Fibers

25 pages, 9394 KiB

Open AccessArticle

Transmitted Light Measurement to Determine the Local Structural Characteristics of Paperboard: Grammage, Thickness, and Fiber Orientation

by Cedric W. Sanjon, Yuchen Leng, Marek Hauptmann, Peter Groche and Jens-Peter Majschak

Fibers 2024, 12(12), 113; https://doi.org/10.3390/fib12120113 - 23 Dec 2024

Viewed by 361

Abstract

This study presents a novel transmission-based method for characterizing local structural features, including the grammage, thickness, and fiber orientation, of paper materials. Some non-destructive techniques, such as micro-computed tomography (

μ

-CT), microscopy, and radiation-based methods, are costly, time-consuming, and lack the ability [...] Read more.

This study presents a novel transmission-based method for characterizing local structural features, including the grammage, thickness, and fiber orientation, of paper materials. Some non-destructive techniques, such as micro-computed tomography (

μ

-CT), microscopy, and radiation-based methods, are costly, time-consuming, and lack the ability to provide comprehensive local structural information within a single measurement. The proposed method utilizes a single light transmission measurement to assess local grammage and thickness through histogram matching with reference data obtained via

β

-radiography and profilometry. The same light transmission images are also used to determine local fiber orientation, employing image analysis techniques. The structure tensor method, which analyzes gradients of light transmission images, provides detailed insight into the local fiber orientation. The results show that thickness and grammage measurements are independent of which side of the paper is evaluated, while the fiber orientation distribution varies between the front and back sides, reflecting differences in fiber arrangement due to manufacturing processes. Various distribution functions are compared, and the Pearson Type 3, log-normal, and gamma distributions are found to most accurately describe the grammage, thickness, and fiber orientation distributions. The study includes a variety of paper types, ensuring a robust and comprehensive analysis of material behavior, and confirms that the method can effectively infer the inhomogeneous features from a single light transmission measurement. Full article

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13 pages, 7651 KiB

Open AccessArticle

The Influence of Ultraviolet Radiation on the Surface Roughness of Prints Made on Papers with Natural and Bleached Hemp Fibers

by Željka Barbarić-Mikočević, Irena Bates, Maja Rudolf and Ivana Plazonić

Fibers 2024, 12(12), 112; https://doi.org/10.3390/fib12120112 - 20 Dec 2024

Viewed by 431

Abstract

In the papermaking industry, cellulose fibers often undergo a bleaching process which affects the surface of the fibers, or their overall morphology. The surface of the produced paper, which is most often used as a printing substrate, depends on the production method, the [...] Read more.

In the papermaking industry, cellulose fibers often undergo a bleaching process which affects the surface of the fibers, or their overall morphology. The surface of the produced paper, which is most often used as a printing substrate, depends on the production method, the arrangement of the cellulose fibers, and the quantity and fineness of the filler. The micro-irregularities caused by the uneven distribution of fibers and surface particles of the filler make the paper’s surface rough and affect the print quality and its stability when exposed to light from the moment of production to use. The unbleached cellulose fibers in the printing substrate contain natural pigments, lignin and hemicellulose that absorb UV radiation, as opposed to bleached fibers, which have higher whiteness and lightfastness. Therefore, the influence of UV radiation on the surface roughness of prints made on papers with natural unbleached and bleached hemp fibers was analyzed. This research confirmed that papers formed from unbleached fibers have rougher surface and that printed graphic products from bleached fibers have higher stability to UV radiation than those from natural, unbleached hemp fibers after 96 h of treatment in the Suntest chamber. Full article

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

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22 pages, 26921 KiB

Open AccessArticle

Impact of Defects on Tensile Properties of Ancient and Modern Egyptian Flax Fibers: Multiscale X-Ray Microtomography and Numerical Modeling

by Vasuki Rajakumaran, Sofiane Guessasma, Angélina D’Orlando, Alessia Melelli, Mario Scheel, Timm Weitkamp, Jonathan Perrin, Alain Bourmaud, Henry Proudhon and Johnny Beaugrand

Fibers 2024, 12(12), 111; https://doi.org/10.3390/fib12120111 - 16 Dec 2024

Viewed by 661

Abstract

Flax fibers, while offering numerous benefits, are susceptible to mechanical weakening due to the presence of kink-bands within their structure. The novelty of this study lies in linking mechanical behavior to fiber morphology and defects at multiple scales by utilizing X-ray microtomography to [...] Read more.

Flax fibers, while offering numerous benefits, are susceptible to mechanical weakening due to the presence of kink-bands within their structure. The novelty of this study lies in linking mechanical behavior to fiber morphology and defects at multiple scales by utilizing X-ray microtomography to generate detailed 3D images of elementary flax fibers, enabling the creation of accurate finite element (FE) models for analysis. Aging reduces flax fibers’ strength, so both modern and ancient fibers were analyzed to understand their structural evolution over time. Static X-ray microtomography images were converted into 3D FE models for tensile simulations, and tensile tests provided essential properties for numerical modeling. Morphological analysis for both fiber types revealed that kink-bands contain multiple pores oriented ~45° to the fiber/lumen axis, with ancient fibers showing higher porosity (5.6%) and kink-band density (20.8 mm⁻¹) than modern fibers (3.3% and 16.6 mm⁻¹). SEM images confirmed that the intricate lumen and kink-bands lead to fiber failure under tensile loading. Numerical analysis highlighted higher stress concentrations at the kink-band region, particularly at pores in the kink-band region, which can initiate cracks and lead to rupture. Full article

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Graphical abstract

15 pages, 1780 KiB

Open AccessArticle

Relaxation Modeling of Unidirectional Carbon Fiber Reinforced Polymer Composites Before and After UV-C Exposure

by Flavia Palmeri and Susanna Laurenzi

Fibers 2024, 12(12), 110; https://doi.org/10.3390/fib12120110 - 11 Dec 2024

Viewed by 639

Abstract

Carbon fiber-reinforced polymers (CFRPs) are widely used in aerospace for their lightweight and high-performance characteristics. This study examines the long-term viscoelastic behavior of CFRP after UV-C exposure, simulating low Earth orbit conditions. The viscoelastic properties of the polymer were evaluated using dynamic mechanical [...] Read more.

Carbon fiber-reinforced polymers (CFRPs) are widely used in aerospace for their lightweight and high-performance characteristics. This study examines the long-term viscoelastic behavior of CFRP after UV-C exposure, simulating low Earth orbit conditions. The viscoelastic properties of the polymer were evaluated using dynamic mechanical analysis and the time-temperature superposition principle on both unexposed and UV-C-exposed samples. After UV-C exposure, the polymer’s instantaneous modulus decreased by about

15 %

. Over a 32-year period, the modulus of the unexposed resin is expected to degrade to approximately

25 %

of its initial value, while the exposed resin drops to around

15 %

. These experimental results were incorporated into finite element method models of a unidirectional CFRP representative volume element. The simulations showed that UV-C exposure caused only a slight reduction in the CFRP’s axial relaxation coefficient along the fiber’s axis, with no significant time-dependent degradation, as the fiber dominates this behavior. In contrast, the axial relaxation coefficient perpendicular to the fiber’s axis, as well as the off-diagonal and shear relaxation coefficients, showed more notable changes, with an approximate

10 %

reduction in their initial values after UV-C exposure. Over 32 years, degradation became much more severe, with differences between the pre- and post-exposure coefficient values reaching up to nearly

60 %

. Full article

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19 pages, 3580 KiB

Open AccessArticle

Predicting the Tensile Properties of Carbon FRCM Using a LASSO Model

by María Rodríguez-Marcos, Paula Villanueva-Llaurado, Jaime Fernández-Gómez, Joaquín Abellán-García and Augusto Sisa-Camargo

Fibers 2024, 12(12), 109; https://doi.org/10.3390/fib12120109 - 9 Dec 2024

Viewed by 561

Abstract

The use of Fibre Reinforced Cementitious Matrix (FRCM) for structural retrofitting requires prior assessment of the composite’s mechanical properties, particularly its tensile stress–strain response. This paper presents a LASSO regression model applied to 107 uniaxial tensile tests on Carbon FRCM in order to [...] Read more.

The use of Fibre Reinforced Cementitious Matrix (FRCM) for structural retrofitting requires prior assessment of the composite’s mechanical properties, particularly its tensile stress–strain response. This paper presents a LASSO regression model applied to 107 uniaxial tensile tests on Carbon FRCM in order to investigate the impact of both the material and testing parameters on FRCM performance. A highly effective LASSO regression model was trained using k-fold validation, resulting in concise and comprehensible models. Within the testing parameters, both the gripping system and load–speed ratio significantly affected the performance. A substantial impact on ultimate values was found for the load–speed ratio. From the material-related parameters, the most influential was the textile coating in terms of strength and the existence of bilinear or trilinear behaviour. It was also concluded that the combination of textile and matrix properties influenced the stress–strain response at all stages, with high-performance mortars resulting in better textile-to-matrix interaction. Full article

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28 pages, 10795 KiB

Open AccessArticle

Advanced Structural Technologies Implementation in Designing and Constructing RC Elements with C-FRP Bars, Protected Through SHM Assessment

by Georgia M. Angeli, Maria C. Naoum, Nikos A. Papadopoulos, Parthena-Maria K. Kosmidou, George M. Sapidis, Chris G. Karayannis and Constantin E. Chalioris

Fibers 2024, 12(12), 108; https://doi.org/10.3390/fib12120108 - 5 Dec 2024

Viewed by 590

Abstract

The need to strengthen the existing reinforced concrete (RC) elements is becoming increasingly crucial for modern cities as they strive to develop resilient and sustainable structures and infrastructures. In recent years, various solutions have been proposed to limit the undesirable effects of corrosion [...] Read more.

The need to strengthen the existing reinforced concrete (RC) elements is becoming increasingly crucial for modern cities as they strive to develop resilient and sustainable structures and infrastructures. In recent years, various solutions have been proposed to limit the undesirable effects of corrosion in RC elements. While C-FRP has shown promise in corrosion-prone environments, its use in structural applications is limited by cost, bonding, and anchorage challenges with concrete. To address these, the present research investigates the structural performance of RC beams reinforced with C-FRP bars under static loading using Structural Health Monitoring (SHM) with an Electro-Mechanical Impedance (EMI) system employing Lead Zirconate Titanate (PZT) piezoelectric transducers which are applied to detect damage development and enhance the protection of RC elements and overall, RC structures. This study underscores the potential of C-FRP bars for durable tensile reinforcement in RC structures, particularly in hybrid designs that leverage steel for compression strength. The study focuses on critical factors such as stiffness, maximum load capacity, deflection at each loading stage, and the development of crack widths, all analyzed through voltage responses recorded by the PZT sensors. Particular emphasis is placed on the bond conditions and anchorage lengths of the tensile C-FRP bars, exploring how local confinement conditions along the anchorage length influence the overall behavior of the beams. Full article

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13 pages, 5759 KiB

Open AccessArticle

Impact of Micro- and Nanocellulose Coating on Properties of Wool Fabric by Using Solution Blow Spinning

by Yi Zhang, Abu Naser Md Ahsanul Haque and Maryam Naebe

Fibers 2024, 12(12), 107; https://doi.org/10.3390/fib12120107 - 5 Dec 2024

Viewed by 523

Abstract

This study investigates the impact of micro- and nanocellulose coatings on the properties of wool fabrics using the solution blow spinning technique. The objective is to assess how varying cellulose sizes influence key fabric attributes, including physical properties, UV-shielding ability, air permeability and [...] Read more.

This study investigates the impact of micro- and nanocellulose coatings on the properties of wool fabrics using the solution blow spinning technique. The objective is to assess how varying cellulose sizes influence key fabric attributes, including physical properties, UV-shielding ability, air permeability and water vapour permeability, with a focus on their practical applications. Coating with microcrystalline cellulose (MCC) was found to increase the air permeability of fabric significantly, whereas coating with cellulose nanocrystals (CNCs) enhanced water vapour permeability and reduced pore size. The air permeability could relate to the breathability, and water vapour permeability could relate to the comfortability. Coated fabric with both sizes of cellulose could have different applications, like pollen filtration and printable cloth, and further functionality could be achieved by modifying the cellulose structure. This research establishes a platform for the effective application of cellulose coatings on wool fabric, offering promising advancements for textile performance and sustainability. Full article

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12 pages, 3318 KiB

Open AccessArticle

Carbon Fiber Recycling from Waste CFRPs via Microwave Pyrolysis: Gas Emissions Monitoring and Mechanical Properties of Recovered Carbon Fiber

by Kai-Yen Chin, Angus Shiue, Jhu-Lin You, Yi-Jing Wu, Kai-Yi Cheng, Shu-Mei Chang, Yeou-Fong Li, Chao-Heng Tseng and Graham Leggett

Fibers 2024, 12(12), 106; https://doi.org/10.3390/fib12120106 - 5 Dec 2024

Viewed by 1591

Abstract

Disposing of carbon fiber-reinforced polymers (CFRPs) has become a pressing issue due to their increasing application across various industries. Previous work has focused on removing silane coupling agent residues on recovered carbon fibers via microwave pyrolysis, making them suitable for use in new [...] Read more.

Disposing of carbon fiber-reinforced polymers (CFRPs) has become a pressing issue due to their increasing application across various industries. Previous work has focused on removing silane coupling agent residues on recovered carbon fibers via microwave pyrolysis, making them suitable for use in new materials. However, the mechanical performance and structural characteristics of these fibers have not been fully reported. This study investigates the time–temperature curves of CFRPs treated through microwave pyrolysis and analyzes the mechanical and structural properties of silane-controllable recovered carbon fibers. Additionally, emissions—including carbon monoxide, carbon dioxide, and particulate aerosols—were measured using handheld monitors and thermal desorption–gas chromatography/mass spectrometry to determine the composition of fugitive gases around the microwave pyrolysis system. The pyrolysis process at 950 °C, with an additional 1 h holding time, reduced the crystallite size from 0.297 Å to 0.222 Å, significantly enhancing tensile strength (3804 ± 713 MPa) and tensile modulus (200 ± 13 GPa). This study contributes to more sustainable CFRP waste treatment and highlights the potential for reusing high-quality carbon fibers in new applications, enhancing both environmental and worker safety. Full article

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14 pages, 4358 KiB

Open AccessArticle

Challenges and Opportunities in Recycling Upholstery Textiles: Enhancing High-Density Fiberboards with Recycled Fibers

by Matylda Wojciechowska and Grzegorz Kowaluk

Fibers 2024, 12(12), 105; https://doi.org/10.3390/fib12120105 - 5 Dec 2024

Viewed by 672

Abstract

Recycling upholstery textiles is challenging due to the complexity of materials, which often include a mix of fabrics, foams, and adhesives that are difficult to separate. The intricate designs and layers in upholstered furniture make it labor-intensive and costly to dismantle for recycling. [...] Read more.

Recycling upholstery textiles is challenging due to the complexity of materials, which often include a mix of fabrics, foams, and adhesives that are difficult to separate. The intricate designs and layers in upholstered furniture make it labor-intensive and costly to dismantle for recycling. Additionally, contaminants like stains, finishes, and flame retardants complicate recycling. Despite these difficulties, recycling upholstery textiles is crucial to reducing landfill waste and conserving resources by reusing valuable materials. It also helps mitigate environmental pollution and carbon emissions associated with producing new textiles from virgin resources. The presented research aimed to establish the feasibility of incorporating textile fibers from waste artificial leather fibers from the upholstery furniture industry into the structure of high-density fiberboards. The bulk density of samples with wood fiber was 28.30 kg m⁻³, while it was 25.77 kg m⁻³ for textile fiber samples. The lowest modulus of elasticity (MOE) was 2430 N mm⁻², and it was 3123 N mm⁻² for the reference sample. The highest bending strength (MOR) was 42 N mm⁻², and the lowest was 27.2 N mm⁻². Screw withdrawal resistance decreased from 162 N mm⁻¹ in the reference sample to 92 N mm⁻¹ with 25% artificial leather fibers. The internal bond (IB) strength ranged from 1.70 N mm⁻² (reference) to 0.70 N mm⁻² (25% of artificial leather fibers content). Water absorption ranged from 81.8% (1% of artificial leather fibers) to 66% (25% of artificial leather fibers content). It has been concluded that it is possible to meet the European standard requirements with 10% addition of the artificial leather fiber content. This approach positively contributes to carbon capture and storage (CCS) policy and mitigates the problem of such waste being sent to landfills. The research shows that while selected mechanical and physical parameters of the panels decrease with a rising content of recycled textile fibers, it is possible to meet proper European standard requirements by adjusting technological parameters such as nominal density. Full article

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23 pages, 4772 KiB

Open AccessReview

Comprehensive Bibliometric Review on the Sustainability and Environmental Impact of Fiber-Reinforced Polymers

by Maria Tănase, Alin Diniță, Daniela Roxana Popovici, Alexandra Ileana Portoacă, Cătălina Călin and Elena-Emilia Sirbu

Fibers 2024, 12(12), 104; https://doi.org/10.3390/fib12120104 - 3 Dec 2024

Viewed by 698

Abstract

Fiber-reinforced polymers (FRPs) are increasingly recognized in sustainable materials research due to their potential environmental advantages. This study presents a focused bibliometric review of the sustainability research on FRPs. An initial search of the Web of Science (WOS) database identified 803 documents, which [...] Read more.

Fiber-reinforced polymers (FRPs) are increasingly recognized in sustainable materials research due to their potential environmental advantages. This study presents a focused bibliometric review of the sustainability research on FRPs. An initial search of the Web of Science (WOS) database identified 803 documents, which were refined to 749 relevant articles, reviews, and proceedings. A co-authorship analysis highlights the significant contributions of the USA and India, with European countries forming regional collaborations. The research output has steadily increased since 2011, peaking in 2022 and 2023. The multidisciplinary nature of the research spans materials science, engineering, and environmental sciences, with journals such as *Polymers*, *Sustainability*, and the *Journal of Cleaner Production* emphasizing sustainability themes. This analysis covers key aspects such as keyword co-occurrence, overlay visualizations, co-authorship networks, and the distribution of publications by year, research area, and journal. The findings underscore the evolving research landscape of sustainable FRPs and highlight the ongoing need for life cycle assessments and interdisciplinary collaboration. Full article

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17 pages, 6107 KiB

Open AccessArticle

Effects of Ply Misalignment in Material Characterization of Composite Laminates

by Michael Franz, Racim Radjef, Boris Eisenbart and Sandro Wartzack

Fibers 2024, 12(12), 103; https://doi.org/10.3390/fib12120103 - 26 Nov 2024

Viewed by 567

Abstract

Carbon fiber reinforced plastic (CFRP) parts find a rising number of applications as structural components. Therefore, new manufacturing technologies are developed, enabling high volume production of such parts. With those higher volumes, variation management during product design becomes more critical. While manufacturing variations [...] Read more.

Carbon fiber reinforced plastic (CFRP) parts find a rising number of applications as structural components. Therefore, new manufacturing technologies are developed, enabling high volume production of such parts. With those higher volumes, variation management during product design becomes more critical. While manufacturing variations in CFRP materials occur on different scales, detecting and considering those on the meso (ply) scale becomes more important. Thus, the question arises whether such variations can be detected with standardized testing methods. In this study, artificial fiber misalignment has been introduced into the outer plies of standardized tensile specimens to explore the influence of such variations on the mechanical properties. A simulation model was developed to identify these variations and the test results were used to calibrate and optimize the material parameters of the simulation model. The effects of the artificially induced variation were distinguishable in the test data as well as in the simulation models. Furthermore, the simulation models showed good agreement with the experimental data, which leads to the conclusion that the utilized measuring techniques are well suited to characterize the fiber misalignment. The developed simulation models can be used to investigate the effects of fiber misalignment within the product development process without the need for physical testing. Full article

(This article belongs to the Special Issue Mechanical Behaviour of Reinforced Thermosetting Polymers with Fibers: Analytical/Numerical Models and Experimental Evidence)

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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

Viewed by 798

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

Viewed by 795

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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Fibers, Volume 12, Issue 12 (December 2024) – 13 articles

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