit on VS from bioactive database showing high binding energy and pharmacophore fit value with respect to EGFR receptor and its mutants. Optimistically, presented drug discovery based on the computational study serves as a foundation in identifying and designing of more potent EGFR next-generation kinase inhibitors and warrants further experimental studies to fight against lung cancer.