Fibers

16 pages, 306 KiB

Open AccessReview

The Use of Asbestos and Its Consequences: An Assessment of Environmental Impacts and Public Health Risks

by António Curado, Leonel J. R. Nunes, Arlete Carvalho, João Abrantes, Eduarda Lima and Mário Tomé

Fibers 2024, 12(12), 102; https://doi.org/10.3390/fib12120102 - 25 Nov 2024

Abstract

The use of asbestos, once celebrated for its versatility and fire-resistant properties, has left a lasting legacy of environmental degradation and public health risks. This paper provides a comprehensive assessment of the environmental impacts and health risks associated with asbestos, highlighting its widespread [...] Read more.

The use of asbestos, once celebrated for its versatility and fire-resistant properties, has left a lasting legacy of environmental degradation and public health risks. This paper provides a comprehensive assessment of the environmental impacts and health risks associated with asbestos, highlighting its widespread use, environmental persistence, and adverse effects on human health. Through a literature review, this study examines the historical context of asbestos use, its adverse environmental effects and the mechanisms by which exposure to asbestos poses significant health risks, including the development of asbestos-related diseases such as mesothelioma, lung cancer, asbestosis, etc. It also assesses the current regulatory framework and provides a methodological analysis of the strategy for recycling end-of-life materials containing asbestos fibers, proposing the inclusion of asbestos-containing materials (ACMs) in the rock wool industry to reduce Greenhouse Gasses (GHG) emissions. Drawing on interdisciplinary insights from environmental science, public health, and regulatory analysis, this paper concludes with recommendations for improving asbestos management strategies, promoting safer alternatives and mitigating the long-term environmental and human health impacts of asbestos. Full article

(This article belongs to the Collection Review Papers of Fibers)

17 pages, 7158 KiB

Open AccessArticle

Coaxial Electrospinning of PCL-PVA Membranes Loaded with N-Heterocyclic Gold Complex for Antitumoral Applications

by Raffaele Longo, Luigi Vertuccio, Francesca Aliberti, Annaluisa Mariconda, Marialuigia Raimondo, Pasquale Longo and Liberata Guadagno

Fibers 2024, 12(12), 101; https://doi.org/10.3390/fib12120101 - 21 Nov 2024

Abstract

Coaxial electrospun membranes made of polycaprolactone (PCL) and polyvinylalcohol (PVA) were produced and filled with a promising synthetic gold complex (AuM1) for antitumoral applications. Coaxial nanofibers characterized by a PVA shell and PCL + AuM1 core were made to design a multi-step release [...] Read more.

Coaxial electrospun membranes made of polycaprolactone (PCL) and polyvinylalcohol (PVA) were produced and filled with a promising synthetic gold complex (AuM1) for antitumoral applications. Coaxial nanofibers characterized by a PVA shell and PCL + AuM1 core were made to design a multi-step release in a physiological environment. The coaxial structure can sensitively limit the burst effect, allowing the release of 90% of the active substance AuM1 in about three days. By comparison, the PCL membrane loaded with AuM1 produced via uniaxial electrospinning releases 90% of the drug in about 1 h. The correlation of release kinetic data with the morphological evolution and the spectroscopic investigation highlighted how coaxial electrospinning is a promising process for designing drug delivery systems to control the release of active substances over time. The proper design of core–shell systems could be of great interest for prolonged therapies, such as antitumoral therapy. Full article

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14 pages, 4247 KiB

Open AccessArticle

Thermal, Optical, and Emission Traits of SM³⁺-Ion-Doped Fluoride/Chloride/Oxide Glass for Red/Orange Laser Fiber Applications

by Bozena Burtan-Gwizdala, Jan Cisowski, Radoslaw Lisiecki, Kinga J. Kowalska, Bozena Jarzabek, Natalia Nosidlak, Manuela Reben, Ali M. Alshehri, Khalid I. Hussein and El Sayed Yousef

Fibers 2024, 12(11), 100; https://doi.org/10.3390/fib12110100 - 15 Nov 2024

Abstract

This study examined spectroscopic, thermal, and other qualities, such as the lasing parameters, of Sm³⁺-doped glass with the composition 40P₂O₅–30ZnO–20LiCl–10BaF₂. The ellipsometric data were used in a Sellmeier dispersion relation to estimate the refractive index [...] Read more.

This study examined spectroscopic, thermal, and other qualities, such as the lasing parameters, of Sm³⁺-doped glass with the composition 40P₂O₅–30ZnO–20LiCl–10BaF₂. The ellipsometric data were used in a Sellmeier dispersion relation to estimate the refractive index values of the glasses investigated. The measured absorption spectra of the doped glass reveal the presence of various absorption bands assigned to transitions from the ⁶H_5/2 ground state attributed to Sm³⁺-ion-excited states. We studied the decay of the ⁴G_5/2 level of the Sm³⁺ ions in the doped glass by analyzing its absorption and emission fluorescence spectra. The Judd–Ofelt hypothesis allowed us to determine that the quantum efficiency of the ⁴G_5/2–⁶H_7/2 transition is high: 96% and 97% for glass doped with 4.05

\times

10¹⁹ ions/cm⁻³ and 11

\times

10¹⁹ ions/cm⁻³, respectively. Furthermore, this glass exhibits efficient red/orange enhanced spontaneous emission that matches the excitation band of the photosensitizer material used in medical applications. Full article

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15 pages, 2102 KiB

Open AccessArticle

Waste Bombyx Mori Silk Textiles as Efficient and Reuseable Bio-Adsorbents for Methylene Blue Dye Removal and Oil–Water Separation

by Hansadi Jayamaha, Isabel Schorn and Larissa M. Shepherd

Fibers 2024, 12(11), 99; https://doi.org/10.3390/fib12110099 - 14 Nov 2024

Abstract

Many adsorbent materials are being studied for dye and oil removal from the environment. Bio-based materials such as silk are promising candidates due to their enhanced affinity for dyes and intrinsic hydrophobicity. This work extensively studies various silk textiles as dye and oil [...] Read more.

Many adsorbent materials are being studied for dye and oil removal from the environment. Bio-based materials such as silk are promising candidates due to their enhanced affinity for dyes and intrinsic hydrophobicity. This work extensively studies various silk textiles as dye and oil adsorbents. For comparison, we use electrospun fiber mats and hollow silk microparticle-treated silk fabrics. Our work is motivated by two factors: (i) massive amounts of silk waste is being discarded annually from textile factories, and (ii) the limited studies on the adsorption phenomena of pristine silk textiles. Based on our findings, 12 mg of silk filament yarn has a 90% methylene blue (MB) removal efficiency within 10 min of exposure for concentrations up to 100 ppm and exhibits adsorption capacities of 145 mg/g for 800 ppm concentrations. The adsorption kinetics obey a pseudo-second order, where the rate-controlling step is chemisorption, and isotherms follow the Langmuir model with homogenous monolayer adsorption. Furthermore, noil woven fabrics with contact angles of 140⁰ have oil adsorbent capacities that are double the fabric weight. Our work confirms that silk waste textiles are efficient and reusable bio-adsorbents for MB dye and oil removal, outperforming materials made with additional and energy-intensive techniques such as silk dissolution and electrospinning. Full article

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24 pages, 8849 KiB

Open AccessReview

Non-Circular Cross-Section Fibres for Composite Reinforcement—A Review with a Focus on Flat Glass Fibres

by James Thomason, Andrew Carlin and Liu Yang

Fibers 2024, 12(11), 98; https://doi.org/10.3390/fib12110098 - 11 Nov 2024

Abstract

Glass fibre reinforcements form the backbone of the composites industry. Today, glass fibre products account for more than 95% of the fibre reinforcements used in the composites industry. Since the first commercialisation of glass fibres for composite reinforcement in the 1930s, the cross-sectional [...] Read more.

Glass fibre reinforcements form the backbone of the composites industry. Today, glass fibre products account for more than 95% of the fibre reinforcements used in the composites industry. Since the first commercialisation of glass fibres for composite reinforcement in the 1930s, the cross-sectional shape of glass fibres has remained exclusively circular. However, many of the other types of fibre reinforcement have a non-circular cross section (NCCS). This paper reviews the available knowledge on the production of NCCS glass fibres and some of the possibilities that such fibres offer to enhance the performance of glass reinforced polymer composites. The three parts of the review focus on early research work on different shapes of glass fibre, the developments leading to industrial-level production of NCCS glass fibres, and the more recent data available on the influence of the available commercially produced NCCS flat glass fibres on composite performance. It Is concluded that the continued development of NCCS glass fibres may offer interesting potential to generate composites with increased performance and may also enable further tailoring of composite performance to enable new applications to be developed. Full article

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20 pages, 21295 KiB

Open AccessArticle

Influence of the PAN:PEO Ratio on the Morphology of Needleless Electrospun Nanofiber Mats Before and After Carbonization

by Nonsikelelo Sheron Mpofu, Yusuf Topuz, Elzbieta Stepula, Uwe Güth, Timo Grothe, Jan Lukas Storck, Martin Wortmann, Boris Mahltig and Andrea Ehrmann

Fibers 2024, 12(11), 97; https://doi.org/10.3390/fib12110097 - 8 Nov 2024

Abstract

Nanofiber mats with a high surface-to-volume ratio can be prepared by electrospinning. The Porosity is sometimes reported to be tunable by blending different materials, e.g., water-soluble poly(ethylene oxide) (PEO) with not water-soluble poly(acrylonitrile) (PAN). Here, nanofiber mats were electrospun from different PAN:PEO ratios, [...] Read more.

Nanofiber mats with a high surface-to-volume ratio can be prepared by electrospinning. The Porosity is sometimes reported to be tunable by blending different materials, e.g., water-soluble poly(ethylene oxide) (PEO) with not water-soluble poly(acrylonitrile) (PAN). Here, nanofiber mats were electrospun from different PAN:PEO ratios, using a wire-based electrospinning machine “Nanospider Lab”. Investigations of the as-spun nanofiber mats as well as of membranes after washing off the water-soluble PEO by scanning electron microscopy (SEM) revealed severe differences in the nanofiber mat morphologies, such as varying fiber diameters and especially non-fibrous areas in the carbonized nanofiber mats, depending on the amount of PEO in the nanofiber mat as well as the molecular weight of the PEO. Similarly, the ratio and molecular weight of PEO influenced the results of stabilization and carbonization. This paper discusses the possibility of tailoring nanofiber porosity for the potential use of PAN nanofiber mats in tissue engineering, filtration, and other applications. Full article

(This article belongs to the Special Issue Electrospinning Nanofibers)

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20 pages, 7109 KiB

Open AccessArticle

Coating of Hemp Fibres with Hydrophobic Compounds Extracted from Pine Bark

by Robert Abbel, Regis Risani, Maxime Nourtier, Lloyd Donaldson, Christel Brunschwig, Claire Mayer-Laigle, James H. Bridson, Armin Thumm, Alan Dickson, Rachel Murray, Jessica Harris, Johnny Beaugrand and Stefan Hill

Fibers 2024, 12(11), 96; https://doi.org/10.3390/fib12110096 - 7 Nov 2024

Abstract

Applying coatings of paraffins and other synthetic waxes is a common approach to impart hydrophobic properties to fibres and thus control their surface characteristics. Replacing these fossil-based products with alternatives derived from renewable resources can contribute to humankind’s transition to a sustainable bioeconomy. [...] Read more.

Applying coatings of paraffins and other synthetic waxes is a common approach to impart hydrophobic properties to fibres and thus control their surface characteristics. Replacing these fossil-based products with alternatives derived from renewable resources can contribute to humankind’s transition to a sustainable bioeconomy. This study presents the coating of hemp fibres with waxes extracted from pine bark as an exemplar application. Two bio-based emulsifiers were used to prepare wax emulsions suitable for a dry blending process. The coatings on the fibres were characterised, quantified, and visualised using a combination of spectroscopic and microscopic techniques. Confocal fluorescence microscopy was an excellent tool to investigate the spatial distribution of the pine bark waxes on the fibre surfaces. While successful deposition was demonstrated for all tested formulations, coating homogeneity varied for different emulsifiers. Compounding the hemp fibres with a bio-based polyester resulted in the substantial improvement of the mechanical behaviour. However, the presence of a wax coating on the fibres did not lead to a significant change in mechanical properties compared to the controls with uncoated fibres. Optimising the composite chemistry or adjusting the processing conditions might improve the compatibility of the hemp fibres with the matrix material, resulting in enhanced mechanical performance. Full article

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22 pages, 7258 KiB

Open AccessArticle

Self-Healing and Mechanical Behaviour of Fibre-Reinforced Ultra-High-Performance Concrete Incorporating Superabsorbent Polymer Under Repeated and Sustained Loadings

by Mohammad Alameri, M.S. Mohamed Ali, Mohamed Elchalakani, Abdul Sheikh and Rong Fan

Fibers 2024, 12(11), 95; https://doi.org/10.3390/fib12110095 - 5 Nov 2024

Abstract

This study investigated the mechanical responses and self-healing capability of incorporating superabsorbent polymer (SAP) particles in Fibre-Reinforced Ultra-High-Performance Concrete (UHPC) mixes under repetitive flexural and sustained tensile loadings. UHPC with SAP addition of 0.3% and 0.4% of the binder ratio were studied along [...] Read more.

This study investigated the mechanical responses and self-healing capability of incorporating superabsorbent polymer (SAP) particles in Fibre-Reinforced Ultra-High-Performance Concrete (UHPC) mixes under repetitive flexural and sustained tensile loadings. UHPC with SAP addition of 0.3% and 0.4% of the binder ratio were studied along with a control UHPC mix. The methodology included investigating the mechanical properties of these mixes under ambient, water, and 100% of relative humidity (RH) curing conditions. In addition, the mechanical performance of ambient-, water-, and 100% RH-cured prismatic specimens (100 mm × 100 mm × 500 mm) under repeated load was studied under the same curing conditions. Prismatic specimens (75 mm × 75 mm × 500 mm) were kept under cure conditions of wet and dry cycles with applied tensile load for 28 days for the sustained tensile load. The results showed that incorporating SAP into UHPC enhances the elastic modulus, flexural strength, and tensile strength. Also, mixes with SAP have exhibited compressive strength above 120 MPa after 90 days. Furthermore, the load recovery of the prisms under repetitive flexural load and prisms under sustained tensile loading demonstrated the self-healing efficiency of SAP incorporated into the UHPC mixes higher than the control mix specimens. Full article

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15 pages, 3412 KiB

Open AccessArticle

Experimental and Statistical Investigations for Tensile Properties of Hemp Fibers

by Peyman Sadeghi, Quang Cao, Ragab Abouzeid, Mohammad Shayan, Meensung Koo and Qinglin Wu

Fibers 2024, 12(11), 94; https://doi.org/10.3390/fib12110094 - 1 Nov 2024

Abstract

This study investigated the tensile behaviors of hemp fiber bundles and examined how properties including tensile strength and Young’s modulus vary with the bundle diameter. Hemp fibers were extracted, degummed, and separated into bundles of different diameters ranging from less than 50 μm [...] Read more.

This study investigated the tensile behaviors of hemp fiber bundles and examined how properties including tensile strength and Young’s modulus vary with the bundle diameter. Hemp fibers were extracted, degummed, and separated into bundles of different diameters ranging from less than 50 μm to over 150 μm. Tensile tests were conducted on these fiber bundles using a rheometer-based tensile testing machine. The results showed that hemp fibers exhibited a tensile strength of 97.33 MPa and a Young’s modulus of 3.77 GPa at a 50% survival probability. However, the scale parameters for breaking stress and Young’s modulus were determined to be 620.57 MPa and 29.88 GPa, respectively. As the fiber bundle diameter increased, the tensile strength decreased significantly. This was attributed to the higher probability of defects and irregularities acting as weakness points in larger fiber bundles. In contrast, Young’s modulus (stiffness) increased with increasing bundle diameter, likely due to improved fiber–fiber interactions. To further understand the variability and reliability of the tensile properties, statistical models were developed. The Weibull distribution analysis was applied, revealing critical insights into the variability of diameter, stress at break, Young’s modulus, and strain at break. The Weibull parameters provided a comprehensive understanding of the fibers’ mechanical reliability. Additionally, the Griffith model was employed to predict the strength and Young’s modulus based on fiber diameters, supporting the observation that thinner fibers generally exhibited higher tensile strength due to fewer defects. Overall, this work highlights the importance of understanding structure–property relationships in natural fibers like hemp for optimizing their performance in composites. Full article

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15 pages, 3387 KiB

Open AccessReview

A Brief Review of Hemp Fiber Length Measurement Techniques

by Joia Green, Xiaorui Liu and Rong Yin

Fibers 2024, 12(11), 93; https://doi.org/10.3390/fib12110093 - 31 Oct 2024

Abstract

Accurate fiber length measurement is essential for the processing and quality management of textile products. This article reviews the current methods used to measure fiber length, including manual, photoelectric, capacitive, and optical techniques. Existing sample preparation processes for natural fiber characterization have been [...] Read more.

Accurate fiber length measurement is essential for the processing and quality management of textile products. This article reviews the current methods used to measure fiber length, including manual, photoelectric, capacitive, and optical techniques. Existing sample preparation processes for natural fiber characterization have been primarily developed for cotton and wool fibers. However, hemp fibers present unique challenges due to their greater length variability, high strength, and low elongation, making some traditional sample preparation methods less effective. Image processing offers a promising approach for scalable and precise measurement of hemp fiber length. Nevertheless, current image processing techniques are limited by the inability to effectively handle overlapping fibers, which increases both the time and cost of testing. Continued research into developing more advanced segmentation algorithms could lead to more widely adopted commercial methods for fiber measurement. Full article

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22 pages, 12067 KiB

Open AccessArticle

Cent-Hydro: A Novel Temperature and Pressure-Controlled Hybrid System for Large-Scale Nanofiber Production

by Samia Farhaj, Noman Ahmad, Alan M. Smith, Barbara R. Conway and Muhammad Usman Ghori

Fibers 2024, 12(10), 92; https://doi.org/10.3390/fib12100092 - 21 Oct 2024

Abstract

The present study aimed to develop a novel temperature and pressure-controlled hybrid system (Cent-Hydro) for large-scale nanofiber production. Nanofibers from a hydrophilic carrier matrix were prepared using the Cent-Hydro system. This study explores the effect of increasing working temperature on the surface tension [...] Read more.

The present study aimed to develop a novel temperature and pressure-controlled hybrid system (Cent-Hydro) for large-scale nanofiber production. Nanofibers from a hydrophilic carrier matrix were prepared using the Cent-Hydro system. This study explores the effect of increasing working temperature on the surface tension and viscosity of polymer solutions. The Cent-Hydro system was calibrated through the process of jet formation, and spinning parameters were identified for the jet path. The formation of fingers in front of the thin liquid occurred due to Rayleigh–Taylor instability, and a lower concentration of polymer solution favoured the development of thinner and longer fingers. The critical angular velocity and initial velocity for jet formation were obtained when the balance between surface tension, centrifugal force, and viscous force was achieved. The effect of increasing rotational speed and working temperature on finger velocity and length was experimentally evaluated, concluding that an increase in working temperature increases finger velocity and length. Additionally, the effect of increasing rotational speed, polymer concentration, and working temperature on the diameter of the nanofiber was evaluated. Overall, the Cent-Hydro system presents a compelling proposition for large-scale nanofiber production, offering distinct advantages over conventional methods and paving the way for advancements in various applications. Full article

(This article belongs to the Collection Feature Papers in Fibers)

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16 pages, 5248 KiB

Open AccessArticle

The Influence of Dew Retting on the Mechanical Properties of Single Flax Fibers Measured Using Micromechanical and Nanomechanical Approaches

by Ali Reda, Thomas Dargent, Louis Thomas, Sebastien Grec, Lionel Buchaillot and Steve Arscott

Fibers 2024, 12(10), 91; https://doi.org/10.3390/fib12100091 - 18 Oct 2024

Abstract

The mechanical properties of single flax fibers are characterized here as a function of dew retting. The fibers are measured using micromechanical and nanomechanical techniques over a large retting period (91 days). Damage-free single flax fibers in various stages of dew retting were [...] Read more.

The mechanical properties of single flax fibers are characterized here as a function of dew retting. The fibers are measured using micromechanical and nanomechanical techniques over a large retting period (91 days). Damage-free single flax fibers in various stages of dew retting were manually extracted from retted flax plant stems. The flexural modulus and strength of the flax fibers were determined using micromechanical methods. The effective modulus of the outer surface of the single fibers was measured using AFM-based nanoindentation. The micromechanical methods revealed that the flexural modulus and strength of the manually extracted single fibers does not vary significantly as the retting progresses. The micromechanical methods revealed two distinct values of flexural strength in the fibers attributed to different failure modes. The values of these strengths do not vary significantly with retting or over-retting. The nanomechanical methods revealed that the effective modulus of the outer surface of the single fibers does evolve with retting. The physical/chemical origin of these observations remains to be established and could be the objective of future work. Full article

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13 pages, 1963 KiB

Open AccessArticle

Moisture and Surface Properties of Radically Photo-Grafted Poly-(Ethylene Terephthalate) Woven Fabric

by Roberta Bongiovanni, Jinping Guan, Ada Ferri and Alessandra Vitale

Fibers 2024, 12(10), 90; https://doi.org/10.3390/fib12100090 - 15 Oct 2024

Abstract

This study aims at the modification of the surface properties of twill-5 polyethylene terephthalate (PET) fabric, in particular to improve its hydrophilicity. It compares the hydrophilic potential and efficacy of two vinyl monomers radically grafted onto the fabric by photoinduced processes. Poly(ethylene glycol) [...] Read more.

This study aims at the modification of the surface properties of twill-5 polyethylene terephthalate (PET) fabric, in particular to improve its hydrophilicity. It compares the hydrophilic potential and efficacy of two vinyl monomers radically grafted onto the fabric by photoinduced processes. Poly(ethylene glycol) diacrylate (PEGDA) and [2-(methacryloyloxy)-ethyl]-trimethylammonium chloride (METAC) affected the wettability of the fabric towards water, significantly reducing the water contact angle (WCA). As a consequence, the treated fabrics showed a good improvement of dynamic moisture management. Adopting specific conditions (e.g., type of monomer and grafting monomer concentration), the grafted PET fabrics remained hydrophilic after washing, laudering, dry cleaning, and rubbing tests; thus, the surface treatment modification resulted to be durable overall. Full article

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15 pages, 4093 KiB

Open AccessArticle

The Influence of Abaca Fiber Treated with Sodium Hydroxide on the Deformation Coefficients Cc, Cs, and Cv of Organic Soils

by Carlos Contreras, Jorge Albuja-Sánchez, Oswaldo Proaño, Carlos Ávila, Andreina Damián-Chalán and Mateo Peñaherrera-Aguirre

Fibers 2024, 12(10), 89; https://doi.org/10.3390/fib12100089 - 15 Oct 2024

Abstract

This study shows the influence of the inclusion of abaca fiber (Musa Textilis) on the coefficients of consolidation, expansion, and compression for normally consolidated clayey silt organic soil specimens using reconstituted samples. For this purpose, abaca fiber was added according to the dry [...] Read more.

This study shows the influence of the inclusion of abaca fiber (Musa Textilis) on the coefficients of consolidation, expansion, and compression for normally consolidated clayey silt organic soil specimens using reconstituted samples. For this purpose, abaca fiber was added according to the dry mass of the soil, in lengths (5, 10, and 15 mm) and concentrations (0.5, 1.0, and 1.5%) subjected to a curing process with sodium hydroxide (NaOH). The virgin and fiber-added soil samples were reconstituted as slurry, and one-dimensional consolidation tests were performed in accordance with ASTM D2435. The results showed a reduction in void ratio (compared to the soil without fiber) and an increase in the coefficient of consolidation (Cv) as a function of fiber concentration and length, with values corresponding to 1.5% and 15 mm increasing from 75.16 to 144.51 cm²/s. Although no significant values were obtained for the compression and expansion coefficients, it was assumed that the soil maintained its compressibility. The statistical analysis employed hierarchical linear models to assess the significance of the effects of incorporating fibers of varying lengths and percentages on the coefficients, comparing them with the control samples. Concurrently, mixed linear models were utilized to evaluate the influence of the methods for obtaining the Cv, revealing that Taylor’s method yielded more conservative values, whereas the Casagrande method produced higher values. Full article

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20 pages, 6696 KiB

Open AccessArticle

Raman Scattering for Tensile Testing of Polyacrylonitrile-Based and Pitch-Based Single Carbon Fibers

by Kimiyoshi Naito and Chiemi Nagai

Fibers 2024, 12(10), 88; https://doi.org/10.3390/fib12100088 - 10 Oct 2024

Abstract

The tensile properties of polyacrylonitrile (PAN)-based and pitch-based single carbon fibers were assessed using Raman scattering. Parameters and ratios related to Raman scattering and stress measurement for the G- and D-bands were analyzed. These include the peak values of Raman shifts (R [...] Read more.

The tensile properties of polyacrylonitrile (PAN)-based and pitch-based single carbon fibers were assessed using Raman scattering. Parameters and ratios related to Raman scattering and stress measurement for the G- and D-bands were analyzed. These include the peak values of Raman shifts (R_G, R_D), full width at half maximum (FWHM_G, FWHM_D), peak value slopes (|A_G|, |A_D|), peak value intercepts (B_G, B_D), the intensity ratio (I_D/I_G), the peak value ratio (R_D/R_G), the full width at half maximum ratio (FWHM_D/FWHM_G), the slope ratio (A_D/A_G), and the intercept ratio (B_D/B_G). These parameters and ratios were determined by analyzing the PAN-based and pitch-based carbon fibers and were correlated to the tensile modulus (E), interlayer spacing (d₀₀₂), lattice spacing (d₁₀), and crystalline size (L_c and L_a). In addition, a linear relationship was identified between the Raman scattering, stress measurement parameters, ratios and E, d₀₀₂, d₁₀, as well as between the Raman scattering, stress measurement parameters, ratios and L_a and L_C on the log–log scale. Full article

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14 pages, 18487 KiB

Open AccessArticle

Synthesis of Carbon Nanofibers from Lignin Using Nickel for Supercapacitor Applications

by Meruyert Nazhipkyzy, Anar B. Maltay and Tulegen M. Seilkhanov

Fibers 2024, 12(10), 87; https://doi.org/10.3390/fib12100087 - 9 Oct 2024

Abstract

Carbon fiber is known for being lightweight and adaptable, making it useful for various current and future applications. However, to broaden the use of carbon fibers beyond niche applications, production costs must be lowered. A potential approach to achieving this is by using [...] Read more.

Carbon fiber is known for being lightweight and adaptable, making it useful for various current and future applications. However, to broaden the use of carbon fibers beyond niche applications, production costs must be lowered. A potential approach to achieving this is by using more affordable raw materials, such as lignin, which is renewable, cost-effective, and widely available compared with the materials commonly used in industry today. This study explores the impact of metal ions on the quality of carbon fiber derived from lignin, focusing on its mechanical and electrochemical properties and morphology. The effect of a specific metal ion (Ni(NO₃)₂·6H₂O) was examined by incorporating it into the spinning solution. The carbonization stage of the fiber was conducted at temperatures of 800, 900, and 1000 °C in an inert atmosphere. Scanning electron microscopy (SEM) analysis showed no defects or damage in any of the fibers. Therefore, it was concluded that moderate concentrations of Ni²⁺ ions in the fibers do not influence the stabilization or carbonization processes, thus leaving the mechanical properties of the final carbon fiber unchanged. These carbon nanofibers were also tested as a sustainable alternative to the non-renewable materials used in electrodes for energy storage and conversion devices, such as supercapacitors. Electrochemical performance was assessed in a 6 M KOH solution using a two-electrode cell configuration. Galvanostatic charge–discharge tests were performed at different current densities (0.1, 0.25, 0.5, 1.0, and 2.0 A g⁻¹). The specific capacitance of the carbon nanofibers was determined from CVA data at various scan rates: 5, 10, 20, 40, 80, and 160 mV s⁻¹. The results indicated that at 0.1 A g⁻¹, the capacitance reached 108 F g⁻¹, and at a scan rate of 5 mV s⁻¹, it was 91 F g⁻¹. The innovation of this work lies in its use of lignin, a renewable and widely available material, to produce carbon fibers, reducing costs compared with traditional methods. Additionally, the incorporation of nickel ions enhances the electrochemical properties of the fibers for supercapacitor applications without compromising their mechanical performance. Full article

(This article belongs to the Special Issue Use of Fibers in Organic and Inorganic Composite Solutions for Structural Strengthening: Advances, Applications, and Challenges)

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17 pages, 1488 KiB

Open AccessArticle

A Comparative Analysis of Denim Fabric Performances from Cotton/Polyester Blended Rigid and Stretched Yarns

by Md Abul Shahid, Neslihan Okyay and Osman Babaarslan

Fibers 2024, 12(10), 86; https://doi.org/10.3390/fib12100086 - 9 Oct 2024

Abstract

Cotton and polyester fiber blends are commonly used to improve the aesthetic features of finished items. The denim industry’s growing need for polyester fiber aids in analyzing the performance of denim fabrics woven from rigid and stretched weft yarn combined with cotton and [...] Read more.

Cotton and polyester fiber blends are commonly used to improve the aesthetic features of finished items. The denim industry’s growing need for polyester fiber aids in analyzing the performance of denim fabrics woven from rigid and stretched weft yarn combined with cotton and polyester. This study evaluates the weight, dimensional changes, stiffness, tensile and tearing strength, stretch, and comfort properties of denim fabric woven from cotton and polyester in various blended ratios. Here, Ne 14/1 (42 tex) 100% cotton warp yarn and Ne 18/1 (33 tex) weft yarns, consisting of 100% cotton, 75/25, 50/50, and 25/75 cotton/polyester (CO/PES) blends, as well as 100% polyester, were used to produce 3/1 Z twill denim fabric. The weft yarns were categorized into three groups: rigid, core-spun, and dual-core-spun yarns. Experimental results showed a higher polyester content in weft yarn, and denim fabrics’ tensile and tearing strength was improved, whereas fabrics’ weight loss, dimensional changes, and stretch properties were reduced. Furthermore, different statistical analyses were conducted to evaluate the type of weft yarn and blending ratio interaction and correlation with fabric properties. Additionally, a regression model was developed with the weft yarn type and blending ratio as independent variables to predict the fabric properties. Full article

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10 pages, 3002 KiB

Open AccessArticle

Forensic Discrimination of Various Subtypes of Regenerated Cellulose Fibers in Clothing Available on the Consumer Market

by Jolanta Wąs-Gubała, Mateusz Migdał and Zuzanna Brożek-Mucha

Fibers 2024, 12(10), 85; https://doi.org/10.3390/fib12100085 - 8 Oct 2024

Abstract

The discrimination of five subtypes of regenerated cellulose fibers, i.e., viscose, bamboo, lyocell, modal, and cupro, from both men’s and women’s clothing available on the prevalent apparel market was described. The examinations were conducted using optical microscopy (in transmitted white light and polarized [...] Read more.

The discrimination of five subtypes of regenerated cellulose fibers, i.e., viscose, bamboo, lyocell, modal, and cupro, from both men’s and women’s clothing available on the prevalent apparel market was described. The examinations were conducted using optical microscopy (in transmitted white light and polarized light), scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM–EDX), and Fourier Transform Infrared Spectroscopy (FTIR). The microscopic methods revealed characteristic features of the morphological structure of the examined fibers, enabling the identification of differences between the subtypes. As a result, the microscopic methods were found to be the most effective for identifying and distinguishing between the types of examined fibers. Although the FTIR technique did not allow for distinguishing between the fiber subcategories, it contributed to the enlargement of the IR spectra databases for regenerated cellulose fibers. Based on the findings, a general scheme of the procedure for identifying the tested fibers was proposed. Full article

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16 pages, 14229 KiB

Open AccessArticle

Influence of Genetic and Non-Genetic Factors on the Physical and Mechanical Properties of Mongolian Cashmere Fiber Properties

by Wafa Mahjoub, Sarangoo Ukhnaa, Jean-Yves Drean and Omar Harzallah

Fibers 2024, 12(10), 84; https://doi.org/10.3390/fib12100084 - 1 Oct 2024

Abstract

Cashmere is widely acclaimed as one of the most luxurious textile fibers. Mongolia, a major player in cashmere production and processing, is key to this industry. Despite the rich history of cashmere, there is limited research on cashmere fiber properties, which are essential [...] Read more.

Cashmere is widely acclaimed as one of the most luxurious textile fibers. Mongolia, a major player in cashmere production and processing, is key to this industry. Despite the rich history of cashmere, there is limited research on cashmere fiber properties, which are essential in producing high-quality garments. This study aims to improve our understanding of cashmere fibers’ physical and mechanical properties and to assess how genetic and non-genetic factors affect these characteristics. We analyzed key fiber characteristics, including scale morphology, and the physical and mechanical properties (such as fineness, length parameters, stress, and strain) in 11 samples from Mongolian goats of varying areas, breeds, ages, and genders. Through detailed statistical analysis, our experimental results revealed that both genetic and non-genetic factors significantly affect fiber fineness and the specific energy of rupture. Additionally, we observed that the influence of these factors can inform better classification systems for raw cashmere and enhance the determination of the fiber’s spinability limit. Full article

(This article belongs to the Special Issue Natural Fibers for Advanced Materials: Addressing Challenges)

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