Spinning Conditions Research Articles

Quality Parameter Adaptive Optimization for Spinning Process Using Dynamic Non-Dominated Sorting Algorithm

ABSTRACT Intelligent textile equipment can discover potential patterns in the production process through data mining, and utilize these patterns through intelligent optimization, ultimately achieving intelligent and automated textile production. This paper focuses on the spinning process parameters optimization under changing spinning conditions and proposes a dynamic non-dominant ranking parameter quality adaptive optimization algorithm. The factors of spinning process condition changes are transformed into mathematical dynamic constraints and constructing an adaptive optimization model for spinning parameter quality. Based on this, the response mechanism of spinning environment is established to readjust the optimization direction according to the change of spinning conditions, and the DNSGA-II is used to solve the quality adaptive optimization model. A case study is designed to validate the effectiveness, results show that for different usage periods of wire rings, the optimal breaking strength is 5.6, and the number of details is 33.3, 31.1, and 41.6 respectively. In some degree, the proposed algorithm can effectively adapt to the quality optimization problem of spinning process parameters under different spinning conditions, which could provide corresponding parameter optimization combinations for different spinning conditions.

Methods for increasing productivity of AC-electrospinning using weir-electrode

The presented work brings new knowledge in the field of spinning electrodes for AC‑electrospinning technology, which is used for producing nanofibrous structures using a solution of polyvinyl butyral. It presents new types of spinning weir‑electrodes and describes research on the influence of electrode design parameters on the stability of the spinning process and the productivity of nanofiber production. The multistage spinning electrode is presented in the ratio of stages one to five. Research is also focused on the effect of the parameters of the electric signal used as a source for the spinning electrode on spinning stability and productivity. Observed parameters were voltage level, frequency and shape such as sine wave, rectangle wave and modified sine wave. An analysis of the influence of the spinning conditions on the resulting nanofibrous structure was also performed by analyzing results gained by SEM; the defects were investigated mainly. The results of the research presented in the thesis open up new possibilities for follow-up research in the field of AC-electrospinning.

Composite nanofibres of CuI‐polystyrene via electrospinning through critical control of solvation conditions

AbstractComposite nanofibres of copper (II) with various polymer matrices have been frequently reported. However, due to the lack of solubility of the Cu(I) moieties, Cu(I) electrospinning has proved more challenging. The objective of this study was to find a route to and prepare nanofibres containing copper iodide. This investigation describes the successful electrospinning of composite nanofibres of copper iodide (CuI) and polystyrene (PS) using a combination of two solvents to provide critical spinning conditions. The electrospinning solution was prepared by combining dimethylformamide (DMF) as the main solvent for PS and triethylamine (TEA) as a cosolvent; this mediates the dissolution of CuI. Electrospinning was accomplished under different parameters such as PS concentration, CuI concentration, and applied voltage. The outcome of the process was colored and smooth nanofibres that underwent analysis using scanning electron microscopy (SEM), energy dispersive X‐ray (EDX), X‐ray diffraction (XRD) and inductively coupled plasma ‐ mass spectrometry (ICP‐MS). The analysis findings emphasized the importance of the electrospinning parameters, specifically the concentration of PS and the applied voltage on successful fiber generation. However with control of these conditions composite nanofibres of CuI‐PS with uniform distribution of nanoscale crystallites of CuI can be successfully produced.

Modeling and analysis of a flexible spinning Euler-Bernoulli beam with centrifugal stiffening and softening: A linear fractional representation approach with application to spinning spacecraft

The derivation of a linear fractional representation (LFR) model for a flexible, spinning and uniform Euler-Bernoulli beam is accomplished using the Lagrange technique, fully capturing the centrifugal force generated by the spinning motion and accounting for its dependence on the angular velocity. This six degrees of freedom (DOF) model accounts for the behavior of deflection in the moving body frame, encompassing the bending, traction and torsion dynamics. The model is also designed to be compliant with the Two-Input-Two-Output Port (TITOP) approach, which offers the possibility to model complex multibody mechanical systems, while keeping the uncertain nature of the plant and condensing all the possible mechanical configurations in a single LFR. To evaluate the effectiveness of the model, various scenarios are considered and their results are tabulated. These scenarios include uniform beams with fixed root boundary conditions for different values of tip mass, root offset and angular velocity. The results from the analysis of the uniform cantilever beam are compared with solutions found in the literature and obtained from a commercial finite element software. Ultimately, this paper presents a multibody model for a spinning spacecraft mission scenario. A comprehensive analysis of the system dynamics is conducted, providing insights into the behavior of the spacecraft under spinning conditions.

High-resolution indirect detection of spin-3/2 quadrupolar nuclei in solids using multiple-quantum-filtered through-space D-HMQC experiments

Through-space heteronuclear correlation experiments under magic-angle spinning (MAS) conditions can provide unique insights into inter-atomic proximities. In particular, it has been shown that experiments based on two consecutive coherence transfers, 1H → I → 1H, like D-HMQC (dipolar-mediated heteronuclear multiple-quantum correlation), are usually more sensitive for the indirect detection via protons of spin-3/2 quadrupolar nuclei with low gyromagnetic ratio. Nevertheless, the resolution is often decreased by the second-order quadrupolar broadening along the indirect dimension. To circumvent this issue, we incorporate an MQMAS (multiple-quantum MAS) quadrupolar filter into the t1 evolution period of the D-HMQC sequence, which results in a novel pulse sequence called D-HMQC-MQ. The triple-quantum coherences evolving during this filter are excited and reconverted using cosine-modulated long-pulses synchronized with the sample rotation to avoid spinning sidebands in the indirect dimension. The desired coherence transfer pathways during this sequence are selected using two nested cogwheel phase cycles with 56 steps. This high-resolution heteronuclear correlation technique is demonstrated experimentally for the indirect detection via 1H of spin-3/2 isotopes, such as 11B, 23Na and 35Cl, in zinc borate hydrate, NaH2PO4 and l-histidine hydrochloride, respectively. We show that this experiment can be applied at high magnetic fields up to 28.2 T for protons subject to chemical shift anisotropies larger than 20 ppm, provided the MAS frequency is sufficiently stable since the D-HMQC-MQ experiment, like the parent D-HMQC, is sensitive to MAS fluctuations, which can produce t1-noise.

Numerical Study of Melt-Spinning Dynamic Parameters and Microstructure Development with Ongoing Crystallization.

In response to an investigation on the paths of changes in the crystallization and radial differences during the forming process of nascent fibers, in this study, we conducted numerical simulation and analyzed the changes in crystallization mechanical parameters and tensile properties through a fluid dynamics two-phase model. The model was based on the melt-spinning method focusing on melt spinning, the environment of POLYFLOW, and the method of joint simulation, coupled with Nakamura crystallization kinetics, including the development of process collaborative parameters, stretch-induced crystallization, viscoelasticity, filament cooling, gravity term, inertia, and air resistance. Finally, for nylon 6 BHS and CN9987 resin spinning, the model successfully predicted the distribution changes in temperature, velocity, strain rate tensor, birefringence, and stress tensor along the axial and radial fibers and obtained the variation pattern of fibers' crystallinity along the entire spinning process under different stretching rates. Furthermore, we also explored the effects of spinning conditions, including inlet flow rate, winding speeds, and the extrusion temperature, on the fibers' crystallization process and obtained the influence rules of different spinning conditions on fiber crystallization. Knowing the paths of changes in mechanical performance can provide important guidance and optimization strategies for the future industrial preparation of high-performance fibers.

Physical Properties of Alkali Resistant-Glass Fibers with Refused Coal Ore in Continues Fiber Spinning Conditions

Physical Properties of Alkali Resistant-Glass Fibers with Refused Coal Ore in Continues Fiber Spinning Conditions

Selective correlations between aliphatic 13C nuclei in protein solid-state NMR

Solid-state nuclear magnetic resonance (NMR) is a potent tool for studying the structures and dynamics of insoluble proteins. It starts with signal assignment through multi-dimensional correlation experiments, where the aliphatic 13Cα-13Cβ correlation is indispensable for identifying specific residues. However, developing efficient methods for achieving this correlation is a challenge in solid-state NMR. We present a simple band-selective zero-quantum (ZQ) recoupling method, named POST-C4161 (PC4), which enhances 13Cα-13Cβ correlations under moderate magic-angle spinning (MAS) conditions. PC4 requires minimal 13C radio-frequency (RF) field and proton decoupling, exhibits high stability against RF variations, and achieves superior efficiency. Comparative tests on various samples, including the formyl-Met-Leu-Phe (fMLF) tripeptide, microcrystalline β1 immunoglobulin binding domain of protein G (GB1), and membrane protein of mechanosensitive channel of large conductance from Methanosarcina acetivorans (MaMscL), demonstrate that PC4 selectively enhances 13Cα-13Cβ correlations by up to 50 % while suppressing unwanted correlations, as compared to the popular dipolar-assisted rotational resonance (DARR). It has addressed the long-standing need for selective 13C–13C correlation methods. We anticipate that this simple but efficient PC4 method will have immediate applications in structural biology by solid-state NMR.

Solid-state NMR backbone chemical shift assignments of α-synuclein amyloid fibrils at fast MAS regime.

The α-synuclein (α-syn) amyloid fibrils are involved in various neurogenerative diseases. Solid-state NMR (ssNMR) has been showed as a powerful tool to study α-syn aggregates. Here, we report the 1H, 13C and 15N back-bone chemical shifts of a new α-syn polymorph obtained using proton-detected ssNMR spectroscopy under fast (95kHz) magic-angle spinning conditions. The manual chemical shift assignments were cross-validated using FLYA algorithm. The secondary structural elements of α-syn fibrils were calculated using 13C chemical shift differences and TALOS software.

Enhancing thin-film composite polyethersulfone hollow fiber membranes through alkali-induced interfacial polymerization modification for effective separation of monovalent/divalent salts

Amidst the escalating global water scarcity issues, finding better ways to sustainably treat brackish water and seawater while simultaneously recovering resources becomes increasingly important. In this work, we investigated the fabrication strategies to produce polyethersulfone hollow fiber membranes (PES HFMs) with robust characteristics and uniformly arranged shape. The presence of an air gap (AG) in the dry-wet spinning process facilitates the chain orientation due to the gravitational force and elongational stretch and moisture-induced early phase inversion, therefore preventing corrugations on the shell side. We extensively studied the correlation between HFM spinning parameters and the appearance and disappearance of buckling effects. Moreover, it was proven that the addition of N-methyl-2-pyrrolidone (NMP) to the bore fluid composition prolongs the demixing process, overcoming the HFMs' delamination issue. After optimizing the spinning conditions, a facile alkali-induced interfacial polymerization (IP) was employed to enhance the formation of a selective polyamide (PA) layer on PES HFM substrates. The final membrane made by this modification process, denoted as PES-IP-BOH, exhibits a Na2SO4 rejection higher than 96 %, while maintaining low rejections for other monovalent salts. Accordingly, it achieved a high ideal selectivity of >23 for the selective separation of monovalent and divalent salts.

A Study of Structure–Property Correlation on Wet Spinning Conditions in Heat-Resistant Poly(m-phenylene isophthalamide) Hollow Fiber Membranes

A Study of Structure–Property Correlation on Wet Spinning Conditions in Heat-Resistant Poly(m-phenylene isophthalamide) Hollow Fiber Membranes

VISUALIZING SPUN YARN DEFORMATION: INSIGHTS FROM OPTICAL INSTRUMENTATION

This article presents a comprehensive analysis of key quality indicators for spun yarns, focusing on yarns with a linear density of T=20 (Ne=30) tex produced on both simple and compact ring spinning machines. Through the utilization of optical instrumentation, various parameters including relative breaking strength (Rkm), strength, elongation at break (E %), and hairiness (H %) were meticulously examined to evaluate yarn quality. The study delves into the assessment of yarn unevenness (CV %) as a crucial quality metric, aiming to provide insights into the deformation characteristics of spun yarns. By employing advanced optical techniques, such as high-resolution imaging and precise measurements, the deformation behaviour of yarns under different spinning conditions is elucidated. The findings shed light on the influence of spinning machine type on yarn quality parameters, revealing nuanced differences in strength, elongation, and hairiness between simple and compact spinning processes. Additionally, the analysis highlights the correlation between yarn deformation and overall yarn quality, emphasizing the significance of understanding deformation mechanisms in optimizing textile manufacturing processes. Through a rigorous examination of these quality indicators, this research contributes valuable insights into the intricate dynamics of spun yarn deformation and its implications for textile production. The utilization of optical instrumentation offers a novel approach to visualize and quantify yarn deformation, providing a deeper understanding of the factors influencing yarn quality and performance in industrial settings.

Hybrid processing of melt electrospinning/blowing for polypropylene/polyethylene glycol fiber fabrication with various diameter distribution

Many studies have been conducted to develop and optimize the manufacturing process of polymer fibers in various forms. In particular, many melt-spinning processes have been developed for the manufacture of nanofibers of polymer materials with excellent chemical resistance. In this study, we investigated the effects of various spinning conditions and their spinning behavior on the fiber manufacturing process and properties using a melt electrospinning/blowing process that combines conventional melt blowing and electrospinning. We also report a discontinuous spinning process that produces a web with a very wide diameter distribution from the nanoscale to the microscale with gradient fibers. They are generally compared with webs, which have a narrow diameter distribution. We believe that by using this process, it is possible to produce diameters of various distributions in one step. These results show remarkable potential for many applications in which gradient fibers are required.

PROBIOTICS APPLICATION FOR POTENTIAL FEMININE HYGIENE PRODUCTS

The aim of the present research was to develop probiotic delivery systems intended for short-term application in feminine hygiene products. For this, freeze-dried and fresh probiotics (Lactobacillus paragasseri K7), encapsulated into hydroxy-β-cyclodextrins, with and without inulin used as a prebiotic, were at first electrospun onto inert polypropylene carrier fabrics, in order to establish the optimal spinning conditions and confirm the successful formation of fibers. The characteristics of the functionalized materials were analyzed by Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In order to evaluate the functionality of the probiotic delivery systems, in the subsequent stage of the research, the optimum electrospinning formulation was deposited, under the defined optimal conditions, on a different carrier material, namely, a cellulose-based cotton stripe, to get a preliminary demonstration of the suitability of the developed material for its intended application as a feminine hygiene product. For this, the antioxidant properties of the materials and the probiotic release were observed. Experimental results confirmed that the material (cellulose-based cotton stripe/deposited nanofiber) possessed antioxidant properties and released probiotics within 4 hours, being in agreement with the recommended use of such products. This preliminary research underscores the potential usability and applicability of the developed material for tampon use, considering its anti-inflammatory property and beneficial effects in maintaining healthy vaginal microbiota.

Influence of Low-Molecular-Weight Esters on Melt Spinning and Structure of Poly(lactic acid) Fibers.

Poly(lactic acid) has great potential in sectors where degradability is an important advantage due to its polymer nature. The medical, pharmaceutical, and packaging industries have shown interest in using PLA. To overcome the limitations of stiffness and brittleness in the polymer, researchers have conducted numerous modifications to develop fibers with improved properties. One such modification involves using plasticizing modifiers that can provide additional and desired properties. The scientific reports indicate that low-molecular-weight esters (LME) (triethyl citrate and bis (2-ethylhexyl) adipate) affect the plasticization of PLA. However, the research is limited to flat structures, such as films, casts, and extruded shapes. A study was conducted to investigate the impact of esters on the process of forming, the properties, and the morphology of fibers formed through the melt-spinning method. It was found that the modified PLA required different spinning and drawing conditions compared to the unmodified polymer. DSC, FTIR, WAXD, and GPC/SEC analyses were performed for the modified fibers. Mechanical tests and morphology evaluations using SEM microscopy were also conducted. The applied plasticizers lowered the temperature of the spinning process by 40 °C, and allowed us to obtain a higher degree of crystallinity and a better tenacity at a lower draw ratio. GPC/SEC analysis confirmed that the polymer-plasticizer interaction is physical because the booth plasticizer peaks were separated in the chromatographic columns. The use of LME in fibers significantly reduces the temperature of the spinning process, which reduces production costs. Additives significantly change the production process and the structure of the fiber depending on their rate, which may affect the properties, e.g., the rate of degradation. We can master the degree of crystallinity through the variable amount of LME. The degree of crystallization of the polymers has a significant influence on polymer application.

Wet Twisting in Spinning for Rapid and Cost‐Effective Fabrication of Superior Carbon Nanotube Yarns

AbstractCarbon nanotubes (CNTs) are promising blocks for building advanced yarns with unique structural and functional attributes. However, the complexity of fabrication and high cost has hindered the widespread adoption of CNT yarns. In this study, a rapid and continuous twisting wet spun yarn strategy to produce highly densified CNT yarns is presented. The method involves effectively dispersing CNTs in the surfactant dispersion, swiftly removing the surfactant in the coagulation bath and twisting treatment to effectively improve the density of yarn and the orientation of CNT. Detailed characterizations on the influence of each spinning conditions reveal that twisting treatment significantly enhances the packing density of yarns, improves the orientation of CNTs, and mitigates the impact of impurities on conductivity. The resulting CNT yarns exhibit a remarkable tensile strength of 600 MPa, a Young's modulus of ≈40 GPa, and a high conductivity of 8990 S cm−1. When utilized as a yarn heater, the CNT yarn demonstrates an ultra‐fast electrothermal response of over 1000 °C s−1 at a low operating voltage of 5 V. Impressively, the mechanical properties of CNT yarns show good stability during heating. This study provides a perspective of structural engineering for the large‐scale preparation of high‐performance CNT yarns.

Experimental aspects of 14N overtone RESPDOR solid-state NMR spectroscopy under MAS beyond 60 kHz

Nitrogen-14 (14N) overtone (OT) spectroscopy under fast magic angle spinning (MAS) conditions (>60 kHz) has emerged as a powerful technique for observing correlations and distances between 14N and 1H, owing to the absence of the first-order quadrupolar broadenings. In addition, 14NOT allows selective manipulation of 14N nuclei for each site. Despite extensive theoretical and experimental studies, the spin dynamics of 14NOT remains under debate. In this study, we conducted experimental investigations to assess the spin dynamics of 14NOT using the rotational-echo saturation-pulse double-resonance (RESPDOR) sequence, which monitors population transfer induced by a14NOT pulse. The 14NOT spin dynamics is well represented by a model of a two-energy-level system. Unlike spin-1/2, the maximum excitation efficiency of 14NOT coherences of powdered solids, denoted by p, depends on the radiofrequency field (rf-field) strength due to orientation dependence of effective nutation fields even when pulse lengths are optimized. It is also found that the p factor, contributing to the 14NOT spin dynamics, is nearly independent of the B0 field. Consequently, the filtering efficiency of RESPDOR experiments exhibits negligible dependence on B0 when the 14NOT pulse length is optimized. The study also identifies the optimal experimental conditions for 14NOT/1H RESPDOR correlation experiments.

Hydrogel-assisted microfluidic wet spinning of poly(lactic acid) fibers from a green and pro-crystallization spinning dope

Poly(lactic acid) (PLA) fibers have found a broad range of applications in medical textiles. While traditional spinning methods usually involve harsh conditions, such as high temperatureor toxic organic solvents, the challenges in producing PLA fibers via a green route are yet to be overcome. Herein, we described a new strategy for PLA fiber production, which combines the controlled and benign spinning conditions enabled by microfluidics and a novel green spinning dope with bio-sourced CyreneTMas a non-toxic solvent for PLA. This strategy is enabled by the in-situ formation of ahydrogel shell around the focused PLA/Cyrene™spinning dope stream. This hydrogel shell stabilizes the core stream and facilitates the solidification of the PLA fiber. Our hydrogel-assisted microfluidic wet spinning (HA-MWS) strategy represents the first-ever method that allows for the continuous room-temperature production of highly porous PLA fibers (porosity > 80 %) without the need for petroleum-based chemicals. We characterized the solution properties of the PLA/CyreneTMspinning dope and discovered that CyreneTMcan induce PLA crystallization, with resultant crystals acting as cross-linking centers for the spinning dope gelation. We then explored the microfluidic wet spinning process, using the spinning dope as the core flow and the alginate aqueous solution as the shell flow to achieve controlled fiber production. The resulting PLA fibers underwent comprehensive morphological, structural, and mechanical characterization. Our process enables the green productionofPLA fibers under mild conditions.More importantly, a bio-based green and pro-crystallization solvent was for the first time used to develop PLA spinning dope, which gives rise to a range of promising fiber properties (e.g. high porosity), which can broaden potential biomedical applications of PLA fibers.

Preparation of porous polylactic acid nanofibers and application in non-electret high-efficiency filtration composites.

Air pollution caused by fine particulate matter (PM0.3) has drawn increasing attention as an overwhelming threat to public health. Electret treatment is commonly used to improve the filtration performance of commercial fibrous filter materials by enhancing the electrostatic adsorption effect, but it is greatly affected by environmental factors (especially humidity). Moreover, filter materials are generally non-degradable and non-recyclable, causing serious environmental pollution. Herein, a strategy to manufacture fully degradable polylactic acid (PLA) filtration composites based on porous PLA nanofibers prepared by electrospinning was investigated in this study. Porous, bead-on-string and conventional PLA nanofibers could be obtained by adjusting spinning condition parameters. The porous PLA nanofibers exhibited 9.8 times greater specific surface area (24.01 m2 g-1) and 18 times more cumulative pore volume (0.108 cm3 g-1) than conventional PLA nanofibers. More importantly, fibrous filtration composites based on porous PLA nanofibers possessed a high PM0.3 filtration efficiency (99.9989%), low pressure drop (90.35 Pa) and high air permeability (72.4 Pa-1) at an air flow rate of 32 L min-1 without electret treatment. The fibrous filtration composites based on conventional or bead-on-string PLA nanofibers also exhibited excellent filtration performance (>99.99%), but the associated high pressure drop and low air permeability limited their application.

Synthesis of centrifugally spun polyacrylonitrile-carbon fibers

This work demonstrates the carbonization of centrifugally spun polyacrylonitrile (PAN) fibers. Initially, the optimal centrifugal spinning conditions for producing homogeneous PAN fibers were identified. Second, the process continued by stabilization and carbonization of PAN to ensure a pure carbonaceous fiber material by eliminating all non-carbonaceous matter. The spun PAN fibers were stabilized at 240 °C in air at a heating rate of 1 °C/min, then carbonized between 600 and 1200 °C in argon at 5 °C/min. After carbonization, the fibers were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Raman spectroscopy (RS). The SEM results showed that by increasing the carbonization temperature, the prolonged elimination of other functional groups resulted in the formation of thinner carbon fibers. FTIR spectra of PAN fibers revealed that the peaks associated with C≡N bonds were substantially reduced and C–H bonds were eliminated in the fibers during the stabilization. These reductions are attributed to the cyclization of nitrile groups and the stabilizing process, and increasing carbonization temperatures resulted in flatter FTIR curves, supporting the findings. According to XRD, the structure of PAN was disturbed, as desired, and carbonization led to the formation of broad bumps resulting from amorphous carbon. Raman investigations found that increasing the carbonization temperature from 600 to 1200 °C resulted in no significant R values, suggesting that all fibers had no structural ordering. The study results could be used in many other areas, such as the fabrication of electrodes, supporting catalytic reactions, filter media, and energy.