Fiber Spinning Research Articles

Advancement of Nonwoven Fabrics in Personal Protective Equipment.

While nonwoven fabrics have existed for several decades, their usage in personal protective equipment (PPE) has been met with a rapid surge of demands, in part due to the recent COVID-19 pandemic. This review aims to critically examine the current state of nonwoven PPE fabrics by exploring (i) the material constituents and processing steps to produce fibers and bond them, and (ii) how each fabric layer is integrated into a textile, and how the assembled textiles are used as PPE. Firstly, filament fibers are manufactured via dry, wet, and polymer-laid fiber spinning methods. Then the fibers are bonded via chemical, thermal, and mechanical means. Emergent nonwoven processes such as electrospinning and centrifugal spinning to produce unique ultrafine nanofibers are discussed. Nonwoven PPE applications are categorized as filters, medical usage, and protective garments. The role of each nonwoven layer, its role, and textile integration are discussed. Finally, the challenges stemming from the single-use nature of nonwoven PPEs are discussed, especially in the context of growing concerns over sustainability. Then, emerging solutions to address sustainability issues with material and processing innovations are explored.

Carbon Footprint and Water Footprint Assessment of Down Jackets

Down jackets consume a lot of energy and water, and emit greenhouse gases, wastewater and other pollutants during the life cycle. For example, melt spinning polyester fibre production, spinning, weaving, fabric dyeing and finishing are high-energy consumption processes. Down processing, fabric dyeing and finishing are typical water consumption and wastewater pollutant discharge processes. Carbon and water footprints are practical tools for evaluating the environmental impact of a product in its life cycle. This article quantified and evaluated the carbon and water footprints of the life cycle of 100 down jackets – from raw material production to recycling and disposal without transportation activities. The results showed that the carbon footprint of the 100 down jackets production was 2544.1 kgCO2e with recycling. As for the water footprint, it showed that fabric production had a great impact on water eutrophication and water scarcity. The water scarcity footprint of 100 down jackets production was 27.46 m3H2Ot, respectively. The water eutrophication footprint generated by producing 100 down jackets in new industry was 1.91 kgPO43−eq. The comprehensive assessment of carbon footprint and water footprint with the life cycle assessment polygon method indicated that the raw material production phase of down jackets generated a more significant impact on the environment than the use phase. The impact on the environment during the use phase is primarily the environmental load on water resources.

Levocetirizine-Loaded Electrospun Fibers from Water-Soluble Polymers: Encapsulation and Drug Release.

Electrospun fibers containing levocetirizine, a BCS III drug, were prepared from three water-soluble polymers, hydroxypropyl methylcellulose (HPMC), polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA). Fiber-spinning technology was optimized for each polymer separately. The polymers contained 10 wt% of the active component. An amorphous drug was homogeneously distributed within the fibers. The solubility of the drug in the polymers used was limited, with a maximum of 2.0 wt%, but it was very large in most of the solvents used for fiber spinning and in the dissolution media. The thickness of the fibers was uniform and the presence of the drug basically did not influence it at all. The fiber diameters were in the same range, although somewhat thinner fibers could be prepared from PVA than from the other two polymers. The results showed that the drug was amorphous in the fibers. Most of the drug was located within the fibers, probably as a separate phase; the encapsulation efficiency proved to be 80-90%. The kinetics of the drug release were evaluated quantitatively by the Noyes-Whitney model. The released drug was approximately the same for all the polymers under all conditions (pH), and it changed somewhere between 80 and 100%. The release rate depended both on the type of polymer and pH and varied between 0.1 and 0.9 min-1. Consequently, the selection of the carrier polymer allowed for the adjustment of the release rate according to the requirements, thus justifying the use of electrospun fibers as carrier materials for levocetirizine.

Improved sensitivity of liquid sensing melt-spun polymer fibers filled with carbon nanoparticles by considering solvent-polymer solubility parameters

The Hansen Solubility Parameters (HSPs) and the Relative Energy Differences (REDs) were used to select suitable polymers to perform sensing experiments of electrically conductive nanocomposites against different solvents to employ such materials for sensor applications. From the solvent-polymer HSPs and their REDs, it was determined that polycarbonate (PC) is a polymer with potential towards high liquid sensitivity for different organic solvents. Furthermore, PC is spinnable and sensing fibers of different diameters can be easily produced. In order to get electrically conductive materials, PC was melt-mixed with carbon nanoparticles such as Multi-walled Carbon Nanotubes (MW) and Carbon Black (CB). The materials were then spun into fibers via melt-spinning and evaluated for liquid sensing. It was found that combining MW and CB (50/50 wt%) improved the fiber spinnability and their sensing range in comparison to fibers made of PC and only MW. Liquid sensing evaluations showed that knowing the REDs in advance allows predictions on the ability of nanocomposite fibers to be highly sensitive to specific solvents. From the sensing evaluations it was found that fibers made with hybrid fillers of CB+MW, drawing down ratios of 4 to 12 and filler contents between 3 and 6 wt% showed the best liquid sensing abilities. Depending on the composition and the conditions of fiber production, the maximum values of relative resistance change for fibers with CB+MW were always higher than for fibers containing MW only. Testing for instance butyl acetate as solvent, the fibers with MW+CB achieved values between 600%–3200% for long immersion times, while values between 390 and 1200% were obtained for the fibers with only MW. Testing a selected fiber under a simulated leakage scenario and as sheath/core bi-component fiber showed the effectiveness of these fibers working as liquid detector as well as potential for applications beyond single component fiber sensors.

Response surface optimization for the electromagnetohydrodynamic Cu-polyvinyl alcohol/water Jeffrey nanofluid flow with an exponential heat source

This article examines the sensitivity analysis of Jeffrey fluid flow in the presence of copper nanoparticles with polyvinyl alcohol water serving as the base fluid under the influence of source terms like Joule heating, viscous dissipation, exponential heat source, and Arrhenius activation energy via a non-linear vertically elongating surface of non-uniform thickness. Governing PDEs are first converted into ODEs using a suitable similarity transformation. The resulting coupled ODEs are converted into a system of first-order ODEs and then solved using the shooting iteration technique with the RK-4th order method. The remarkable impacts of numerous parameters like Deborah number, Hartmann number, electric field parameter, thermal and solutal Grashof number, Prandtl and Eckert numbers, exponential heat source parameter, Lewis number, chemical reaction parameter, and activation energy parameter associated with the flow properties are discussed graphically. The effects of various physical parameters and the dependence of the response factors on the input parameter are explored using an experimental design and sensitivity analysis based on Response Surface Methodology. Response Surface Methodology is utilized to determine the output response variables of model dependencies, such as the drag coefficient and Nusselt number on the independent input parameters, namely the electric field parameter and Deborah numbers for the drag coefficient, and electric field parameter, thermophoresis diffusion parameter, and exponential heat source parameter for the Nusselt number. Local Nusselt number enhances with increment in the electric field parameter and thermophoresis diffusion parameter values, whereas it decelerates with the rise in exponential heat source parameter. The non-Newtonian nanofluids have proven their great potential in thermal transportation which has a diverse range of applications in thermal energy technologies such as lubrication, natural gas networks, spray processes, and cooling of nuclear reactors, spinning of fibers, cryopreservation, drawing of copper wires, nano-drug delivery, electronics, and many more.

Sound Waveguiding by Spinning: An Avenue toward Unidirectional Acoustic Spinning Fibers

Although optical fiber has revolutionized modern life, creating a corresponding fiber as a waveguide for airborne sound has proven difficult, due to the scarcity of high-index acoustic materials. In this study the authors utilize spinning of the air inside a metamaterial tube to create an acoustic fiber. Their simulations demonstrate nonreciprocal propagation resulting from the acoustic equivalent of the Zeeman effect, which leads to robust waveguiding in the proposed fiber. This contribution may open avenues for studying the physics of acoustic vortex beams and nonreciprocal phenomena.

Wet Spinning of Graphene Oxide Fibers with Different MnO2 Additives.

We present the fabrication of graphene oxide (GO) and manganese dioxide (MnO2) composite fibers via wet spinning processes, which entails the effects of MnO2 micromorphology and mass loading on the extrudability of GO/MnO2 spinning dope and on the properties of resulted composite fibers. Various sizes of rod and sea-urchin shaped MnO2 microparticles have been synthesized via hydrothermal reactions with different oxidants and hydrothermal conditions. Both the microparticle morphology and mass loading significantly affect the extrudability of the GO/MnO2 mixture. In addition, the orientation of MnO2 microparticles within the fibers is largely affected by their microscopic surface areas. The composite fibers have been made electrically conductive via chemical or thermal treatments and then applied as fiber cathodes in Zn-ion battery prototypes. Thermal annealing under an argon atmosphere turns out to be an appropriate method to avoid MnO2 dissolution and leaching, which have been observed in the chemical treatments. These rGO/MnO2 fiber cathodes have been assembled into prototype Zn-ion batteries with Zn wire as the anode and xanthan-gum gel containing ZnSO4 and MnSO4 salts as the electrolyte. The resulted electrochemical output depends on the annealing temperature and MnO2 distribution within the fiber cathodes, while the best performer shows stable cycling stability at a maximum capacity of ca. 80 mA h/g.

Advances in the Synthesis of Preceramic Polymers for the Formation of Silicon-Based and Ultrahigh-Temperature Non-Oxide Ceramics.

Preceramic polymers (PCPs) are a group of specialty macromolecules that serve as precursors for generating inorganics, including ceramic carbides, nitrides, and borides. PCPs represent interesting synthetic challenges for chemists due to the elements incorporated into their structure. This group of polymers is also of interest to engineers as PCPs enable the processing of polymer-derived ceramic products including high-performance ceramic fibers and composites. These finished ceramic materials are of growing significance for applications that experience extreme operating environments (e.g., aerospace propulsion and high-speed atmospheric flight). This Review provides an overview of advances in the synthesis and postpolymerization modification of macromolecules forming nonoxide ceramics. These PCPs include polycarbosilanes, polysilanes, polysilazanes, and precursors for ultrahigh-temperature ceramics. Following our review of PCP synthetic chemistry, we provide examples of the application and processing of these polymers, including their use in fiber spinning, composite fabrication, and additive manufacturing. The principal objective of this Review is to provide a resource that bridges the disciplines of synthetic chemistry and ceramic engineering while providing both insights and inspiration for future collaborative work that will ultimately drive the PCP field forward.

High consistency enzymatic pretreatment of eucalyptus and softwood kraft fibres for regenerated fibre products

Sustainability of regenerated cellulosic fibres could be improved by using paper grade pulp instead of dissolving pulp as a raw material in the fibre spinning process. However, the use of paper grade pulp calls for adjustment of the molar mass distribution (MMD) prior to dissolution to obtain good solubility and spinnability. The objective of this work was to adjust MMD of softwood and eucalyptus kraft pulps by enzymatic treatments at high pulp consistency. The reduction of the MMD of eucalyptus kraft pulp was found to require a nearly 30-fold higher dose of endoglucanase compared to the treatment of softwood pulp. Interestingly, when xylanase was used in combination with endoglucanase to treat eucalyptus kraft pulp, 27% of the xylan was dissolved and the required endoglucanase dose could be decreased from 0.57 to 0.06 mg/g. The endoglucanase dose could be further decreased to 0.028 mg/g when 67% of xylan was removed chemically before the enzymatic treatment. This suggests that xylan hinders endoglucanase action on eucalyptus kraft pulp. For softwood pulp, the addition of xylanase and mannanase had only a minor impact on the treatment efficiency. The different processabilities of softwood and eucalyptus kraft pulps are suggested to originate from the deviating cellulose accessibility which is affected by the fibre structures as well as their hemicellulose composition and localisation. The effect of the treatment consistency was further studied with softwood kraft pulp. Treatment at high consistency clearly enhanced the endoglucanase action whereas the effect of solid content on the hemicellulase action was modest.

Model to Predict Polymer Fibre Diameter during Melt Spinning

Polymeric materials were evaluated with regard to their spinnability and respective fibre diameters. A modified single fibre spinning device was firstly used to derive a novel generalised model, utilising process parameters (die diameter, throughput, and stretching relevant take-up pressures) and material properties (zero shear viscosity) to predict the diameter of polymeric fibres on the basis of four different polymers. Further evaluation of the resulting power law dependence was conducted on filaments produced via conventional melt spinning and meltblown processes. Fibres produced on the pilot machines showed close agreement with the model equation with only the need to adjust an easily calculable device dependent factor. The outcome of the presented work is a user-friendly model of high practical relevance, which can be used to predict the diameter of amorphous and semicrystalline polymeric fibres, independent of material and machine used with sufficient accuracy for fast estimations.

Tungsten trioxide integrated all-fiber phase shifter

This work proposes an all-fiber phase shifter based on tapered optical fiber spin coated with tungsten trioxide (WO3). Different WO3 coating thickness was tested by varying the spin coating time from 30 to 150 s at constant 1000 rpm. Evanescent field induced by the non-adiabatic taper generated thermal optic effect through interaction with the WO3 layer, which changed its refractive index and produced phase shifting effect. The optimum spin coating time of 120 s yielded maximum phase shift of 2.52 π with wavelength shift coefficient of 0.0859 nm/mW as 980 nm pump power was varied up to 220 mW. Integration of phase shifter in fiber laser cavity produced wavelength tuning with shift coefficient of about 0.06 nm/mW. This work presents a feasible all-fiber phase shifter with simple fabrication and operation that suits current need in communication field.

Assessment of process integration approach for coir biosoftening and lignin‐modifying enzyme production from agro residues

AbstractLignin present in the inner core of natural lignocellulosic fibers is preferably removed for use in the textile industry as it hinders fiber spinnability. This study focuses on integrating the bioprocessing of agro residues and a natural fiber source (coir) for the effective production of lignin‐modifying enzymes while simultaneously softening the natural fibers. The lignin content in the raw fibers (42.17%) could be reduced by 14–31% by treating them with Phanerochaete chrysosporium for 30 days in the presence of agro waste, such as paddy straw, groundnut husk, corn husk, coir pith, sugarcane bagasse, saw dust and coconut leaf. Among the lignocellulosic wastes tested, P. chrysporium‐fermented groundnut husk with coir produced the maximum yield of lignin‐modifying enzymes (lignin peroxidase, 2.05 U mg−1; manganese peroxidase, 7.50 U mg−1; laccase, 0.43 U mL−1), while the tensile strength of the fiber was decreased by 9.9% compared with the raw fiber (110.14 MPa) on 30 days of incubation. Similarly, SB dust demonstrated good lignin‐modifying enzyme activity (lignin peroxidase, −1.57 U mg−1; manganese peroxidase, 8.14 U mg−1; and laccase, 0.35 U mg−1) as well as the tensile strength of the coir also being increased. A reduction in flexural rigidity owing to delignification was observed and hence a minimum 16% increase in softness was achieved in the integrated process. Our study presents an efficient strategy that exploits low‐cost agro residues for enzyme production and generates bio‐softened coir of acceptable quality in the export and domestic markets. © 2023 Society of Industrial Chemistry and John Wiley & Sons Ltd.

Anisotropic Nanomaterial Liquid Crystals: From Fiber Spinning to Additive Manufacturing.

There have long been synergistic relationships among the discovery of new anisotropic materials, advancements in liquid crystal science, and the production of manufactured goods with exciting new properties. Ongoing progress in understanding the phase behavior and shear response of lyotropic liquid crystals comprised of one-dimensional and two-dimensional nanomaterials, coupled with advancements in extrusion-based manufacturing methods, promises to enable the scalable production of solid materials with outstanding properties and controlled order across multiple length scales. This Perspective highlights progress in using anisotropic nanomaterial liquid crystals in two extrusion-based manufacturing methods: solution spinning and direct ink writing. It also describes current challenges and opportunities at the interface of nanotechnology, liquid crystalline science, and manufacturing. The intent is to inspire additional transdisciplinary research that will enable nanotechnology to fulfill its potential for producing advanced materials with precisely controlled morphologies and properties.

Effects of Glucose and Coagulant on the Structure and Properties of Regenerated Cellulose Fibers.

Regenerated cellulose fiber (RCF) is an environmentally friendly material with outstanding mechanical properties and recyclability, which has been used in a large number of applications. However, during the spinning process using ionic liquids (ILs) as solvents, the dissolved cellulose continues to degrade and even produces degradation products such as glucose, which can enter the recycled solvent and coagulation bath. The presence of glucose can seriously affect the performance of the produced RCFs and hinder their applications, so it has become critical to clarify the regulation and mechanism of this process. In this study, 1-ethyl-3-methylimidazolium diethyl phosphate ([Emim]DEP) with different glucose contents was selected to dissolve wood pulp cellulose (WPC) and obtained RCFs in different coagulation baths. The effect of glucose content in spinning solution on fiber spinnability was investigated by rheological analysis, and the influence of coagulation bath composition and glucose content on the morphological characteristics and mechanical properties of the RCFs was also studied in depth. The results indicated that the morphology, crystallinity, and orientation factor of RCFs were influenced by the presence of glucose in the spinning solution or coagulation bath, resulting in corresponding changes in mechanical properties, which can provide practical reference and guidance for the industrial production of new type fiber.

Fiber Spinning of Ultrahigh Molecular Weight Isotactic Polypropylene: Melt Spinning and Melt Drawing.

Herein, this work reports fiber spinning of tailored isotactic polypropylene (iPP) by melt spinning and melt drawing, yielding an adjustable diameter of 40-400 μm. The crystallinity of all obtained fibers with a molecular weight between 330-1400 kg/mol is increased by thermal annealing and investigated via differential scanning calorimetry (DSC) as well as wide angle X-ray scattering (WAXS). The potential of ultrahigh molecular weight iPP (UHMW-iPP) fibers compared to fibers manufactured from industrially available iPP becomes evident when the mechanical performance is compared: fibers spun from UHMW-iPP (1400 kg/mol) enable a tensile strength of up to 400 MPa, whereas commercially available fibers (330 kg/mol) show a tensile strength of approximately 50 MPa. However, UHMW-iPP exhibits a short timeframe, in which extrusion is possible, thereafter extrusion rupture occurs, probably induced by an increased melt viscosity.

Fabrication of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) Fibers Using Centrifugal Fiber Spinning: Structure, Properties and Application Potential

Biobased and biodegradable polyhydroxyalkanoates (PHAs) are currently gaining momentum. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) polymer has a useful processing window for extrusion and injection molding of packaging, agricultural and fishery applications with required flexibility. Processing PHBHHx into fibers using electrospinning or centrifugal fiber spinning (CFS) can further broaden the application area, although CFS remains rather unexplored. In this study, PHBHHx fibers are centrifugally spun from 4-12 wt.% polymer/chloroform solutions. Beads and beads-on-a-string (BOAS) fibrous structures with an average diameter (ϕav) between 0.5 and 1.6 µm form at 4-8 wt.% polymer concentrations, while more continuous fibers (ϕav = 3.6-4.6 µm) with few beads form at 10-12 wt.% polymer concentrations. This change is correlated with increased solution viscosity and enhanced mechanical properties of the fiber mats (strength, stiffness and elongation values range between 1.2-9.4 MPa, 11-93 MPa, and 102-188%, respectively), though the crystallinity degree of the fibers remains constant (33.0-34.3%). In addition, PHBHHx fibers are shown to anneal at 160 °C in a hot press into 10-20 µm compact top-layers on PHBHHx film substrates. We conclude that CFS is a promising novel processing technique for the production of PHBHHx fibers with tunable morphology and properties. Subsequent thermal post-processing as a barrier or active substrate top-layer offers new application potential.

Wet spinning of strong cellulosic fibres with incorporation of phase change material capsules stabilized by cellulose nanocrystals

Incorporating a phase change material (PCM) into fibres allows the fabrication of smart textiles with thermo-regulating properties. Previously, such fibres have been made from thermoplastic polymers, usually petroleum-based and non-biodegradable, or from regenerated cellulose, such as viscose. Herein, strong fibres are developed from aqueous dispersions of nano-cellulose and dispersed microspheres with phase changing characteristics using a wet spinning technique employing a pH shift approach. Good distribution of the microspheres and proper compatibility with the cellulosic matrix was demonstrated by formulating the wax as a Pickering emulsion using cellulose nanocrystals (CNC) as stabilizing particles. The wax was subsequently incorporated into a dispersion of cellulose nanofibrils, the latter being responsible for the mechanical strength of the spun fibres. It was possible to produce fibres highly loaded with the microspheres (40 wt%) with a tenacity of 13 cN tex−1 (135 MPa). The fibres possessed good thermo-regulating features by absorbing and releasing heat without undergoing structural changes, while maintaining the PCM domain sizes intact. Finally, good washing fastness and PCM leak resistance were demonstrated, making the fibres suitable for thermo-regulative applications. Continuous fabrication of bio-based fibres with entrapped PCMs may find applications as reinforcements in composites or hybrid filaments.

Sustainable Production of Polyamide 6 Fibers: Direct Melt Spinning and Efficient Reuse of Residual Oligomers during Polymerization

Direct melt spinning of PA6 from a polymerization reactor is currently unachievable in the industrial production of polyamide 6 (PA6) fibers because the hydrolysis polymerization of its monomer (caprolactam) is a reversible reaction which requires a boiling water extraction of oligomers from the polymer before melt spinning. Here, we proposed a polymerization method where the content of the cyclic dimer is controlled by reducing the temperature at the monomer ring-opening stage and the content of oligomers is monitored by rapid devolatilization through the polycondensation stage. As a result, the content of oligomers in PA6 is less than 1.5 wt % and the cyclic dimer is at 0.1–0.3 wt %, which are 80 and 48% lower than the values for the conventional PA6 production process. This allows for direct melt spinning of PA6 fibers at the industrial scale (spinning speed: 4000 m/min and a continuous production line of 10 kg/h), which reduces the production time from over 40 h to within 10 h, and the resource consumption reduces by over 30%. The resulting PA6 fibers show comparable mechanical and dyeing properties to those spun with the conventional multistep spinning method. In addition, the unreacted oligomers extracted during the polymerization stage can be directly reused in the polymerization, with no further treatment. This work provides an effective route to the sustainable production of PA6 fibers at the industrial scale, which significantly decreases the consumption of resources and the generation of chemical wastes while improving the production efficiency.

Flexible, Bifunctional Sensing Platform Made with Biodegradable Mats for Detecting Glucose in Urine

We report on a flexible, bifunctional platform made with solution-blow spinning fiber mats of polylactic acid (PLA) and polyethylene glycol (PEG). The PLA/PEG mats were designated bifunctional because they were used as a substrate for screen-printed carbon electrodes (SPCEs) and as a matrix to attach glucose oxidase (GOx) covalently. By attaching GOx only on the fiber mats, and not on the SPCE, the detection of hydrogen peroxide generated from glucose oxidation by the enzyme was efficient, especially with Prussian blue (PB) nanoparticles electrodeposited on the SPCE surface. The bifunctional device detected hydrogen peroxide (H2O2) in synthetic and human urine at a low applied potential (0 V vs Ag/AgCl) in the range from 1.0 to 6.0 mM, with a detection limit of 0.197 mM, being also interference-free. The biosensor whose cost is <US$ 0.25 per unit (estimated from the price of the materials used) had performance comparable to the gold standard method while measuring glucose in human urine samples, in addition to exhibiting a rapid response and long lifetime. The design of the bifunctional device is generic and may be extended to other biosensors for on-site monitoring as well as for wearable devices and in monitoring the environment and water in varied resources.

Life cycle assessment of carbon fiber and bio-fiber composites prepared via vacuum bagging technique

Over the past few decades, increasing demand for light weight material have grown in various applications including aerospace, and other structural applications with added focus on green engineering and sustainability. Particularly in aerospace industries, utilisation of carbon fiber composites results in increased rate of pollution due to its inability to be repaired and recycled. Therefore, it is envisaged that migrating to biocomposites could be the solution forward depending on the manufacturing techniques. This life cycle assessment concentrates on understanding the emission rate of vacuum bagged carbon fiber and biocomposites with focus on its recycling abilities. In this study, carbon composites indicated a global warming potential (GWP) of 54 kgCO2Eq. whereas biocomposites showcased 12 kgCO2Eq. This implies that GWP of biocomposites were approximately four times less than carbon composites and if pesticides and fiber spinning are controlled, emission could be further reduced along with the overall energy consumption along with other emissions. Although biocomposites showcased lower environmental impact in mostly every scenario, the transition towards biocomposites still requires research to fulfil gaps with regards to the enhancement of mechanical properties compared to carbon fiber composites.