Functional Bionanocomposite Fibers of Chitosan Filled with Cellulose Nanofibers Obtained by Gel Spinning

Abstract

Extremely high mechanical performance spun bionanocomposite fibers of chitosan (CHI), and cellulose nanofibers (CNFs) were successfully achieved by gel spinning of CHI aqueous viscous formulations filled with CNFs. The microstructural characterization of the fibers by X-ray diffraction revealed the crystallization of the CHI polymer chains into anhydrous chitosan allomorph. The spinning process combining acidic–basic–neutralization–stretching–drying steps allowed obtaining CHI/CNF composite fibers of high crystallinity, with enhanced effect at incorporating the CNFs. Chitosan crystallization seems to be promoted by the presence of cellulose nanofibers, serving as nucleation sites for the growing of CHI crystals. Moreover, the preferential orientation of both CNFs and CHI crystals along the spun fiber direction was revealed in the two-dimensional X-ray diffraction patterns. By increasing the CNF amount up to the optimum concentration of 0.4 wt % in the viscous CHI/CNF collodion, Young’s modulus of the spun fibers significantly increased up to 8 GPa. Similarly, the stress at break and the yield stress drastically increased from 115 to 163 MPa, and from 67 to 119 MPa, respectively, by adding only 0.4 wt % of CNFs into a collodion solution containing 4 wt % of chitosan. The toughness of the CHI-based fibers thereby increased from 5 to 9 MJ.m−3. For higher CNFs contents like 0.5 wt %, the high mechanical performance of the CHI/CNF composite fibers was still observed, but with a slight worsening of the mechanical parameters, which may be related to a minor disruption of the CHI matrix hydrogel network constituting the collodion and gel fiber, as precursor state for the dry fiber formation. Finally, the rheological behavior observed for the different CHI/CNF viscous collodions and the obtained structural, thermal and mechanical properties results revealed an optimum matrix/filler compatibility and interface when adding 0.4 wt % of nanofibrillated cellulose (CNF) into 4 wt % CHI formulations, yielding functional bionanocomposite fibers of outstanding mechanical properties.

Synthesis of High Performance Thiophene–Aromatic Polyesters from Bio-Sourced Organic Acids and Polysaccharide-Derived Diol: Characterization and Degradability Studies

“…Commodity polymers are ubiquitous in our lives, and current state-of-the-art on polymers include multiple studies devoted to the development of new approaches for the synthesis of man-made polymeric materials with precise structures and functions [ 1 , 2 , 3 , 4 ]. For example, fabrics derived from polyester fibers are widely used in clothing and furnishing, from shirts and pants to jackets and hats, sheets, blankets, upholstery, and computer mouse pads.…”

Development of Bioinspired Functional Chitosan/Cellulose Nanofiber 3D Hydrogel Constructs by 3D Printing for Application in the Engineering of Mechanically Demanding Tissues

“…Its chains naturally form a highly crystalline structure (namely cellulose I allomorph), assem-bled into microfibrils [39][40][41][42][43]. The unique crystalline properties of the processed native cellulose nanofibrils, combined with their high aspect ratio and renewability, have placed the cellulose nanofibers (CNF) as a green nanoreinforcement alternative for the design of environmentally friendly and high mechanical performance composites [39,[44][45][46]. Specially, the nano/microfibrillated cellulose (MFC) can be produced from the peeling of the native fibers into a network of hairy fibrils [47][48][49].…”

Preparation and Characterization of Cellulose Acetate Film Reinforced with Cellulose Nanofibril

“…The viscosity was increased with an increasing amount of CNF filler. The increase of viscosity upon the addition of CNF filler could indicate good dispersion of CNF in the CA matrix which leads to a good interaction between CNF and CA macromolecules [ 37 ].…”