Adsorption of xyloglucan and cellulose nanocrystals on natural fibres for the creation of hierarchically structured fibres

Hemicellulose and unlocking potential for sustainable applications in biomedical, packaging, and material sciences: A narrative review

Hemicellulose, a complex polysaccharide abundantly found in plant cell walls, has garnered significant attention for its versatile applications in various fields including biomedical, food packaging, environmental, and material sciences. This review systematically explores the composition, extraction methods, and diverse applications of hemicellulose-derived materials. Various extraction techniques such as organic acid, organic base, enzyme-assisted, and hydrothermal methods are discussed in detail, highlighting their efficacy and potential drawbacks. The applications of hemicellulose encompass biodegradable films, edible coatings, advanced hydrogels, and emulsion stabilizers, each offering unique properties suitable for different industrial needs. Current challenges in hemicellulose research include extraction efficiency, scalability of production processes, and optimization of material properties. Opportunities for future research are outlined, emphasizing the exploration of new applications and interdisciplinary approaches to harness the full potential of hemicellulose. This comprehensive review aims to provide valuable insights for researchers and industry professionals interested in utilizing hemicellulose as a sustainable and functional biomaterial.

Composite hydrogels formed from okara cellulose nanofibers and carrageenan: Fabrication and characterization

Currently, there is great interest in converting edible agro-waste, such as okara from soybean production, into value-added products. For this study, we focus on fabricating composite hydrogels from okara cellulose nanofibers (CNFs) and carrageenan (CA). We also examined the effects of TEMPO oxidation of the okara CNFs, as well as CA concentration, on the microstructure and physicochemical properties of the composite hydrogels. The water holding capacity, oil holding capacity, surface tension, gel strength, and viscoelasticity of the composite microgels increased with increasing CA concentration, and it was found that the highest values were obtained for TC-CA2 hydrogel: contact angle = 43.6° and surface tension = 45.12 mN/m, which was attributed to the formation of a more regular and dense three-dimensional gel network. All the CNF-CA microgels had highly anionic ζ-potential values (-38.8 to -50.1 mV), with the magnitude of the negative charge increasing with TEMPO oxidation and carrageenan concentration. These results suggest there would be strong electrostatic repulsion between the composite hydrogels. The composite microgels produced in our work may be useful functional materials for utilization within the food industry, thereby converting a waste product into a valuable commodity.

Development of Bio-Inspired Hierarchical Fibres to Tailor the Fibre/Matrix Interphase in (Bio)composites

Several naturally occurring biological systems, such as bones, nacre or wood, display hierarchical architectures with a central role of the nanostructuration that allows reaching amazing properties such as high strength and toughness. Developing such architectures in man-made materials is highly challenging, and recent research relies on this concept of hierarchical structures to design high-performance composite materials. This review deals more specifically with the development of hierarchical fibres by the deposition of nano-objects at their surface to tailor the fibre/matrix interphase in (bio)composites. Fully synthetic hierarchical fibre reinforced composites are described, and the potential of hierarchical fibres is discussed for the development of sustainable biocomposite materials with enhanced structural performance. Based on various surface, microstructural and mechanical characterizations, this review highlights that nano-objects coated on natural fibres (carbon nanotubes, ZnO nanowires, nanocelluloses) can improve the load transfer and interfacial adhesion between the matrix and the fibres, and the resulting mechanical performances of biocomposites. Indeed, the surface topography of the fibres is modified with higher roughness and specific surface area, implying increased mechanical interlocking with the matrix. As a result, the interfacial shear strength (IFSS) between fibres and polymer matrices is enhanced, and failure mechanisms can be modified with a crack propagation occurring through a zig-zag path along interphases.

Hierarchical thermoplastic biocomposites reinforced with flax fibres modified by xyloglucan and cellulose nanocrystals

This work is focused on the modification of the interphase zone in short flax fibres / polypropylene (PP) composites by a bio-inspired modification of fibres called "nanostructuration" that uses the adsorption of biomass by-products, i.e. cellulose nanocrystals (CNC) and xyloglucan (XG), to create hierarchical flax fibres. The wettability and interfacial adhesion study reveals a strong decrease in the polar character of CNC modified flax fibres, hence increasing the work of adhesion with PP. Moreover, combining XG/CNC modified interphases with MAPP coupling agent enhances the ultimate mechanical properties of biocomposites with higher tensile strength and work of rupture, and modifies failure mechanisms as revealed by in situ micro-mechanical tensile SEM experiments. Bio-based hierarchical composites inspired by naturally occurring nanostructures open a new path for the development of sustainable composites with enhanced structural properties.