Bio-based Fibers Research Articles

Are Biobased Microfibers Less Harmful than Conventional Plastic Microfibers: Evidence from Earthworms.

Biobased plastics are sometimes promoted as "environmentally friendly" compared to their conventional petrochemical-based counterparts, but their ecotoxicity is only partially understood. Biobased fibers are widely used in clothing and wet wipes and can accumulate in soils through the application of biosolid fertilizers. This study examined the lethal thresholds and sublethal toxicity of chemically characterized, additive-free, biobased (viscose and lyocell) compared to petrochemical-based (polyester) fibers on the key ecosystem engineer, Esenia fetida. Viscose and lyocell had LC20 values of 14.00 and 22.66 mg·L-1, respectively, and no observed effect concentrations (NOEC) of 0-2.8 mg·L-1 (72 h, OECD TG207 filter paper method), while for polyester these were LC20 15.6-31.3 mg·L-1 and NOEC 0-15.6 mg·L-1. Following 28 days of exposure to soils (OECD TG222) contaminated with environmentally relevant concentrations (100 mg kg-1), viscose significantly reduced the mass of progeny compared to polyester. Earthworms exposed to lyocell had a marginal growth reduction (-18%; compared to -11% to -13% in other treatments) linked to increased bioturbation activity. The biobased fibers examined here have greater acute toxicity at high concentrations and broadly similar sublethal effects on E. fetida compared to polyester. Our study highlights the importance of detailed testing before advocating specific materials as plastic alternatives/substitutes to conventional plastics.

Reversibly crosslinked polyurethane fibres from sugar-based 5-chloromethylfurfural: Synthesis, fibre-spinning and fibre-to-fibre recycling.

The development of recyclable crosslinked thermosetting fibres is a challenging research topic. In the present work, we have designed and synthesized polyurethane fibres from fructose-derived 5-chloromethylfurfural (CMF) and lignin-derived monomeric phenols. The greenhouse gas emissions associated with the production of CMF showed comparable results to that of 5-hydroxymethylfurfural (HMF), a high potential sugar-based platform molecule. The wet-spun biobased polyurethane fibres produced could be conveniently crosslinked using Diels-Alder chemistry to effectively enhance the glass transition temperature and mechanical properties. At a mildly elevated temperature (140 °C), the chemically crosslinked fibres could be effectively de-crosslinked, which enabled complete separation from a mixture with poly(ethylene terephthalate) (PET) and cotton fibres. These results outline a potential strategy to design and fabricate new biobased fibres with reversible crosslinking, which may enable fibre-to-fibre recycling.

Optimizing dielectric constant of noncommercial biobased fibres - Acacia Nilotica, Acacia Leucophloea and Prosopis juliflora - For composite applications with selected fillers

In recent decades, most electrical/electronic products possess non – biodegradable components. The expanding consumption of these goods and their eventual disposal pose a serious environmental threat. To cope up with this issue, biodegradable electrical/electronic components using biobased fibres can be an alternative option. The novel exploration of this research work is the usage of underutilized biobased fibres, such as Acacia Nilotica, Acacia Leucophloea and Prosopis Juliflora, as sustainable alternatives to traditional synthetic fibres in natural fibre-reinforced epoxy composites. The novelty lies in the combination of these natural fibres with ceramic fillers like Silicon Carbide, Boron Nitride and Aluminium Oxide, aiming to enhance the composite properties. The objective of the study is to optimize the type of fibre, fibre content (2 wt%, 4 wt% and 6 wt%) and types of fillers (1 wt%) combinations using the Box-Behnken Design to improve the dielectric properties of these composites. Analysis of Variance (ANOVA) is used to evaluate the relevance of each parameter on dielectric constant of the biobased fibre reinforced epoxy composite. The significant outcome is identified that Prosopis Juliflora (6 wt%) combined with Boron Nitride (1 wt%) yields an optimal dielectric constant of 1.11, highlighting the potential of these biobased fibres to serve as effective substitutes for conventional glass and carbon fibres for electrical insulating materials used in switchboards and socket pins to prevent electrical conduction and ensure safety. This research not only contributes to the field of sustainable materials but also addresses critical environmental concerns associated with electric/electronic waste.

Sustainable and Naturally Derived Wet Spun Fibers: A Systematic Literature Review

Increasing economic and environmental concerns arising from the extensive exploration and dependence on fossil fuel-based materials have encouraged the search for eco-friendly alternatives. Fibers based on biomass-derived materials have been attracting growing interest. Among other features, the mechanical performance of bio-based fibers needs to be improved to effectively compete with their counterparts and emerge as viable substitutes. This review presents scientific advancements in the development of naturally derived fibers, and strategies for their production with tailored mechanical properties. The potential of natural precursor-based fibers for their conversion into high-performance carbon fibers is also emphasized. Studies reporting the mechanical properties of bio-based fibers developed by wet spinning are identified, analyzed, and discussed. These studies show that cellulose is the most studied material, while Ioncell technology is identified as the most suitable method for producing cellulose-based fibers with the highest tensile strength. Studies have also demonstrated that silk fibroin exhibits tensile strength and elongation at break ranging from 300 to 600 MPa and 30 to 50%. Although several novel processes have been explored, there are still challenges that need to be addressed for bio-based fibers to become feasible options, and to boost their usage across industries.

Engineering characteristics, techno-economic feasibility and life cycle assessment of bio-fiber based green engineered cementitious composites

The objective of the present work is to understand the microstructural, and life cycle analysis of novel engineered cementitious composites (ECC) where the conventional synthetic micro-fibers are replaced using bio-based fibers. A detailed mechanical and microstructural characteristics of the developed ECC mix are presented first to understand the feasibility of introducing natural fibers without compromising the ductility and strength of the mix. To prove the cost-effectiveness and sustainable balance, a detailed life cycle analysis (LCA) was performed using different sustainability indices such as cost, embodied energy, and carbon emissions. The natural fiber ECC mixes developed in this work are compared with similar artificial fiber ECC mixes for different LCA parameters. Results from the tensile tests revealed that using natural fibers in an ECC mix aided in achieving significant tensile strength (4.3–10.2 MPa) and failure strain levels (2.5 %–3.5 %). Specifically, using flax fibers in the ECC mix aided in achieving a high tensile strength of 10.2 MPa corresponding to an ultimate strain of 2.5 %. From the outcomes of LCA, the use of kenaf and pineapple can be recommended for sustainable ECC production without compromising its mechanical characteristics.

An eco-friendly and flame-retardant bio-based fibers separator with fast lithium-ion transport towards high-safety lithium-ion batteries

As one of the most important parts in lithium-ion batteries (LIBs), commercial polyolefin separators suffer from inherent drawbacks such as thermal-dimensional shrinkage, poor electrolyte wettability, and environmental pollution. In this study, a green bio-based composite separator with good flame retardancy and high ion conductivity is designed by a facile paper-making process and subsequently borate salts crosslinking, which consists of marine-derived calcium alginate fibers bridge and land-derived cellulose micro-fibers filler. The composite separator reveals a multi-hierarchical porous structure and homogeneous boron crosslinking, and consequently has a superior liquid electrolyte wettability and high strength. Impressively, the composite separator delivers better flame retardancy and higher lithium-ion transference number (tLi+ = 0.4) and ion conductivity (σ = 1.53 mS cm−1) compared with the commercial polypropylene separator, attributing to the abundant polar groups upon the fibers and the incorporation of sp3 Boron. As a result, the LIBs equipped with composite separator demonstrate excellent interface stability and rate capability. More importantly, the LIBs exhibit greater security at the elevated temperature of 140 °C. Additionally, the composite separator shows a potential degradation in natural environments. This eco-friendly bio-based separator paves a new insight for the design of heat-resistance separator as well as the safe running of LIBs.

The elastic stiffness tensor of cellulosic viscose fibers measured with Brillouin spectroscopy

Brillouin light scattering spectroscopy is applied to study the micromechanics of cellulosic viscose fibers, one of the commercially most important, man-made biobased fibers. Using an equal angle scattering geometry, we provide a thorough description of the procedure to determine the complete transversely isotropic elastic stiffness tensor. From the stiffness tensor the engineering-relevant material parameters such as Young’s moduli, shear moduli, and Poisson’s ratios in radial and axial fiber direction are evaluated. The investigated fiber type shows that, at ideal conditions, the material exhibits optical waveguide properties resulting in spontaneous Brillouin backscattering which can be used to obtain additional information from the Brillouin spectra, enabling the measurement of two different scattering processes and directions with only one scattering geometry.

Impact Characteristics and Repair Approaches of Distinct Bio-Based Matrix Composites: A Comparative Analysis

Increasing global concerns regarding environmental issues have driven significant advancements in the development of bio-based fiber reinforced polymer composites. Despite extensive research on bio-composites, there remains a noticeable gap in studies specifically addressing the challenges of repairing bio-composites for circular economy adoption. Traditional repair techniques for impacted composites, such as patching or scarf methods, are not only time-consuming but also require highly skilled personnel. This paper aims to highlight cost-effective repair strategies for the restoration of damaged composites, featuring flax fiber as the primary reinforcement material and distinct matrix systems, namely bio-based epoxy and bio-based vitrimer matrix. Glass fiber was used as a secondary material to validate the bio-based vitrimer matrix. The damage caused specifically by low impact is detrimental to the structural integrity of the composites. Therefore, the impact resistance of the two composite materials is evaluated using instrumented drop tower tests at various energy levels, while thermography observations are employed to assess damage evolution. Two distinct repair approaches were studied: the resin infiltration repair method, employing bio-based epoxy, and the reconsolidation (self-healing) repair method, utilizing the bio-based vitrimer matrix. The efficiency of these repair methods was assessed through active thermography and compression after impact tests. The repair outcomes demonstrate successful restoration and the maintenance of ultimate strength at an efficiency of 90% for the re-infiltration repair method and 92% for the reconsolidation repair method.

Preparation of Antibacterial Biobased Fibers by Triaxial Microfluidic Spinning Technology Using Ionic Liquids as the Solvents.

Bacterial infections have become a serious threat to public health. The utilization of antibacterial textiles offers an effective way to combat bacterial infections at the source, instead of relying solely on antibiotic consumption. Herein, efficient and durable antibacterial fibers based on quercetin and cellulose were prepared by a triaxial microfluidic spinning technology using ionic liquids (ILs) as the solvents. It was indicated that the structure and properties of the antibacterial fibers were affected by the type of IL and the flow rates during the triaxial microfluidic spinning process. Quercetin regenerated from [Emim]Ac underwent structural transformation and obtained an increased water solubility, while quercetin regenerated from [Emim]DEP remained unchanged, which was proven by FI-IR, XRD, and UV analyses. Furthermore, antibacterial fibers regenerated from [Emim]Ac exhibited the highest antibacterial activity of 96.9% against S. aureus, achieved by reducing the inner-to-outer flow rate ratio to 0 and concentrating quercetin at the center of fibers. On the other hand, when [Emim]DEP was used as the solvent, balancing the inner-to-outer flow rate ratio to concentrate quercetin in the middle layer of the fiber was optimal for achieving the best antibacterial activity of 93.3% because it promised both the higher encapsulation efficiency and release rate. Computational fluid dynamics (CFD) mathematically predicted the solvent exchange process during triaxial spinning, explaining the influence of IL types and flow rates on quercetin distribution and encapsulation efficiency. It was indicated that optimizing the distribution of antibacterial agents within the fibers can fully unleash its antibacterial potential while preserving the mechanical properties of the fiber. Therefore, the proposed simple triaxial spinning strategy provides valuable insights into the design of biomedical materials.

Cellulose/Polyhydroxybutyrate (PHB) Composites as a Sustainable Bio-Based Feedstock to 3D-Printing Applications.

In this work, we have studied the potential application for 3D-printing of a polymer made from combining a biodegradable and biocompatible polymer (i.e., polyhydroxybutyrate, PHB) with natural bio-based fiber (i.e., cellulose). To this end, a masterbatch at 15 wt.% in filler content was prepared by melt-blending, and then this system was "diluted" with pure PHB in a second extrusion phase in order to produce filaments at 1.5 and 3 wt.% of cellulose. For comparison, a filament made of 100% virgin PHB pellets was prepared under the same conditions. All the systems were then processed in the 3D-printer apparatus, and specimens were mainly characterized by static (tensile and flexural testing) and dynamic mechanical analysis. Thermogravimetric analysis, differential scanning calorimetry, spectroscopic measurements, and morphological aspects of PHB polymer and composites were also discussed. The results showed a significant negative impact of the process on the mechanical properties of the basic PHB with a reduction in both tensile and flexural mechanical properties. The PHB-cellulose composites showed a good dispersion filler in the matrix but a poor interfacial adhesion between the two phases. Furthermore, the cellulose had no effect on the melting behavior and the crystallinity of the polymer. The addition of cellulose improved the thermal stability of the polymer and minimized the negative impact of extrusion. The mechanical performance of the composites was found to be higher compared to the corresponding (processed) polymer.

Strategies for Making High-Performance Artificial Spider Silk Fibers.

Artificial spider silk is an attractive material for many technical applications since it is a biobased fiber that can be produced under ambient conditions but still outcompetes synthetic fibers (e.g., Kevlar) in terms of toughness. Industrial use of this material requires bulk-scale production of recombinant spider silk proteins in heterologous host and replication of the pristine fiber's mechanical properties. High molecular weight spider silk proteins can be spun into fibers with impressive mechanical properties, but the production levels are too low to allow commercialization of the material. Small spider silk proteins, on the other hand, can be produced at yields that are compatible with industrial use, but the mechanical properties of such fibers need to be improved. Here, the literature on wet-spinning of artificial spider silk fibers is summarized and analyzed with a focus on mechanical performance. Furthermore, several strategies for how to improve the properties of such fibers, including optimized protein composition, smarter spinning setups, innovative protein engineering, chemical and physical crosslinking as well as the incorporation of nanomaterials in composite fibers, are outlined and discussed.

Solutions on improving spider silk experimentation

Difference in experimental setup can lead to misconceptions on the mechanical properties of silk and bio-based fibers.

Bio-based sandwich beams made of paper honeycomb cores and flax FRP facings: Flexural and shear characteristics

Sandwich composite panels have been used in construction as building envelopes and cladding systems. The sandwich composite used today are mainly made of conventional synthetic foam cores and synthetic fiber-reinforced polymer (FRP) facings, typically made of glass or carbon fibers and synthetic polymers. With increasing environmental consciousness, it is important to develop sustainable building materials to replace conventional building materials with more sustainable materials such as bio-based fibers and polymers. There is lack of studies on sandwich composites made of bio-based materials for both core and facings. In this study, 18 sandwich beam specimens (1200 mm long and 100 mm wide) made of flax FRP facings and 75 mm thick paper honeycomb core were fabricated and tested under three-point bending. The parameters of the tests were facing thickness (1, 2 and 3 layers of flax FRP) and core types (hollow and foam-filled). It was found that the paper honeycomb has comparable performance with lighter weight to other synthetic counterparts and foam-filling was effective in improving the performance of the core and sandwich beams. In addition, as the nonlinear behavior of the specimens was evident, a new analytical model was developed based on the material nonlinearity of both facings and core materials to predict the test data and perform a parametric study. Overall, the bio-based sandwich system showed substantial potential to be used for building applications with much less environmental footprints in comparison with other synthetic counterparts.

Copper-Coordinated Cellulose Fibers for Electric Devices with Motion Sensitivity and Flame Retardance.

Nanocomposite conductive fibers are of great significance in applications of wearable devices, smart textiles, and flexible electronics. Integration of conductive nanomaterials into flexible bio-based fibers with multifunctionality remains challenging due to interface failure, poor flexibility, and inflammability. Although having broader applications in textiles, regenerated cellulose fibers (RCFs) cannot meet the requirements of wearable electronics owing to their intrinsic insulation. In this study, we constructed conductive RCFs fabricated by coordinating copper ions with cellulose and reducing them into stable Cu nanoparticles coated on their surface. The Cu sheath offered excellent electrical conductivity (4.6 × 105 S m-1), electromagnetic interference shielding, and enhanced flame retardance. Inspired by plant tendrils, the conductive RCF was wrapped around an elastic rod to develop wearable sensors for human health and motion monitoring. The resultant fibers not only form stable conductive nanocomposites on the fiber surface by chemical bonds but also exhibit a huge potential for wearable devices, smart sensors, and flame-retardant circuits.

Wet spinning of strong cellulosic fibres with incorporation of phase change material capsules stabilized by cellulose nanocrystals

Incorporating a phase change material (PCM) into fibres allows the fabrication of smart textiles with thermo-regulating properties. Previously, such fibres have been made from thermoplastic polymers, usually petroleum-based and non-biodegradable, or from regenerated cellulose, such as viscose. Herein, strong fibres are developed from aqueous dispersions of nano-cellulose and dispersed microspheres with phase changing characteristics using a wet spinning technique employing a pH shift approach. Good distribution of the microspheres and proper compatibility with the cellulosic matrix was demonstrated by formulating the wax as a Pickering emulsion using cellulose nanocrystals (CNC) as stabilizing particles. The wax was subsequently incorporated into a dispersion of cellulose nanofibrils, the latter being responsible for the mechanical strength of the spun fibres. It was possible to produce fibres highly loaded with the microspheres (40 wt%) with a tenacity of 13 cN tex−1 (135 MPa). The fibres possessed good thermo-regulating features by absorbing and releasing heat without undergoing structural changes, while maintaining the PCM domain sizes intact. Finally, good washing fastness and PCM leak resistance were demonstrated, making the fibres suitable for thermo-regulative applications. Continuous fabrication of bio-based fibres with entrapped PCMs may find applications as reinforcements in composites or hybrid filaments.

The Initial Development and Evaluation of Cross-Linked Casein Films for Sustainable Footwear

To increase the sustainability of footwear and align it with the circular bioeconomy, there is a pressing need to develop novel bio-based materials to replace the synthetic polymers currently used. In this study, casein-based films were prepared by solution casting with a tannic acid cross-linker, and a glycerol plasticizer. The properties important to footwear materials were characterised, including tensile strength and elongation, stitch strength, hardness, grain cracking strength, water vapour permeability, and thermal properties. The tannic acid imparted a brown colour to the films with good resistance to light-induced fading. Their tensile strengths were 4–5 N/mm2, elongation at break 45%–73%, and water vapour permeability 0.2–0.6 mg/(cm2h), depending upon the levels of the cross-linker and plasticiser. The strength of the films was close to those of some non-leather footwear materials such as compact rubbers and insock materials, but below that required for leather shoe vamps/uppers. The casein films were successfully used in sneaker- and ballerina-style shoes as components of the insock and decorative design elements on the vamp. This work has demonstrated the concept of using casein films in footwear. The properties of the films could be improved by further research, particularly with respect to cross-linking, plasticizing, and combining with bio-based fibers and fabrics.

The impact of potassium permanganate (KMnO4) treatment on the tensile strength of pineapple leaf fiber reinforced with tapioca-based bio resin

PurposeThe impact of potassium permanganate (KMnO4) treatment on the tensile strength of an alkali-treated pineapple leaf fiber (PALF) reinforced with tapioca-based bio resin (cassava starch) was studied.Design/methodology/approachThe PALF was exposed to sodium hydroxide (NaOH) treatment in varying concentrations of 2.0, 3.7, 4.5 and 5.5g prior to the fiber treatment with KMnO4. The treated and untreated PALFs were reinforced with tapioca-based bio resin. Subsequently, they were subjected to Fourier transform infrared (FTIR) and tensile test analysis.FindingsThe FTIR analysis of untreated PALF revealed the presence of O-H stretch, N-H stretch, C=O stretch, C=O stretch and H-C-H bond. The tensile test result confirmed the highest tensile strength of 35N from fiber that was reinforced with 32.5g of cassava starch and treated with 1.1g of KMnO4. In comparison, the lowest tensile strength of 15N was recorded for fiber reinforced with 32.5g of cassava starch without KMnO4 treatment.Originality/valueBased on the results, it could be deduced that despite the enhancement of bioresin (cassava starch) towards strength-impacting on the fibers, KMnO4 treatment on PALF is very vital for improved tensile strength of the fiber when compared to untreated fibers. Hence, KMnO4 treatment on alkali-treated natural fibers preceding reinforcement is imperative for bio-based fibers.

Recent progress in biobased synthetic textile fibers

The use of synthetic fibers in our daily life is growing continuously; however, the excessive dependence of these chemical fibers on petroleum-based chemicals will lead to large consumption of non-renewable resources. The scarcity of oil resources, economic and environmental problems, reliance on a few oil-rich countries, and predicted depletion of these resources. Therefore, research and development of biobased materials to reduce the use of fossil fuels have become increasingly important. Biobased synthetic fiber has a low carbon footprint in the synthesis process because its raw materials are derived from biomass. In addition, most biobased synthetic fibers have excellent biodegradability, which can be composted and degraded in natural environments or by microorganisms with or without specific conditions. However, all biobased fibers cannot be proven to be biodegradable, so the development of biodegradability is an important driving force for the progress of research on biobased fibers. In the past, biobased fiber was obtained, extracted, or synthesized from food crops, which was soon replaced by non-food crops. With environmental protection, sustainability, and resource conservation, it has become necessary to make non-food crops and food residues biobased raw materials to obtain biobased textile fibers and even to develop ideal biobased raw materials that are carbon negatives, such as moss and CO2. Besides, there is huge potential for these biobased textile fibers to be used for sustainable clothing and medical textiles due to their non-toxicity, skin friendliness, and antibacterial properties. This review paper introduces biobased synthetic textile fibers, summarizes the recent development, and clarifies key concepts in this domain.

Doped CNC-Na2CO3 reinforcing alginate bio-based fiber as fire-safety composite applied in the household textile

We adopted a straightforward yet efficient method to improve mechanical property of alginate fiber by doping cellulose nanocrystal and Na2CO3 in the spinning solution to fabricate CaCO3-cellulose nanocrystal reinforced alginate fiber. Comparative analysis demonstrated that this composite fiber containing 0.30% cellulose nanocrystal and 0.40% Na2CO3 achieved a maximum breaking strength of 1.42 ± 0.32 cN/dtex, three times more than the pristine alginate fiber. Doped Na2CO3 triggered in situ generating CaCO3 particle during formation of the fiber and deposited extra NaCl particle, which can endow the composite fiber with remarkable fire resistant performance. Also, the composite fiber released limited heat, smoke and toxic gaseous compounds, assisting to reduce fire hazard. Finally, the flame-retardant mechanism of fuel-dilution cooperating with a physical barrier of residue char was proposed. It has a synergistic effect with nonflammable emissions on the inhibition of inflammable emission, generated heat and incoming oxygen transmission, which impeded further combustion. The prepared composite fiber has robust mechanical performance and excellent fire-proofing ability, making it an ideal candidate as flame resistant household textile.

Continuum damage micromechanics description of the compressive failure mechanisms in sustainable biocomposites and experimental validation

We investigate the compressive failure mechanisms in flax fiber composites, a promising eco-friendly alternative to synthetic composite materials, both numerically and experimentally, and explain their low compressive-compared-to-tensile strength, the compressive-to-tensile strength ratio being 0.28−0.6. We present a novel thermodynamically consistent continuum damage micromechanics model capturing events on the fiber-matrix scale. It describes the microstructure of a unidirectional composite and includes the instantaneous constitutive behavior of matrix and fibers. We show that flax fibers behave as elastic-plastic-damaged solids in compression. Furthermore, we show that fiber damage plays an utmost role in the compressive failure of flax fiber composites – it is a major determinant of the material's compressive stress-strain response. Using X-ray Computed Tomography (XCT) and Scanning Electron Microscopy (SEM), we identify the fiber damage as intra-technical fiber splitting and elementary fiber crushing. Due to microstructural similarities among natural fibers, the same micro-mechanisms are likely to appear in other bio-based fibers and their composites.