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•The microwave digestion method was analyzed to be effective in the extraction of MCF.•NCF’s were extracted by balling milling assisted ultra-sonication method.•NCF’s of banana peel ...and bracts were found to possess high thermal stability.•NCF’s of banana peel and bracts were examined to be type I cellulose.•NCF’s were found to be a good source for the production of cellulose based polymers.
The principal aim of the present study is to develop a method for the production of cellulose nanofibers, from the banana peel (BP) and bract (BB). It is also the aim of this study to produce cellulose-based biopolymers through acetyl and lauroyl modifications. The microwave digestion method and ball milling assisted ultra-sonication method was optimized for sustainable extraction of micro and nano cellulose fibers, respectively. The microwave digestion method was found to be effective in the removal of hemicellulose and lignin. Micro and nano cellulose fibers of BP and BB were found to contain type I cellulose structure. Thermal stability and crystallinity index of cellulose nanofibers were examined to be higher than it’s native micro cellulose. Nano cellulose fibers were examined to be a potential source for production of acetyl and lauroyl cellulose, with a high degree of substitution and thermal stability. Hence, microwave digestion and ball milling assisted ultra-sonication method was proven to be effective in the extraction of nano cellulose fiber for development of cellulose-based polymers.
Enhancing the flame retardancy and durability of cellulose fibers, particularly environmentally friendly regenerated cellulose fibers types like Lyocell fibers, is essential for advancing their ...broader application. This study introduced a novel approach to address this challenge. Cationic-modified Lyocell fibers (Lyocell@CAT) were prepared by introducing quaternary ammonium structures into the molecular chain of Lyocell fibers. Simultaneously, a flame retardant, APA, containing -COO−NH4+ and -P=O(O−NH4+)2 groups was synthesized. APA was then covalently bonded to Lyocell@CAT to prepare Lyocell@CAT@APA. Even after undergoing 30 laundering cycles (LCs), Lyocell@CAT@APA maintained a LOI value of 37.2 %, exhibiting outstanding flame retardant durability. The quaternary ammonium structure within Lyocell@CAT@APA formed asymmetric ionic bonds with the phosphate and carboxylate groups in APA, effectively shielding the binding of Na+ ions with phosphate groups during laundering, thereby enhancing the durability. Additionally, the consumption of Na+ ions by carboxylate groups further prevented their binding to phosphate groups, which contributed to enhance the durability properties. Flame retardant mechanism analysis revealed that both gas and condensed phase synergistically endowed excellent flame retardancy to Lyocell fibers. Overall, this innovative strategy presented a promising prospect for developing bio-safe, durable, and flame retardant cellulose textiles.
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•A novel biomass-based flame retardant APA was prepared.•Durable flame-retardant Lyocell fibers were prepared.•The durability was reinforced by asymmetric ionic bond and metal ions capture of carboxylate.•A novel method for enhance the durability of ammonium phosphate flame retardants was proposed.
The production of sustainable and high-performance fabrics requires high mechanical strength of the individual (staple) fibers. Although Ioncell fibers already exhibit higher fiber strength than ...commercial man-made cellulose fibers or cotton fibers, we further aimed to increase both strength and toughness to gradually approach synthetic fibers in these properties. Decisive factors for the achievable mechanical properties of the fibers were the pulp purity, the cellulose concentration in the spinning solution and length-to-diameter (L/D) ratio of the cylindrical part of the spinneret. The absence of low molecular weight fractions in combination with an increased average molecular weight had the highest impact on the achievement of both high strength and toughness. Using a spinneret with a high L/D ratio, it was possible to spin Ioncell fibers with a tensile strength of 925 MPa (61.5 cN/tex) and a modulus of toughness of 83.3 MPa (55.5 J/g). According to a fluid dynamic simulation, uniformly longer molecular cellulose chains in combination with a longer cylindrical capillary promoted an effective alignment of the cellulose molecules inside the spinneret capillary before entering the airgap, thus creating the conditions for a simultaneous increase in tensile strength and elongation
i.e.
toughness of the fiber. Mechanistically, high fiber toughness is caused by the structural parameters in longitudinal direction, in particular by a higher tilt angle, a longer periodicity of the lamellar plane and lower micro void orientation. In summary, we have developed lyocell-type fibers with high strength and toughness, which can potentially be used as a surrogate for synthetic fibers.
Graphic abstract
Rising environmental concerns and implementing restrictions on the use of copper in friction materials (FM) make it mandatory for manufacturers to look for a reliable replacement. Two commercial ...pads: 1) low metallic FM contains 7 wt.% copper fibers and 2) low metallic FM contains thermal graphite (TG), and cellulose fibers as replacements for copper were studied. The two FMs showed almost identical thermal behavior. However, Cu-contained FM exhibited a bit more thermal stability. The fade ratio and recovery ratio in the first fade and recovery stages showed almost the same values. Moreover, in the second fade, change from 86% to 78% and second recovery change from 90% to 77%, respectively, for Cu-contained and Cu-Free FMs.
•The frictional behavior of a copper-free and low-met commercialize friction composites is investigated.•As substitutions for copper, thermo-graphite and cellulose fiber were used.•Cellulose fiber at elevated temperature act as a pore generator leads to an improvement in fade resistance.•Graphite and wear debris in C7 facilitate the formation of secondary contact plateaus.•Both low-metallic and copper-free materials can be interchangeably used based on restrictions, code compliance, and economic issues.
Thermal insulating fibers can effectively regulate the human body temperature and decrease indoor energy consumption. However, designing super thermal insulating fibers integrating a sponge and ...aerogel structure based on biomass resources is still a challenge. Herein, a flow-assisted dynamic dual-cross-linking strategy is developed to realize the steady fabrication of regenerated all-cellulose graded sponge-aerogel fibers (CGFs) in a microfluidic chip. The chemically cross-linked cellulose solution is used as the core flow, which is passed through two sheath flow channels, containing either a diffusion solvent or a physical cross-linking solvent, resulting in CGFs with a porous sponge outer layer and a dense aerogel inner layer. By regulating and simulating the flow process in the microfluidic chip, CGFs with adjustable sponge thicknesses, excellent toughness (26.20 MJ m
), and ultralow thermal conductivity (0.023 W m
K
) are fabricated. This work provides a new method for fabricating graded biomass fibers and inspires attractive applications for thermal insulation in textiles.
Bacteria and virus infections have posed a great threat to public health and personnel safety. For realizing rapid sterilization of the bacteria and virus, electrical stimulation sterilization was ...adopted to endow cellulose fibers with instantaneous antibacterial and antiviral properties. In the proposed strategy, the fiber is fluffed by mechanical refining, and then by means of the hydrogen bond between hydroxyl and aniline, the polyaniline (PANI) directionally grows vertically along the fine fibers via in-situ oxidative polymerization. Benefiting from the conductive polyaniline nanorod arrays on the fiber stem, the paper made from PANI modified refined fibers (PANI/BCF/P) exhibited excellent antibacterial and antiviral activity, the inhibition rates against S. aureus, E. coli, and bacteriophage MS2 can up to 100 %, 100 %, and 99.89 %, respectively when a weak voltage (2.5 V) was applied within 20 min. This study provides a feasible path for plant fiber to achieve efficient antibacterial and antiviral activity with electrical stimulation, which is of great significance for the preparation of electroactive antibacterial and antiviral green health products.
•Refining makes the fiber to be fluffed.•Nanorod arrays can be realized by in-situ growth of PANI on the fine fibers.•Electrical stimulation sterilization is feasible for cellulosic fibers.
The particulate matters (PMs) and toxic gases in air have resulted in serious impacts on public health. The development of “green” air filtering materials for isolating these pollutants is of vital ...importance. Here, we prepared a multi-functional cellulose-based air filter (CFs@ZIF-8 filter) by in situ growth of ZIF-8 nanocrystals on the surface of cellulose fibers. The incorporation of ZIF-8 nanocrystals increased the specific surface area of filter, strengthened the interactions between filter and PMs, and provided abundant cavities and gas adsorption sites for filter. The filtration efficiency of CFs@ZIF-8 filter for PM
0.3
could reach to an ultrahigh level of 99.9%. The gas (nitrogen) adsorption capacity of CFs@ZIF-8 filter was 200 times higher than that of original cellulose-based filter (CFs-filter). The contributions of ZIF-8 on these surpassing properties of CFs@ZIF-8 filter were deeply analyzed. This study provided an effective strategy for developing “green” and multi-functional cellulose-based air filter.
The nanometric internal structure of polymeric fibres is fundamental for their mechanical properties. Two-dimensional small angle neutron scattering patterns were collected to obtain structural ...parameters of the elementary fibrils in regenerated cellulose fibres prepared by various fibre spinning technologies. Scattering features were fitted to model functions to derive parameters such as elementary fibril radius, long period of the repeating units of crystal and amorphous phase along the fibre axis, degree of orientation, and ellipticity. The correlation between structural parameters and the mechanical properties was studied for the fibres of different existing spinning processes and for the high-strength fibres. Former group showed high correlation with mechanical properties. The latter group showed generally lower correlation, but showed relatively high correlation with the long period. These structural parameters provide a basis for understanding the structure-property relationship of regenerated cellulose fibres as function of spinning types and conditions for further optimization.
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•Scattering length density of amorphous cellulose was modulated by solvation.•Four-point pattern were observed for Lyocell-based fibres.•Nanostructural parameters were evaluated from small angle neutron scattering.•Divergent nanostructures of regenerated cellulose fibres by spinning types.•Correlation between structural parameters and tensile properties were discussed.
Crop stalk is a valuable source of cellulosic biomass and has attracted increasing attention as one kind of renewable resource. Cellulose fibers have potential as a reinforcement material to replace ...synthetic fibers used in biopolymer composites. This study addresses the modification and characterization of corn stem fibers extracted from corn stalk waste. The corn stem fibers were treated with alkali, silane and NaOH-silane solutions, and then, the chemical properties, surface morphology, mechanical behaviors and thermal stability of the corn stem fibers were characterized. The surface treatments improved the chemical and mechanical properties of the corn stem fibers. The fibers had rougher surfaces after the surface treatments. EDX and FTIR analysis confirmed that the surface treatments removed a certain amount of hemicelluloses, lignin and pectin from the natural fiber surface. XRD analysis results showed that the surface treatments had a positive impact on the crystallinity index of the natural fibers. The mechanical properties and thermal stability of the treated corn stem fibers were also found to be improved.
Cellulose is the most abundant biopolymer on Earth, found in trees, waste from agricultural crops and other biomass. The fibres that comprise cellulose can be broken down into building blocks, known ...as fibrillated cellulose, of varying, controllable dimensions that extend to the nanoscale. Fibrillated cellulose is harvested from renewable resources, so its sustainability potential combined with its other functional properties (mechanical, optical, thermal and fluidic, for example) gives this nanomaterial unique technological appeal. Here we explore the use of fibrillated cellulose in the fabrication of materials ranging from composites and macrofibres, to thin films, porous membranes and gels. We discuss research directions for the practical exploitation of these structures and the remaining challenges to overcome before fibrillated cellulose materials can reach their full potential. Finally, we highlight some key issues towards successful manufacturing scale-up of this family of materials.
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