Preparation Of Fibers Research Articles

Simple preparation of high-temperature resistant BN-coated BCN fiber with a porous surface to enhance microwave absorption

Addressing this issue has become a significant concern in current research to enhance the performance and thermal stability of carbon electromagnetic wave (EMW) absorption materials. This study synthesizes BN-coated BCN fibers through wet spinning and precursor pyrolysis routes. A porous structure is incorporated between the BN and BCN fiber substrates to enhance EMW absorption performance. The results show that the BN-coated BCN fibers with a porous surface exhibit superior EMW absorption performance with the minimum reflection loss (RLmin) of -46.79 dB and the effective absorption bandwidth (EAB) of 5.5 GHz at 2mm, almost covering the Ku band. This straightforward co-doping and cost-effective synthesis strategy offers a novel design approach for preparing EMW absorption materials.

Preparation and Experimental Study of Corrosion-induced Shape-memory Fibers for Crack Repair

Repairing concrete cracks is crucial for enhancing the safety and durability of concrete structures. However, current repair technologies face limitations in corrosive environments such as marine settings. This study presents a novel corrosion-induced shape-memory fiber (CSF) based on the concept of corrosion-induced intelligent fiber (CIF). The CSF1 was made by coating elongated spandex-covered yarn with polyvinyl alcohol, and the CSF2 was prepared by winding stretched nylon fiber with iron wire. Experimental results demonstrate that CSF1 specimens can rapidly heal a 10mm wide crack within two seconds when exposed to water, while CSF2 specimens exhibit obvious shape recovery when exposed to seawater. Moreover, under midspan loads, pre-cracked CSF2-acrylic plate specimens achieve effective crack closure in seawater. These findings confirm the successful transfer of prestress from CSFs to the matrix, thereby validating the feasibility of CIF-based crack repair theory. This research provides experimental evidence for designing and optimizing self-repairing composite materials tailored for various corrosive environments and engineering applications.

High-filler content electrospun fibers from biodegradable polymers and hydroxyapatite: Toward improved scaffolds for tissue engineering.

One of the key challenges in tissue engineering area is the creation of biocompatible scaffolds that support cell growth and mimic the structural and mechanical properties of native tissues. Among various materials used for scaffold fabrication, composite materials based on biodegradable polymers reinforced with bioactive inorganic fillers have attracted significant attention due to their properties. One of the important problems with the preparation of composite electrospun fibers is the low filler content in the fiber. This study aims to select the best composition for electrospun polymer fibers in terms of potential application in tissue engineering. The effect of the viscosity of polymer solution/dispersion and filler content on the structure and properties of the fibers was determined. Morphology and filler content were compared. Series of electrospun composite fibers were fabricated from poly(ĺ-caprolactone) (PCL), poly(L-lactic acid) (PLLA) and hydroxyapatite (HAP), containing from 10 wt% to 40 wt% HAP. The properties of the resulting composites were studied using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and viscosimetry measurements. The addition of HAP to the polymer solution caused a significant increase in viscosity, but the results showed that it is possible to obtain composite electrospun fibers even with 40 wt% filler content. Scanning electron microscopy analysis shows randomly oriented electrospun fibers with an average diameter in the range of 3.8-8.5 ěm for solution and dispersion with high viscosity (1,210-2,000 mPa·s) and significantly larger diameters (approx. 12 ěm) for the PCL solution (326 mPa·s). It is possible to transform the composite dispersion from biopolymers and HAP into nonwoven fabrics at up to 40 wt% filler content. Due to their unique properties, such materials are promising for application in tissue engineering.

Preparation, Structural Characterization, and Hypoglycemic Activity of Dietary Fiber from Sea Buckthorn Pomace.

Sea buckthorn pomace is often discarded as a by-product during the sea buckthorn processing stage. Consequently, its richness in dietary fiber is usually overlooked. In this study, soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were extracted from sea buckthorn pomace using ultrasound combined with the enzyme method. The optimal values of the independent variable were determined by a combinatorial design and a response surface optimization test with SDF/IDF as the dependent variable, prepared as follows: 5% enzyme addition, ultrasonic power of 380 W, enzymatic time of 30 min, and alcoholic precipitation liquid ratio of 4:1. Under these conditions, the SDF/IDF ratio was 17.07%. The structural characterization and hypoglycemic activity of the two dietary fibers were then compared. The results show that two dietary fibers have respective structures and functional groups of fibers. SDF was less crystalline than IDF, and its structure was looser. Furthermore, the hypoglycemic activity of SDF was significantly better than IDF's (p < 0.05). The glucose adsorption capacity of SDF was 1.08-1.12 times higher than that of IDF. SDF inhibited α-amylase and α-glucosidase by 1.76 and 4.71 times more than IDF, respectively. These findings provide a reference for improving the utilization of sea buckthorn processing by-products.

Preparation of citrus fiber from lemon peel residue: Effects of structure and endogenous pectin components on emulsifying properties of citrus fiber

This study evaluated and compared the differences in structure and physicochemical properties between citrus fibers prepared after different degrees of pectin extraction and untreated citrus fibers. The results showed that the partial hydrolysis and release of internal pectin would cause the physical and chemical properties of citrus fibers to show a tendency to increase and then decrease with treatment time, with a steady increase in crystallinity and thermal stability. The water-holding capacity (15.81 g/g), swelling capacity (12.50 mL/g), and oil-holding capacity (3.33 g/g) of CF-5 h still remained noticeably higher than those of CF. The SEM results demonstrated that at the pectin extraction time of 5 h, the internal network structure of the cell wall of CF-5 h prepared at this time was maximized in terms of looseness. Meanwhile, the emulsion prepared from CF-5 h had the best emulsification properties, which were characterized by the smallest emulsion particle size(d4，3 = 10.40 μm), the best rheological properties, and excellent emulsion stability. Overall, the citrus fibers prepared after a certain degree of pectin extraction showed good performance in terms of physicochemical properties and emulsification performance.

Microstructural optimization of lignin‐based carbon fiber: Effects of purification and high‐temperature heat treatment

AbstractLignin is a renewable biomass polymer with a carbon content of more than 60% and has been extensively studied for making lignin‐based carbon fibers (CFs). However, impurities and high carbohydrate content in lignin materials severely limit their molding in melt spinning, and pre‐oxidation and carbonization processes also affect the subsequent preparation of CFs. This paper presents a detailed study of lignin‐based carbon fiber preparation. Pretreatment increased lignin's decomposition temperature to 302.1°C and enabled melt‐spun fiber preparation. Then, pre‐oxidation and carbonization of lignin fibers were further discussed. The pre‐oxidized fibers prepared at 280°C and 0.4°C min−1 have high thermal stability and excellent carbonization performance. The lignin‐based carbon fibers (LCFs) prepared at 1100°C and 3°C min−1 have the highest degree of graphitization, and the surface is smooth without obvious holes. Under these conditions, LCFs have a graphitization degree of 1.50 and conductivity of 62.50 S cm−1, making them suitable for sensors and capacitors.Highlights Effects of pretreatment on lignin structure and properties have been studied. Effects of pre‐oxidation and carbonization on the lignin fibers were studied. Lignin‐based carbon fibers with high conductivity were obtained.

Core-Sheath Fibers via Single-Nozzle Spinneret Electrospinning of Emulsions and Homogeneous Blend Solutions.

The preparation of core-sheath fibers by electrospinning is a topic of significant interest for producing composite fibers with distinct core and sheath functionalities. Moreover, in core-sheath fibers, low-molecular-weight substances or nanosized inorganic additives can be deposited in a targeted manner within the core or the sheath. Commonly, for obtaining a core-sheath structure, coaxial electrospinning is used. It requires a coaxial spinneret and suitable immiscible solvents for the inner and outer solutions. The single-nozzle spinneret electrospinning of emulsions can address these issues, but use of a stabilizing agent is needed. A third approach-preparation of core-sheath fibers by single-nozzle spinneret electrospinning of homogeneous blend solutions of two polymers or of a polymer/low-molecular-weight substance-has been much less studied. It circumvents the difficulties associated with the coaxial and the emulsion electrospinning and is thoroughly discussed in this review. The formation of core-sheath fibers in this case is attributed to phase-separation-driven self-organization during the electrospinning process. Some possibilities for obtaining core-double sheath fibers using the same method are also indicated. The gained knowledge on potential applications of core-sheath fibers prepared by single-nozzle spinneret electrospinning of emulsions and homogeneous blend solutions is also discussed.

Comparing solution blow spinning and electrospinning methods to produce collagen and gelatin ultrathin fibers: A review.

Ultrathin fibers have been used to design functional nanostructured materials for technological and biomedical applications. Combining the use of renewable and compatible sources with the emerging alternative SBS (solution blow spinning) technique opens new opportunities for material applications. In this review, we introduce the benefits of SBS over the classical electrospinning technique by following studies that use collagen or gelatin. SBS offers distinct advantages over electrospinning in the preparation of ultrathin fibers based on natural proteins, including the absence of high-voltage sources and the possibility of using fewer toxic solvents. Notably, there is also the prospect of using SBS directly in injured tissues, opening new strategies for in situ structure assembly SBS is a suitable approach to produce fibers at the nanoscale that can be tailored to distinct diameters by blending or simply adjusting experimental conditions. The focus on producing collagen or gelatin fibers contributes to designing highly biocompatible mats with potential for promoting cellular growth and implantation, even though their applications can be found also in food packaging, energy, and the environment. Therefore, a comprehensive analysis of the topic is essential to evaluate the current strategies regarding these materials and allow for their expanded production and advanced applications.

Low-cost and rapid preparation of high-performance carbon fiber reinforced ceramic matrix composites by molding-in situ densification

Carbon fiber reinforced ceramic matrix composites (CFCMCs), demonstrated huge demand of braking and transmission systems for heavy-loading equipment. However, high production cost, cumbersome preparation process and long preparation cycle severely limited its application and industrialization in the defense industry. In this work, a molding-in situ densification process was proposed to prepare AlN-modified CFCMCs under the synergistic effects of Al and Al2O3 fillers, facilitating a significant reduction in the preparation steps and treating temperature. The existence of active Al fillers was conducive to inducing the formation of Al-Si alloy melt and increasing contact area between Si and C to reduce the temperature of the Si-C reaction and promote the densification of composite materials. Meanwhile, the addition of Al2O3 effectively limited long-range flow of the alloy melt, further inhibiting severe volume deformation of the composites and the generation of large pores. When the maximum heat treatment temperature reached 1300 °C, the preparation cycle of AlN-modified CFCMCs reduced as low as 23–28 h after the molding-in situ densification process, which was roughly decreased by a 50 % drop. The compressive and flexural strength of AlN-modified CFCMCs achieved 308.51 MPa and 115.68 MPa, respectively. This molding-in situ densification strategy provided a pathway toward to achieve low-cost and rapid preparation of high-performance CFCMCs for the scale-up application in the fields of defense and military industry.

Preparation and pressure-bearing performance of polymer-encapsulated optical fiber for high lateral pressure sensing

Abstract High pressure resin transfer molding technology is used for the mass production of lightweight composite parts. The external pressure exerted has an impact on the actual pressure value of the preform in the mold cavity, which affects product quality. A polymer-encapsulated optical fiber pressure sensor is proposed to measure the lateral pressure in a closed and severely confined mold cavity. The quartz sand particles were mixed with water-borne polyurethane in a semi-cured state, and then made into a thin ribbon, and single-mode bare optical fiber was embedded between the two layers for overall curing and molding to obtain an ultra-thin polymer optical fiber transverse pressure sensor. Several sensor samples with two specifications of length×width×thickness of 150 mm×1.3 mm×0.45 mm and 150 mm×4.0 mm×1.0 mm were prepared, and both samples were placed simultaneously in the middle layer of 30 layers of uniaxial non-crimped glass fiber, namely 15 layers, for pressure experiments. The experimental results show that the optical loss of polymer-encapsulated optical fibers is proportional to pressure, and optical fiber samples with a width of 4 mm can withstand lateral pressures up to 40 MPa, providing an important monitoring method for pressure measurement in high-pressure resin transfer molding chambers.

Low Fibrillation Lyocell Fiber: Analysis of Fiber and its Crosslinking Agent

AbstractIn this paper, the hydrolysis process of Dichlorohydroxytriazine (NHDT) under alkaline conditions are studied. A qualitative and quantitative method for the determination of HNDT and its hydrolysis products are established, which further clarified the hydrolysis mechanism of NHDT. Under alkaline conditions, the hydrolysis products are mainly compound 4, compound 6 and chloride (Cl−). The hydrolysis rate of NHDT at different NaOH concentration and temperature is studied. This research can be used to guide the high efficiency preparation of low fibrillation Lyocell fiber. According to the quantitative detection of wet abrasion numbers and the qualitative analysis of the fiber by SEM after slapping, it is concluded that the low fibrillation Lyocell fiber is less prone to fibrillation under the combined action of wet state and mechanical force. Due to hydrolysis of the unreacted second chlorine resulting in harmful products on the low fibrillation Lyocell fiber, the fibrillation propensity increased with the increase of storage time. The mechanical properties of low fibrillation Lyocell fiber prepared under different fiber states are studied. The tensile breaking strength of low fibrillation Lyocell fiber prepared in the form of sequentially arranged fiber bundles are better, which is closely related to the fiber surface.

Preparation of Lyocell Fibers from Solutions of Miscanthus Cellulose.

Both annual (cotton, flax, hemp, etc.) and perennial (trees and grasses) plants can serve as a source of cellulose for fiber production. In recent years, the perennial herbaceous plant miscanthus has attracted particular interest as a popular industrial plant with enormous potential. This industrial crop, which contains up to 57% cellulose, serves as a raw material in the chemical and biotechnology sectors. This study proposes for the first time the utilization of miscanthus, namely Miscanthus Giganteus "KAMIS", to generate spinning solutions in N-methylmorpholine-N-oxide. Miscanthus cellulose's properties were identified using standard methods for determining the constituent composition, including also IR and atomic emission spectroscopy. The dry-jet wet method was used to make fibers from cellulose solutions with an appropriate viscosity/elasticity ratio. The structural characteristics of the fibers were studied using IR and scanning electron microscopy, as well as via X-ray structural analysis. The mechanical and thermal properties of the novel type of hydrated cellulose fibers demonstrated the possibility of producing high-quality fibers from miscanthus.

Simulation and experimental investigation of electret polypropylene fiber preparation via centrifugal melt electrospinning for enhanced air filtration

Rapid urbanization and industrialization have led to severe air pollution, enabling bacteria and viruses to become suspended in aerosol particles, which can be inhaled and pose a significant threat to human health. Electrostatic filtration offers a solution to enhance filtration efficiency without increasing resistance. However, traditional electret methods involve the usage of toxic solvent evaporation, and electret filter materials like polypropylene (PP) often suffer from rapid charge dissipation. In this study, we combined centrifugal melt electrospinning with Dissipative Particle Dynamics simulations to achieve continuous electret production and investigate the influence of experimental conditions and polymer additives on the charge-trapping capability of PP fibers. The results show that centrifugal melt electrospinning significantly enhances the charge storage capacity of PP fibers. The α crystal form of PP enhances electret performance by generating more effective charge traps, and experimental parameters influence electret performance by altering crystal forms. Additives effectively promote charge stability, resulting in stable voltages up to 11.09 kV with 1.5 wt% electret additive. Moreover, our study elucidates the correlation between crystal structure and electret performance, providing valuable data for regulating electret PP fibers.

Wet-spinning fabrication of stretchable multicolor fluorescent fibers augmented with dual-state emissive dyes

Flexible luminous fibers have attracted wide attention in the field of functional and smart textiles. In this work, stretchable multicolor fluorescent fibers were successfully prepared by wet-spinning using thermoplastic polyurethane (TPU) and the boron ketoimine fluorophores (TPA-BKI dyes). Due to the donor (D)-acceptor (A) push-pull electronic system and highly twisted triphenylamine (TPA) skeleton, TPA-BKI dyes exhibited bright emission in both solution and solid states. Meanwhile, the polymer chains further improved the emission efficiency of TPA-BKI dyes in TPU matrix by avoiding close contact between dye molecules, as well as preventing intramolecular rotations in the excited states. Wet-spinning can be used for large-scale and continuous preparation of fluorescent fibers. The TPA-BKI/TPU fibers showed excellent flexibility, high mechanical strength, and bright multicolor fluorescent emission (green, yellow, and red, respectively) when the dye content was as low as 0.1 wt%. Overall, the feasibility of large-scale preparation of fluorescent fibers and their excellent properties, such as flexibility, multicolor fluorescence, and mechanical stability, make them suitable for potential applications, including clothing displays, fashion designs, security, and anti-counterfeiting.

Preparation of continuous carbon fiber reinforced PA6 prepreg filaments with high fiber volume fraction

High-performance continuous carbon fiber prepreg filaments have been a research hotspot in the field of additive manufacturing in recent years, and are considered to be an effective option for improving the mechanical strength of thermoplastic composite parts. However, the effect of fiber volume fraction on the microstructure and tensile properties of 3D printed prepreg filaments remains miss. Therefore, this study selected suitable impregnation processes and materials to prepare prepreg filaments with different fiber volume fraction and investigated their mechanical properties and microscopic morphologies. The results show that the increase of fiber volume fraction effectively promoted the interface bonding between fiber and resin, and increased capacity for load transfer. When the fiber volume fraction was 54.0 %, the tensile strength of the prepreg filaments and specimens reached 1977 MPa and 334 MPa, respectively. This study can provide a process optimization strategy for the preparation of more types of continuous fiber prepreg filaments with high fiber volume fraction, as well as a data reference for the preparation of high-performance 3D-printed thermoplastic composites.

The preparation of melt electrospun fiber containing tandospirone for drug sustained release

AbstractElectrospun fibers membrane is considered an efficient drug carrier for transdermal drug delivery due to its breathability and high drug loading percentage, compared with coating film. However, pollution and safety risk caused by the use of organic solvents during the solution electrospinning process limit its industrialization and direct application in the biomedical field. Herein, a fiber membrane containing tandospirone was prepared using the melt electrospinning process and to be used for sustained drug release. The process of fiber preparation is an eco‐friendly and safe process due to the characteristics of solvent‐free. The in vitro drug release results showed that the fiber membranes containing tandospirone had slower initial drug release and higher end drug release compared with coating film containing tandospirone. The sustained‐release property can be attributed to the crystalline structure of fibers and the higher‐end drug release can be attributed to the spatial packing structures in the fiber membrane. The large pores generated by the stack structure of the large fiber in the fiber membrane leads to low gas resistance (10.7 Pa), which is much lower than that of the coating film (511.2 Pa). Overall, this study presents a green and safe preparation method of fiber membrane containing tandospirone, providing an effective and adjunctive treatments for mental disorders.Highlights The tandospirone‐loaded fiber patch was prepared using an eco‐friendly method. Burst release inhibition and higher final release of tandospirone in fibers. The fiber patch provided excellent breathability compared to coating patch. Fibers with higher crystallinity showed better controlled release.

Preparation of Antistatic Polyester Fiber via Layer-by-Layer Self-Assembly

Polyester fibers tend to generate static electricity during the weaving and application processes, posing a threat to their production. Enhancing the water absorbency and electrical conductivity of polyester fibers themselves is an effective approach to improving their antistatic properties. In this study, multifunctional chitosan (CS), sodium phytate (SP), and Cu2+ were loaded on polyester fibers through layer-by-layer (LBL) self-assembly. The antistatic and water absorption capability of the modified polyester fibers was investigated by designing different process parameters combined with a surface resistance test and water contact angle tests. The antistatic property test results confirmed the positive effect of CS and Cu2+ on discharging electrostatic charge. Within a definite scope, with the increase in the number of assembly layers, assembly duration, and the concentration of the assembly substances, the wettability of the modified polyester fibers became more favorable and the antistatic effect became more remarkable.

Preparation of carrageenan fibers promoted by hydrogen bonding in a NaCl coagulation bath

Carrageenan fibers developed by wet spinning have been extensively studied due to their remarkable flame-retardant characteristics. However, its mechanical properties have not been significantly improved, which limits the further development of carrageenan fibers. Traditionally, the first coagulation bath has been selected as a KCl solution, which can promote the formation of gels from carrageenan without reacting with NaOH to produce precipitates. In this study, a new type of carrageenan fiber was prepared for the first time employing an underappreciated NaCl solution as the first coagulation bath in combination with an AlCl3 coagulation bath. A comparison was made using fibers produced with KCl as the first coagulation bath under the same conditions. The potential mechanism of wet forming of carrageenan fibers was revealed using performance testing, compositional analysis, and structural characterization, which systematically investigated the differences between the two fibers. In contrast to prior studies, the NaCl coagulation bath primarily promoted hydrogen bonding between carrageenan molecular chains, and the produced fibers outperformed the KCl coagulation bath.

The Fifth Position in the Periodic Table Belongs to Boron

Despite the very low proportion of boron in the Earth's crust, boron and its compounds have found wide application in practical life and in scientific research. The article presents the importance of this element for plants and for humans. It enumerates the properties of boron and its compounds for the technical use in the preparation of glass, glass fibres, highly resistant and hard materials for industrial applications and for nuclear technology. It also mentions the use of boron compounds in medicine and synthetic chemistry.

Dynamic mechanism and structural property analysis of microfluidic-obtained pea protein fiber

Although protein-based fibers have been developed, the preparation of inexpensive, safe and environmentally friendly plant protein fibers is still a hot topic. Herein, we constructed the microfluidic chip to produce protein fiber using pea protein and a small amount of cellulose nanofibers. The results demonstrated that compared to pea protein alone, the pea protein-based fiber produced through microfluidic spinning exhibited a smooth and dense surface structure, good thermal stability, higher Zeta potential and antioxidant activity, and lower surface hydrophobicity and sensitization. Furthermore, we comprehensively revealed the dynamic formation mechanism of pea protein-based fiber. During the fiber preparation process, hydrodynamics led the protein and cellulose nanofibers to align gradually along the flow direction, enhancing their molecular orientation. Additionally, strong hydrodynamic shear force altered the protein structure, transitioning its spatial structure from random coil and α-helix to β-sheet, and promoting a binding of protein to cellulose nanofibers. This research may offer theoretical guidance for the application of pea protein-based fiber in the preparation of hypoallergenic protein-based fibers and the construction of foodborne delivery materials.