Open AccessArticle
Various Extraction Methods Influence the Adhesive Properties of Dried Distiller’s Grains and Solubles, and Press Cakes of Pennycress (Thlaspi arvense L.) and Lesquerella [Lesquerella fendleri (A. Gary) S. Watson], in the Fabrication of Lignocellulosic Composites
Fibers 2018, 6(2), 26; doi:10.3390/fib6020026 (registering DOI) -
Abstract
Lignocellulosic composite (LC) panels were fabricated using an adhesive matrix prepared from three different agricultural by-products: dried distillers grains with solubles (DDGS), pennycress (Thlaspi arvense L.) press cake (PPC), or lesquerella [Lesquerella fendleri (A. Gary) S. Watson] press cake (LPC) reinforced
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Lignocellulosic composite (LC) panels were fabricated using an adhesive matrix prepared from three different agricultural by-products: dried distillers grains with solubles (DDGS), pennycress (Thlaspi arvense L.) press cake (PPC), or lesquerella [Lesquerella fendleri (A. Gary) S. Watson] press cake (LPC) reinforced with Paulownia elongata L. wood (PW) particles. The goal in this study was to assess the mechanical properties of composites utilizing these low-cost matrix materials, which were subjected to various oil extraction methods. Three types of oil extraction methods were utilized: ethanol, supercritical CO2, and hexane, in order to generate matrix materials. These matrix materials were mixed with equal proportions of PW and hot pressed to generate panels. Overall, hexane extraction was the best method to enhance the mechanical properties of the matrices used to fabricate lignocellulosic composites. LPC’s produced a matrix that gave the resulting composite superior flexural properties compared to composites generated from DDGS and PPC matrices. The mechanical properties of composites generated from soy products (soybean meal flour or soy protein isolate) were similar to those derived from DDGS, PPC, or LPC. The dimensional stability properties of LCs were improved when the hexane extraction method was employed, unlike with the other extraction methods that were used to generate matrices. Full article
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Open AccessReview
Modelling and Design of Lanthanide Ion-Doped Chalcogenide Fiber Lasers: Progress towards the Practical Realization of the First MIR Chalcogenide Fiber Laser
Fibers 2018, 6(2), 25; doi:10.3390/fib6020025 -
Abstract
This paper presents the progress in the fields of the modelling and design of lanthanide ion-doped chalcogenide glass fiber lasers. It presents laser cavity designs that have been developed in order to optimize the performance of lanthanide ion-doped chalcogenide glass fiber lasers. Additionally,
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This paper presents the progress in the fields of the modelling and design of lanthanide ion-doped chalcogenide glass fiber lasers. It presents laser cavity designs that have been developed in order to optimize the performance of lanthanide ion-doped chalcogenide glass fiber lasers. Additionally, various numerical algorithms that have been applied for the optimization of chalcogenide glass lasers are reviewed and compared. The comparison shows that a combination of less accurate but more robust algorithms with more accurate ones gives the most promising performance. Full article
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Open AccessArticle
Fabrication of Shatter-Proof Metal Hollow-Core Optical Fibers for Endoscopic Mid-Infrared Laser Applications
Fibers 2018, 6(2), 24; doi:10.3390/fib6020024 -
Abstract
A method for fabricating robust and thin hollow-core optical fibers that carry mid-infrared light is proposed for use in endoscopic laser applications. The fiber is made of stainless steel tubing, eliminating the risk of scattering small glass fragments inside the body if the
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A method for fabricating robust and thin hollow-core optical fibers that carry mid-infrared light is proposed for use in endoscopic laser applications. The fiber is made of stainless steel tubing, eliminating the risk of scattering small glass fragments inside the body if the fiber breaks. To reduce the inner surface roughness of the tubing, a polymer base layer is formed prior to depositing silver and optical-polymer layers that confine light inside the hollow core. The surface roughness is greatly decreased by re-coating thin polymer base layers. Because of this smooth base layer surface, a uniform optical-polymer film can be formed around the core. As a result, clear interference peaks are observed in both the visible and mid-infrared regions. Transmission losses were also low for the carbon dioxide laser used for medical treatments as well as the visible laser diode used for an aiming beam. Measurements of bending losses for these lasers demonstrate the feasibility of the designed fiber for endoscopic applications. Full article
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Open AccessArticle
Antifungal Composite Fibers Based on Cellulose and Betulin
Fibers 2018, 6(2), 23; doi:10.3390/fib6020023 -
Abstract
Composite fibers and films based on cellulose and betulin were spun for the first time from solutions in N-methylmorpholine-N-oxide using the dry–wet jet method. The rheological properties of the composite solutions did not reveal any fundamental difference from those of
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Composite fibers and films based on cellulose and betulin were spun for the first time from solutions in N-methylmorpholine-N-oxide using the dry–wet jet method. The rheological properties of the composite solutions did not reveal any fundamental difference from those of the cellulose solutions. Introduction of betulin into the cellulose matrix (up to 10%) led to a decrease in the mechanical properties of the obtained fibers. The structure of the composite fibers was analyzed using SEM and X-ray diffraction methods. It was shown that the introduction of an additive into the cellulose matrix led to a decrease in the structural ordering of the cellulose. Comparative studies of the antibacterial activity of the composite films on Escherichia coli (E. coli) were carried out. The antifungal activity of the composite films was estimated using the strain of the O-97 Trichoderma viride Pers ex Fr (Gause Institute of New Antibiotics, Moscow, Russia). Full article
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Open AccessArticle
Facile Synthesis of Highly Hydrophobic Cellulose Nanoparticles through Post-Esterification Microfluidization
Fibers 2018, 6(2), 22; doi:10.3390/fib6020022 -
Abstract
A post-esterification with a high degree of substitution (hDS) mechanical treatment (Pe(hDS)M) approach was used for the production of highly hydrophobic cellulose nanoparticles (CNPs). The process has the advantages of substantially reducing the mechanical energy input for the production
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A post-esterification with a high degree of substitution (hDS) mechanical treatment (Pe(hDS)M) approach was used for the production of highly hydrophobic cellulose nanoparticles (CNPs). The process has the advantages of substantially reducing the mechanical energy input for the production of CNPs and avoiding CNP aggregation through drying or solvent exchange. A conventional esterification reaction was carried out using a mixture of acetic anhydride, acetic acid, and concentrated sulfuric acid, but at temperatures of 60–85 °C. The successful hDS esterification of bleached eucalyptus kraft pulp fibers was confirmed by a variety of techniques, such as Fourier transform infrared (FTIR), solid state 13C NMR, X-ray photoelectron spectroscopy (XPS), elemental analyses, and X-ray diffraction (XRD). The CNP morphology and size were examined by atomic force microscopy (AFM) as well as dynamic light scattering. The hydrophobicity of the PeM-CNP was confirmed by the redispersion of freeze-dried CNPs into organic solvents and water contact-angle measurements. Finally, the partial conversion of cellulose I to cellulose II through esterification improved PeM-CNP thermal stability. Full article
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Open AccessArticle
Routes towards Novel Collagen-Like Biomaterials
Fibers 2018, 6(2), 21; doi:10.3390/fib6020021 -
Abstract
Collagen plays a major role in providing mechanical support within the extracellular matrix and thus has long been used for various biomedical purposes. Exemplary, it is able to replace damaged tissues without causing adverse reactions in the receiving patient. Today’s collagen grafts mostly
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Collagen plays a major role in providing mechanical support within the extracellular matrix and thus has long been used for various biomedical purposes. Exemplary, it is able to replace damaged tissues without causing adverse reactions in the receiving patient. Today’s collagen grafts mostly are made of decellularized and otherwise processed animal tissue and therefore carry the risk of unwanted side effects and limited mechanical strength, which makes them unsuitable for some applications e.g., within tissue engineering. In order to improve collagen-based biomaterials, recent advances have been made to process soluble collagen through nature-inspired silk-like spinning processes and to overcome the difficulties in providing adequate amounts of source material by manufacturing collagen-like proteins through biotechnological methods and peptide synthesis. Since these methods also open up possibilities to incorporate additional functional domains into the collagen, we discuss one of the best-performing collagen-like type of proteins, which already have additional functional domains in the natural blueprint, the marine mussel byssus collagens, providing inspiration for novel biomaterials based on collagen-silk hybrid proteins. Full article
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Open AccessFeature PaperReview
Key Stages of Fiber Development as Determinants of Bast Fiber Yield and Quality
Fibers 2018, 6(2), 20; doi:10.3390/fib6020020 -
Abstract
Plant fibers find wide application in various fields that demand specific parameters of fiber quality. To develop approaches for the improvement of yield and quality of bast fibers, the knowledge of the fiber developmental stages and of the key molecular players that are
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Plant fibers find wide application in various fields that demand specific parameters of fiber quality. To develop approaches for the improvement of yield and quality of bast fibers, the knowledge of the fiber developmental stages and of the key molecular players that are responsible for a certain parameter, are vitally important. In the present review the key stages of fiber development, such as initiation, intrusive growth, and formation of thickened cell wall layers (secondary and tertiary cell walls) are considered, as well as the impact of each of these stages on the final parameters of fiber yield and quality. The problems and perspectives of crop quality regulation are discussed. Full article
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Open AccessArticle
Effect of Adding Carbon Nanotubes on the Freeze-Thaw and Thermal Fatigue Resistance of Latex Modified Mortar
Fibers 2018, 6(2), 19; doi:10.3390/fib6020019 -
Abstract
This paper aims to investigate the effect of adding carbon nanotubes (CNTs) on the durability of latex modified mortar (LMM). Up to 2.5% of CNTs by wt. of styrene-butadiene latex (SBR latex) CNTs were added to latex modified mortar (LMM) specimens before they
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This paper aims to investigate the effect of adding carbon nanotubes (CNTs) on the durability of latex modified mortar (LMM). Up to 2.5% of CNTs by wt. of styrene-butadiene latex (SBR latex) CNTs were added to latex modified mortar (LMM) specimens before they are subjected to two different thermal tests: freeze-thaw and thermal fatigue. LMM specimens were subjected to a number of freeze-thaw cycles according to American Society for Testing and Materials (ASTM) C-666 in order to simulate winter outdoor conditions in the United States (US) northern areas. Also, the specimens were subjected to thermal fatigue cycles similar to summer outdoor conditions. A large number of specimens were prepared in cubes, cylinders, and prisms, and were mechanically tested in compression, splitting tension, and flexure in order to evaluate the LMM specimens after the thermal exposure. Compression and tension specimens were tested after 50% and after 100% of the total number of cycles in order to assess the effect of the number of cycles on the mechanical performance. For LMM prims, dimensional stability was assessed first by monitoring the development of shrinkage strains during the application of thermal cycles. The LMM prisms were then tested in flexure after the completion of all the thermal cycles. The effectiveness of adding CNTs was evaluated by comparing between the performance of control LMM specimens and those with different CNTs contents. CNTs were found to alter the compressive strength, tensile strength, and flexural load carrying capacity of LMM specimens. Full article
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Open AccessCommentary
Does Dietary Fiber Reduce the Risk of Rheumatoid Arthritis?
Fibers 2018, 6(2), 18; doi:10.3390/fib6020018 -
Abstract
Accumulating evidence has suggested the effects of a higher dietary fiber intake on weight loss and reduced inflammation. In line with this, recent observations presented higher consumption of dietary fiber in relation to the lower risks of symptomatic knee osteoarthritis and worsening knee
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Accumulating evidence has suggested the effects of a higher dietary fiber intake on weight loss and reduced inflammation. In line with this, recent observations presented higher consumption of dietary fiber in relation to the lower risks of symptomatic knee osteoarthritis and worsening knee pain. Because both obesity and inflammation are commonly linked with knee osteoarthritis and rheumatoid arthritis, and preliminary results have suggested a role of microbiome in both joint disorders, we hypothesized that increased dietary fiber intakes might confer benefits in reducing the risk of rheumatoid arthritis and/or delaying disease progression. In this commentary, we sought to provide rationales regarding fiber’s physiological characteristics and its influence in the gut microbiome to postulate a potential link between fiber intake and the risk of rheumatoid arthritis. Verification of these hypotheses requires data from observational and experimental studies. Full article
Open AccessFeature PaperArticle
Dynamic In-Situ Observation on the Failure Mechanism of Flax Fiber through Scanning Electron Microscopy
Fibers 2018, 6(1), 17; doi:10.3390/fib6010017 -
Abstract
In order to develop and improve bio-inspired fibers, it is necessary to have a proper understanding of the fracture behavior of bio-fibers such as flax fibers from an individual fiber down to the constituent micro-fibrils and nano-fibrils. For investigating the failure mechanism of
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In order to develop and improve bio-inspired fibers, it is necessary to have a proper understanding of the fracture behavior of bio-fibers such as flax fibers from an individual fiber down to the constituent micro-fibrils and nano-fibrils. For investigating the failure mechanism of individual and technical flax fibers, a tensile test bench was placed within a scanning electron microscope, and the entire process of fiber failure was investigated through the capture of an SEM movie. Next, fractographic analysis was performed on the failure surface of single fibers as well as meso-fibrils that failed at a displacement rate of 0.25 mm/min, 0.75 mm/min, and 1.6 mm/min. The analysis also enabled visualization of a few internal details of flax fiber such as the arrangement of meso-fibrils and micro-fibrils (nano-fibrils). It was shown that the crack bridging mechanism and successive fiber pull-out contributed to the high work of fracture of flax fiber and the value may reach as high as 106J/m2. Full article
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Open AccessArticle
Investigation of Transcrystalline Interphases in Polypropylene/Glass Fiber Composites Using Micromechanical Tests
Fibers 2018, 6(1), 16; doi:10.3390/fib6010016 -
Abstract
In composites, a strong interphase between the components is essential for mechanical properties. By using a suitable sizing (i.e., surface modification) of the fiber, the interphase may be varied, e.g., by suppressing or promoting heterogeneous nucleation of a thermoplastic matrix. In the latter
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In composites, a strong interphase between the components is essential for mechanical properties. By using a suitable sizing (i.e., surface modification) of the fiber, the interphase may be varied, e.g., by suppressing or promoting heterogeneous nucleation of a thermoplastic matrix. In the latter case, three-dimensional transcrystallized interphases with properties differing from those of the bulk matrix are formed. Polypropylene-glass fiber composites are prepared as single-fiber model composites with (a) sizings either inducing or suppressing a transcrystalline interphase, (b) different amounts of modifier maleic acid anhydride grafted polypropylene, and (c) different molecular weights of the matrix polymer. These are studied in quasi-static or cyclic load tests. Static tests permit insights in the interfacial characteristics such as critical interface energy release rate, adhesion strength and frictional stress. Cyclic tests on these model composites can be used to study the nature of dissipative processes and the damage behavior. Atomic Force Microscopy (AFM) investigations of the fiber fracture surfaces provide supplementary information. The transcrystalline layer can indeed improve the mechanical parameters (a 70–100% increase of strength and a 25 or 125% increase in toughness, depending on the molecular weight (MW) of the matrix polymer at low modifier concentration). However, the effect is partially neutralized by an opposing effect: high nucleation in the bulk in samples with commonly used concentrations of modifier. Full article
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Open AccessFeature PaperReview
Synthetic Strategies for the Fabrication of Cationic Surface-Modified Cellulose Nanocrystals
Fibers 2018, 6(1), 15; doi:10.3390/fib6010015 -
Abstract
Cellulose nanocrystals (CNCs) are renewable nanosized materials with exceptional physicochemical properties that continue to garner a high level of attention in both industry and academia for their potential high-end material applications. These rod-shaped CNCs are appealing due to their non-toxic, carbohydrate-based chemical structure,
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Cellulose nanocrystals (CNCs) are renewable nanosized materials with exceptional physicochemical properties that continue to garner a high level of attention in both industry and academia for their potential high-end material applications. These rod-shaped CNCs are appealing due to their non-toxic, carbohydrate-based chemical structure, large surface area, and the presence of ample surface hydroxyl groups for chemical surface modifications. CNCs, generally prepared from sulfuric acid-mediated hydrolysis of native cellulose, display an anionic surface that has been exploited for a number of applications. However, several recent studies showed the importance of CNCs’ surface charge reversal towards the design of functional cationic CNCs. Cationization of CNCs could further open up other innovative applications, in particular, bioapplications such as gene and drug delivery, vaccine adjuvants, and tissue engineering. This mini-review focuses mainly on the recent covalent synthetic methods for the design and fabrication of cationic CNCs as well as their potential bioapplications. Full article
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Open AccessArticle
Use of a Simple Non-Destructive Technique for Evaluation of the Elastic and Vibration Properties of Fiber-Reinforced and 3D Fiber-Metal Laminate Composites
Fibers 2018, 6(1), 14; doi:10.3390/fib6010014 -
Abstract
The aim of this paper is to assess the accuracy and reliability of a simple non-destructive sonic technique for evaluating the effective elastic and vibration properties (damping coefficient) of various isotropic and orthotropic materials—in particular, of a recently developed class of 3D fiber-metal
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The aim of this paper is to assess the accuracy and reliability of a simple non-destructive sonic technique for evaluating the effective elastic and vibration properties (damping coefficient) of various isotropic and orthotropic materials—in particular, of a recently developed class of 3D fiber-metal laminates (FML). Aluminum, E-glass/epoxy composite, 3D-FML, and glass-reinforced aluminum FML (GLARE) materials were considered. It is exhibited that the 3D-FML offers the greatest damping characteristics in comparison to all the considered materials. Moreover, the sonic technique, facilitated through the use of a GrindoSonic equipment, proves to produce accurate and reliable results with minimal effort. Finite element analysis is also employed to further establish the accuracy of the properties evaluated by the experimental data. The utility of the established homogenized experimental properties within the finite element framework is also discussed. Full article
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Open AccessReview
Advances on Polymer Optical Fiber Gratings Using a KrF Pulsed Laser System Operating at 248 nm
Fibers 2018, 6(1), 13; doi:10.3390/fib6010013 -
Abstract
This paper presents the achievements and progress made on the polymer optical fiber (POF) gratings inscription in different types of Fiber Bragg Gratings (FBGs) and long period gratings (LPGs). Since the first demonstration of POFBGs in 1999, significant progress has been made where
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This paper presents the achievements and progress made on the polymer optical fiber (POF) gratings inscription in different types of Fiber Bragg Gratings (FBGs) and long period gratings (LPGs). Since the first demonstration of POFBGs in 1999, significant progress has been made where the inscription times that were higher than 1 h have been reduced to 15 ns with the application of the krypton fluoride (KrF) pulsed laser operating at 248 nm and thermal treatments such as the pre-annealing of fibers. In addition, the application of dopants such as benzyl dimethyl ketal (BDK) has provided a significant decrease of the fiber inscription time. Furthermore, such improvements lead to the possibility of inscribing POF gratings in 850 nm and 600 nm, instead of only the 1550 nm region. The progress on the inscription of different types of polymer optical fiber Bragg gratings (POFBGs) such as chirped POFBGs and phase-shifted POFBGs are also reported in this review. Full article
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Open AccessArticle
Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete
Fibers 2018, 6(1), 12; doi:10.3390/fib6010012 -
Abstract
Concrete shrinkage and volume reduction happens due to the loss of moisture, which eventually results in cracks and more concrete deformation. In this study, the effect of polypropylene (PP), steel, glass, basalt, and polyolefin fibers on compressive and flexural strength, drying shrinkage, and
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Concrete shrinkage and volume reduction happens due to the loss of moisture, which eventually results in cracks and more concrete deformation. In this study, the effect of polypropylene (PP), steel, glass, basalt, and polyolefin fibers on compressive and flexural strength, drying shrinkage, and cracking potential, using the ring test at early ages of high-strength concrete mixtures, was investigated. The restrained shrinkage test was performed on concrete ring specimens according to the ASTM C1581 standard. The crack width and age of restrained shrinkage cracking were the main parameters studied in this research. The results indicated that the addition of fiber increases the compressive strength by 16%, 20%, and 3% at the age of 3, 7, and 28 days, respectively, and increases the flexural toughness index up to 7.7 times. Steel and glass fibers had a better performance in flexural strength, but relatively poor action in the velocity reduction and cracking time of the restrained shrinkage. Additionally, cracks in all concrete ring specimens except for the polypropylene-containing mixture, was developed to a full depth crack. The mixture with polypropylene fiber indicated a reduction in crack width up to 62% and an increasing age cracking up to 84%. Full article
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Open AccessFeature PaperArticle
Structural Evolution of Gossypium hirsutum Fibers Grown under Greenhouse and Hydroponic Conditions
Fibers 2018, 6(1), 11; doi:10.3390/fib6010011 -
Abstract
Cotton is the leading fiber source in the textile industry and one of the world’s most important crops. Despite its economic interest, cotton culture exerts an enormous pressure on natural resources (land and water) and has a negative impact on the environment (abuse
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Cotton is the leading fiber source in the textile industry and one of the world’s most important crops. Despite its economic interest, cotton culture exerts an enormous pressure on natural resources (land and water) and has a negative impact on the environment (abuse of pesticides). Thus, alternative cotton growing methods are urged to be implemented. Recently, we have demonstrated that Gossypium hirsutum (“Upland” cotton) can be grown in a greenhouse (controlled conditions) and hydroponically. Here we report on the elucidation of the structural changes of the Gossypium hirsutum fibers during maturation grown [10, 14, 17, 20, 36 and 51 days post anthesis (dpa)] under a greenhouse and hydroponically, by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy with attenuated total reflectance (FT-IR ATR) and thermal gravimetric analysis/differential scanning calorimetry (TGA/DSC). The transition from primary to secondary cell wall growth occurs between 17 and 20 dpa—similarly to the soil-based cultures. However, this new cotton culture offers an advantageous pesticide and soil-free all year-round closed system with efficient water use yielding standardized mature fibers with improved properties (maturity, strength, length, whiteness). Full article
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Open AccessArticle
Influence of Stem Diameter on Fiber Diameter and the Mechanical Properties of Technical Flax Fibers from Linseed Flax
Fibers 2018, 6(1), 10; doi:10.3390/fib6010010 -
Abstract
The continued search for sustainable and eco-friendly materials has led to the integration of bio-fibers, such as flax fiber, as reinforcement in composite materials; however, a wide variation in their diameters and mechanical properties poses a considerable challenge for their incorporation in load
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The continued search for sustainable and eco-friendly materials has led to the integration of bio-fibers, such as flax fiber, as reinforcement in composite materials; however, a wide variation in their diameters and mechanical properties poses a considerable challenge for their incorporation in load bearing and structural bio-composite materials. In this paper, a rigorous experimental investigation was performed using two varieties of linseed flax from two growing locations to determine if the variations observed in ultimate tensile strength, Young’s modulus, failure strain and diameter could be attributed to the diameters of the stems that produced the fibers. Tests were performed in two different facilities and the results were compared and analyzed using Welch’s t-tests. Results showed that samples which differed by stem diameter had statistically significant positive correlation with fiber diameter and negative correlation with tensile strength. No correlations for tensile strength, Young’s modulus or fiber diameter were found in samples with the same stem diameter range that were grown in different locations or were of different varieties, that is the effect of location and variety is not statistically significant. Failure strain did not show any statistical significance with respect to differences in stem diameter and only showed one statistically significant result between both facilities for one of the two growing location comparisons. Full article
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Open AccessFeature PaperArticle
Effect of Polypropylene Fibers on Self-Healing and Dynamic Modulus of Elasticity Recovery of Fiber Reinforced Concrete
Fibers 2018, 6(1), 9; doi:10.3390/fib6010009 -
Abstract
This study aims to evaluate self-healing properties and recovered dynamic moduli of engineered polypropylene fiber reinforced concrete using non-destructive resonant frequency testing. Two types of polypropylene fibers (0.3% micro and 0.6% macro) and two curing conditions have been investigated: Water curing (at ~25
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This study aims to evaluate self-healing properties and recovered dynamic moduli of engineered polypropylene fiber reinforced concrete using non-destructive resonant frequency testing. Two types of polypropylene fibers (0.3% micro and 0.6% macro) and two curing conditions have been investigated: Water curing (at ~25 Celsius) and air curing. The Impact Resonance Method (IRM) has been conducted in both transverse and longitudinal modes on concrete cylinders prior/post crack induction and post healing of cracks. Specimens were pre-cracked at 14 days, obtaining values of crack width in the range of 0.10–0.50 mm. Addition of polypropylene fibers improved the dynamic response of concrete post-cracking by maintaining a fraction of the original resonant frequency and elastic properties. Macro fibers showed better improvement in crack bridging while micro fiber showed a significant recovery of the elastic properties. The results also indicated that air-cured Polypropylene Fiber Reinforced Concrete (PFRC) cylinders produced ~300 Hz lower resonant frequencies when compared to water-cured cylinders. The analyses showed that those specimens with micro fibers exhibited a higher recovery of dynamic elastic moduli. Full article
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Open AccessBrief Report
Transcriptome Assembly of the Bast Fiber Crop, Ramie, Boehmeria nivea (L.) Gaud. (Urticaceae)
Fibers 2018, 6(1), 8; doi:10.3390/fib6010008 -
Abstract
Ramie (Boehmeria nivea) is a perennial crop valued for its strong bast fibers. Unlike other major bast fiber crops, ramie fiber processing does not include retting, but does require degumming, suggesting distinctive features in pectin and the development and composition of
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Ramie (Boehmeria nivea) is a perennial crop valued for its strong bast fibers. Unlike other major bast fiber crops, ramie fiber processing does not include retting, but does require degumming, suggesting distinctive features in pectin and the development and composition of fibers. A comprehensive transcriptome assembly of ramie has not been made available, to date. We obtained the sequence of RNA transcripts (RNA Seq) from the apical region of developing ramie stems and combined these with reads from public databases for a total of 157,621,051 paired-end reads (30.3 billion base pairs Gbp) used as input for de novo assembly, resulting in 70,721 scaffolds (≥200 base pairs (bp); N50 = 1798 bp). As evidence of the quality of the assembly, 36,535 scaffolds aligned to at least one Arabidopsis protein (BLASTP e-value ≤ 10−10). The resource described here for B. nivea will facilitate an improved understanding of bast fibers, cell wall, and middle lamella development in this and other comparative species. Full article
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Open AccessArticle
Interfacial Characterization by Pull-Out Test of Bamboo Fibers Embedded in Poly(Lactic Acid)
Fibers 2018, 6(1), 7; doi:10.3390/fib6010007 -
Abstract
In this work, the apparent shear strength at the interface between a bamboo fiber and the surrounding poly(lactic acid) (PLA) matrix is quantified. A method for processing pull-out test samples within a controlled embedded length is proposed and the details of the test
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In this work, the apparent shear strength at the interface between a bamboo fiber and the surrounding poly(lactic acid) (PLA) matrix is quantified. A method for processing pull-out test samples within a controlled embedded length is proposed and the details of the test procedure are presented, along with a critical discussion of the results. Two series of samples are considered: untreated and mercerized bamboo fibers from the same batch, embedded in the same polyester matrix. Electron and optical microscopy are used to observe the fiber–matrix interface before and after the test, and to identify the failure mode of each sample, especially as regards the occurrence of fibrillation in the fiber bundles. The values of apparent interfacial shear strength are calculated only for regular fibers successfully pulled out from the matrix, and reported with their statistical variations. Mercerization, whose efficiency was proven by Fourier transform infrared (FTIR) spectroscopy, did not appear though to improve the quality of the interface (τapp = 7.0 ± 3.1 MPa for untreated fibers and τapp = 5.3 ± 2.4 MPa for treated fibers). Full article
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