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1
Hu, Jin Lian, i Jing Lu. "Shape Memory Polymers in Textiles". Advances in Science and Technology 80 (wrzesień 2012): 30–38. http://dx.doi.org/10.4028/www.scientific.net/ast.80.30.
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This paper highlight the most important areas and directions of shape memory polymers in textiles. The textiles of shape memory polymers involve fibre spinning (including wet-spinning, melt-spinning and electro-spinning), fabric, smart apparel, actively finishing technology and WVP investigation. Based on the molecular structure of shape memory polymer, the shape memory transformation from polymer to textiles and application theory are illustrated and stated. Additionally, the challenges of shape memory polymers in textiles are pointed out and some research directions are also suggested in this paper.
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Karim, Siti Saniah Ab, Abu Bakar Sulong, Che Husna Azhari, Ng Min Hwei i Mohd Reusmaazran Yusof. "Influence of Polyacrilonitrile (PAN) Concentration on the Mechanical and Physical Properties of Electrospun Fibres". Key Engineering Materials 471-472 (luty 2011): 43–48. http://dx.doi.org/10.4028/www.scientific.net/kem.471-472.43.
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Electrospinning is direct process to produce polymer fibre with high specific surface area ratio. Apart from polymer fibre producing; electrospinning also can produce a continuous nano size of polymer fibre, which the benefit of this process is the fibre can be produced straight away with lower cost than conventional melt spinning process. Recently, successful attempts have been made to produce polymer fibre by adjusting the parameters of electrospinning such as the collector distance, needle size, polymer concentration voltage applied. From this study, the electrospun fibre was distributed randomly on collector plate surface. The diameter of the fibre produced increase as the polymer concentration was increased. The fibre distribution does not affected by the differ polymer concentrations electrospun, but there were polymer beads formed at the low polymer concentration in solvents. The fiber elongation value is the highest by polymer fiber of 9 wt % while the highest strength is by polymer fiber of 7 wt %. The polymer fibre with low concentration consequently showed the brittle characteristic.
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Bier, Alexander M., Michael Redel i Dirk W. Schubert. "Model to Predict Polymer Fibre Diameter during Melt Spinning". Advances in Polymer Technology 2023 (23.03.2023): 1–11. http://dx.doi.org/10.1155/2023/7983819.
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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.
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Yalcinkaya, Fatma, Baturalp Yalcinkaya i Oldrich Jirsak. "Influence of Salts on Electrospinning of Aqueous and Nonaqueous Polymer Solutions". Journal of Nanomaterials 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/134251.
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A roller electrospinning system was used to produce nanofibres by using different solution systems. Although the process of electrospinning has been known for over half a century, knowledge about spinning behaviour is still lacking. In this work, we investigated the effects of salt for two solution systems on spinning performance, fibre diameter, and web structure. Polyurethane (PU) and polyethylene oxide (PEO) were used as polymer, and tetraethylammonium bromide and lithium chloride were used as salt. Both polymer and salt concentrations had a noteworthy influence on the spinning performance, morphology, and diameter of the nanofibres. Results indicated that adding salt increased the spinnability of PU. Salt created complex bonding with dimethylformamide solvent and PU polymer. Salt added to PEO solution decreased the spinning performance of fibres while creating thin nanofibres, as explained by the leaky dielectric model.
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Brzezińska, Magdalena, i Grzegorz Szparaga. "The Effect Of Sodium Alginate Concentration On The Rheological Parameters Of Spinning Solutions". Autex Research Journal 15, nr 2 (1.06.2015): 123–26. http://dx.doi.org/10.2478/aut-2014-0044.
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Abstract The aim of the study was to determine the rheological properties of solutions of two types of sodium alginate in water. Rheological studies were carried out to determine the rheological properties of the spinning solutions. Polymer solutions of different concentrations were obtained. Based on the preliminary research of the concentrations of solutions, the proper n and k parameters were selected in order to obtain fibre by wet spinning from solution method. For selected concentrations of polymer solutions, the calcium alginate fibres were obtained.
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Genis, A. V., i A. V. Kuznetsov. "The Relationship of the Activity of the Filler and the Structure of the Polymer Matrix with the Properties of Composite Fibre Material". International Polymer Science and Technology 44, nr 12 (grudzień 2017): 39–46. http://dx.doi.org/10.1177/0307174x1704401207.
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The influence of the activity of the filler and also structural factors of composite fibre material (CFM) on its physicochemical and physicomechanical properties was studied. The CFM was obtained by introducing sorption-active filler of different particle size into polymer fibre and onto the surface of the fibre in the process of aerodynamic spinning from polymer solution.
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Gupta, Karan, i Paresh Chokshi. "Weakly nonlinear stability analysis of polymer fibre spinning". Journal of Fluid Mechanics 776 (8.07.2015): 268–89. http://dx.doi.org/10.1017/jfm.2015.284.
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The extensional flow of a polymeric fluid during the fibre spinning process is studied for finite-amplitude stability behaviour. The spinning flow is assumed to be inertialess and isothermal. The nonlinear extensional rheology of the polymer is described with the help of the eXtended Pom-Pom (XXP) model, which is known to exhibit a significant strain hardening effect necessary for fibre spinning applications. The linear stability analysis predicts an instability known as draw resonance when the draw ratio, $\mathit{DR}$, defined as the ratio of the velocities at the two ends of the fibre in the air gap, exceeds a certain critical value, $\mathit{DR}_{c}$. The critical draw ratio $\mathit{DR}_{c}$ depends on the fluid elasticity represented by the Deborah number, $\mathit{De}={\it\lambda}v_{0}/L$, the ratio of the polymer relaxation time to the flow time scale, thus constructing a stability diagram in the $\mathit{DR}_{c}$–$\mathit{De}$ plane. Here, ${\it\lambda}$ is the characteristic relaxation time of the polymer, $v_{0}$ is the extrudate velocity through the die exit and $L$ is the length of the air gap for the spinning flow. In the present study, we carry out a weakly nonlinear stability analysis to examine the dynamics of the disturbance amplitude in the vicinity of the transition point. The analysis reveals the nature of the bifurcation at the transition point and constructs a finite-amplitude manifold providing insight into the draw resonance phenomena. The effect of the fluid elasticity on the nature of the bifurcation and the finite-amplitude branch is examined, and the findings are correlated to the extensional rheological behaviour of the polymer fluid. For flows at small Deborah number, the Landau constant, which captures the role of nonlinearities, is found to be negative, indicating supercritical Hopf bifurcation at the transition point. In the linearly unstable region, the equilibrium amplitude of the disturbance is estimated and shows a limit cycle behaviour. As the fluid elasticity is increased, initially the equilibrium amplitude is found to decrease below its Newtonian value, reaching the lowest value for $\mathit{De}$ when the strain hardening effect is maximum. With further increase in elasticity, the material undergoes strain softening behaviour which leads to an increase in the equilibrium amplitude of the oscillations in the fibre cross-section area, indicating a destabilizing effect of elasticity in this regime. Interestingly, at a certain high Deborah number, the bifurcation crosses over from supercritical to subcritical nature. In the subcritical regime, a threshold amplitude branch is constructed from the amplitude equation.
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Zhiganov, N. K., V. I. Yankov i E. P. Krasnov. "Cooling of the polymer jet in fibre spinning". Fibre Chemistry 19, nr 6 (1988): 392–94. http://dx.doi.org/10.1007/bf00544917.
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Zhang, Xiaolin, Lin Weng, Qingsheng Liu, Dawei Li i Bingyao Deng. "Facile fabrication and characterization on alginate microfibres with grooved structure via microfluidic spinning". Royal Society Open Science 6, nr 5 (maj 2019): 181928. http://dx.doi.org/10.1098/rsos.181928.
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Alginate microfibres were fabricated by a simple microfluidic spinning device consisting of a coaxial flow. The inner profile and spinnability of polymer were analysed by rheology study, including the analysis of viscosity, storage modulus and loss modulus. The effect of spinning parameters on the morphological structure of fibres was studied by SEM, while the crystal structure and chemical group were characterized by FTIR and XRD, respectively. Furthermore, the width and depth of grooves on the fibres was investigated by AFM image analysis and the formation mechanism of grooves was finally analysed. It was illustrated that the fibre diameter increased with an increase in the core flow rate, whereas on the contrary of sheath flow rate. Fibre diameter exhibited an increasing tendency as the concentration of alginate solution increased, and the minimum spinning concentration of alginate solution was 1% with the finest diameter being around 25 µm. Importantly, the grooved structure was obtained by adjusting the concentration of solutions and flow rates, the depth of groove increased from 278.37 ± 2.23 µm to 727.52 ± 3.52 µm as the concentration varied from 1 to 2%. Alginate fibres, with topological structure, are candidates for wound dressing or the engineering tissue scaffolds.
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Feng, Pei, Dashuang Liu, Ronggen Zhang i Chongchang Yang. "Distribution of the Polymer Melt Velocity and Temperature in the Spinneret Channel of Bi-component Fibre Melt Spinning: a Mathematical Model". Fibres and Textiles in Eastern Europe 29, nr 6(150) (31.12.2021): 49–53. http://dx.doi.org/10.5604/01.3001.0015.2722.
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For the stability of composite fibre spinning, the difference in and distribution of the polymer melt velocity during the spinning are among the factors of importance. Based on the basic equation for the control of composite spinning dynamics, boundary conditions are identified and reported in this paper. A mathematical model for the symmetric and asymmetric distribution of the melt flow velocity in the microhole of the spinneret of the composite spinning assembly was developed. The accuracy of the mathematical model was also ascertained. It gives a theoretical basis for the designing of a composite spinning assembly.
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Al-Obaidy, Asrar. "A Morphological Study of Alumina Hollow Fiber Membrane". Iraqi Journal of Chemical and Petroleum Engineering 17, nr 3 (30.09.2016): 117–23. http://dx.doi.org/10.31699/ijcpe.2016.3.11.
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Morphologies of ceramic hollow fiber membranes prepared by a combined phase-inversion and sintering method were studied. The organic binder spinning solution containing suspended Al₂O₃ powders was spun to a hollow fiber precursor, which was then sintered at elevated temperatures( 300 ˚C, 1400 ˚C, 25 ˚C) in order to obtain the Al₂O₃ hollow fiber membranes. The spinning solution consisted of polyether sulfone (PES), N-methyl-2-pyrrolidone (NMP), which were used as polymer binder, solvent, respectively. The prepared Al₂O₃ hollow fiber membranes were characterized by a scanning electron microscope (SEM). It is believed that finger-like void formation in asymmetric ceramic membranes is initiated by hydrodynamically unstable viscous fingering developed when a less viscous fluid (non-solvent) is in contact with a higher viscosity fluid (ceramic suspension containing invertible polymer binder). The effects of the air-gap (0 cm, 2 cm, 15 cm) on fibre morphology have been studied and it has been determined that viscosity due to change in air-gap is the dominating factor for ceramic systems.
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Abdullah@Shukry, Nur Athirah, Khairunnadim Ahmad Sekak i Mohd Rozi Ahmad. "Effect of Molecular Weight on Morphological Structure of Electrospun PVA Nanofibre". Advanced Materials Research 1134 (grudzień 2015): 203–8. http://dx.doi.org/10.4028/www.scientific.net/amr.1134.203.
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This work focuses on the preparation of electrospun Polyvinyl Alcohol (PVA) nanofibres of three different molecular weights. The electrospinning process parameters were varied in terms of the voltage and feed rate. Scanning Electron Microscopy technique was used to characterize the morphological structure of the electrospun PVA nanofibre. The results show that the average fibre diameter increased as the molecular weight of the polymer increased. The formation of beads occurs from the lowest molecular weight sample of 89K However, long, continuous and beaded-free fibres were obtained from the 125K and 205K polymer weight PVA. The results also suggest that higher spinning voltage and feed rate produce larger fibre diameter, respectively.Keywords : Polyvinyl Alcohol, nanofibres, molecular weight, electrospinningCorresponding Author:Khairunnadim Ahmad Sekak, Faculty of Applied Sciences, Universiti Teknologi MARA (UiTM), Shah Alam, 40450 Selangor Darul Ehsan.Email: nadim821@salam.uitm.edu.my
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Arbab, Shahram, A. Zeinolebadi i Parviz Noorpanah. "Exploring the Thermodynamic Aspects of Structure Formation During Wet-Spinning of Polyacrylonitrile Fibres". International Journal of Chemoinformatics and Chemical Engineering 1, nr 2 (lipiec 2011): 36–52. http://dx.doi.org/10.4018/ijcce.2011070103.
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Wet-spun polyacrylonitrile fibres are the main precursor for high strength carbon fibres. The properties of carbon fibres strongly depend on the structure of the precursor fibre. Polyacrylonitrile fibres were spun from solutions with varying solvent/nonsolvent content and different draw ratios. Wet-spinning is an immersion precipitation process, thus thermodynamic affinity of spinning dope to the coagulation medium was considered as the driving force of phase-separation, while viscosity of the solution accounted for the resistive force against phase separation and growth of the nucleated voids. Thermodynamic affinity was estimated by modifying Ruaan’s theory and viscosity of the solution was assessed on-line by measuring flow rate and back pressure at the spinneret. Hence, the parameter X (thermodynamic affinity/viscosity) was introduced to predict the porous morphology of the fibres. Generally, an increase in X led to fibres with higher porosity. A combination of electron scanning microscopy (SEM), porosimetry and thermoporometry was applied to fully characterize microstructure of fibres. Based on image analysis of SEM micrographs and data obtained from thermoporometry and porosimetry fractions of dense polymer ligament, micrometer size voids (macrovoids) and nanometer size voids (nanovoids) were estimated. Increasing polymer content or nonsolvent content in the spinning dope caused an increase in the solution viscosity and resulted in fibres with lower porosity. Imposing drawing on the as-spun fibres further decreased the porosity. Drawing also shifted the size distribution of nanovoids toward smaller values.
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Hong, Wei, Qing Shan Li, Jun Liu, Li Ping Wang i Guang Zhong Xing. "Study of Fibre Tourmaline/PVA Nanofibre Prepared by Electrospinning". Advanced Materials Research 295-297 (lipiec 2011): 41–45. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.41.
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This is the first time, prepared fiber-tourmaline nano powder use of Fiber-tourmaline. Vinyl acetate, fiber-tourmaline nano powder and EDTA as raw material, use micro-polymer chemistry laboratory equipment, preparation of the fiber-tourmaline/PVA spinning solution. The first time, prepared Fiber-tourmaline/PVA composite nanofibers, use of micro-polymer processing equipment—— electrospinning machine. The samples were characterized and tested the performance of its release anions. Analysis the effects of the fiber-tourmaline powder quantity on the properties of nano-fibers, and to explore the best tourmaline content.
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Atif, Rasheed, Madeleine Combrinck, Jibran Khaliq, James Martin, Ahmed H. Hassanin, Nader Shehata, Eman Elnabawy i Islam Shyha. "Study of Air Pressure and Velocity for Solution Blow Spinning of Polyvinylidene Fluoride Nanofibres". Processes 9, nr 6 (8.06.2021): 1014. http://dx.doi.org/10.3390/pr9061014.
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Solution blow spinning (SBS) is gaining popularity for producing fibres for smart textiles and energy harvesting due to its operational simplicity and high throughput. The whole SBS process is significantly dependent on the characteristics of the attenuation force, i.e., compressed air. Although variation in the fibre morphology with varying air input pressure has been widely investigated, there is no available literature on the experimentally determined flow characteristics. Here, we have experimentally measured and calculated airflow parameters, namely, output air pressure and velocity in the nozzle wake at 12 different pressure values between 1 and 6 bar and 11 different positions (retracted 5 mm to 30 mm) along the centreline. The results obtained in this work will answer many critical questions about optimum protrusion length for the polymer solution syringe and approximate mean fibre diameter for polyvinylidene fluoride (PVDF) at given output air pressure and velocity. The highest output air pressure and velocity were achieved at a distance of 3–5 mm away from the nozzle wake and should be an ideal location for the apex of the polymer solution syringe. We achieved 250 nm PVDF fibres when output air pressure and velocity were 123 kPa and 387 m/s, respectively.
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Yu, Yuxi, Xiaodong Li i Feng Cao. "A Near-Stoichiometric Sic-Based Fibre Obtained from a Polyaluminocarbosilane Precursor". Advanced Composites Letters 13, nr 5 (wrzesień 2004): 096369350401300. http://dx.doi.org/10.1177/096369350401300504.
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A near-stoichiometric SiC-based fibre containing ∼2 wt% aluminum, called SiC(Al) fibre, has been developed. SiC(Al) fibre can be obtained from an organometallic polymer precursor polyaluminocarbosilane by melt-spinning, oxidation curing, sintering at 1800°C in argon. SiC(Al) fibre was characterised by elemental chemical analysis, tensile test, Scanning electron microscopy, X-ray diffraction and Auger electron spectroscopy. Physical and mechanical properties of SiC(Al) fibre under thermal exposure, oxidation resistance and creep properties at elevated temperature were examined. The SiC(Al) fibre has more excellent oxidation resistance than Nicalon, Hi-Nicalon fibre and better creep resistance than the Tyranno SA fibre.
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Stankovic, Snezana, Dusan Popovic i Goran Poparic. "Thermal properties of directionally oriented polymer fibrous materials as a function of fibre arrangement at mesoscopic level". Thermal Science 23, nr 5 Part B (2019): 3117–27. http://dx.doi.org/10.2298/tsci181011105s.
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Thermal properties of directionally oriented fibrous materials have been investigated in this research with the purpose of considering the influence of fibre arrangement at mesoscopic level. The range of various distributions of fibres in the fibrous materials was obtained by applying different twist intensity during spinning of cotton fibres. From various twisted cotton yarns the knitted fabrics were produced under controlled conditions, so as to obtain as similar as possible constructions. This made possible to obtain the heterogeneity of the porous fibrous structures coming from the mesoscopic level. Thermal conductivity and heat transfer coefficient of the materials were investigated. The results obtained indicate the arrangement of fibres (or their compactness, orientation and migration), which, in turn, was determined by twist intensity (mesoscopic scale), as the key factor influencing thermal properties. Yarn compactness and fibre migration, determined by lateral forces imposed by the twist inserted in yarn, affected variations in structural parameters of the knitted fabrics, and thus influenced their thermal properties. Fibre orientation manifested itself in surface geometry of the yarn was also proved to have a considerable influence on heat transfer properties.
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Atif, Rasheed, Madeleine Combrinck, Jibran Khaliq, Ahmed H. Hassanin, Nader Shehata, Eman Elnabawy i Islam Shyha. "Solution Blow Spinning of High-Performance Submicron Polyvinylidene Fluoride Fibres: Computational Fluid Mechanics Modelling and Experimental Results". Polymers 12, nr 5 (16.05.2020): 1140. http://dx.doi.org/10.3390/polym12051140.
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Computational fluid dynamics (CFD) was used to investigate characteristics of high-speed air as it is expelled from a solution blow spinning (SBS) nozzle using a k-ε turbulence model. Air velocity, pressure, temperature, turbulent kinetic energy and density contours were generated and analysed in order to achieve an optimal attenuation force for fibre production. A bespoke convergent nozzle was used to produce polyvinylidene fluoride (PVDF) fibres at air pressures between 1 and 5 bar. The nozzle comprised of four parts: a polymer solution syringe holder, an air inlet, an air chamber, and a cap that covers the air chamber. A custom-built SBS setup was used to produce PVDF submicron fibres which were consequently analysed using scanning electron microscope (SEM) for their morphological features. Both theoretical and experimental observations showed that a higher air pressure (4 bar) is more suitable to achieve thin fibres of PVDF. However, fibre diameter increased at 5 bar and intertwined ropes of fibres were also observed.
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Zhiganov, N. K., V. I. Yankov, E. N. Alekseev i A. V. Genis. "Effect of aerodynamic spinning parameters and polymer properties on fibre diameter". Fibre Chemistry 20, nr 5 (1989): 322–26. http://dx.doi.org/10.1007/bf00545399.
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Müller, Michael Thomas, Kristina Eichhorn, Uwe Gohs i Gert Heinrich. "In-Line Nanostructuring of Glass Fibres Using Different Carbon Allotropes for Structural Health Monitoring Application". Fibers 7, nr 7 (10.07.2019): 61. http://dx.doi.org/10.3390/fib7070061.
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By the in-line nanostructuring of glass fibres (GF) during the glass fibre melt spinning process, the authors achieve an electro-mechanical-response-sensor. The glass fibre interphase was functionalized with different highly electrically conductive carbon allotropes such as carbon nanotubes, graphene nanoplatelets, or conductive carbon black. On-line structural health monitoring is demonstrated in continuous glass fibre-reinforced polypropylene composites during a static or dynamic three-point bending test. The different carbon fillers exhibit qualitative differences in their signal quality and sensitivity due to the differences in the aspect ratio of the nanoparticles, the film homogeneity, and the associated electrically conductive network density in the interphase. The occurrence of irreversible signal changes during dynamic loading may be attributed to filler reorientation processes caused by polymer creeping or to the destruction of the electrically conductive paths due to the presence of cracks in the glass fibre interphase. Further, the authors found that sensor embedding hardly influences the tensile properties of continuous GF reinforced polypropylene (PP) composite.
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Gupta, Karan, i Paresh Chokshi. "Stability analysis of non-isothermal fibre spinning of polymeric solutions". Journal of Fluid Mechanics 851 (30.07.2018): 573–605. http://dx.doi.org/10.1017/jfm.2018.504.
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The stability of fibre spinning flow of a polymeric fluid is analysed in the presence of thermal effects. The spinline is modelled as a one-dimensional slender-body filament of the entangled polymer solution. The previous study (Gupta & Chokshi,J. Fluid Mech., vol. 776, 2015, pp. 268–289) analysed linear and nonlinear stability behaviour of an isothermal extensional flow in the air gap during the fibre spinning process. The present study extends the analysis to take in to account the non-isothermal spinning flow in which the spinline loses heat by convection to the surrounding air as well as by solvent evaporation. The nonlinear rheology of the polymer solution is described using the eXtended Pom-Pom (XPP) model. The non-isothermal effects influence the rheology of the fluid through viscosity, which is taken to be temperature and concentration dependent. The linear stability analysis is carried out to obtain the draw ratio for the onset of instability, known as the draw resonance, and a stability diagram is constructed in the$DR_{c}{-}De$plane.$DR_{c}$is the critical draw ratio, and$De$is the flow Deborah number. The enhancement in viscosity driven by spinline cooling leads to postponement in the onset of draw resonance, indicating the stabilising role of non-isothermal effects. Weakly nonlinear stability analysis is also performed to reveal the role of nonlinearities in the finite amplitude manifold in the vicinity of the flow transition point. For low to moderate Deborah numbers, the bifurcation is supercritical, and the flow attains an oscillatory state with an equilibrium amplitude post-transition when$DR>DR_{c}$. The equilibrium amplitude of the resonating state is found to be smaller when non-isothermal effects are incorporated in comparison to the isothermal spinning flow. For very fast flows in the regime of high Deborah numbers, the finite amplitude manifold crosses over to a subcritical state. In this limit, the nonlinearities render the flow unstable even in the linearly stable regime of$DR<DR_{c}$.
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Korovitsyn, K. O., A. V. Genis, V. I. Yankov i V. A. Kheiso. "Isothermal stretching of the jet of polymer melt in aerodynamic fibre spinning". Fibre Chemistry 20, nr 2 (1988): 104–8. http://dx.doi.org/10.1007/bf00549240.
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Genis, A. V. "Strengthening of thermally bonded fibre materials fabricated in spinning from polymer melts". Fibre Chemistry 30, nr 5 (wrzesień 1998): 325–31. http://dx.doi.org/10.1007/bf02407331.
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Geysoğlu, M., i F. C. Çallıoğlu. "SOLVENT OPTIMIZATION OF ELECTROSPUN POLY(ACRYLIC ACID) NANOFIBERS". TEXTEH Proceedings 2021 (22.10.2021): 178–84. http://dx.doi.org/10.35530/tt.2021.27.
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In this study, it was investigated experimentally the influence of various solvents (distilled water and ethanol) on the solution properties, spinning performance, and fibre morphology of the electro spun Poly (acrylic acid) nanofibers. Firstly, polymer solutions were prepared at 5 wt % PAA with various solvent ratios of ethanol and distilled water. Then, solution properties such as viscosity, density, pH, conductivity, and surface tension were determined. The production of nanofiber samples was carried out by electrospinning under the optimum process parameters (voltage, distance between electrodes, feed rate, and atmospheric conditions). Finally, the morphological characterization of the nanofiber surface was carried out with SEM. According to the results, it was observed that conductivity, surface tension and the density of the solution increase as the ethanol ratio decreases. On the other hand, pH value increases as the ethanol ratio increases and, so, the acidic value of the solutions decreases. The viscosity increased until the ethanol/distilled water ratio was 50/50 and then decreased as the ethanol percentage decreased to under 50%. In addition, average fibre diameter decreases with ethanol ratio decreases. It is possible to say that solvent type affects solution properties, fibre morphology and spinning performance significantly. Generally, fine, uniform and bead free nanofibers could be electro spun and the PAA solution containing 70 wt % distilled water and 30 wt % ethanol was selected as the optimum in terms of fibre morphology, web quality and spinning performance.
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Vogli, Effrosyni D., Ozlem Turkarslan, Sofia M. Iconomopoulou, Deniz Korkmaz, Amaia Soto Beobide i George A. Voyiatzis. "From lab-scale film preparation to up- scale spinning fibre manufacturing of multiwall carbon nanotube/poly ethylene terephthalate composites". Journal of Industrial Textiles 47, nr 6 (6.01.2017): 1241–60. http://dx.doi.org/10.1177/1528083716686936.
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Carbon nanotubes are among the stiffest and strongest fibres known and they are thus considered as ideal fillers for polymeric fibre reinforcement. Carbon nanotube polymer composites have consequently attracted huge academic and industrial interest with thousands of relevant research works being published every year. In current work, we present a quite integrated study of multiwall carbon nanotube (MWCNT)-reinforced poly ethylene terephthalate (PET) composites prepared at laboratory scale along with industrial melt-spun fibres. For an optimum dispersion of the nanomaterial in the polymer matrix, we proceeded to appropriate functionalization of multiwall carbon nanotubes. The morphology of the composites was inspected by scanning electron microscope and transmission electron microscope, while the physical properties, such as crystallinity and orientation, by differential scanning calorimetry, X-ray diffraction and Raman spectroscopy. The addition of well-dispersed carbon nanotubes acts as a nucleation agent increasing the crystallization of poly ethylene terephthalate matrix, however, decreasing the orientation of either films or fibres. Carbon nanotubes /poly ethylene terephthalate polymer composite films present an increment of Young’s modulus and tensile strength to detriment of failure strain; namely, stiffness is accompanied by a less ductile behaviour. With the addition of carbon nanotubes to poly ethylene terephthalate fibres, a decrease in shrinkage and only a slight improvement in dimensional stability was attained; this once more explains the slow growth of their commercial applications since the mechanical properties of these materials still remain a fraction of the expected theoretical values.
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McColgan-Bannon, Kegan, Sarah Upson, Piergiorgio Gentile, Muhammad Tausif, Stephen Russell, Kenneth Dalgarno i Ana Ferreira. "Biomimetic Properties of Force-Spun PHBV Membranes Functionalised with Collagen as Substrates for Biomedical Application". Coatings 9, nr 6 (28.05.2019): 350. http://dx.doi.org/10.3390/coatings9060350.
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The force-spinning process parameters (i.e., spin speed, spinneret-collector distance, and polymer concentration), optimised and characterised in previous work by this group, allowed the rapid fabrication of large quantities of high surface area poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) polymeric fibre membranes. This paper examined the potential application for force-spun PHBV fibres functionalised with type I collagen for tissue regeneration applications. PHBV fibre scaffolds provide a biologically suitable substrate to guide the regeneration of dermal tissues, however, have poor cellular adhesion properties. The grafting of collagen type-I to PHBV fibres demonstrated improved cell adhesion and growth in Neo-NHDF (neonatal human dermal fibroblasts) fibroblasts. The examination of fibre morphology, thermal properties, collagen content, and degradability was used to contrast the physicochemical properties of the PHBV and PHBV-Collagen fibres. Biodegradation models using phosphate buffered saline determined there was no appreciable change in mass over the course of 6 weeks; a Sirius Red assay was performed on degraded samples, showing no change in the quantity of collagen. Cell metabolism studies showed an increase in cell metabolism on conjugated samples after three and 7 days. In addition, in vitro cytocompatibility studies demonstrated superior cell activity and adhesion on conjugated samples over 7 days.
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Foroughi, Javad, Dennis Antiohos i Gordon G. Wallace. "Effect of post-spinning on the electrical and electrochemical properties of wet spun graphene fibre". RSC Advances 6, nr 52 (2016): 46427–32. http://dx.doi.org/10.1039/c6ra07226g.
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Zhiganov, N. K., V. I. Yankov i E. P. Krasnov. "A mathematical model of a nonstationary process of fibre spinning from polymer melts". Fibre Chemistry 18, nr 4 (1987): 314–17. http://dx.doi.org/10.1007/bf00556559.
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NAVEED, TAYYAB, AHMED AIJAZ NABAR, BABAR MUHAMMAD RAMZAN, AWAID MUHAMMAND NAEEM, MUHAMMAD AWAIS, FAIZA ANWAR, AHMAD FRAZ i MUDASSAR ABBAS. "Influence of rotor structure and process parameters on polyethylene oxide (PEO) nanofibers produced through centrifugal". Industria Textila 73, nr 05 (26.10.2022): 479–91. http://dx.doi.org/10.35530/it.073.05.202134.
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The application of new tools and equipment in conventional spinning has increased with the advancements in operations, handling and optimal yarn production. For example, in the centrifugal electrospinning process (CESP), the rotor is assembled for its high-speed production. Therefore, the purpose of this study is to introduce a new rotor design with a triangular groove structure and to investigate its influence on the fast industrial manufacturing of polyethylene oxide (PEO) nanofibers. In addition, electric voltage (45 kV, 55 kV, 65 kV), concentrations of the spinning solution of PEO polymer (6 wt. %, 7 wt. % and 8 wt. %) and the flow rate of the spinning solution were analysed at different levels (45 ml/h, 55 ml/h, 65 ml/h). The subsequent PEO nanofibers were characterized through a scanning electron microscope (FESEM). It was observed that the diameter of PEO nanofibers changed with the variation in voltage, concentration and flow rate. The results revealed the best and uniform fibre diameter dimension at 65 kV, with an 8 wt.% solution concentration and flow rate of 55 ml/h. The outcomes also implied that the proposed triangular groove rotor was an efficient approach for the improvement in the nano fibres with its high uniformity as compared to the conventional structure (rectangular rotor structure).
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Macajová, Eva. "Manufacturing and Evaluation of Porous PLA Nano/Micro Fibres". Defect and Diffusion Forum 368 (lipiec 2016): 146–49. http://dx.doi.org/10.4028/www.scientific.net/ddf.368.146.
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This study is mainly focused on the study of pore size and shape, fibre diameter and also on the optimization of polymer solution composition and electrospinning parameters with respect to the final structure and morphology of PLA nano/microfibrous layers. The nano/microfibres were produced by electrospinning from the needle. Except the spinning process parameters, the morphology of nanofibrous layers can be also affected by the composition of the polymer solution and by the used solvents. Variations in technological process allows us to design the shape and form of nanofibrous structures upon request. The morphology of nano/microfibres was observed by scanning electron microscopy (SEM). Following image analysis and calculation enables the assessment of porosity contribution to the increase in micro/nanofibre surface area.
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Zhang, Jian Min, Qingsong Hua, Christopher T. Reynolds, Yuling Zhao, Zuoqiang Dai, Emiliano Bilotti, Jie Tang i Ton Peijs. "Preparation of High Modulus Poly(Ethylene Terephthalate): Influence of Molecular Weight, Extrusion, and Drawing Parameters". International Journal of Polymer Science 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/2781425.
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Poly(ethylene terephthalate) (PET) which is one of the most commercially important polymers, has for many years been an interesting candidate for the production of high performance fibres and tapes. In current study, we focus on investigating the effects of the various processing variables on the mechanical properties of PET produced by a distinctive process of melt spinning and uniaxial two-stage solid-state drawing (SSD). These processing variables include screw rotation speed during extrusion, fibre take-up speed, molecular weight, draw-ratio, and drawing temperature. As-spun PET production using a single-screw extrusion process was first optimized to induce an optimal polymer microstructure for subsequent drawing processes. It was found that less crystallization which occurred during this process would lead to better drawability, higher draw-ratio, and mechanical properties in the subsequent SSD process. Then the effect of drawing temperature (DT) in uniaxial two-stage SSD process was studied to understand how DT (<Tg or close to Tg or close to Trec) would affect the crystallization, draw-ratio, and final mechanical properties of PET. The designed process in current work is simulated to an industrial production process for PET fibres; therefore, results and analysis in this paper have significant importance for industrial production.
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Stompel, Semyon, Edward T. Samulski, Jack Preston, Benjamin S. Hsiaok, KennCorwin H. Gardner i Hsiang Shih. "A Thiophene-Based Liquid Crystalline Aromatic Polyamide". High Performance Polymers 9, nr 3 (wrzesień 1997): 229–49. http://dx.doi.org/10.1088/0954-0083/9/3/004.
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We have synthesized a liquid crystalline, aromatic polyamide from p-phenylene diamine (PPD) and 2, 5-thiophene dicarboxylic acid (Th). The new polymer, poly( p-phenylene thiophenylamide), abbreviated PPD-Th, like its terephthalic acid precursor, poly( p-phenylene terepthalamide) (PPD-T), exhibits a lyotropic mesophase in concentrated sulphuric acid solutions. Polarizing optical microscopy and deuterium NMR show that concentrated PPD-Th solutions exhibit nematic-to-isotropic phase transitions at a much lower temperature than comparable PPD-T solutions. More importantly, unlike PPD-T, lyotropic PPD-Th solutions do not form a crystallo-solvate complex gel phase at room temperature, i.e. the fluid PPD-Th mesophase persists below 300 K enabling the spinning of PPD-Th fibres from a lyotropic dope at ambient temperatures. Thermogravimetric analysis shows that the 2, 5-thiophene heterocycle in the PPDTh backbone does not significantly diminish its thermal stability relative to that of PPD-T. Preliminary x-ray diffraction results show that PPD-Th crystallizes in a tentative two-chain, orthorhombic unit cell with dimensions a = 3.73 Å, b = 5.04 Å and c = 25.20 Å (fibre axis). The fibre repeat corresponds to two chemical repeats related by a twofold screw axis. Mechanical properties (tensile strength, modulus and elongation to break) are presented for as-spun and heat-treated PPD-Th fibres.
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ŞARAPNAL, DILEK, i OSMAN BABAARSLAN. "INVESTIGATION OF THE USAGE OF ALTERNATIVE NEW GENERATION ECO-FRIENDLY FIBER BLENDS IN SYNTHETIC BASED DENIM FABRICS". Fibres and Textiles 30, nr 1 (2023): 11–17. http://dx.doi.org/10.15240/tul/008/2023-1-002.
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Polyester yarn is made from post-consumer waste such as bottles, fabrics, etc., in the composition of polyester ethylene terephthalate (PET). Polyester (mainly polyethylene terephthalate, PET) is the most commonly employed textile fibre with over 50% share in total production of textile fibres. Pla is a biobased and biodegradable polymer produced from renewable resources. PLA is also a thermoplastic aliphatic compostable polyester. In this study, 75% Cotton - 25% PLA, 75% Lyocell - 25% PLA and 75% Cotton - 25% PET blended yarns were produced as rigid, corespun and dualcore in the ring spinning system .The fabrics were weaved with produced yarn. In the finishing processes, some of the fabrics were treated with caustic and some of the fabrics were only washed. Fabrics containing PLA and PET were compared with each other. Fabrics containing PLA and PET fiber were evaluated in terms of strength, elasticity, abrasion and pilling performances. Although the weft tensile and tear properties of Cotton-PLA blended fabrics are lower than Lyocell-PLA and Cotton-PET blends, it has been indicated that PLA blended yarns can be used as an alternative to PET based yarns and fabrics.
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Siriorn, Isarankura Na Ayutthaya, i Wootthikanokkhan Jatuphorn. "Investigation of Morphology and Photocatalytic Activities of Electrospun Chicken Feather Keratin/PLA/TiO2/Clay Nanofibers". E3S Web of Conferences 141 (2020): 01003. http://dx.doi.org/10.1051/e3sconf/202014101003.
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This research has focused on the fabrication of electro spun-keratin base composite nanofiber, in order to develop the organic dye removal filters. The filters were prepared from a keratin-base material, which was extracted from chicken feathers. A biodegradable polymer including Poly (lactic acid) was blended into keratin to improve fibre process-ability. Titanium dioxide (anatase) and clay (Na-montmorillonite) were mixed into the PLA/Keratin blended solution prior to fabrication into non-woven fibre using the electro-spinning process. The objective of this research was to study the effect of TiO2 and clay on the process-ability, the morphology, and the filter efficiency (methylene blue removal) of the fibres. SEM images showed the morphology of small PLA/Keratin/clay-base fibres. SEM-scan mapping EDX technique showed a good dispersion of keratin, clay and TiO2 along the fibres. XRD pattern also showed the existence of PLA, keratin and TiO2. But the peak of clay was not strong enough. However, the evidence of clay was clearly shown by SEM-EDX technique as reported above. The capability to remove organic dye (methylene blue) was investigated by using UV-Vis spectrophotometer technique. From all of our results, it can be concluded that PLA/Keratin/TiO2/clay is an effective filter for the removal of organic dye from wastewater.
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Matysiak, W., T. Tański i W. Smok. "Electrospinning of PAN and composite PAN-GO nanofibres". Journal of Achievements in Materials and Manufacturing Engineering 1, nr 91 (1.11.2018): 18–26. http://dx.doi.org/10.5604/01.3001.0012.9653.
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Purpose: The aim of this study was to present the influence of used reinforcement phase – graphene oxide (GO) and the electrospinning process parameters (the distance between the nozzle and collector) on the morphology and the structure of the obtained composite PAN-GO nanofibres. Design/methodology/approach: To produce pure polymer nanofibers, a 10% (wt.) electrospinning solution the polyacrylonitrile (PAN) was dissolved in N, N-dimethylformamide (DMF). The spinning solution used for electrospinning PAN-GO composite fibres was made by dissolving the PAN in a mixture of GO and DMF. By changing the configuration of the distance between the nozzle and collector (10 and 20 cm) and maintaining the remaining parameters (solution flow rate and potential difference between the electrodes), four samples in the form of nanofibrous mats were made. In order to identify the structure and morphology of the reinforcing phase, X-ray microanalysis (EDX) and scanning electron microscopy (SEM) were performed. In addition, the structure of graphene oxide microparticles was investigated by a Raman spectrometer. In order to determine the influence of the distance between the nozzle and the collector used in the electrospinning process and the addition of the reinforcing phase to the morphology and structure of the obtained PAN polymer nanofibres and PAN-GO composite nanofibres, they were examined using SEM. The analysis of the chemical composition of PAN and PAN-GO fibres was carried out using X-ray microanalysis. Findings: The morphology and structure analysis indicated that polymer nanofibres PAN for both the distances between the nozzle and the collector show no structural defects and presented same diameter over the entire length of the fibre. Nanofibres with the addition of GO obtained at both distances between the electrodes, showed defects in the form of beads. In addition, it was observed that with increasing distance between the nozzle and collector the diameter of obtained nanofibres is smaller for both pure PAN and composite PAN-GO samples. Research limitations/implications: The paper is the basis for further research in the field of the use of PAN-GO composite nanofibres as water purification materials. Originality/value: The electrospinning method can be an alternative to conventional methods for the production of filtering membranes due to the ease of carrying out the process and the fact that a material with a high specific surface area is obtained.
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Bostan, Lars, Omid Hosseinaei, Renate Fourné i Axel S. Herrmann. "Upscaling of lignin precursor melt spinning by bicomponent spinning and its use for carbon fibre production". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, nr 2209 (13.09.2021): 20200334. http://dx.doi.org/10.1098/rsta.2020.0334.
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Upscaling lignin-based precursor fibre production is an essential step in developing bio-based carbon fibre from renewable feedstock. The main challenge in upscaling of lignin fibre production by melt spinning is its melt behaviour and rheological properties, which differ from common synthetic polymers used in melt spinning. Here, a new approach in melt spinning of lignin, using a spin carrier system for producing bicomponent fibres, has been introduced. An ethanol extracted lignin fraction from LignoBoost process of commercial softwood kraft black liquor was used as feedstock. After additional heat treatment, melt spinning was performed in a pilot-scale spinning unit. For the first time, biodegradable polyvinyl alcohol (PVA) was used as a spin carrier to enable the spinning of lignin by improving the required melt strength. PVA-sheath/lignin-core bicomponent fibres were manufactured. Afterwards, PVA was dissolved by washing with water. Pure lignin fibres were stabilized and carbonized, and tensile properties were measured. The measured properties, tensile modulus of 81.1 ± 3.1 GPa and tensile strength of 1039 ± 197 MPa, are higher than the majority of lignin-based carbon fibres reported in the literature. This new approach can significantly improve the melt spinning of lignin and solve problems related to poor spinnability of lignin and results in the production of high-quality lignin-based carbon fibres. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)’.
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Munir, Nimra, Ross McMorrow, Konrad Mulrennan, Darren Whitaker, Seán McLoone, Minna Kellomäki, Elina Talvitie, Inari Lyyra i Marion McAfee. "Interpretable Machine Learning Methods for Monitoring Polymer Degradation in Extrusion of Polylactic Acid". Polymers 15, nr 17 (28.08.2023): 3566. http://dx.doi.org/10.3390/polym15173566.
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This work investigates real-time monitoring of extrusion-induced degradation in different grades of PLA across a range of process conditions and machine set-ups. Data on machine settings together with in-process sensor data, including temperature, pressure, and near-infrared (NIR) spectra, are used as inputs to predict the molecular weight and mechanical properties of the product. Many soft sensor approaches based on complex spectral data are essentially ‘black-box’ in nature, which can limit industrial acceptability. Hence, the focus here is on identifying an optimal approach to developing interpretable models while achieving high predictive accuracy and robustness across different process settings. The performance of a Recursive Feature Elimination (RFE) approach was compared to more common dimension reduction and regression approaches including Partial Least Squares (PLS), iterative PLS (i-PLS), Principal Component Regression (PCR), ridge regression, Least Absolute Shrinkage and Selection Operator (LASSO), and Random Forest (RF). It is shown that for medical-grade PLA processed under moisture-controlled conditions, accurate prediction of molecular weight is possible over a wide range of process conditions and different machine settings (different nozzle types for downstream fibre spinning) with an RFE-RF algorithm. Similarly, for the prediction of yield stress, RFE-RF achieved excellent predictive performance, outperforming the other approaches in terms of simplicity, interpretability, and accuracy. The features selected by the RFE model provide important insights to the process. It was found that change in molecular weight was not an important factor affecting the mechanical properties of the PLA, which is primarily related to the pressure and temperature at the latter stages of the extrusion process. The temperature at the extruder exit was also the most important predictor of degradation of the polymer molecular weight, highlighting the importance of accurate melt temperature control in the process. RFE not only outperforms more established methods as a soft sensor method, but also has significant advantages in terms of computational efficiency, simplicity, and interpretability. RFE-based soft sensors are promising for better quality control in processing thermally sensitive polymers such as PLA, in particular demonstrating for the first time the ability to monitor molecular weight degradation during processing across various machine settings.
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Ellison, Michael S., Paulo E. Lopes i William T. Pennington. "In-Situ X-Ray Characterization of Fiber Structure during Melt Spinning". Journal of Engineered Fibers and Fabrics 3, nr 3 (wrzesień 2008): 155892500800300. http://dx.doi.org/10.1177/155892500800300302.
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The properties of a polymer are strongly influenced by its morphology. In the case of fibers from semi-crystalline polymers this consists of the degree of crystallinity, the spacing and alignment of the crystalline regions, and molecular orientation of the polymer chains in the amorphous regions. Information on crystallinity and orientation can be obtained from X-ray analysis. In-situ X-ray characterization of a polymer during the melt spinning process is a major source of information about the effects of material characteristics and processing conditions upon structure evolution along the spinline, and the final structure and properties of the end product. We have recently designed and installed an X-ray system capable of in-situ analysis during polymer melt spinning. To the best of our knowledge this system is unique in its capabilities for the simultaneous detection of wide angle and small angle X-ray scattering (WAXS and SAXS, respectively), its use of a conventional laboratory radiation source, its vertical mobility along the spinline, and its ability to simulate a semi-industrial environment. Setup, operation and demonstration of the capabilities of this system is presented herein as applied to the characterization of the melt spinning of isotactic poly(propylene). Crystallinity and crystalline orientation calculated from WAXS patterns, and lamellar long period calculated from SAXS patterns, were obtained during melt spinning of the polymer along the spinline.
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Gan, Xue Hui, Na Na Liu, Xiao Jian Ma, Qiang Liu i Chong Chang Yang. "Study on the Co-Extrusion Process Morphology and Performance of Skin-Core Bicomponent Fiber". Advanced Materials Research 332-334 (wrzesień 2011): 553–59. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.553.
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In fiber melt spinning, a bunch of polymer melt filaments are continuously drawn and simultaneously cooled with air in order to obtain solidified yarns, which later compose the synthetic fiber in the bobbin. Melt spinning is a basic non-isothermal operation in the production of synthetic fibers, and the velocity and temperature fields in the filaments can be useful to control the quality of the final product. Therefore, the research of the temperature and the speed in the spinning path will be very important. Based on the theory of melt rheology, the co-extrusion morphology and performance of polymer melts PA6 /PET which extrude from circular spinning porous are simulated using finite element method. The effects of the fluid flux ration、cooling air temperature and winding speed on co-extrusion fiber interface and spinning process temperature are analyzed. And the simulated results show that the interfacial offset increases with the increase of the flow rate ratio of two polymers; changing the cooling air temperature, the temperature distribution has the same trend; low winding speed is conducive to the convergence of stretching rate. The simulated results can dynamically and quantitatively reflect the melt flow process, and these results can make guiding sense to engineering application.
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Zelca, Zane, Andres Krumme, Silvija Kukle, Mihkel Viirsalu i Laimdota Vilcena. "Effect of Electrode Type on Electrospun Membrane Morphology Using Low-Concentration PVA Solutions". Membranes 12, nr 6 (11.06.2022): 609. http://dx.doi.org/10.3390/membranes12060609.
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Electrospun polymer nanofiber materials have been studied as basic materials for various applications. Depending on the intended use of the fibers, their morphology can be adjusted by changing the technological parameters, the properties of the spinning solutions, and the combinations of composition. The aim of the research was to evaluate the effect of electrode type, spinning parameters, polymer molecular weight, and solution concentration on membranes morphology. The main priority was to obtain the smallest possible fiber diameters and homogeneous electrospun membranes. As a result, five electrode types were selected, the lowest PVA solution concentration for stable spinning process was detected, spinning parameters for homogenous fibers were obtained, and the morphology of electrospun fiber membranes was analyzed. Viscosity, conductivity, pH, and density were evaluated for PVA polymers with five different molecular weights (30–145 kDa) and three concentration solutions (6, 8, and 10 wt.%). The membrane defects and fiber diameters were compared as a function of molecular weight and electrode type. The minimum concentration of PVA in the solution allowed more additives to be added to the solution, resulting in thinner diameters and a higher concentration of the additive in the membranes. The molecular weight, concentration, and electrode significantly affected the fiber diameters and the overall quality of the membrane.
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Yi, Lan, Lu Cui, Linrui Cheng, János Móczó i Béla Pukánszky. "Levocetirizine-Loaded Electrospun Fibers from Water-Soluble Polymers: Encapsulation and Drug Release". Molecules 28, nr 10 (19.05.2023): 4188. http://dx.doi.org/10.3390/molecules28104188.
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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.
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Hendrick, Erin, i Margaret Frey. "Increasing Surface Hydrophilicity in Poly(Lactic Acid) Electrospun Fibers by Addition of Pla-b-Peg Co-Polymers". Journal of Engineered Fibers and Fabrics 9, nr 2 (czerwiec 2014): 155892501400900. http://dx.doi.org/10.1177/155892501400900219.
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Poly (lactic acid) – b – poly (ethylene glycol) (PLA-b-PEG) co-polymers with block lengths of 1000–750, 5000–1000, 1000–5000, and bulk PEG were added to PLA electrospinning dopes to create hydrophilic but non-water soluble nanofibers. PLA-b-PEG block lengths strongly affected the total amount of PEG that could be incorporated, as well as spinnability and fiber morphology. Solutions containing >1% w/w of the lowest molecular weight co-polymer PLA (1000) – b – PEG (750) formed an unspinnable, cloudy gel. Addition of the PLA (5000) – b – PEG (1000) to the base spinning solution influenced fiber diameters and spinnability in the same manner as simply increasing PLA concentration in the spinning dope. Addition of PLA (1000) – b – PEG (5000) resulted in decreased fiber diameters, and allowed for the highest overall co-polymer loading. In final fiber formulations, maximums of 0.9, 2.9 and 9.3 wt% PEG could be achieved using the PLA-b-PEG 1000–750, 5000–1000 and 1000–5000 respectively. PEG (MW = 3350 g/mol) homopolymer was added to the spinning dopes to prepare fibers with 1.0 and 5.0 wt% PEG. The resulting fibers had non-uniform morphology and more variable diameter size than occurred with the addition of PEG in block co-polymer form. Water absorbance by electrospun nonwoven fabrics increased by four times over the control PLA with the addition of 1.0 wt% PEG, and by eighteen times with the addition of 9.3 wt% PEG with the block co-polymers. At similar overall PEG loadings, the addition of PLA-b-PEG resulted in a two to four fold increase in water wicking over the addition of PEG homopolymer.
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Benecke, Lukas, Robert Tonndorf, Chokri Cherif i Dilbar Aibibu. "Influence of Spinning Method on Shape Memory Effect of Thermoplastic Polyurethane Yarns". Polymers 15, nr 1 (3.01.2023): 239. http://dx.doi.org/10.3390/polym15010239.
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Shape memory polymers are gaining increasing attention, especially in the medical field, due to their ability to recover high deformations, low activation temperatures, and relatively high actuation stress. Furthermore, shape memory polymers can be applied as fiber-based solutions for the development of smart devices used in many fields, e.g., industry 4.0, medicine, and skill learning. These kind of applications require sensors, actors, and conductive structures. Textile structures address these applications by meeting requirements such as being flexible, adaptable, and wearable. In this work, the influence of spinning methods and parameters on the effect of shape memory polymer yarns was investigated, comparing melt and wet spinning. It is shown that the spinning method can significantly influence the strain fixation and generated stress during the activation of the shape memory effect. Furthermore, for wet spinning, the draw ratio could affect the stress conversion, influencing its efficiency. Therefore, the selection of the spinning process is essential for the setting of application-specific shape-changing properties.
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Matysiak, W., A. Kapica, T. Tański i A. Dubiel. "Analysis of the influence of electrospinning process parameters on the morphology of poly(lactic acid) fibres". Archives of Materials Science and Engineering 2, nr 96 (1.04.2019): 73–78. http://dx.doi.org/10.5604/01.3001.0013.2386.
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Purpose: The article focuses on the production of polymer nanofibres from poly(lactic acid) using the electro-spinning method, i.e. the technique of forming fibres in an electrostatic field. The main aim of the publication was to analyse the influence of the distance between electrodes on the morphology of one-dimensional polymeric materials obtained. Design/methodology/approach: In the practical part of the study solutions of polylactide in acetone and a mixture of chloroform/dimethylformamide (DMF) were produced. After 72 hours of mixing, no homogeneous solutions were obtained, therefore a solution consisting of a polylactide dissolved in chloroform was prepared, to which dimethylformamide was added in order to dilute the mixture. The morphology of the nanostructures obtained was analysed by means of a scanning electron microscope (SEM) equipped with an X-ray energy dispersion spectrometer (EDS), which allowed to analyse the chemical composition of the nanofibres produced. The electro-spinning method used to obtain fibres is characterized by high versatility - it gives the possibility to produce fibres from a wide range of polymers. Electro-spinning is also an economic method, and spinned fibres have a wide application potential. Findings: Nanofibres obtained by electro-spinning from the previously produced solution, regardless of the distance between the nozzle and the collector (10 or 20 cm) did not show any significant discrepancies in the values of measured diameters. Fibres obtained at increased distance between electrodes (20 cm) are characterized by a smaller average diameter value, but the difference is small, fluctuating between 48-49 nm. In the case of the sample formed during electro-spinning at the distance of the nozzle - collector equal to 10 cm and the sample produced at the distance doubled, no defects in the structure of the obtained nanofibres were observed. The analysis of topographic images of surfaces produced in the course of nanostructures' work did not show any significant influence of the distance between the nozzle and collector on the diameter of fibres. No defects in the structure of one-dimensional polymer materials obtained allowed to state that the distance between the nozzle and the collector in the range of 10-20 cm is the optimal parameter of the electro-spinning process allowing to obtain smooth, untangled fibres. Practical implications: The fibrous polymer mats obtained during the electro-spinning process of polylactide can be used as protective clothing materials, as drug delivery systems, as tissue scaffolding and as filtration membranes. Originality/value: At present, there are few articles in the literature on the electrospinning process, due to the fact that it is a constantly developing matte for the production of nanofibres. Moreover, most of the research focuses on fibres obtained from nonbiodegradable polymers, which do not have the advantages of fibres obtained from polylactide.
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Dong, Shaoce, Guijun Xian i Xiao-Su Yi. "Life Cycle Assessment of Ramie Fiber Used for FRPs". Aerospace 5, nr 3 (3.08.2018): 81. http://dx.doi.org/10.3390/aerospace5030081.
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With the depletion of natural resources and the deterioration of environment, natural fiber based biomaterials are attracting more and more attentions. Natural fibers are considered to be renewable, biodegradable, and ecofriendly, and have been applied to be used as alternative reinforcements to traditional glass fibers for polymer based composites (GFRP). Natural fiber reinforced polymer (NFRP) composites have been found to be manufactured as secondary structures or interior parts of aircrafts or automobiles. In this paper, a cradle-to-gate life cycle assessment (LCA) study was performed to demonstrate the possible advantages of ramie fiber on environmental impacts and to provide fundamental data for the further assessment of ramie fiber reinforced polymers (RFRP) and its structures. By collecting the material inventories of the production process of ramie fiber, the environmental impacts of ramie fiber (characterized by eight main impact categories, which are climate change, terrestrial acidification, freshwater eutrophication, human toxicity potential, ozone depletion, photochemical oxidant creation, freshwater ecotoxicity, and fossil depletion) were calculated and compared with that of glass fiber. Found if spinning process is ignored within the production of the ramie fiber, ramie fiber exhibits better ozone depletion and they have almost the same values of climate change and terrestrial acidification in terms of glass fiber. However, if the spinning process is included, ramie fiber only performs better in terms of ozone depletion. And degumming and carding and spinning processes are the processes that cause more pollution.
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Chen, Long, Dan Pan i Houkang He. "Morphology Development of Polymer Blend Fibers along Spinning Line". Fibers 7, nr 4 (25.04.2019): 35. http://dx.doi.org/10.3390/fib7040035.
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Melt spinning is an efficient platform to continuously produce fiber materials with multifunctional and novel properties at a large scale. This paper briefly reviews research works that reveal the morphology development of immiscible polymer blend fibers during melt spinning. The better understanding of the formation and development of morphology of polymer blend fibers during melt spinning could help us to generate desired morphologies and precisely control the final properties of fiber materials via the melt spinning process.
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Xiao, Hong, Mei Wu Shi, Li Li Liu i Guo Liang Dai. "The Crystallinity and Orientation Structure and Crimp Properties of PET/PTT Bicomponent Filament". Advanced Materials Research 627 (grudzień 2012): 110–16. http://dx.doi.org/10.4028/www.scientific.net/amr.627.110.
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In order to develop PET/PTT bicomponent filament, the structure informations of PET/PTT fibers with different spinning parameters were got by density method, Wide Angle X-ray Diffraction (WAXD), sonic orientation and Differiential Scanning Calority (DSC). Their mechanical and crimp properties were got from Instron 5566. On the spinning line, the PET component will crystal firstly and has higher draw inducing orientation and crystallinity than the PET fiber under the same spinning parameters, and those of PTT component are lower than those of PTT fiber. The crimp shrinkage and the elongation, the sonic orientation factor and the crystallinity of each component will improve with the increasing difference of the viscousity of two polymers. The crimp shrinkage and the elongation of the PET/PTT fiber are the highest when the content of the two components is equal. The crystallinity of each component decreases and the sonic orientation factor increases with the increasing difference of the content of two polymer.
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Grothe, Timo, Jan Lukas Storck, Marius Dotter i Andrea Ehrmann. "Impact of Solid Content in the Electrospinning Solution on the Physical and Chemical Properties of Polyacrylonitrile (PAN) Nanofibrous Mats". TEKSTILEC 63, nr 3 (28.09.2020): 225–32. http://dx.doi.org/10.14502/tekstilec2020.63.225-232.
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Polyacrylonitrile (PAN) belongs to the group of polymers that are often used for electrospinning, as it can be applied as a pre-cursor for carbon nanofibres and is spinnable from the low-toxic solvent dimethyl sulfoxide (DMSO). While the influence of different spinning parameters on fibre morphology and mass per unit area was investigated in a previous study, here we report on the impact of the spinning solution, using DMSO as a solvent and wire-based (needleless) electrospinning. Our results show that a broad range of solid contents can be applied, providing the opportunity to tailor the fibre diameter distribution or to optimize the areal weight of the nanofibrous mat by changing this parameter, while the chemical composition of the fibres remains identical.
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Merchiers, Jorgo, Willem Meurs, Wim Deferme, Roos Peeters, Mieke Buntinx i Naveen K. Reddy. "Influence of Polymer Concentration and Nozzle Material on Centrifugal Fiber Spinning". Polymers 12, nr 3 (5.03.2020): 575. http://dx.doi.org/10.3390/polym12030575.
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Centrifugal fiber spinning has recently emerged as a highly promising alternative technique for the production of nonwoven, ultrafine fiber mats. Due to its high production rate, it could provide a more technologically relevant fiber spinning technique than electrospinning. In this contribution, we examine the influence of polymer concentration and nozzle material on the centrifugal spinning process and the fiber morphology. We find that increasing the polymer concentration transforms the process from a beaded-fiber regime to a continuous-fiber regime. Furthermore, we find that not only fiber diameter is strongly concentration-dependent, but also the nozzle material plays a significant role, especially in the continuous-fiber regime. This was evaluated by the use of a polytetrafluoroethylene (PTFE) and an aluminum nozzle. We discuss the influence of polymer concentration on fiber morphology and show that the choice of nozzle material has a significant influence on the fiber diameter.
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Ponomarev, Igor I., Ivan Y. Skvortsov, Yulia A. Volkova, Ivan I. Ponomarev, Lydia A. Varfolomeeva, Dmitry Y. Razorenov, Kirill M. Skupov, Mikhail S. Kuzin i Olga A. Serenko. "New Approach to Preparation of Heat-Resistant “Lola-M” Fiber". Materials 12, nr 21 (25.10.2019): 3490. http://dx.doi.org/10.3390/ma12213490.
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A new approach to the synthesis of polynaphthoylenebenzimidazoles and heat resistant fiber spinning has been developed using an environmentally friendly and energy efficient method, which operates with solutions of pre-polymers based on 3,3’,4,4’-tetraaminodiphenyl ether and 1,4,5,8-naphthalenetetracarboxylic acid dianhydride in N-methylpyrrolidone. Rheological properties of polymer reaction solutions and appropriate coagulant mixtures were investigated for further wet spinning process. The coagulation process was investigated through microscopic observation of solution droplets which imitate jet/fiber cross section surrounded with coagulants of different composition. For the case of the most optimal viscoelastic properties of dopes the best coagulant was found to be a ternary mixture ethanol/water/NMP (20/10/70). Fibers were prepared through the wet spinning from pre-polymers of various molecular weight characterized by intrinsic viscosity. As a result, complex yarns were spun, and their morphology was characterized and mechanical properties were measured. The strength of ~300 MPa and elastic modulus of ~2 GPa and elongation at break of ~20% were reached for the best fibers at average diameter of ~20 µm. After heat treatment “Lola-M” fibers do not burn and do not support combustion in open flame.