Plant Fibers Research Articles

Mechanical behavior and apparent stiffness of flax, hemp and nettle fibers under single fiber transverse compression tests

While plant fibers find extensive use across numerous applications, their transverse behavior and mechanical properties lack direct and fiber-scale characterization, posing a significant knowledge gap. This paper investigates, for the first time, the transverse behavior of flax, hemp and nettle fibers through Single Fiber Transverse Compression Tests (SFTCTs). Finite element analysis is used to study the influence of time-dependent and irreversible inelastic behavior on the fiber’s response and identify configurations fit for the identification of apparent elastic properties. SFTCTs are performed experimentally with a repeated progressive loading protocol using a custom micro-mechatronic setup. An apparent fiber transverse elastic modulus of 1 to 3 GPa is identified by inverse method for all tested fibers, demonstrating high fiber anisotropy. Important inelastic features are also observed on fiber behavior. Their origin is discussed with both material behavior and structural mechanisms such as lumen collapse, identified as the main potential causes.

Keratinous Natural Fibres as Sustainable Flame Retardants and Reinforcements in Polymer Composites

Natural fibres have been used as fibre reinforcements in composites as they offer eco-friendly and economic advantages, but their susceptibility to deterioration when exposed to heat and flames has limited their practical application in fibre-reinforced polymeric composites. Fire-reaction properties have been explored in reasonable detail for plant fibres, but a gap exists in the understanding of animal fibre-reinforced composites. Understanding the thermal and fire reactions of these keratin-rich animal fibres is crucial for material selection and advancing composite product development. The current paper critically discusses the existing research landscape and suggests future research directions. The use of keratinous fibres in composites can definitely improve their thermal stability and fire performance, but it also appears to adversely affect the composite’s mechanical performance. The main part of this paper focuses on the flame-retardant treatment of keratinous fibres and polymer composites, and their behaviour under fire conditions. The final part of this paper includes a brief look at the environmental impact of the treatment methods; the overall processing of keratinous fibre-reinforced composites is also presented to gain further insight.

Synthesis and characterization of nanocelluloses isolated through acidic hydrolysis and steam explosion of Gliricidia sepium plant fiber

Synthesis and characterization of nanocelluloses isolated through acidic hydrolysis and steam explosion of Gliricidia sepium plant fiber

Effect of Aminating Lignin Loading with Arbuscular Mycorrhizal Fungi on Soil Aggregate Structure Improvement.

Lignin is an important component of plant fiber raw materials, and is a three-dimensional network structure aromatic polymer with abundant resources and a complex structure in nature. Lignin is generally used as industrial waste, and its potential value has not been fully utilized. Modern agriculture extensively uses chemical fertilizers, leading to the gradual degradation of soil fertility and structure, which seriously affects crop growth, nutrient transport, and root respiration function. Based on soil bulk density, porosity, aggregates, and their stability indicators, this study analyzed the effects of aminated industrial lignin and its loading with arbuscular mycorrhizal fungi on soil structure improvement and plant growth. It was hoped that resource-rich lignin could play a beneficial role in improving soil structure and promoting crop growth. The phenolic hydroxyl group of lignin was epoxidized and further aminated to load with arbuscular mycorrhizal fungi. The results indicated that amine-modified lignin could effectively load with arbuscular mycorrhizal fungi. The application of arbuscular mycorrhizal fungi-supported aminated lignin to soil aggregate structure improvement greatly reduced the bulk density of soil, and increased the porosity of soil and the content of large granular soil. Compared with unmodified soil, soil bulk density decreased by 73.08%, the porosity of soil increased by 70.43%, and the content of large granular soil increased by 56.38%. Using the improved soil for corn cultivation efficiently increased the biomass of corn. The plant height was increased by 72.16%, the root-shoot ratio was increased by 156.25%, and other indexes were also improved to varying degrees. The experimental method provides an important basis for the effective utilization of lignin materials in agriculture in the future.

Working at home. Reconstructing activities within the LBK household through the systemic use-wear analysis of flint industries, bone and antler tools and ground stone implements

The systematic analysis of use-wear traces on flint, ground stone and bone tools, has rarely been carried out at Early Neolithic sites in continental Europe. Hence, it is a powerful means of identifying possible economic differences. As part of the ongoing HOMES project, we are investigating the importance and nature of acquisition strategies (hunting, harvesting), food preparation techniques (butchery, grain milling) and the processing of other resources (plant fibres) in a large set of LBK households in the Aisne Valley (France). After re-examining and integrating new results on the flint industry (366 tools), bone and antler tools (414 tools) and ground stone tools (114 tools), the aim here is to examine whether the processing of soft flint plants, hides and wood remains the dominant activity and how it coexists with more marginal activities such as the processing of soft minerals and textile fibres. The absence of certain activities is scrutinised in relation to their location within and outside the domestic and village space. Discrete functional characteristics are tracked to improve our understanding of the observed differences between the domestic units: segmentation of production processes, differences in the use of each type of raw material, intensity of use. In this way, we can test the hypothesis of autonomous or interdependent households in terms of production and consumption and investigate the economic structure of LBK villagers.

Enhancing plant fiber antibacterial and antiviral performance through synergistic action of amino and sulfonic acid groups

As the most abundant renewable resource, cellulose fibers are potential candidates for use in health-protective clothing. Herein, we demonstrate a novel strategy for preparing cellulose fiber with prominent antibacterial and antiviral performance by the synergistic effect of amino groups and sulfonic acid groups. Specifically, guanylated chitosan oligosaccharide (GCOS) and N-sulfopropyl chitosan oligosaccharide (SCOS) were synthesized and chemically grafted onto cellulose fibers (CFs) to endow the fibers with antibacterial and antiviral properties. Moreover, a compounding strategy was applied to make the fibers with simultaneously high antibacterial and antiviral activity, especially in short contact time. The bacteriostatic rate (against S. aureus: 95.81 %, against E. coli: 92.07 %, 1 h) of the compounded fibers improved substantially when a few GCOS-CFs were mixed with SCOS-CFs; especially, it was much higher than both the individual GCOS-CFs and SCOS-CFs. By contrast, the improvement of the antiviral properties was less dramatic; however, even a few SCOS-CFs was mixed, the antiviral properties increased pronouncedly. Although the electrostatic interaction between SCOS and GCOS can make the SCOS-GCOS mixture lose some extent of antibacterial activity, the long chains of cellulose restrain the electrostatic interaction between sulfonic and amino groups, leading to their synergistic action and eventually superior antibacterial and antiviral effects.

Experimental characterization of Grewia Ferruginea fiber reinforced polyester matrix composite materials

Researchers have recently altered their focus and have become more interested in natural fiber-reinforced polymer composites because they are more ecologically friendly and environmentally conscious than synthetic fiber-reinforced polymer composites. Among the best sources of natural fiber, Grewia ferruginea, sometimes known locally as Lenquata, is a source of natural fiber from other plant fibers. The goal of this study was to create polyester matrix composites reinforced with short Grewia ferruginea plant fibers measuring 10, 20, and 30 mm. The fibers were extracted using the traditional water-retting method and chemically treated with 5% NaOH. The findings indicated that the average tensile strength of a single fiber from Grewia ferruginea plants is 214 MPa, with a density of 1.11 g/cm3. Furthermore, the composite, which was created with a fiber length of 10 mm, fiber weight ratio of 25 %, and polyester matrix composite of 75 %, exhibited superior performance since it is stronger than any combination that was used to create the composite in this investigation, with 18.3 MPa tensile and 35.2 MPa flexural strength.

Comparative study of the thermomechanical properties of natural fiber reinforced thermoplastic composites: A structural application for quadcopter design

The growing global demand for sustainability has led bio-sourced fibers to be identified as an alternative to synthetic fibers. In this paper, micromechanics and multiscale modeling approaches are used to predict the thermomechanical behavior of thermoplastic (polypropylene PP matrix) composites reinforced with four different natural fibers: flax, vegetal-technic, woodforce and a hybrid of flax and vegetal-technic, for random and aligned fiber orientations. Different microstructural orientations (0°, 45°, 90° and random) are generated and computed using the finite element method. Besides, an analytical modeling based on the Mori-Tanaka homogenization scheme is used to validate numerical results. The thermomechanical results showed a good agreement between the numerical computation and analytical approach for the aligned fiber orientations. In addition, the mechanical results obtained for the random fiber orientation remain in agreement with the experimental and analytical results reported in the literature. Besides, a user-defined material (UMAT) is implemented on tensile, compression and shear specimens. Through a virtual characterization, a material card for a 50% volume fraction of fiber is established for a flax-PP composite. Finally, an application made on a quadcopter frame, gives the failure indicators under thermomechanical loads at −20 °C and 55 °C, demonstrating the capability of plant fibers composites to withstand extreme conditions.

Comparative Analysis of Nickel Adsorption by Natural Sisal Fiber and Treated with Citric Acid

Introduction: Removing nickel from wastewater is complex and costly, requiring research into alternatives with technical and economic solutions. An alternative would be the use of plant biomass. In the Northeast region of Brazil, one of these alternatives, with a large cultivation area, is sisal (Agave Sisaliana), which may have greater yields for this purpose through surface chemical treatment with citric acid, which inserts carboxylic groups into the structure of the plant fiber. Thus, the objective was to analyze the ability to remove nickel in solution by sisal fibers. Methodology: For this purpose, part of the sisal fibers was cut into 0.5 cm, washed and dried; initially treated with NaOH (0.1 mol/L); washed with distilled water and treated with citric acid (1.2 mol/L). The fibers were identified by FTIR; XRD; XRF and SEM. Adsorption tests were carried out with nickel solution for the parameters: kinetics, balance, influence of pH and adsorbent mass. Results: The XRF analysis demonstrated a greater presence of NiO adhered to the treated fiber (55.74%); FTIR confirmed the presence of non-ionized carbonyl in the region from 1700 to 1750 cm-1; the adsorption kinetic test demonstrated greater effectiveness of the treated fiber > 80%; an ideal adsorbent mass was observed to be 0.1g; the ideal pH for removal was 5.0 while the equilibrium test has the best Languimuir isotherm, the uncontrolled fiber obtained R2 = 0.9810 and the controlled fiber R2 = 0.9643. Conclusion: Therefore, it was observed that the treatment of sisal fiber with citric acid increases the removal efficiency of nickel ion in aqueous solution, presenting itself as a low-cost and widely available material.

A Review on Surface Modification of Plant Fibers for Enhancing Properties of Biocomposites

AbstractOver the past decade, significant progress has been made in creating environmentally friendly products using natural resources. Plant fibers, also known as lignocellulosic fibers, are hydrophilic due to the interaction and attraction between water molecules and the hydroxyl groups present in their components. The inherent hydrophilicity of plant fibers often prevents them from interacting effectively with hydrophobic polymer matrices. In order to improve the adhesion between plant fibers and the matrix, it is necessary to modify the surface of the fibers. Commonly used chemical processes include mercerization, silane treatment, acetylation, permanganate treatment, acrylation, benzoylation, peroxide treatment, stearic acid treatment, isocyanate treatment and sodium chlorite intervention. The desirability of chemically modifying the surface of plant fibers has declined due to several limitations. Plant fibers can be modified in an environmentally friendly way by various methods, such as plasma therapy and treatments using fungi, enzymes and bacteria. This part provides an analysis of the impact of different environmentally friendly surface modification techniques on the properties of plant fibers and reinforced polymers.

Livmats Pavilion: Design and Development of a Novel Building System Based on Natural Fibres Coreless-Wound Structural Components for Applications in Architecture

Robotic coreless filament winding with natural fibres and bio-based resin systems offers potential solutions to address productivity and sustainability challenges in the construction sector. Their use in modular, prefabricated structures enables efficient, controlled, and eco-friendly production, yielding high-quality building components with minimal production waste. Plant fibres like flax provide good strength and stiffness while requiring less non-renewable energy compared to traditional fibres like glass or carbon. This research focuses on the use and implementation of flax fibre for coreless filament wound structural components by describing the conceptualization, design, fabrication, and assembly of a full-scale architectural demonstrator, the livMats Pavilion.

Influence of NaHCO3 treated kenaf/nettle fiber on mechanical and sliding wear performance of epoxy composites

This investigation addresses the experimental research on the mechanical and sliding wear behavior of kenaf/nettle-epoxy composites. The mechanical properties like tensile strength, flexural strength, and hardness in this investigation were found to be greatly affected by the kenaf/nettle fiber content. The variation of reinforcement (keanf/nettle) from 0 wt% to 12 wt% was used for fabricating the composites. Moreover, up-to 8 wt% of fiber loading, tensile strength-153.20 MPa (61.75 %) and flexural strength- 68.57 MPa (55.24 %) are increased as compared to neat epoxy composites, whereas higher hardness (63.42 Hv) is achieved at 12 wt% of fiber loading. Sliding wear tests are conducted at different normal loads (10-40N) and reveal that higher wear resistance is achieved at 12 wt% at 30N of fiber loading, which is 4.0033/N-m × 10-8. From this investigation, it can be clearly shown that plant fiber (kenaf/nettle) could be innovative feasible alternative to renewable, eco-friendly, and light weight fiber reinforced composites with moderate mechanical and wear properties.

A round-robin study on the tensile characterization of single fibres: A multifactorial analysis and recommendations for more reliable results

In this benchmark, the tensile properties of three types of organic fibres – flax, hemp and aramid − were determined using single-fibre tensile tests performed by nine research groups. Flax and hemp were chosen due to their prevalence among European fibre plants. Aramid was selected for its synthetic nature and comparable dimensional properties. Due to the morphological complexity and variability of plant fibres, the scatter in the apparent tangent modulus and strength is more pronounced for flax and hemp compared to aramid. The primary source of scatter in the tensile properties results from human factors and experimental procedures, particularly regarding the fibre selection, the measurement of the fibre cross-sectional area and of the tensile strain. The post-processing procedure also turns out to be a key factor. Finally, recommendations and guidelines for best practices are proposed to reduce the main sources of dispersion associated with the reproducibility of single fibre tensile tests.

High-performance flexible magnetic textile fabricated using porous Juncus effusus fiber for biomechanical energy harvesting

Mechanical energy produced by human motion is ubiquitous, continuous, and usually not utilized, making it an attractive target for sustainable electricity-harvesting applications. In this study, flexible magnetic Juncus effusus (M-JE) fibers were prepared from plant-extracted three-dimensional porous Juncus effusus (JE) fibers decorated with polyurethane and magnetic particles. The M-JE fibers were woven into fabrics and used for mechanical energy harvesting through electromagnetic induction. The M-JE fabric and induction coil, attached to the human wrist and waist, yielded continuous and stable voltage (2 V) and current (3 mA) during swinging. The proposed M-JE fabric energy harvester exhibited good energy harvesting potential and was capable of quickly charging commercial capacitors to power small electronic devices. The proposed M-JE fabric exhibited good mechanical energy harvesting performance, paving the way for the use of natural plant fibers in energy-harvesting fabrics.

Research on properties and cellular structure of nano‐CaCO3/rice‐husk fiber/polypropylene three‐phase thermoplastic microcellular foaming composites

AbstractMicrocellular foamed plant fiber composites have the advantages of low density, low cost, and biodegradability, so it has great development potential in the industry. Nevertheless, the existence of cellular structures diminishes the mechanical performance of plant fiber composites. To overcome this problem, in this study, nano‐CaCO3 was used to enhance the microcellular foamed plant fiber composites, and the three‐phase thermoplastic composites, comprised of nano‐CaCO3, rice‐husk fiber, and polypropylene (PP), were fabricated using a chemical foaming injection molding technique. The study analyzed how the nano‐CaCO3 concentration affected the melt viscosity, crystallization characteristics, mechanical properties, and cellular structure of the composites. According to the findings, the mechanical characteristics of microcellular foamed three‐phase thermoplastic composites were enhanced initially and subsequently diminished as the nano‐CaCO3 content was augmented, and obtained optimal value at 2 wt% nano‐CaCO3 content. By observing the cells of microcellular foamed three‐phase thermoplastic composites in vertical and parallel melt flow directions, it was found that the nano‐CaCO3 content of 2 wt% three‐phase thermoplastic composite had the best cellular structure.Highlights The role of nano‐CaCO3 in plant fiber composite materials was explored. The relationship between the content of nano‐CaCO3 and the various properties of tri‐phasic plant fiber composite materials was demonstrated. The mechanisms by which nano‐CaCO3 enhances plant fiber composite materials were analyzed at both macroscopic and microscopic levels.

Methylcellulose replacement with different enzymatically treated plant fibres as a binder in the production of plant-based meat patties

Texturised vegetable protein (TVP) is a sustainable and economical base for plant-based meat patties but requires binders to create an emulsified gel and hold the patty structure together. This study evaluated the physicochemical and sensory attributes of TVP patties incorporated with three different enzymatically-treated plant fibres i.e., pea (EPF), citrus (ECF) or apple (EAF) as a binder compared to positive control (methylcellulose, MC) and negative control (no binder, NC). All the patties with plant fibres had similar water-holding capacity compared to the MC. EAF exhibited the least fluid release and uniform surface, while ECF demonstrated the least cooking loss and shrinkage, uniform surface, hard texture, better cohesiveness, gumminess and chewiness compared to other samples. All the plant fibre-incorporated patties scored similarly for taste, texture, juiciness and overall acceptability compared to the positive control. The agglomerative hierarchical clustering revealed that the EPF had similar characteristics to the MC but the principal component analysis indicated that citrus fibre was a superior binder to pea fibre, therefore it could be used to replace methylcellulose for plant-based meat patties. Future research should explore more variations in plant-based binders to optimise the performance and sensory attributes of different types of texturised vegetable protein-based meat analogues.

Cellulose Fiber based self-supporting paper cathode with multi-scale network structure for high performance lithium-sulfur battery

Lithium-sulfur batteries (LSBs) are gaining attention as a potential energy storage option due to their impressive theoretical specific capacity. However, the main challenges hindering its implementation include the expansion in volume of sulfur and lithium sulfide during the conversion process of charge-discharge, the limited conductivity of the active material, and specifically, the phenomenon known as shuttle effect caused by lithium polysulfides (LiPSs). The development of high-performance LSBs have led to the need for self-supporting cathode materials that can efficiently accommodate volume expansion, build up efficient conductive pathways, and suppress shuttle effects. The poly(3,4-ethylenedioxythiophene) (PEDOT) was synthesized in situ on cellulose nanofibers (CNFs), resulting in the formation of CNF@PEDOT. Subsequently, CNF@PEDOT was combined with plant fibers (PFs) and multi-wall carbon nanotubes (MWCNTs) to fabricate a self-supporting cathode featuring a multi-scale network structure denoted as CNF@PEDOT/MWCNT/PF/S. The PFs serve as the primary backbone network, CNF@PEDOT to form the secondary conductive network, and MWCNTs act as tertiary conducting networks. In fact, the design of multi-level conductive network effectively improves the conductivity of the material, and PEDOT can further adsorb and catalyze LiPSs. The incorporation of PFs significantly enhanced the mechanical robustness of the cathode and augmented its electrolyte permeability. The self-supporting CNF@PEDOT/MWCNT/PF/S cathode exhibits an initial capacity of 1204.6 mA h g−1 when loaded with 2.4 mg cm−2 of sulfur at a rate of 0.2 C. Notably, it maintains an initial discharge specific capacity of 712.9 mA h g−1 even when the sulfur load is increased to 4.3 mg cm−2. This study presents a comprehensive framework for the development of self-supporting cathodes in LSBs.

Micromechanics stiffness upscaling of plant fiber-reinforced composites

Fiber-reinforced green composites made from natural plant fibers are an increasingly popular sustainable alternative to conventional high-performance composite materials. Given the variety of natural fibers themselves, and the even larger variety of possible composites with specific fiber dosage, fiber orientation distribution, fiber length distribution, and fiber–matrix bond characteristics, micromechanics-based modeling is essential for characterizing the macroscopic response of these composites. Herein, an analytical multiscale micromechanics model for elastic homogenization is developed, capable of capturing the variety. The model features (i) a nanoscopic representation of the natural fibers to predict the fiber stiffness from the universal stiffness of the fiber constituents, mainly cellulose, (ii) a spring-interface model to quantify the compliance of the fiber–matrix bond, and (iii) the ability to model any (and any combination of) orientation distribution and aspect ratio distribution. Validation is performed by comparing the predicted stiffness to experimental results for as many as 73 composites available in the literature. Extensive sensitivity analyses quantify the composite stiffening upon increasing fiber volume fraction, fiber alignment, fiber length, and fiber–matrix interface stiffness, respectively.

Preparation and heat-insulating properties of hollow mullite fibers achieved via template impregnation method to replicate the structure of metaplexis fibers

Mullite fibers possess low thermal conductivity, excellent high-temperature stability, and thermal shock resistance, making them extensively utilized in high-temperature heat-insulating components. However, the majority of current mullite fibers have solid structures, limiting the potential for further enhancement of their heat-insulating properties. Metaplexis fiber, a plant fiber with a hollow structure, effectively obstructs heat transfer, and therefore exhibits excellent heat-insulating properties. In this study, we employed metaplexis fibers as templates to fabricate mullite fibers with hollow structures. First, a precursor solution was prepared using Al(NO3)3·9H2O and ethyl orthosilicate as the solute and anhydrous ethanol as the solvent. The metaplexis fibers were immersed in the solution, removed, and dried to obtain precursor fibers. Finally, the precursor fibers were heated to the target temperature to obtain hollow mullite fibers. The investigation focused on the impact of preparation parameters such as sintering temperature, precursor solution concentration, and aluminum–silicon molar ratio on the morphologies, phases, pore-size distributions, and thermal conductivities of the resulting hollow mullite fibers. The results demonstrated that the prepared mullite fibers inherited the hollow structure of metaplexis fibers, with the cavity diameter in the range of 3–6 μm and porosity of 91 %. Compared to traditional solid mullite fibers, the thermal insulation performance was improved by more than 59 %. These findings highlight the significant potential of hollow ceramic fibers for the development of heat-insulating materials. Using the unique characteristics of their hollow structure, these fibers offer improved heat-insulating properties compared to their solid counterparts.

Exploring agro-morphological and fiber traits diversity in cotton (G. barbadense L.)

Cotton (Gossypium barbadense L.) is a leading fiber and oilseed crop globally, but genetic diversity among breeding materials is often limited. This study analyzed genetic variability in 14 cotton genotypes from Egypt and other countries, including both cultivated varieties and wild types, using agro-morphological traits and genomic SSR markers. Field experiments were conducted over two seasons to evaluate 12 key traits related to plant growth, yield components, and fiber quality. Molecular diversity analysis utilized 10 SSR primers to generate DNA profiles. The Molecular diversity analysis utilized 10 SSR primers to generate DNA profiles. Data showed wide variation for the morphological traits, with Egyptian genotypes generally exhibiting higher means for vegetative growth and yield parameters. The top-performing genotypes for yield were Giza 96, Giza 94, and Big Black Boll genotypes, while Giza 96, Giza 92, and Giza 70 ranked highest for fiber length, strength, and fineness. In contrast, molecular profiles were highly polymorphic across all genotypes, including 82.5% polymorphic bands out of 212. Polymorphism information content was high for the SSR markers, ranging from 0.76 to 0.86. Genetic similarity coefficients based on the SSR data varied extensively from 0.58 to 0.91, and cluster analysis separated genotypes into two major groups according to geographical origin. The cotton genotypes displayed high diversity in morphology and genetics, indicating sufficient variability in the germplasm. The combined use of physical traits and molecular markers gave a thorough understanding of the genetic diversity and relationships between Egyptian and global cotton varieties. The SSR markers effectively profiled the genotypes and can help select ideal parents for enhancing cotton through hybridization and marker-assisted breeding.