Subjects -> TEXTILE INDUSTRIES AND FABRICS (Total: 41 journals)


Showing 1 - 16 of 16 Journals sorted alphabetically - Revista Eletrônica de Moda     Open Access  
Asian Journal of Textile     Open Access   (Followers: 5)
Autex Research Journal     Open Access   (Followers: 1)
Composites Science and Technology     Hybrid Journal   (Followers: 157)
Fashion and Textiles     Open Access   (Followers: 11)
Fashion Practice : The Journal of Design, Creative Process & the Fashion     Hybrid Journal   (Followers: 13)
Fibers     Open Access   (Followers: 4)
Fibre Chemistry     Hybrid Journal   (Followers: 2)
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Geosynthetics International     Hybrid Journal   (Followers: 4)
Geotextiles and Geomembranes     Hybrid Journal   (Followers: 5)
Indian Journal of Fibre & Textile Research (IJFTR)     Open Access   (Followers: 6)
International Journal of Fashion Design, Technology and Education     Hybrid Journal   (Followers: 15)
International Journal of Textile Science     Open Access   (Followers: 4)
Journal of Engineered Fibers and Fabrics     Open Access  
Journal of Fashion Technology & Textile Engineering     Hybrid Journal   (Followers: 5)
Journal of Industrial Textiles     Hybrid Journal   (Followers: 4)
Journal of Leather Science and Engineering     Open Access  
Journal of Natural Fibers     Hybrid Journal   (Followers: 5)
Journal of Textile Design Research and Practice     Full-text available via subscription   (Followers: 5)
Journal of Textile Science & Engineering     Open Access   (Followers: 2)
Journal of Textiles and Fibrous Materials     Full-text available via subscription  
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal   (Followers: 2)
Journal of the Textile Institute     Hybrid Journal   (Followers: 6)
Research Journal of Textile and Apparel     Full-text available via subscription   (Followers: 1)
Text and Performance Quarterly     Hybrid Journal   (Followers: 5)
Textile History     Hybrid Journal   (Followers: 13)
Textile Progress     Hybrid Journal   (Followers: 3)
Textile Research Journal     Hybrid Journal   (Followers: 8)
Third Text     Hybrid Journal   (Followers: 11)
Wearables     Open Access   (Followers: 1)
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Number of Followers: 4  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2079-6439
Published by MDPI Homepage  [84 journals]
  • Fibers, Vol. 10, Pages 47: Electromagnetic Interference Shielding with
           Electrospun Nanofiber Mats—A Review of Production, Physical
           Properties and Performance

    • Authors: Tomasz Blachowicz, Andreas Hütten, Andrea Ehrmann
      First page: 47
      Abstract: With a steadily increasing number of machines and devices producing electromagnetic radiation, especially, sensitive instruments as well as humans need to be shielded from electromagnetic interference (EMI). Since ideal shielding materials should be lightweight, flexible, drapable, thin and inexpensive, textile fabrics belong to the often-investigated candidates to meet these expectations. Especially, electrospun nanofiber mats are of significant interest since they can not only be produced relatively easily and cost efficiently, but they also enable the embedding of functional nanoparticles in addition to thermal or chemical post-treatments to reach the desired physical properties. This paper gives an overview of recent advances in nanofiber mats for EMI shielding, discussing their production, physical properties and typical characterization techniques.
      Citation: Fibers
      PubDate: 2022-05-24
      DOI: 10.3390/fib10060047
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 48: Transverse Loading on Single High-Performance
           Fibers by Round-Head Indenters and the Fibers’ Failure Visualization

    • Authors: Jinling Gao, Nesredin Kedir, Boon Him Lim, Yizhou Nie, Xuedong Zhai, Weinong Chen
      First page: 48
      Abstract: High-performance fibers are well-known for their high stiffness and strength under axial tension. However, in their many applications as critical components of textiles and composites, transverse loads widely exist in their normal service life. In this study, we modified a micro material testing system to transverse load single fibers using round-head indenters. By integrating the loading platform with the Scanning Electron Microscopy (SEM) operating at a low-vacuum mode, we visualized the failure processes of fibers without conductive coatings. Post-fracture analysis was conducted to provide complementary information about the fibers’ failure. The energy dissipation was compared with the axial tensile experiments. Three inorganic and two organic fibers were investigated, namely carbon nanotube, ceramic, glass, aramid, and ultrahigh molecule weight polyethylene fibers. Different failure characteristics were reported. It is revealed that the organic fibers had higher energy dissipation than the inorganic fibers under the transverse loading by the round-head indenters. The fiber’s energy dissipation under transverse loading was no more than 17.9% of that subjected to axial tension. Such a reduced energy dissipation is believed to be due to the stress concentration under the indenter. It is suggested that the fiber’s material constituent, structural characteristics, and stress concentration under the indenter should be considered in the fiber model for textiles and composites.
      Citation: Fibers
      PubDate: 2022-05-30
      DOI: 10.3390/fib10060048
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 49: Influence of Different Surfactants on Carbon
           Fiber Dispersion and the Mechanical Performance of Smart Piezoresistive
           Cementitious Composites

    • Authors: Athanasia K. Thomoglou, Maria G. Falara, Fani I. Gkountakou, Anaxagoras Elenas, Constantin E. Chalioris
      First page: 49
      Abstract: This experimental study presents the effect of different surfactants on micro-scale carbon fiber (CFs) distribution into carbon fiber reinforced cement-based composites (CFRC) in terms of flexural and compressive strength, stiffness, flexural toughness, and strain-sensing ability. Conducting a narrative review of the literature focusing on the fibers’ separation, this paper follows a methodology introducing a combination of mechanical and chemical carbon fibers dispersion, as well as the different mixing processes (wet or dry). Three types of surfactants: Carboxymethyl cellulose (CMC), cellulose nanocrystal (CNC), and superplasticizer (SP), were applied to evaluate the CFs distribution in the cement paste matrix. Compressive and flexural strength, modulus of elasticity, and ductility of the cement-based composites (CFRC) reinforced with 0.5 wt.% CFs were investigated by three-point bending and compressive tests; flexure tests were also conducted on notched 20 × 20 × 80 mm specimens using the Linear Elastic Fracture Mechanics (L.E.F.M.) theory. Moreover, the electrical conductivity and the piezoresistive response were determined by conducting electrical resistance measurements and applying compressive loading simultaneously. The results clearly reveal that the CFs/SP solution or the CFs’ dry incorporation led to a significant enhancement of flexural strength by 32% and 23.7%, modulus of elasticity by 30% and 20%, and stress-sensing ability by 20.2% and 18.2%, respectively. Although the wet mixing method exhibits improved mechanical and electrical conductivity performance, constituting an adequate strain and crack sensor, the authors propose dry mixing as the most economical method, in addition to the enhanced mechanical and electrical responses. The authors recommend an effective method for structural health monitoring systems combining an economical CFs insertion in cementitious smart sensors with great mechanical and self-sensing responses.
      Citation: Fibers
      PubDate: 2022-05-31
      DOI: 10.3390/fib10060049
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 50: Fiber Spinning from Cellulose Solutions in
           Imidazolium Ionic Liquids: Effects of Natural Antioxidants on Molecular
           Weight, Dope Discoloration, and Yellowing Behavior

    • Authors: Hubert Hettegger, Jiaping Zhang, Mitsuharu Koide, Uwe Rinner, Antje Potthast, Yasuo Gotoh, Thomas Rosenau
      First page: 50
      Abstract: Spinning of cellulosic fibers requires the prior dissolution of cellulose. 3-Alkyl-1-methylimidazolium ionic liquids have proven to be suitable solvents for that purpose, but the degradation of cellulose in the spinning dope can be severe. Suitable stabilizers are therefore required that prevent cellulose degradation, but do not adversely affect spinnability or the long-term yellowing behavior of the fibers. A group of twelve renewables-based antioxidants was selected for stabilizing 5% cellulose solutions in the ionic liquids and their effects on cellulose integrity, dope discoloration, and aging behavior were tested by gel permeation chromatography (GPC) and ISO brightness measurements. Propyl gallate (a gallic acid derivative), hydroxytyrosol (from olives), and tocopheramines (a vitamin E derivative) performed best in the three test categories, minimizing both cellulose degradation, chromophore formation in the spinning dope, and yellowing upon accelerating aging of the spun fibers. The use of these stabilizers for cellulose solutions in the imidazolium-based solvent system can therefore be recommended from the point of view of both performance and sustainability.
      Citation: Fibers
      PubDate: 2022-06-07
      DOI: 10.3390/fib10060050
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 51: Understanding the PLA–Wood Adhesion
           Interface for the Development of PLA-Bonded Softwood Laminates

    • Authors: Warren J. Grigsby, Marc Gaugler, Desiree Torayno
      First page: 51
      Abstract: With polylactic acid (PLA) usage projected to increase in wood-based composite materials, a study comparing composite processing parameters with resulting PLA−wood adhesion and panel performance is warranted. In this study, PLA-softwood veneer laminates have been prepared and spatial chemical imaging via FTIR analysis was applied to identify PLA bondlines characterizing bondline thickness and the extent of PLA migration into the wood matrix. These PLA–wood adhesion interface characteristics have been compared with the performance of panels varying in pressing temperature, pressing time and PLA grades. For amorphous PLA, bondline thicknesses (60–120 μm) were similar, pressing at 140 °C or 160 °C, whereas with semi-crystalline PLA, the bondline thickness (340 μm) significantly reduced (155–240 μm) only when internal panel temperatures exceeded 140 °C during pressing. Internal temperatures also impacted PLA penetration, with greater PLA migration from bondlines evident with higher pressing temperatures and times with distinctions between PLA grades and bondline position. Performance testing revealed thinner PLA bondlines were associated with greater dry strength for both PLA grades. Cold-water soaking revealed laminated panels exhibit a range of wet-strength performance related to panel-pressing regimes with the semi-crystalline PLA pressed at 180 °C having similar tensile strength in dry and wet states. Moreover, an excellent correlation between wet-strength performance and bondline thickness and penetration values was evident for this PLA grade. Overall, study findings demonstrate PLA wood composite performance can be tuned through a combination of the PLA grade and the pressing regime employed.
      Citation: Fibers
      PubDate: 2022-06-09
      DOI: 10.3390/fib10060051
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 52: Multifunctional Material Extrusion 3D-Printed
           Antibacterial Polylactic Acid (PLA) with Binary Inclusions: The Effect of
           Cuprous Oxide and Cellulose Nanofibers

    • Authors: Markos Petousis, Nectarios Vidakis, Nikolaos Mountakis, Vassilis Papadakis, Sotiria Kanellopoulou, Aikaterini Gaganatsiou, Nikolaos Stefanoudakis, John Kechagias
      First page: 52
      Abstract: In this work, we present an effective process easily adapted in industrial environments for the development of multifunctional nanocomposites for material extrusion (MEX) 3D printing (3DP). The literature is still very limited in this field, although the interest in such materials is constantly increasing. Nanocomposites with binary inclusions were prepared and investigated in this study. Polylactic acid (PLA) was used as the matrix material, and cuprous oxide (Cu2O) and cellulose nanofibers (CNF) were used as nanoadditives introduced in the matrix material to enhance the mechanical properties and induce antibacterial performance. Specimens were built according to international standards with a thermomechanical process. Tensile, flexural, impact, and microhardness tests were conducted. The effect on the thermal properties of the matrix material was investigated through thermogravimetric analysis, and Raman spectroscopic analysis was conducted. The morphological characteristics were evaluated with atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDS) analyses. The antibacterial performance of the prepared nanomaterials was studied against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria, with a screening agar well diffusion method. All nanocomposites prepared exhibited biocidal properties against the bacteria tested. The tested PLA/1.0 CNF/0.5 Cu2O material had 51.1% higher tensile strength and 35.9% higher flexural strength than the pure PLA material.
      Citation: Fibers
      PubDate: 2022-06-10
      DOI: 10.3390/fib10060052
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 53: Mechanical Properties of Hybrid
           Steel-Polypropylene Fiber Reinforced High Strength Concrete Exposed to
           Various Temperatures

    • Authors: Maged Tawfik, Amr El-said, Ahmed Deifalla, Ahmed Awad
      First page: 53
      Abstract: Combining different types of fibers inside a concrete mixture was revealed to improve the strength properties of cementitious matrices by monitoring crack initiation and propagation. The contribution of hybrid fibers needs to be thoroughly investigated, taking into consideration a variety of parameters such as fibers type and content. In this paper, the impact of integrating hybrid steel-polypropylene fibers on the mechanical properties of the concrete mixture was investigated. Hybrid fiber-reinforced high-strength concrete mixtures were tested for compressive strength, tensile strength, and flexural strength. According to the results of the experiments, the addition of hybrid fibers to the concrete mixture improved the mechanical properties significantly, more than adding just one type of fiber for specimens exposed to room temperature. Using hybrid fibers in the concrete mixture increased compressive, tensile, and flexural strength by approximately 50%, 53%, and 46%, respectively, over just using one type of fiber. Furthermore, results showed that including hybrid fibers into the concrete mixture increased residual compressive strength for specimens exposed to high temperatures. When exposed to temperatures of 200 °C, 400 °C, and 600 °C, the hybrid fiber reinforced concrete specimens maintained 87%, 65%, and 42% of their initial compressive strength, respectively. In comparison, the control specimens, which were devoid of fibers, would be unable to tolerate temperatures beyond 200 °C, and an explosive thermal spalling occurred during the heating process.
      Citation: Fibers
      PubDate: 2022-06-12
      DOI: 10.3390/fib10060053
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 54: Improving Transverse Compressive Modulus of
           Carbon Fibers during Wet Spinning of Polyacrylonitrile

    • Authors: Sherman Wong, Linda K. Hillbrick, Jasjeet Kaur, Aaron J. Seeber, Jurg A. Schutz, Anthony P. Pierlot
      First page: 54
      Abstract: The performance of carbon fibers depends on the properties of the precursor polyacrylonitrile (PAN) fibers. Stretching of PAN fibers results in improved tensile properties, while potentially reducing its compressive properties. To determine optimization trade-offs, the effect of coagulation conditions and the stretching process on the compressive modulus in the transverse direction (ET) was investigated. A method for accurately determining ET from polymer fibers with non-circular cross-sectional shapes is presented. X-ray diffraction was used to measure the crystallite size, crystallinity, and crystallite orientation of the fibers. ET was found to increase with decreasing crystallite orientation along the drawing direction, which decreases the tensile modulus in the longitudinal direction (EL) proportionally to crystallite orientation. Stretching resulted in greater crystallite orientation along the drawing direction for fibers formed under the same coagulation conditions. Increasing the solvent concentration in the coagulation bath resulted in a higher average orientation, but reduced the impact of stretching on the orientation. The relationship between ET and EL observed in the precursor PAN fiber is retained after carbonization, with a 20% increase in ET achieved for a 2% decrease in EL. This indicates that controlled stretching of PAN fiber allows for highly efficient trading off of EL for ET in carbon fiber.
      Citation: Fibers
      PubDate: 2022-06-14
      DOI: 10.3390/fib10060054
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 55: Recycling Process of a Basalt Fiber-Epoxy
           Laminate by Solvolysis: Mechanical and Optical Tests

    • Authors: Livia Persico, Giorgia Giacalone, Beatrice Cristalli, Carla Tufano, Eudora Saccorotti, Pietro Casalone, Giuliana Mattiazzo
      First page: 55
      Abstract: Basalt fibre epoxy composites well suit various engineering applications for their mechanical properties and chemical stability. However, after basalt/epoxy product lifespan, there are not many established ways to treat and recycle the fibers without deteriorating their physical, mechanical and chemical properties. In this study, a chemical recycling method for basalt fiber reinforced polymers is presented. The process is based on previous studies concerning carbon fibers epoxy composites in which the fibers are separated from the polymeric matrix through a solvolysis reaction at temperature below 160 °C. Firstly, the specimens are thermally pre-treated in a heater set over the glass transition temperature, to promote the polymeric swelling of the matrix. The chemical degradation is obtained by means of a solution of glacial acetic acid (AcOH) and hydrogen peroxide (H2O2): compact, clean, resin-free, recycled woven fabrics are obtained and the original length of the yarns is maintained. Breaking tenacity of the recycled basalt fibers is kept up to 90.5% compared to the virgin ones, while, with a pyrolysis treatment, this value cannot exceed the 35%.
      Citation: Fibers
      PubDate: 2022-06-17
      DOI: 10.3390/fib10060055
      Issue No: Vol. 10, No. 6 (2022)
  • Fibers, Vol. 10, Pages 38: Corrosion Behavior of Fiber-Reinforced
           Concrete—A Review

    • Authors: Ganesh Naidu Gopu, Sofi Androse Joseph
      First page: 38
      Abstract: Corrosion study of conventional reinforcement in concrete has been accorded wider importance in the last few decades based on the losses occurring in monitoring concrete structures. It is well known that the presence of chloride ions is one of the most significant factors contributing to the corrosion of reinforcing steel. Practically, it is observed that in the marine environment, the activating substances such as chlorides that penetrate the steel can counteract the passivity locally when the electrolyte is highly alkaline. The concrete cover is changed chemically when chloride ionspenetrate into the material, whereupon the pore solution is neutralized. Based on numerous studies, it is evident that steel fibers and glass fibers have less impact on cracked sections in a chloride environment and can oppose chloride infiltration. Glass fibers, when exposed to repeated freeze and thaw conditions, protect the passive layer. This review article highlights the corrosion behavior of reinforced concrete involving various factors such as cracking behavior, transportation, electric conductivity, resistivity, and diffusion of chloride ions in the presence of steel and glass fibers.
      Citation: Fibers
      PubDate: 2022-04-21
      DOI: 10.3390/fib10050038
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 39: Impact of Thermal Stress on Abrasive Dust from
           a Carbon Fiber-Reinforced Concrete Composite

    • Authors: Arne Koch, Lukas Friederici, Petra Fiala, Armin Springer, Sebastiano Di Bucchianico, Michael Stintz, Marcus Frank, Christopher Paul Rüger, Thorsten Streibel, Ralf Zimmermann
      First page: 39
      Abstract: Recently, a novel corrosion-resistant construction material, Carbon Concrete Composite (C3), consisting of coated carbon fibers embedded in a concrete matrix, was introduced. However, thermal exposure during domestic fires may impact the release of organic pollutants and fibers during abrasive processing and/or demolition. Consequently, the objective of this study was to explore the emission characteristics of toxic compounds and harmful fibers during the dry-cutting after exposure to 25–600 °C (3 h, air). These parameters mimic the abrasive machining and dismantling after a domestic fire event. Mass spectrometry and chromatography served as analytical methodologies, and no organic pollutants for exposure temperatures ≥ 400 °C were found. In contrast, significant amounts of pyrolysis products from the organic fiber coating were released at lower temperatures. Studying the morphology of the released fibers by electron microscopy revealed a decrease in fiber diameter for temperatures exceeding 450 °C. At ≥550 °C, harmful fibers, according to the World Health Organization (WHO) definition, occurred (28–41 × 104 WHO fibers/m3 at 550–600 °C). This leads to the conclusion that there is a demand for restraining and protection measures, such as the use of wet cutting processes, suction devices, particle filtering masks and protective clothing, to handle thermally stressed C3.
      Citation: Fibers
      PubDate: 2022-04-26
      DOI: 10.3390/fib10050039
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 40: Nanostructural Changes Correlated to Decay
           Resistance of Chemically Modified Wood Fibers

    • Authors: Nayomi Z. Plaza, Sai Venkatesh Pingali, Rebecca E. Ibach
      First page: 40
      Abstract: Reactive chemical modifications have been shown to impart decay resistance to wood. These modifications change hydroxyl availability, water uptake, surface energy, and the nanostructure of wood. Because fungal action occurs on the micro and nano scale, further investigation into the nanostructure may lead to better strategies to prevent fungal decay. The aim of this article is to introduce our findings using small angle neutron scattering (SANS) to probe the effects of chemical modifications on the nanostructure of wood fibers. Southern pine wood fiber samples were chemically modified to various weight percentage gains (WPG) using propylene oxide (PO), butylene oxide (BO), or acetic anhydride (AA). After modification, the samples were water leached for two weeks to remove any unreacted reagents, homopolymers or by-products and then the equilibrium moisture content (EMC) was determined. Laboratory soil-block-decay evaluations against the brown rot fungus Gloeophyllum trabeum were performed to determine weight loss and decay resistance of the modifications. To assist in understanding the mechanism behind fungal decay resistance, SANS was used to study samples that were fully immersed in deuterium oxide (D2O). These measurements revealed that modifying the fibers led to differences in the swollen wood nanostructure compared to unmodified wood fibers. Moreover, the modifications led to differences in the nanoscale features observed in samples that were exposed to brown rot fungal attack compared to unmodified wood fibers and solid wood blocks modified with alkylene oxides.
      Citation: Fibers
      PubDate: 2022-04-28
      DOI: 10.3390/fib10050040
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 41: The Influence of Silica Fume on the Properties
           of Mortars Containing Date Palm Fibers

    • Authors: S. O. Bamaga
      First page: 41
      Abstract: Natural fibers have recently been presented as a promising alternative for manufactured fibers. Date palm fibers showed interesting results when used as an inclusion in concrete and mortar. In this study, Sefri Date Palm Mesh Fibers (SDPMF) were used as an inclusion in mortars. Silica fume (SF) partially replaced the cement by 5%, 10%, 15%, and 20% by mass to improve the mechanical properties of SDPMF mortars. SDPMFs were collected from local farms. The fibers were then cleaned, dried, and cut to 50 mm, and added to mortars with 1%, 2%, and 3% by weight. Density, absorption, open porosity, workability, and compressive strength of mortars were investigated. A comparison with a previous study’s results for mortars containing Sefri Date Palm Leave Fibers (SDPLF) is presented. The results showed that the incorporation of SF as part of cement may lead to improving the properties of the mixtures containing SDPMF fibers.
      Citation: Fibers
      PubDate: 2022-05-06
      DOI: 10.3390/fib10050041
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 42: Influence of Roller Configuration on the
           Fiber–Matrix Distribution and Mechanical Properties of Continuously
           Produced, Mineral-Impregnated Carbon Fibers (MCFs)

    • Authors: Marco Liebscher, Jitong Zhao, Gregor Wilms, Albert Michel, Kai Wilhelm, Viktor Mechtcherine
      First page: 42
      Abstract: The article at hand is envisaged to enumerate significant technological parameters for the successful impregnation of carbon fiber rovings having 50,000 (50 K) filaments, each within a fine-grained, cementitious suspension. Parameters such as the number of rollers as well as the influence of roller deflection and rotation have been investigated and discussed with regard to the quality of the related impregnation and mechanical properties resulting therefrom. Morphological analysis disclosed distinct differences in the fiber matrix distribution, which are particularly reflected in the flexural performance of the mineral-impregnated carbon fibers (MCFs) produced. Moreover, with the best fiber matrix distribution, uniaxial tensile tests on MCFs demonstrated superior tensile strengths, moduli of elasticity, and elongations at rupture.
      Citation: Fibers
      PubDate: 2022-05-07
      DOI: 10.3390/fib10050042
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 43: The Mechanical Response of Epoxy–Sisal
           Composites Considering Fiber Anisotropy: A Computational and Experimental

    • Authors: Olga Sinitsky, Nir Trabelsi, Elad Priel
      First page: 43
      Abstract: Natural-fiber-reinforced composites are seen as a good alternative to traditional synthetic-fiber composites. However, to successfully implement these materials in engineering applications, along with these materials demonstrating satisfactory load-bearing capacity, it is necessary to provide engineers with effective material properties, as well as calculation methods that take into account the distinctive features of natural fibers. This study investigated the effective elastic properties and strength of materials composed of unidirectional sisal fibers within a thermosetting polymer matrix, containing 20%, 40% and 60% fiber-volume fraction. Experiments with axial and off-axis loads in conjunction with finite-element modeling were utilized to determine the effective mechanical response of the composites. Analytical and numerical models were considered, using both isotropic- and anisotropic-fiber approaches. It is shown that only by taking into account the sisal-fiber anisotropy can the experimental results of the off-axis experiments be reproduced. The influence of sisal-fiber transverse modulus on the overall mechanical response is a function of the sisal-fiber volume fraction. It has been shown that the longitudinal specific strength of sisal-fiber-reinforced composites is comparable to classical aluminum alloys or steel. Thus, this environmentally friendly composite can be considered as an alternative in some engineering applications, such as reinforcement in concrete composites.
      Citation: Fibers
      PubDate: 2022-05-15
      DOI: 10.3390/fib10050043
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 44: Impact Resistance of Rendering Mortars with
           Natural and Textile-Acrylic Waste Fibres

    • Authors: Cinthia Maia Pederneiras, Rosário Veiga, Jorge de Brito
      First page: 44
      Abstract: Renders should have an adequate resistance to impacts, since they must protect the substrate. The use of fibres may enhance the energy absorbed when the mortars are submitted to an impact load, which contributes to postpone the first crack, and control its propagation and width. In this study, the impact strength was measured by a falling mass from different heights. The cracking pattern and the impact energy for the appearance of the first crack and until failure were evaluated. An artificial accelerated ageing test was also performed, and the impact resistance was analysed before and after ageing. In order to analyse the effects of recycled fibres, wool, coir, flax and textile-acrylic waste fibres were used as reinforcement in cement and cement-lime mortars. The results indicated that the fibres’ addition significantly improved the impact energy of the rendering mortars in comparison with the reference mortars. Concerning the crack patterns, the recycled fibres prevented the opening or the growth of the cracks, before and after ageing. This effect is mainly due to the fibre’s bridge mechanism, due to crossing the open cracks and hindering their propagation. The fibres’ type, length and volume fraction have influenced the mortars’ performance in terms of impact resistance. Textile-acrylic fibres waste presented the best performance by comparison with the natural fibres used.
      Citation: Fibers
      PubDate: 2022-05-17
      DOI: 10.3390/fib10050044
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 45: Flax Noils as a Source of Cellulose for the
           Production of Lyocell Fibers

    • Authors: Igor S. Makarov, Lyudmila K. Golova, Alexander G. Smyslov, Markel I. Vinogradov, Ekaterina E. Palchikova, Sergei A. Legkov
      First page: 45
      Abstract: The production of long flax fiber for the subsequent production of textile yarn is accompanied by the formation of a significant amount of waste—noils, which is a mechanical mixture of long and short flax fibers and shives. Comparative studies of the structure and chemical composition of the fibrous fraction of noils and shives were carried out using IR spectroscopy. The solubility of shives and flax noils in N-methylmorpholine-N-oxide (NMMO) was studied, a comparative analysis of the rheological behavior of solutions of flax and wood cellulose was carried out and the optimal temperature–concentration conditions for obtaining flax fibers from noils were determined. It was shown for the first time that using the method of solid-phase activation of the cellulose-solvent system makes it possible to obtain fibers in a short period of time (no more than 10 min). The structure of both the raw material and the resulting fibers was studied by X-ray diffraction analysis. The thermal properties of a new type of cellulose fibers was evaluated. The complex of the conducted studies allows us to consider flax fibers from noils along with flax fibers from long-staple flax, as a real alternative to fibers from wood pulp.
      Citation: Fibers
      PubDate: 2022-05-23
      DOI: 10.3390/fib10050045
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 46: Effects of Incorporating Titanium Dioxide with
           Titanium Carbide on Hybrid Materials Reinforced with Polyaniline:
           Synthesis, Characterization, Electrochemical and Supercapacitive

    • Authors: Hafida Belhadj, Imane Moulefera, Lilia Sabantina, Abdelghani Benyoucef
      First page: 46
      Abstract: We report on the synthesis of titanium dioxide by titanium carbide for the preparation of hybrid material reinforced with polyaniline (PANI@TiO2–TiC) using the in situ polymerization technique. The effectiveness of the samples on the thermal, optical and electrochemical properties was investigated. The XRD, XPS, FTIR, SEM and TEM results confirm the successful synthesis of the PANI, PANI@TiC and PANI@TiO2–TiC samples. Through this, a good connection, an excellent relationship between the structures and the properties of the synthesized hybrid materials were obtained. Moreover, the electrical conductivity and optical bandgap were also tested. Remarkably good electrochemical characteristics were identified by cyclic voltammetry. Moreover, the galvanostatic charge–discharge (GCD) of the supercapacitor was remarkably high. Cyclic stability showed good retention after 1500 cycles at 1.5 A·g−1.
      Citation: Fibers
      PubDate: 2022-05-23
      DOI: 10.3390/fib10050046
      Issue No: Vol. 10, No. 5 (2022)
  • Fibers, Vol. 10, Pages 31: Comparative Evaluation of Sisal and
           Polypropylene Fiber Reinforced Concrete Properties

    • Authors: Samantha Acosta-Calderon, Pablo Gordillo-Silva, Natividad García-Troncoso, Dan V. Bompa, Jorge Flores-Rada
      First page: 31
      Abstract: This paper presents a focused comparative case study considering the influence of natural and synthetic fibers on the fresh and mechanical properties of concrete. Locally sourced 19 mm long sisal fibers from sisalana leaves and manufactured polypropylene fibers were incorporated in a normal strength concrete matrix with fiber volumetric contents of 1%. After describing the measured aggregate characteristics, mix designs, and fresh concrete properties, several destructive and non-destructive tests on hardened concrete were undertaken. The former included compression tests on cylinders and flexural tests on prismatic samples, and the latter included ultrasonic pulse velocity and rebound number tests. The workability of sisal-fiber reinforced concrete was generally lower than the nominal concrete and that provided with polypropylene fibers by about 20%, largely due to the hydrophilic nature of the natural fibers. Test results showed that the presence of sisal fibers can improve the compressive strength by about 6%, and the tensile strength by about 4%, compared with the non-reinforced counterpart. This was due to the sisal fibers storing moisture that was released gradually during hydration, helping with the strength development. The concrete with polypropylene had virtually identical properties to the reference concrete. In addition to fresh and mechanical properties, environmental impacts associated with the production of fiber and concrete were also identified and discussed. Based on the assessments from this paper, overall, from the two fibers investigated, the sisal fiber showed more promising results, indicating that natural fibers can be a more sustainable alternative to plastic fibers, providing a good balance between workability and strengths.
      Citation: Fibers
      PubDate: 2022-03-24
      DOI: 10.3390/fib10040031
      Issue No: Vol. 10, No. 4 (2022)
  • Fibers, Vol. 10, Pages 32: Wear Properties and Post-Moisture Absorption
           Mechanical Behavior of Kenaf/Banana-Fiber-Reinforced Epoxy Composites

    • Authors: Sivasubramanian Palanisamy, Mayandi Kalimuthu, Alavudeen Azeez, Murugesan Palaniappan, Shanmugam Dharmalingam, Rajini Nagarajan, Carlo Santulli
      First page: 32
      Abstract: The contribution of natural lignocellulosic fibers to the reduction in wear damage in polymer resins is of interest, especially when two of these fibers can combine their respective effects. Wear properties of hybrid kenaf/banana epoxy composites have been investigated using three different total amount of fibers, 20, 30 and 40 wt.%, at loading forces up to 30 N and to sliding distances of up to 75 m. This demonstrated that the introduction of the highest level of fibers proved the most suitable for consistency of results and containment of wear with increasing load, as was also found from the morphological evaluation of wear degradation using scanning electron microscopy (SEM). Subsequently, tensile, flexural and impact properties of as-received and post-water-saturation hybrid composites were examined. The tests revealed a limited reduction in tensile and flexural strength, not exceeding 10% of the initial values, which were very high compared to similar materials, almost reaching 140 MPa for tensile strength and exceeding 170 MPa for flexural strength. In contrast, a higher standard deviation of values was found for impact strength, although the decrease in average values was only slightly above 10%. The results suggest the availability of these hybrids for wear-resisting applications in high-moisture environments, and the even more limited water absorption conferred by banana fibers added to kenaf ones.
      Citation: Fibers
      PubDate: 2022-04-02
      DOI: 10.3390/fib10040032
      Issue No: Vol. 10, No. 4 (2022)
  • Fibers, Vol. 10, Pages 33: Preparation, Characterization, and Surface
           Modification of Cellulose Nanocrystal from Lignocellulosic Biomass for
           Immobilized Lipase

    • Authors: Elvi Restiawaty, Neng Tresna Umi Culsum, Norikazu Nishiyama, Yogi Wibisono Budhi
      First page: 33
      Abstract: This study reports the synthesis of cellulose nanocrystal (CNC) from sugarcane bagasse and rice straw as the matrix for immobilized lipase enzyme. The CNC surface was modified using cetyltrimethylammonium bromide (CTAB) to improve the interaction of CNC with glutaraldehyde so that CNC can immobilize lipase effectively. The results showed that after surface modification of CNC using CTAB with concentrations of 2–10 mM, the crystallinity of CNC slightly decreased. The presence of immobilized lipase on the modified CNC was confirmed visibly by the appearance of dark spots using transmission electron microscopy (TEM). The bond formed between the enzyme and CNC was approved using Fourier transform infrared spectroscopy (FTIR). FTIR results show a new amine group peak in the immobilized lipase, which is not present in the modified CNC itself. The modified CNC, both from bagasse (SB-20 A1-1) and rice straw (RS-20 B1-1), was successfully applied to the immobilized lipase enzyme with a yield of 88%. The observed free enzyme activity was 3.69 µmol/min∙mL. The degree of hydrolysis of canola oil relative to free lipase (100%) from immobilized lipase at lipase SB-20 A1-1 and lipase RS-20 A1-1 was 23% and 30%, respectively. Therefore, this study successfully immobilized lipase and applied it to the hydrolysis of triglycerides.
      Citation: Fibers
      PubDate: 2022-04-02
      DOI: 10.3390/fib10040033
      Issue No: Vol. 10, No. 4 (2022)
  • Fibers, Vol. 10, Pages 34: Shear and Flexural Behavior of Flat Slabs
           Casted with Polyolefin Fiber-Reinforced Concrete

    • Authors: Abdulnasser M. Abbas, Haleem K. Hussain, Mohammed Farhan Ojaimi
      First page: 34
      Abstract: This paper presents the influence of polyolefin fiber on the flexural and shear attitude on the flat slabs. Three slab sets (80 cm × 80 cm) were tested, each with a thickness of 10 cm. In the first set (S1), the effect of fiber content on the flexural behavior of the flat slab was considered. Therefore, four slab specimens were cast, one of which was considered as a control specimen with no fiber content, while the other three included fibers at 0.5, 1, and 1.5 percent of the total concrete volume. The second series of experiments studied the flexural behavior of flat slabs (S2) with an opening of 15 cm × 15 cm. The first specimen contained nil polyolefin, while the second included 1% polyolefin. In the third set (S3), consideration was taken for 0 and 1% of Polyolefin to realize the shear behavior of the flat slab. The increase in polyolefin fiber content from 0 to 1.5% (for slab set 1) will decrease the deflection from 4.5 mm to 2.3 mm, with an average of 3.58 mm, which is close to the deflection of a 1% polyolefin fiber specimen. Three dimensional models for the tested slabs were simulated numerically via ABAQUS software program. The ratio of the maximum deflection between the experimental and the numerical outcomes were varied with a range of 1.01 to 1.28, with an average of 1.14.
      Citation: Fibers
      PubDate: 2022-04-12
      DOI: 10.3390/fib10040034
      Issue No: Vol. 10, No. 4 (2022)
  • Fibers, Vol. 10, Pages 35: A Review on the Utilization of Date Palm Fibers
           as Inclusion in Concrete and Mortar

    • Authors: S. O. Bamaga
      First page: 35
      Abstract: Currently, natural fibers attract the attention of researchers and builders in the construction industry as they are eco-friendly, cost-effective, lightweight, and renewable resources. The inclusion of natural fibers in the concrete and mortar will contribute to solving the environmental problems associated with dumping or burning them and improve the properties and durability of concrete and mortar. Similar to other natural fibers, Date Palm Fibers (DPF) have been receiving more attention as construction materials. This paper presents a review on the properties of DPF and its effects on the physical, mechanical, and thermal properties of concrete and mortar as well as the processing of DPF and mix design. DPFs can be used in concrete and mortar to improve their properties. However, some of the properties could be reduced. Even though the conducted studies and investigations are promising, it is still not enough to introduce DPF concrete and mortar to the construction industry’s applications.
      Citation: Fibers
      PubDate: 2022-04-16
      DOI: 10.3390/fib10040035
      Issue No: Vol. 10, No. 4 (2022)
  • Fibers, Vol. 10, Pages 36: Nanofiber Polymers for Coating Titanium-Based
           Biomedical Implants

    • Authors: Nthabiseng Nhlapo, Thywill Cephas Dzogbewu, Olga de Smidt
      First page: 36
      Abstract: The excellent combination of properties has seen a steep increase in the demand for titanium (Ti)-based material as biomedical implant devices. However, some features that promote biocompatibility are found to be lacking in Ti implants. The use of polymer nanofiber (NF) coating on the surfaces of the implants has been proven to remedy these setbacks. In particular, electrospun NFs are versatile as natural extracellular matrix mimics and as facilitators in the biocompatibility function of Ti-based implants. Therefore, various properties of Ti implants coated with polymer NFs and the correlations among these properties are explored in this review. Synthetic polymers are favorable in tissue engineering applications because they are biocompatible and have low toxicity and degradation rates. Several approved synthetic polymers and polymer hybrids have been electrospun onto Ti implant surfaces to successfully improve the biomedical applicability of the implants with regard to their physical (including diameter and porosity), chemical (including corrosion resistance), mechanical (including elastic modulus, strength and ductility) and biological properties (including tissue integration, antimicrobial and cytotoxicity).
      Citation: Fibers
      PubDate: 2022-04-18
      DOI: 10.3390/fib10040036
      Issue No: Vol. 10, No. 4 (2022)
  • Fibers, Vol. 10, Pages 37: Fiber-Reinforced Polymer Composites in the
           Construction of Bridges: Opportunities, Problems and Challenges

    • Authors: Paweł Grzegorz Kossakowski, Wiktor Wciślik
      First page: 37
      Abstract: In this review, we discuss the basic issues related to the use of FRP (fiber-reinforced polymer) composites in bridge construction. This modern material is presented in detail in terms of the possibility of application in engineering structures. A general historical outline of the use and development of modern structural materials, such as steel and concrete, is included to introduce composites as a novel material in engineering, and the most important features and advantages of polymers as a construction material are characterized. We also compare FRP to basic structural materials, such as steel and concrete, which enables estimation of the effectiveness of using of FRP polymers as structural material in different applications. The first bridges made of FRP composites are presented and analyzed in terms of applied technological solutions. Examples of structural solutions for deck slabs, girders and other deck elements made of FRP composites are discussed. Particular attention is paid to the systems of deck slabs, especially those composed of pultruded profiles, sandwich panels and hybrid decks. The disadvantages of composites, as well as barriers and limitations in their application in engineering practice, are presented. Exemplary analyses of the costs of construction, maintenance and demolition of FRP composite bridges are presented and compared with the corresponding costs of concrete and steel bridges. The directions of development of composite bridge structures and the greatest challenges facing engineers and constructors in the coming years are discussed.
      Citation: Fibers
      PubDate: 2022-04-18
      DOI: 10.3390/fib10040037
      Issue No: Vol. 10, No. 4 (2022)
  • Fibers, Vol. 10, Pages 22: Algorithm for Solving a System of Coupled
           Nonlinear Schrödinger Equations by the Split-Step Method to Describe the
           Evolution of a High-Power Femtosecond Optical Pulse in an Optical
           Polarization Maintaining Fiber

    • Authors: Anton Bourdine, Vladimir Burdin, Oleg Morozov
      First page: 22
      Abstract: This article proposes an advanced algorithm for the numerical solution of a coupled nonlinear Schrödinger equations system describing the evolution of a high-power femtosecond optical pulse in a single-mode polarization-maintaining optical fiber. We use the algorithm based on a variant of the split-step method with the Madelung transform to calculate the complex amplitude when executing a nonlinear operator. In contrast to the known solution, the proposed algorithm eliminates the need to numerically solve differential equations directly, concerning the phase of complex amplitude when executing the nonlinear operator. This made it possible, other things being equal, to reduce the computation time by more than four times.
      Citation: Fibers
      PubDate: 2022-03-01
      DOI: 10.3390/fib10030022
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 23: Melt-Spun, Cross-Section Modified

    • Authors: Benedict Bauer, Caroline Emonts, Louisa Bonten, Rokaya Annan, Felix Merkord, Thomas Vad, Akram Idrissi, Thomas Gries, Andreas Blaeser
      First page: 23
      Abstract: Tissue Engineering is considered a promising route to address existing deficits of autografts and permanent synthetic prostheses for tendons and ligaments. However, the requirements placed on the scaffold material are manifold and include mechanical, biological and degradation-related aspects. In addition, scalable processes and FDA-approved materials should be applied to ensure the transfer into clinical practice. To accommodate these aspects, this work focuses on the high-scale fabrication of high-strength and highly oriented polycaprolactone (PCL) fibers with adjustable cross-sectional geometry and degradation kinetics applying melt spinning technology. Four different fiber cross-sections were investigated to account for potential functionalization and cell growth guidance. Mechanical properties and crystallinity were studied for a 24-week exposure to phosphate-buffered saline (PBS) at 37 °C. PCL fibers were further processed into scaffolds using multistage circular braiding with three different hierarchical structures. One structure was selected based on its morphology and scaled up in thickness to match the requirements for a human anterior cruciate ligament (ACL) replacement. Applying a broad range of draw ratios (up to DR9.25), high-strength PCL fibers with excellent tensile strength (up to 69 cN/tex) could be readily fabricated. The strength retention after 24 weeks in PBS at 37 °C was 83–93%. The following braiding procedure did not affect the scaffolds’ mechanical properties as long as the number of filaments and the braiding angle remained constant. Up-scaled PCL scaffolds resisted loads of up to 4353.88 ± 37.30 N, whilst matching the stiffness of the human ACL (111–396 N/mm). In conclusion, this work demonstrates the fabrication of highly oriented PCL fibers with excellent mechanical properties. The created fibers represent a promising building block that can be further processed into versatile textile implants for tissue engineering and regenerative medicine.
      Citation: Fibers
      PubDate: 2022-03-02
      DOI: 10.3390/fib10030023
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 24: Hygrothermal and Microstructural Investigation
           of PLA and PLA-Flax Printed Structures

    • Authors: Yassine Elias Belarbi, Ferhat Benmahiddine, Ameur El Amine Hamami, Sofiane Guessasma, Sofiane Belhabib
      First page: 24
      Abstract: The aim of this work is to explore the manufacturing of insulation structures using fused filament deposition of biosourced materials. The approach considers printing of Polylactic acid (PLA) and PLA-flax (PF) structures using varied infill density and printing temperatures. Differential Scanning Calorimetry and Thermal Gravimetry analysis are performed to study thermal behaviour of PLA and PF and derive weight content of fibres within PF. Thermal measurements show a strong dependence of thermal conductivity with infill density and slightly improved thermal insulation of PF compared to PLA. Moreover, both PF and PLA show a hydrophobic behaviour unlike conventional green concretes based on hemp or flax. In addition, both scanning electron and optical microscopies show marked morphological changes induced by the laying down process for PF. This latter exhibits a more complex and tortuous microstructure compared to PLA marked by the presence of inter-filament porosity. This work concludes with superior hygrothermal properties of PLA and PF compared to other biosourced materials such as hemp or flax concrete. This work also concludes with the beneficial role of flax fibres that provides better hygrothermal properties to the printed structures as well as on the need to optimize the infill characteristics including density and cell morphology density.
      Citation: Fibers
      PubDate: 2022-03-03
      DOI: 10.3390/fib10030024
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 25: Acoustic Characterization and Modeling of
           Silicone-Bonded Cocoa Crop Waste Using a Model Based on the Gaussian
           Support Vector Machine

    • Authors: Virginia Puyana-Romero, Gino Iannace, Lilian Gisselle Cajas-Camacho, Christiam Garzón-Pico, Giuseppe Ciaburro
      First page: 25
      Abstract: The sustainable management of waste from agricultural crops represents an urgent challenge. One possible solution considers waste as possible secondary raw materials for specific uses. Among these, the use of agricultural waste as a product for the assembly of panels for the sound absorption of living environments represents a particularly suitable solution. In this study, the acoustic properties of the cocoa pod husk were evaluated, using silicone as a binder. Different proportions of materials and thicknesses were evaluated. A Support Vector Machine (SVM)-based model with a Gaussian kernel was then used to predict the acoustic performance of composite materials. The results obtained suggest the adoption of this material for the acoustic correction of living environments and this methodology for the prediction of the acoustic behavior of materials.
      Citation: Fibers
      PubDate: 2022-03-06
      DOI: 10.3390/fib10030025
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 26: Effectiveness of Hybrid Fibers on the Fracture
           and Shear Behavior of Prestressed Concrete Beams

    • Authors: Chandrashekhar Lakavath, Aniket B. Bhosale, S. Suriya Prakash, Akanshu Sharma
      First page: 26
      Abstract: This study investigates the effectiveness of hybrid fibers (steel and macro-synthetic) on the shear behavior of prestressed concrete beams. The hybrid fiber combination was selected to avoid workability issues at high volume dosages and ensure effective crack arresting over the crack opening range. Fracture studies included testing notched concrete prisms to identify the role of hybrid fibers in the crack bridging mechanism. Seven hybrid fiber reinforced prestressed concrete (HFRPC) beams were tested at a low shear span (a) to depth (d) ratio of 2.4. The effects of hybrid fibers on load–deflection behavior and strain in the strand are reported. Similarly, the crack opening, crack slip and crack angle variation regarding applied shear were investigated using the digital image correlation (DIC) technique. Test results of HFRPC beams showed considerable improvements in peak load and the post-peak response with a higher hybrid fiber dosage. The crack opening and crack slip measurement across the major shear crack revealed continuous dilatant behavior. The kinematic response of critical shear crack reflects the sustained dilation response up to the ultimate load, which depends on the critical shear crack angle of the tested beams. As the fiber dosage increases, the shear crack slip and width are reduced, indicating the roles of hybrid fibers in improving ductility and the change in failure mode from brittle shear tension to relatively ductile shear tension.
      Citation: Fibers
      PubDate: 2022-03-08
      DOI: 10.3390/fib10030026
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 27: A Review of Fibre Reinforced Polymer Structures

    • Authors: Jawed Qureshi
      First page: 27
      Abstract: This paper reviews Fibre Reinforced Polymer (FRP) composites in Civil Engineering applications. Three FRP types are used in Structural Engineering: FRP profiles for new construction, FRP rebars and FRP strengthening systems. Basic materials (fibres and resins), manufacturing processes and material properties are discussed. The focus of the paper is on all-FRP new-build structures and their joints. All-FRP structures use pultruded FRP profiles. Their connections and joints use bolting, bonding or a combination of both. For plate-to-pate connections, effects of geometry, fibre direction, type and rate of loading, bolt torque and bolt hole clearance, and washers on failure modes and strength are reviewed. FRP beam-columns joints are also reviewed. The joints are divided into five categories: web cleated, web and flange cleated, high strength, plate bolted and box profile joints. The effect of both static and cyclic loading on joints is studied. The joints’ failure modes are also discussed.
      Citation: Fibers
      PubDate: 2022-03-08
      DOI: 10.3390/fib10030027
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 28: Influence of Carbon Fiber-Reinforced Ropes
           Applied as External Diagonal Reinforcement on the Shear Deformation of RC

    • Authors: Chris Karayannis, Emmanouil Golias, George I. Kalogeropoulos
      First page: 28
      Abstract: The use of the innovative material of Carbon Fiber-Reinforced (C-FRP) ropes as external near surface mounted reinforcement for the strengthening of reinforced concrete beam-column joints is studied. The ropes are diagonally applied forming external X-type reinforcements on both sides of the joint body. The efficiency of the technique is mainly based on the assumption that the confinement of the joint body due to the applied X-shaped ropes and the contribution of the ropes as shear reinforcement are efficient enough to reduce the shear deformations observed in the joint core during the seismic excitation. Thereof the experimental measurements of the shear deformations of nine full scale beam-column joints tested in cyclic deformations are elaborated and presented herein. The specimens are sorted in two groups. Specimens of group A have been designed in the way that damage is mainly expected in the beam. On the other hand, in order to investigate the efficacy of the use of the ropes for substandard joints the group B specimens have been designed in the way that cracks and some damages are expected to develop in the joint body. Systematic and extended comparative presentations for specimens with and without ropes proved in all the examined cases that the externally mounted C-FRP ropes kept the joint body intact and substantially reduced the shear deformations especially in high drifts. Moreover, the influence of the externally mounted X-shaped C-FRP ropes on the seismic behaviour of these specimens is also examined in terms of the developing principal tensile stresses inside the joint body. From the comparisons of the principal stresses developing in specimens with and without X-form C-FRP ropes it became quite obvious that the ropes kept the joint body intact and allowed the development of higher values of principal stresses comparing with the stresses developing in specimens without ropes.
      Citation: Fibers
      PubDate: 2022-03-10
      DOI: 10.3390/fib10030028
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 29: Influence of Draw Ratio and Take-Up Velocity on
           Properties of Ultrafiltration Hollow Fiber Membranes from Polyethersulfone

    • Authors: George Dibrov, George Kagramanov, Vladislav Sudin, Sergey Molchanov, Evgenia Grushevenko, Alexey Yushkin, Vladimir Volkov
      First page: 29
      Abstract: This study aimed to reveal the influence of the draw ratio and take-up speed on the pore size distribution and morphology of the hollow fiber ultrafiltration membrane selective layer. To this end, spinnerets with ring ducts of 1.8 and 1.3 mm were employed, whereas the external diameter of the obtained fiber was kept equal. Atomic force microscopy and scanning electron microscopy were employed to study the morphology of the selective layer. Liquid–liquid displacement porosimetry was used to determine the limiting pore size distribution. The produced polyethersulfone ultrafiltration membranes had a robust, sponge-like porous structure, permeance 1000 L/(m2·h·bar), smooth selective layer, and mean pore size 25 nm. It was found that limiting pore sizes are affected more by the change in the take-up speed, whereas the surface pore sizes, roughness, and morphology are controlled by the draw ratio. It was shown that excessive draw causes the selective layer stretching and crop-up of the porous sublayer. Consequently, the diameters of the spinneret ring duct and the bore needle should match the hollow fiber outer and lumen diameters, respectively.
      Citation: Fibers
      PubDate: 2022-03-17
      DOI: 10.3390/fib10030029
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 30: Evaluation of the Physical and Mechanical
           Properties of Short Entada mannii-Glass Fiber Hybrid Composites

    • Authors: Oluwayomi Peter Balogun, Kenneth Kanayo Alaneme, Adeolu Adesoji Adediran, Isiaka Oluwole Oladele, Joseph Ajibade Omotoyinbo, Kong Fah Tee
      First page: 30
      Abstract: This study investigates the physical and mechanical properties of short Entada mannii- glass fiber polypropylene hybrid composites. The polymeric hybrid composite was produced by combining different ratios of Entada mannii fiber (EMF)/glass fiber (GF) using the compression molding technique. The tensile properties, compressive strength, impact strength and hardness were evaluated while the fracture surface morphology was examined using the scanning electron microscope (SEM). It further evaluates the moisture absorption and percentage void content of the developed composites. The experimental results show that tensile, compressive, impact and hardness properties of all the hybrid composites were significantly improved as compared with single reinforced composites. Specifically, hybrid composites (EMF/GF5) revealed an overall tensile strength of 41%, hardness of 51% and compressive strength of 47% relative to single reinforced composites, which can be ascribed to enhanced fiber–matrix bonding. The chemical treatment enhanced the EMF fiber surface and promoted good adhesion with the polypropylene (PP) matrix. Moisture absorption properties revealed that the addition of EMF/GF reduces the amount of moisture intake of the hybrid composites attributed to good cementing of the fiber–matrix interface. Morphological analysis revealed that single reinforced composites (EMF1 and GF2) were characterized by fiber pullout and deposition of voids in the composite as compared with the hybrid composites.
      Citation: Fibers
      PubDate: 2022-03-20
      DOI: 10.3390/fib10030030
      Issue No: Vol. 10, No. 3 (2022)
  • Fibers, Vol. 10, Pages 10: Mechanical, Durability and Corrosion Properties
           of Basalt Fiber Concrete

    • Authors: Mohamed T. Elshazli, Kevin Ramirez, Ahmed Ibrahim, Mohamed Badran
      First page: 10
      Abstract: The effect of using basalt fibers on the fresh, mechanical, durability, and corrosion properties of reinforced concrete was investigated in this study. The study was performed using different basalt fiber volume fractions of 0.15%, 0.30%, 0.45%, and 0.50%, while two different water/cement (w/c) ratios of 0.35 and 0.40 were utilized. The results were compared to conventional concrete (PC) as well as steel fiber concrete (SFC) with 0.30% and 0.50% steel fibers volume fractions. An extensive experimental program of 336 samples was conducted in four stages as follows: testing for fresh properties included slump and unit weight tests; mechanical properties testing included compressive strength tests, split tensile strength tests, flexural strength tests, and average residual strength tests; durability testing included unrestrained shrinkage and surface resistivity tests; and a Rapid Macrocell corrosion evaluation test for corrosion properties. The test results showed that the use of basalt fibers reduces slump values as the fiber volume fraction increases; however, with the use of the appropriate amount of High Range Water Admixture (HRWA), target slump values can be achieved. Moreover, a considerable improvement in the compressive, tensile, flexural, average residual strength and durability properties was achieved in case of using basalt fibers. On the other hand, corrosion rates increased with the increase in fiber volumes. However, it can be concluded that utilizing a 0.30% fibers volume fraction is the optimum ratio with an overall acceptable performance with respect to mechanical and corrosion properties.
      Citation: Fibers
      PubDate: 2022-01-21
      DOI: 10.3390/fib10020010
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 11: Concrete Reinforced by Hybrid Mix of Short
           Fibers under Bending

    • Authors: Vitalijs Lusis, Krishna Kiran Annamaneni, Andrejs Krasnikovs
      First page: 11
      Abstract: In the present study, the mechanical behavior of Fiber-Reinforced Concrete (FRC) beams was studied under bending until rupture. Each beam was reinforced with a hybrid mix of short fibers randomly distributed in its volume. Concrete beams with three different fiber combinations were investigated, namely, beams reinforced with (1) a homogeneously distributed mix of short polypropylene fibers (PP) and steel fibers, (2) PP fibers and Alkali Resistant Glass (ARG) fibers, and (3) PP and composite fibers (CF). The amount of short PP fibers was the same in all FRCs. The investigation focused on the fracture mechanisms and the load-bearing capacity of FRC beams with the developing macro cracks. In total, 12 FRC composite prismatic specimens were casted and tested in four-point bending experiments (4PBT). The current load value versus the Crack Mouth Opening Displacement (CMOD) for all FRCs was analyzed. The crack opening relationship and the influence of fibers on the fracture energy and flexural tensile strength were determined. Rupture surfaces of all samples were investigated using an optical microscope.
      Citation: Fibers
      PubDate: 2022-01-25
      DOI: 10.3390/fib10020011
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 12: Vascular Graft Infections: An Overview of Novel
           Treatments Using Nanoparticles and Nanofibers

    • Authors: Emma He, Stefano Serpelloni, Phillip Alvear, Maham Rahimi, Francesca Taraballi
      First page: 12
      Abstract: Vascular disease in elderly patients is a growing health concern, with an estimated prevalence of 15–20% in patients above 70 years old. Current treatment for vascular diseases requires the use of a vascular graft (VG) to revascularize lower or upper extremities, create dialysis access, treat aortic aneurysms, and repair dissection. However, postoperative infection is a major complication associated with the use of these VG, often necessitating several operations to achieve complete or partial graft excision, vascular coverage, and extra-anatomical revascularization. There is also a high risk of morbidity, mortality, and limb loss. Therefore, it is important to develop a method to prevent or reduce the incidence of these infections. Numerous studies have investigated the efficacy of antibiotic- and antiseptic-impregnated grafts. In comparison to these traditional methods of creating antimicrobial grafts, nanotechnology enables researchers to design more efficient VG. Nanofibers and nanoparticles have a greater surface area compared to bulk materials, allowing for more efficient encapsulation of antibiotics and better control over their temporo-spatial release. The disruptive potential of nanofibers and nanoparticles is exceptional, and they could pave the way for a new generation of prosthetic VG. This review aims to discuss how nanotechnology is shaping the future of cardiovascular-related infection management.
      Citation: Fibers
      PubDate: 2022-02-01
      DOI: 10.3390/fib10020012
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 13: Natural ‘Green’ Sugar-Based
           Treatment for Hair Styling

    • Authors: Namrata V. Patil, Anil N. Netravali
      First page: 13
      Abstract: A major drawback of current hair styling treatments is their use of toxic chemicals, such as thioglycolates, sulfites, formaldehyde, and others. Exposure to such chemicals is not only harmful to hairstylists but also to the millions who routinely receive hair treatments. The present research discusses the development of a benign sucrose-based crosslinker consisting of aldehyde groups to stabilize hair via crosslinking amine groups in keratin. ATR-FTIR and 1H-NMR were used to confirm functional groups on sucrose. Hair straightening was carried out by crosslinking via flat ironing. Crosslinked hair swatches were hung in a high humidity environment and subjected to repeated washings with shampoo to characterize the permanency of the treatment. Hair straightening through crosslinking was found to be durable to high humidity and repeat shampoo washings. The tensile characteristics of hair, such as fracture stress, strain, and Young’s modulus, were unaffected by the treatment. SEM images showed no damage to surface scales. The sucrose-based crosslinker could be used to create curls in straight hair as well.
      Citation: Fibers
      PubDate: 2022-02-03
      DOI: 10.3390/fib10020013
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 14: Exploration of Mechanical Properties of
           Enset–Sisal Hybrid Polymer Composite

    • Authors: Abera E. Bekele, Hirpa G. Lemu, Moera G. Jiru
      First page: 14
      Abstract: Enset and sisal fibers are among the most widely used reinforcement to fabricate natural fiber-based composite materials. Hand lay-up techniques were employed in this study to fabricate enset–sisal (E/S) hybrid fiber composite with volume ratios of 100/0, 75/25, 50/50, 25/75, and 0/100 and constant polyester resin. The tensile, flexural, impact strength, water absorption and morphological properties of the fabricated composite were investigated experimentally. The effects of hybridization to volume ratio were determined and the results show that hybrid composites excel in mechanical properties, compared with single composites. For better mechanical properties, the enset fiber has been hybridized with sisal fiber. Tensile and flexural strengths were enhanced by 47.3% and 41.03%, respectively, at 50/50 E/S volume ratio compared with 100/0 E/S composite. The impact strength of sisal fiber composite was improved by adding enset fiber in the composites. The inherent benefits and limitations of these two fibers were balanced out by each other in a positive way. While sisal fiber helped the composite intermesh of tensile, flexural, and reduction of water absorption, enset ensured impact strength. Morphological analysis was carried out in order to observe the fracture behavior and fiber pull-out of the samples by means of scanning electron microscopy.
      Citation: Fibers
      PubDate: 2022-02-08
      DOI: 10.3390/fib10020014
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 15: Application of Electrospun Nonwoven Fibers in
           Air Filters

    • Authors: Iman Azarian Borojeni, Grzegorz Gajewski, Reza A. Riahi
      First page: 15
      Abstract: Air filtration has seen a sizable increase in the global market this past year due to the COVID-19 pandemic. Nanofiber nonwoven mats are able to reach certain efficiencies with a low-pressure drop, have a very high surface area to volume ratio, filter out submicron particulates, and can customize the fiber material to better suit its purpose. Although electrospinning nonwoven mats have been very well studied and documented there are not many papers that combine them. This review touches on the various ways to manufacture nonwoven mats for use as an air filter, with an emphasis on electrospinning, the mechanisms by which the fibrous nonwoven air filter stops particles passing through, and ways that the nonwoven mats can be altered by morphology, structure, and material parameters. Metallic, ceramic, and organic nanoparticle coatings, as well as electrospinning solutions with these same materials and their properties and effects of air filtration, are explored.
      Citation: Fibers
      PubDate: 2022-02-08
      DOI: 10.3390/fib10020015
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 16: The Effect of the Kraft Pulping Process, Wood
           Species, and pH on Lignin Recovery from Black Liquor

    • Authors: Juliana M. Jardim, Peter W. Hart, Lucian A. Lucia, Hasan Jameel, Hou-min Chang
      First page: 16
      Abstract: Lignin has shown a great potential to produce fuels, value-added chemicals, and functional materials due to its high-energy density and intrinsic aromatic-based structure. Yet, the lignin precipitation of different biomasses needs investigation because most of the work has been performed on softwood and much less is known about hardwoods. In fact, the lignin from these two wooden biomasses vary in composition and pulping performance, which can reflect on lignin precipitation. Therefore, the present study investigated the precipitation and composition of 40 distinct kraft lignins obtained from pine, acacia, sweetgum, and eucalyptus black liquors. Two lignin fractions were precipitated at different pHs, according to known industrial lignin separation practices (pH = 9.5 and 2.5) from black liquors taken at different levels of pulping. Overall, lignin recovery increased with increasing lignin concentration in the black liquor, i.e., higher amounts of lignin were obtained at higher levels of delignification. In addition, pine lignins showed superior yields than the hardwoods and were around five times purer. Among the hardwoods, lignin recovery increased with the S–G ratio of the native lignin, and eucalyptus showed the best performance by achieving the highest yields and purities. Finally, the present work compared the lignin recovery yield and the purity of softwood and different hardwood lignins in a systematic way, which will increase awareness of this underutilized green material and could potentially increase the interest in establishing new lignin plants across the globe.
      Citation: Fibers
      PubDate: 2022-02-09
      DOI: 10.3390/fib10020016
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 17: Chemical Imaging of the Polylactic Acid −
           Wood Adhesion Interface of Bonded Veneer Products

    • Authors: Warren J. Grigsby, Desiree Torayno, Marc Gaugler, Jan Luedtke, Andreas Krause
      First page: 17
      Abstract: The increasing use and potential of polylactic acid (PLA) in wood-based composite materials due to its greater performance over common polyolefins provides the justification for a closer examination of the PLA−wood adhesion performance. In PLA-bonded laminates and composites, the optical differentiation between PLA polymer and wood is not possible and necessitates complex techniques such as fluorescence microscopy to characterize the PLA adhesion interface. In this study, spatial chemical imaging via FTIR analysis has been successfully applied to directly identify PLA bondlines within PLA-bonded veneer laminates and to determine the migration of semi-crystalline and amorphous PLAs from the bondline into the wood structure. This method uses involved point contouring line spectra over the bondline area to distinguish the PLA polymer from the wood. From this quantitative analysis, it is revealed that bondline thickness and PLA penetration values depend on pressing temperature, and this has implications for the reinforcement of the adhesion interface and the bondline performance. Furthermore, in developing a methodology for this assessment, this spatial chemical imaging approach can equally be applied to other polyester, amide, and urethane systems used to bond wood laminates.
      Citation: Fibers
      PubDate: 2022-02-09
      DOI: 10.3390/fib10020017
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 18: Effect of Fibre Diameter, Prickle Factor and
           Coarse Fibre Bias on Yarn Surface Hairiness in South American Camelids
           (SAC) Fibre

    • Authors: Ruben Herberht Mamani-Cato, Eduardo Narciso Frank, Alejandro Prieto, Maria Flavia Castillo, Nicoll Condori-Rojas, Michel Victor Hubert Hick
      First page: 18
      Abstract: It is well known that objectionable fibres emerge from the surface of the yarn due to the centrifugal force of the spinning device. Furthermore, the hair removal process is based on the same physical principles. However, the fibres that are >30 µm (PcF) are the fibres that appear in the hairiness of the yarn and are eliminated by dehairing. It has always been presumed that the PcF was linearly correlated with the diameter of the fibre (MFD) in llamas, but not so in alpaca fibres. Nevertheless, there is evidence that this relationship is curvilinear and behaves the same way in both species. The objectives of this study are to explore the relationship between MFD and PcF in both llamas and alpacas, to explore the existence of a breaking point (BP) in this curvilinear relationship, and to determine the frequency of fleeces that do not require dehairing because the PcF ≤ 3.2%. In addition, the existence of a positive bias of coarse fibre content on the hairy surface (CFs) of the yarn to coarse fibre content within the yarn fibres (CFy) was determined, which may explain the effect of the dehairing on the prickle factor of SAC fibres. The relationship of PcF on MFD behaves the same way in alpacas and llamas. It conforms to a power distribution and presents a BP of 23 µm, with PcF being constant before the BP and increasing significantly after it. Most animals (≤91% of alpacas and ≤87% of llamas) are above the threshold (≤3.2%), requiring dehairing to correct it. By means of a shaving technique on the surface of the fabric sample, it was established that the objectionable CFs content is 8.15% higher than the objectionable CFy content. In the evoked-coarse fibre in the dehaired samples, a CFs-CFy difference below 5.9% (p > 0.05) is not significantly detected by panellists. The surface MFD is more than 2.7 µm coarser than the yarn MFD.
      Citation: Fibers
      PubDate: 2022-02-10
      DOI: 10.3390/fib10020018
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 19: Acknowledgment to Reviewers of Fibers in 2021

    • Authors: Fibers Editorial Office Fibers Editorial Office
      First page: 19
      Abstract: Rigorous peer-reviews are the basis of high-quality academic publishing [...]
      Citation: Fibers
      PubDate: 2022-02-11
      DOI: 10.3390/fib10020019
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 20: Chemical Transformation of Lignosulfonates to
           Lignosulfonamides with Improved Thermal Characteristics

    • Authors: Karolina Komisarz, Tomasz M. Majka, Krzysztof Pielichowski
      First page: 20
      Abstract: Lignin is an abundantly occurring aromatic biopolymer that receives increasing attention as, e.g., a biofiller in polymer composites. Though its structure depends on the plant source, it is a valuable component showing biodegradability, antioxidant, and ultra-violet (UV) absorption properties. Lignosulfonates, a by-product of the paper and pulping industries formed as a result of the implementation of the sulfite process, have been used in the presented study as a raw material to obtain a sulfonamide derivative of lignin. Hereby, a two-step modification procedure is described. The obtained materials were investigated by means of FTIR, WAXD, SS-NMR, SEM, and TGA; the results of spectroscopic investigations confirm the formation of a sulfonamide derivative of lignin via the proposed modification method. The obtained modified lignin materials showed significantly improved thermal stability in comparison with the raw material. The internal structure of the lignosulfonate was not altered during the modification process, with only slight changes of the morphology, as confirmed by the WAXD and SEM analyses. The manufactured sulfonamide lignin derivatives show great promise in the potential application as an antibacterial filler in advanced biopolymeric composites.
      Citation: Fibers
      PubDate: 2022-02-14
      DOI: 10.3390/fib10020020
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 21: Ductility and Stiffness of Laminated Veneer
           Lumber Beams Strengthened with Fibrous Composites

    • Authors: Michał Marcin Bakalarz, Paweł Grzegorz Kossakowski
      First page: 21
      Abstract: The paper presents the results of experimental research on unstrengthened and strengthened laminated veneer beams subjected to 4-point bending. Aramid, glass and carbon sheets with high tensile strength (HS) and ultra-high modulus of elasticity (UHM) glued to external surfaces with an epoxy resin adhesive were used as reinforcement. Two reinforcement layouts were used: (1) sheets glued along the bottom surface and (2) sheets glued to the bottom and side surfaces. Based on the test results, the flexural strength, flexural ductility and stiffness were estimated. Compared to the reference beams, the maximum bending moment was higher by 15%, 20%, 30% and by 16%, 22% and 35% for the Aramid Fiber Reinforced Polymers (AFRP), Glass Fiber Reinforced Polymers (GFRP) and Carbon Fiber Reinforced Polymers (CFRP) HS sheets, respectively. There was no significant increase in the flexural bending capacity for beams reinforced with UHM CFRP sheets. Similar values of bending ductility indices based on deflection and energy absorption were obtained. Higher increases in ductility were observed for AFRP, GFRP and CFRP HS sheets in “U” reinforcement layout. The average increase in bending stiffness coefficient ranged from 8% for AFRP sheets to 33% for UHM CFRP sheets compared to the reference beams.
      Citation: Fibers
      PubDate: 2022-02-15
      DOI: 10.3390/fib10020021
      Issue No: Vol. 10, No. 2 (2022)
  • Fibers, Vol. 10, Pages 3: Kenaf Fibre Reinforced Cementitious Composites

    • Authors: Al-Ghazali Noor Abbas, Farah Nora Aznieta Abdul Aziz, Khalina Abdan, Noor Azline Mohd Nasir, Mohd Nurazzi Norizan
      First page: 3
      Abstract: Increased environmental awareness and the demand for sustainable materials have promoted the use of more renewable and eco-friendly resources like natural fibre as reinforcement in the building industry. Among various types of natural fibres, kenaf has been widely planted in the past few years, however, it hasn’t been extensively used as a construction material. Kenaf bast fibre is a high tensile strength fibre, lightweight and cost-effective, offering a potential alternative for reinforcement in construction applications. To encourage its use, it’s essential to understand how kenaf fibre’s properties affect the performance of cement-based composites. Hence, the effects of KF on the properties of cementitious composites in the fresh and hardened states have been discussed. The current state-of-art of Kenaf Fibre Reinforced Cement Composite (KFRCC) and its different applications are presented for the reader to explore. This review confirmed the improvement of tensile and flexural strengths of cementitious composites with the inclusion of the appropriate content and length of kenaf fibres. However, more studies are necessary to understand the overall impact of kenaf fibres on the compressive strength and durability properties of cementitious composites.
      Citation: Fibers
      PubDate: 2022-01-04
      DOI: 10.3390/fib10010003
      Issue No: Vol. 10, No. 1 (2022)
  • Fibers, Vol. 10, Pages 4: Propagation and Transformation of Vortexes in
           Linear and Nonlinear Radio-Photon Systems

    • Authors: Valery H. Bagmanov, Albert Kh. Sultanov, Ivan K. Meshkov, Azat R. Gizatulin, Raoul R. Nigmatullin, Airat Zh. Sakhabutdinov
      First page: 4
      Abstract: The article is devoted to issues related to the propagation and transformation of vortexes in the optical range of frequency. Within the framework of the traditional and modified model of slowly varying envelope approximation (SVEA), the process of converting vortex beams of the optical domain into vortex beams of the terahertz radio range based on nonlinear generation of a difference frequency in a medium with a second-order susceptibility is considered. The modified SVEA splits a slowly varying amplitude into two factors, which makes it possible to more accurately describe the three-wave mixing process. The theoretical substantiation of the rule of vortex beams topological charges conversion is given—the topological charge of the output radio-vortex beam is equal to the difference between the topological charges of the input optical vortex beams. A numerical simulation model of the processes under consideration has been implemented and analyzed.
      Citation: Fibers
      PubDate: 2022-01-08
      DOI: 10.3390/fib10010004
      Issue No: Vol. 10, No. 1 (2022)
  • Fibers, Vol. 10, Pages 5: Cracking Diagnosis in Fiber-Reinforced Concrete
           with Synthetic Fibers Using Piezoelectric Transducers

    • Authors: Maristella E. Voutetaki, Maria C. Naoum, Nikos A. Papadopoulos, Constantin E. Chalioris
      First page: 5
      Abstract: The addition of short fibers in concrete mass offers a composite material with advanced properties, and fiber-reinforced concrete (FRC) is a promising alternative in civil engineering applications. Recently, structural health monitoring (SHM) and damage diagnosis of FRC has received increasing attention. In this work, the effectiveness of a wireless SHM system to detect damage due to cracking is addressed in FRC with synthetic fibers under compressive repeated load. In FRC structural members, cracking propagates in small and thin cracks due to the presence of the dispersed fibers and, therefore, the challenge of damage detection is increasing. An experimental investigation on standard 150 mm cubes made of FRC is applied at specific and loading levels where the cracks probably developed in the inner part of the specimens, whereas no visible cracks appeared on their surface. A network of small PZT patches, mounted to the surface of the FRC specimen, provides dual-sensing function. The remotely controlled monitoring system vibrates the PZT patches, acting as actuators by an amplified harmonic excitation voltage. Simultaneously, it monitors the signal of the same PZTs acting as sensors and, after processing the voltage frequency response of the PZTs, it transmits them wirelessly and in real time. FRC cracking due to repeated loading ad various compressive stress levels induces change in the mechanical impedance, causing a corresponding change on the signal of each PZT. The influence of the added synthetic fibers on the compressive behavior and the damage-detection procedure is examined and discussed. In addition, the effectiveness of the proposed damage-diagnosis approach for the prognosis of final cracking performance and failure is investigated. The objectives of the study also include the development of a reliable quantitative assessment of damage using the statistical index values at various points of PZT measurements.
      Citation: Fibers
      PubDate: 2022-01-09
      DOI: 10.3390/fib10010005
      Issue No: Vol. 10, No. 1 (2022)
  • Fibers, Vol. 10, Pages 6: Characterization of Tensile Properties of Cola
           lepidota Fibers

    • Authors: Rémy Legrand Ndoumou, Damien Soulat, Ahmad Rashed Labanieh, Manuela Ferreira, Lucien Meva’a, Jean Atangana Ateba
      First page: 6
      Abstract: Plant fibers are being increasingly explored for their use in engineering polymers and composites, and many works have described their properties, especially for flax and hemp fibers. Nevertheless, the availability of plant fibers varies according to the geographical location on the planet. This study presents the first work on the mechanical properties of a tropical fiber extracted from the bast of Cola lepidota (CL) plant. After a debarking step, CL fibers were extracted manually by wet-retting. The tensile properties are first identified experimentally at the fibers scale, and the analysis of the results shows the great influence of the cross-section parameters (diameter, intrinsic porosities) on these properties. Tensile properties of CL fibers are also predicted by the impregnated fiber bundle test (IFBT). At this scale of bundles, a hackling step, which reduces shives and contributes to the parallelization of the fibers within bundles, improves tensile properties predicted by IFBT. The comparison with the properties of plant fibers given in the literature shows that CL fibers have tensile properties in the same range as kenaf, flax or hemp fibers.
      Citation: Fibers
      PubDate: 2022-01-12
      DOI: 10.3390/fib10010006
      Issue No: Vol. 10, No. 1 (2022)
  • Fibers, Vol. 10, Pages 7: Application of Activated Carbon Adsorbents
           Prepared from Prickly Pear Fruit Seeds and a Conductive Polymer Matrix to
           Remove Congo Red from Aqueous Solutions

    • Authors: Saadia Lahreche, Imane Moulefera, Abdelkader El Kebir, Lilia Sabantina, M’hamed Kaid, Abdelghani Benyoucef
      First page: 7
      Abstract: The present work was aimed to evaluate the adsorption properties of activated carbons based on prickly pear seeds (PPS) and conductive polymer matrix based on polyaniline (PANI) for the removal of anionic Congo red (CR) dye from aqueous solutions. The adsorbent was prepared by polymerization of aniline in the presence of activated PPS by phosphoric acid and sodium hydroxide. The samples were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and the Brunauer–Emmett–Teller (BET) methods. The adsorption kinetics were studied using UV-visible (UV/Vis) spectroscopy. The characterization data suggest that the adsorption of the Congo red dye is enhanced because PANI chain molecules, which are especially accountable for removal through π–π interaction and H–bonding with the CR, are adsorbed/tethered onto the acid-activated PPS (PPSH), and thus surmount the mass transfer limitation by being best exposed to the CR-adsorbed molecule. The adsorption kinetics follows the pseudo-second order process. The correlation coefficients (R2) for Langmuir, Freundlich and Tempkin showed that the adsorption values obey Freundlich and Tempkin isotherm models. Moreover, the isotherm was most accurately described by the Freundlich model, and the maximum removal percentage was calculated to be 91.14% under optimized conditions of pH 6.6, 1 g/L of adsorbent dosage, and an initial CR dye concentration of 20 mg·L−1. Importantly, the hybrid adsorbent exhibited the highest adsorption capacity (80.15%) after five cycles of the adsorption–desorption process. Thermodynamic parameters, such as entropy changes, enthalpy changes and Gibbs free energy, were also evaluated. These results indicated that the PANI matrix can generally be better utilized for the removal of Congo red dye when appropriately dispersed on the surface of suitable support materials. These results provide a new direction to promote the separable adsorbents with increasing performance for adsorption of dye impurities from wastewater.
      Citation: Fibers
      PubDate: 2022-01-13
      DOI: 10.3390/fib10010007
      Issue No: Vol. 10, No. 1 (2022)
  • Fibers, Vol. 10, Pages 8: Bond between Fibre-Reinforced Polymer Tubes and
           Sea Water Sea Sand Concrete: Mechanisms and Effective Parameters: Critical
           Overview and Discussion

    • Authors: Johanna Dorothea Luck, Milad Bazli, Ali Rajabipour
      First page: 8
      Abstract: Using fibre-reinforced polymers (FRP) in construction avoids corrosion issues associated with the use of traditional steel reinforcement, while seawater and sea sand concrete (SWSSC) reduces environmental issues and resource shortages caused by the production of traditional concrete. The paper gives an overview of the current research on the bond performance between FRP tube and concrete with particular focus on SWSSC. The review follows a thematic broad-to-narrow approach. It reflects on the current research around the significance and application of FRP and SWSSC and discusses important issues around the bond strength and cyclic behaviour of tubular composites. A review of recent studies of bond strength between FRP and concrete and steel and concrete under static or cyclic loading using pushout tests is presented. In addition, the influence of different parameters on the pushout test results are summarised. Finally, recommendations for future studies are proposed.
      Citation: Fibers
      PubDate: 2022-01-14
      DOI: 10.3390/fib10010008
      Issue No: Vol. 10, No. 1 (2022)
  • Fibers, Vol. 10, Pages 9: Special Issue on “Synthesis and
           Characterization of Nanomaterials”

    • Authors: Ioannis A. Kartsonakis
      First page: 9
      Abstract: Nanomaterial is defined a natural, incidental or manufactured material containing particles, in an unbound state, as an aggregate, or as an agglomerate, and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1–100 nm [...]
      Citation: Fibers
      PubDate: 2022-01-15
      DOI: 10.3390/fib10010009
      Issue No: Vol. 10, No. 1 (2022)
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