Subsequent Spinning Research Articles

Comparative analysis of anaerobic degumming effects on different bast fibers from the angle of enzyme activity and microbial community structure

Bast fiber textiles are becoming more and more popular, and degumming is a key process to obtain fiber. However, the more widely used degumming methods currently have a high level of pollution, which has become a primary problem restricting the development of the textile industry. Therefore, this study developed a continuous-flow anaerobic biological degumming system for bast fibers (Ramie and Hemp), with a self-developed spiral symmetry stream anaerobic bioreactor (SSSAB) as the core. The basic indicators of the degumming systems’ operation were analyzed, including pH, COD (Chemical Oxygen Demand), weight loss ratio, fineness, and breaking strength. pH and COD results indicated that the systems are operated continuously and steadily. The breaking strength of Ramie fiber and Hemp fiber were found about 4–6.5 cN/dtex and 2–4 cN/dtex, respectively, which meet subsequent spinning needs. The weight loss ratio of Ramie fiber (maximum value 27.27%) obtained by this anaerobic degumming method was generally higher than that produced by the traditional degumming method. SEM (Scanning Electron Microscopy) found the bast fibers current degumming time was too long and a lot of microorganisms adhered to the surface of the fibers. Enzyme activities testing in different fiber degumming systems found that the Ramie fiber degumming system has a higher cellulase activity than the Hemp fiber degumming system. From the perspective of community structure, it was believed that there were significant differences in microbial flora between Ramie and Hemp degumming systems, but there was no significant difference in archaea between them. This not only explored the adaptability of anaerobic continuous flow biological degumming system varieties but also provided theoretical guidance for enterprises to degum different bast fibers.

Change in incidents of suicidal acts after intervention on a bridge in South Korea.

To investigate whether two novel interventions on a bridge - a Video Incident Detection System (VIDS) and spinning bar barriers - have an impact on suicidal behaviour on the bridge. A total of 146 suicidal acts were retrieved for analyses; 108 interventions before suicidal acts, 35 suicide deaths and 3 suicide attempts. Incident rate ratios (IRR) were calculated to estimate the change in incident rate associated with implementation of the two interventions: VIDS and the spinning bar 2-metre high barrier. The results of the Poisson regression showed that the rate of suicide deaths, after installation the VIDS, did not change significantly (IRR: 1.23, 95% Confidence Interval [95% CI]: 0.59-2.56), although the rate of intervened suicidal acts increased (IRR: 2.40, 95% CI: 1.65-3.47). The results showed that subsequent spinning bar installation resulted in a decrease in the incident rate of intervened suicidal acts (IRR: 0.37, 95% CI: 0.25-0.57) as well as suicide deaths (IRR: 0.23, 95% CI: 0.07-0.71). Comparison of the period when both interventions were in place with the period with no interventions indicated a reduction in suicide deaths (IRR: 0.28, 95% CI: 0.10-0.82), but no change in intervened suicidal acts (IRR: 0.90, 95% CI: 0.59-1.38). The rate of suicide death decreased after the installation of the spinning bar barrier but not after the implementation of VIDS alone. Our findings reinforce that restricting access to means is a highly effective way of preventing suicide on bridges and that spinning bars may be a helpful way to design barriers.

Preparation and characterization of composite-modified PA6 fiber for spectral heating and heat storage applications

Abstract Composite coating technology was used to prepare a modified polyamide 6 (PA6) polymer material masterbatch with low mutual interference and good spinnability using molybdenum oxide, tungsten trioxide, graphene oxide, etc., as modifiers. Experiment shows that using nanoscale composite-coated modified masterbatches capable of spectral heating and heat storage in the preparation of nylon 6 fiber, adding modified masterbatches with a mass ratio of 6% online, and controlling various process parameters can result in good functionality and usability as well as enable consistent production. Optimal production conditions are achieved by utilizing pre-dried PA6 chips with a moisture content of 420 ppm. The master batch is subjected to drying at a temperature of 95°C for 12 h. During this process, the master batch is introduced at an addition ratio of 6%. Subsequent spinning is conducted at a speed of 4,300 m·min−1 and a temperature of 255°C. Cooling is facilitated by air set at a temperature of 17°C, flowing at a speed of 0.45 m·min−1. In the production line, one roller operates without heating, while the second roller is maintained at a temperature range of 160°C. The stretching process is performed at a ratio of 1.3. To ensure proper lubrication, an oil rate of 1.3% is applied. These meticulously controlled process parameters collectively contribute to the most favorable production status.

Microstructure and Microhardness of Conical-Shaped W-Cu Composites Prepared by Spark Plasma Sintering and Subsequent Spinning Process

Microstructure and Microhardness of Conical-Shaped W-Cu Composites Prepared by Spark Plasma Sintering and Subsequent Spinning Process

Mechanically recyclable melt-spun fibers from lignin esters and iron oxide nanoparticles: towards circular lignin materials.

The inferior thermoplastic properties have limited production of melt-spun fibers from lignin. Here we report on the controlled esterification of softwood kraft lignin (SKL) to enable scalable, solvent-free melt spinning of microfibers using a cotton candy machine. We found that it is crucial to control the esterification process as melt-spun fibers could be produced from lignin oleate and lignin stearate precursors with degrees of esterification (DE) ranging from 20-50%, but not outside this range. To fabricate a functional hybrid material, we incorporated magnetite nanoparticles (MNPs) into the lignin oleate fibers by melt blending and subsequent melt spinning. Thermogravimetric analysis and X-ray diffraction studies revealed that increasing the weight fraction of MNPs led to improved thermal stability of the fibers. Finally, we demonstrated adsorption of organic dyes, magnetic recovery, and recycling via melt spinning of the regular and magnetic fibers with 95% and 83% retention of the respective adsorption capacities over three adsorption cycles. The mechanical recyclability of the microfibers represents a new paradigm in lignin-based circular materials.

Yarn apparent evenness detection based on L0 norm smoothing and the expectation maximization method

During spinning, knitting and weaving processes, the yarn apparent evenness is an important factor, which determines the quality of subsequent spinning production and fabric performance. This paper presents a powerful method which is based on L0 norm smoothing and the expectation maximization method to detect the yarn apparent evenness. The L0 norm smoothing method is first applied to remove the noise and enhance the yarn apparent evenness diameter features. Then, the expectation maximization method and the morphological opening operation were used to obtain the yarn evenness. Finally, we calculated the yarn apparent evenness diameter and the coefficient of variation of the evenness of the yarn apparent diameter. Compared with the capacitive evenness testers, the Otsu detection method and the fuzzy C-means detection method, our method can accurately detect the yarn apparent evenness better than the selected state-of-the-art methods.

Evaluation of Keratin-Cellulose Blend Fibers as Precursors for Carbon Fibers.

One main challenge to utilize cellulose-based fibers as the precursor for carbon fibers is their inherently low carbon yield. This study aims to evaluate the use of keratin in chicken feathers, a byproduct of the poultry industry generated in large quantities, as a natural charring agent to improve the yield of cellulose-derived carbon fibers. Keratin–cellulose composite fibers are prepared through direct dissolution of the pulp and feather keratin in the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH]OAc) and subsequent dry jet wet spinning (so-called Ioncell process). Thermogravimetric analysis reveals that there is an increase in the carbon yield by ∼53 wt % with 30 wt % keratin incorporation. This increase is comparable to the one observed for lignin–cellulose composite fibers, in which lignin acts as a carbon booster due to its higher carbon content. Keratin, however, reduces the mechanical properties of cellulose precursor fibers to a lesser extent than lignin. Keratin introduces nitrogen and induces the formation of pores in the precursor fibers and the resulting carbon fibers. Carbon materials derived from the keratin–cellulose composite fiber show potential for applications where nitrogen doping and pores or voids in the carbon are desirable, for example, for low-cost bio-based carbons for energy harvest or storage.

From Grave to Cradle - Development of Weft Knitted Fabrics Based on Hybrid Yarns from Recycled Carbon Fibre Reclaimed by Solvolytic Process from of EOL-Components

Carbon fibre (CF) is widely used in CF reinforced plastic (CFRP) components. However, waste CF, CFRP and the end-of-life (EOL) CFRP structures will cause an even bigger problem in the next years because of strict environmental regulations. Currently, recycling is carried out almost entirely by the use of pyrolysis to regain CF as a valuable resource. This high temperature process is very energy consuming and the resulting fibres are brittle. Hence, not suitable for textile processing into yarns or fabrics. To enable a grave to cradle circle, a new approach based on a solvolytic recovery of CF and the subsequent spinning process to obtain a hybrid yarn suitable for weft knitting processing is the focus of the international research project IGF/CORNET 256EBR “3D-r-CFRP”.

Synthesis and Characterization of Mnbi Magnetic Alloy via Two Different Processing Routes

Manganese bismuth alloy has gained importance due to its rare earth free elements, positive temperature coefficient and unique magnetic properties. Low temperature phase (LTP) MnBi was successfully prepared by arc melting with subsequent heat treatments and melt spinning technique followed by heat treatment for different durations. LTP MnBi formation was confirmed using XRD analysis and microstructural characterization of the samples was done using field emission scanning electron microscope. MnBi with greater LTP amount was formed by melt spinning route when compared with its counter arc melted one. Magnetic energy density of LTP MnBi formed by melt spinning technique with different heat treatment time was studied.

Effects of Bromination-Dehydrobromination on the Microstructure of Isotropic Pitch Precursors for Carbon Fibers.

In this work, isotropic pitch precursors are synthesized by the bromination-debromination method with ethylene bottom oil (EO) as the raw material and bromine as the initiator for pitch formation and condensation reactions. The aggregation structure, molecular weight distribution, and molecular structure of isotropic pitch precursors are characterized by thermal mechanical analyzer (TMA), MALDI TOF-MS, and 13C NMR, respectively, for revealing the mechanism of synthesis of isotropic pitch precursors. The results show that at low bromine concentrations, polycyclic aromatic hydrocarbons (PAHs) were mainly ordered in cross-linked structures by bromination-debromination through substitution reactions of side chains. The condensed reactivity can be improved by the effect of bromine, meaning that condensation reaction was aggravated by the method of bromination-dehydrobromination. In the presence of excess bromine, the cross-linked stereo structure of PAHs changed to the planar structure of condensed PAHs, which was not conducive to the subsequent spinning and preparation of carbon fibers.

The functioning mechanism of Al valid substitution for Co in improving the cycling performance of Zr–Co–Al based hydrogen isotope storage alloys

In order to optimize the hydrogen isotope storage properties of ZrCo alloy and promote its application in the storage and delivery system (SDS), ZrCo alloy is modified by partial substitution of Co with Al and subsequent melt spinning process. The microstructure and hydrogen isotope storage properties, especially the cycling performance, of ZrCo1-xAlx (x = 0–0.15) samples were thoroughly investigated. It is found that all as-cast Al-substituted alloys are consisted of a main phase of ZrCo, while the segregation of Al element at grain boundary is more serious with the increase of Al doping content, which restrains the valid substitution content of Al for Co in ZrCo phase. The initial activation performances of the Al-substituted alloys are enhanced and excellent hydriding kinetics are maintained. With the increase of Al substitution content in ZrCo phase of ZrCo1-xAlx (x = 0–0.15) alloys, the initial saturated hydrogen capacities of α solid-solution phase are improved significantly, which is attributed to the decline of valence electron concentrations (VEC) for Al-substituted alloys. Further analysis shows that the hydrogenation-dehydrogenation process of ZrCo1-xAlx (x = 0–0.15) alloys after multiple cycles has been altered as intercalation and de-intercalation of hydrogen atoms between ZrCo phase and α phase, leading to cycling capacity stabilization. More importantly, the improved terminal saturated hydrogen capacities of α phase in the Al-substituted alloys, which represents enhanced final cycling stable capacities, is linked with the increase of initial saturated hydrogen capacities of α phase after Al substitution for Co in ZrCo phase. In addition, the valid substitution content of Al for Co in ZrCo phase is further increased without any element segregation for ZrCo0.9Al0.1 alloy processed by melt spinning, which behaves further optimized final cycling stable capacity of 0.93 wt%, and its variation of the hydrogenation and dehydrogenation paths is similar to those of the above samples. In this work, the mechanism of cycling capacity stabilization has been explored in detail, which provides guidance to improve the cycling stability of ZrCo-based hydrogen isotope storage alloys from point of phase structure of ZrCo alloy.

MIL-88/PVB nanofiber as recyclable heterogeneous catalyst for photocatalytic and Fenton process under visible light irradiation

The MIL-88/PVB nanofibers were prepared by hydrothermal synthesis and subsequent electrostatic spinning. The composite was used as a high efficiency heterogeneous catalyst for photocatalysis coupling of Fenton process to remove tetracycline hydrochloride (TC-HCl) under visible light irradiation. The results indicated that 99% of TC-HCl (500 mg·L−1) was degraded in 90 min. The MIL-88/PVB nanofibers were easy to separate from solution. The results of scavenging experiments and ESR analysis demonstrated that OH and O2− were the predominant radicals for the TC-HCl degradation. Moreover, the possible mechanism for enhanced degradation performance of TC-HCl in the heterogeneous catalytic oxidation system was proposed.

Optimization design of spinning process of titanium alloy cylinder based on numerical simulation technology

Power spinning is a very complicated plastic forming process, and its processing quality involves many and complicated process parameters. The simufact.forming software is used to simulate the power spinning of the titanium alloy cylindrical parts. The effects of technological parameters such as attacking angle, roller nose radius, feed rate, spinning temperature, etc. on cylindrical parts accuracy, spinning force, and stress-strain distribution are systematically studied. The causes of spinning process defects are analyzed, and the sensitivity of process parameters that affected spinning quality is ranked. Through orthogonal test analysis, it is determined that a set of optimal process parameters for the titanium alloy cylindrical part spinning process: attacking angle is attacking angle 20°, the roller nose radius is 10mm, feed rate is 1mm/r, spinning temperature is 850°C. The spinning process of titanium alloy cylindrical parts is initially formed, which lays the foundation for the subsequent spinning process tests of titanium alloy cylindrical parts.

Carbon fiber from fast pyrolysis bio-oil

The fast pyrolysis bio-oil is a promising product to be used as fuel. It is produced by means of wood particles subjected to high heat rates for very little time. However, the resulting oil has a very high oxygen content, which to be used as fuel requires upgrading processes, which makes its costs higher than mineral oil. The aim of this paper is to study the fast pyrolysis bio-oil as a precursor of carbon fibers. A heat treatment in the bio-oil was used until the optimum softening point temperature was reached for the subsequent melt spinning process. Additives such as kraft lignin and furfuryl alcohol improved the spinning process and caused the fibers to resist the carbonization step. Characterization by Fourier-transformed infrared, 13C VACP-MAS NRM and Raman revealed that the heat-treated bio-oil presented a great amount of oxygenated groups and that mainly the aromatization of the samples was verified after the carbonization process. SEM images showed that the fibers diameters were too high.

Modification of cellulose fibers with inorganic luminescent nanoparticles based on lanthanide(III) ions

This article presents synthesis and properties of the fibers modified with luminescent, inorganic nanoparticles doped with lanthanide(III) ions, i.e. LaF3:Ce3+, Gd3+, Eu3+; CeF3:Tb3+ and CePO4:Tb3+. The fibers with luminescent properties were prepared via so called Lyocell process. This method involves dissolving cellulose in aqueous solution of N-methylmorpholine-N-oxide (NMMO) and a subsequent spinning of the fibers, using a dry-wet method. Thanks to the successful incorporation of the modifier nanoparticles (NPs) into the cellulose matrices, the fibers exhibited bright, multicolor emission upon UV irradiation and good mechanical properties, which allowed further textile processing. This type of fibers, as well as the as-prepared textiles/fabric can be used as an anti-counterfeiting agent for clothes and documents protection.

Influence of LiH addition on electrochemical hydrogen storage performance of Ti45Zr38Ni17 quasicrystal

Ti45Zr38Ni17 quasicrystal ribbons were prepared by arc-melting and subsequent melt spinning technique. Composite materials of Ti45Zr38Ni17 mixed with different amounts of LiH were fabricated via mechanical ball-milling method. The phase structures of the final composite materials consist of the icosahedral quasicrystal phase (I-phase), face-centered cubic phase with a Ti2Ni type crystal, C14 Laves phase and LiH phase. The electrochemical measurements showed that the maximum discharge capacities for the composites were higher than those for the Ti45Zr38Ni17 alloy and reached a maximum (91.5 mAh/g) for 10 wt.% additive content of LiH. Furthermore, the cycling stability and high-rate dischargeability (HRD) of the composite electrodes were improved obviously. The capacity retention of Ti45Zr38Ni17 + 10 wt.% LiH enhanced to 88.1%, and the HRD increased from 75.2% to 88.6%. The improvement of electrochemical properties for the composites may be due to the reversible reaction of LiH in alkaline conditions, which can enhance the electrochemical activity of the alloy during the charging and discharging reactions. The results indicated that LiH was an effective material in improving the hydrogen storage property of the Ti45Zr38Ni17 alloy.

Ultra-soft magnetic Co-Fe-B-Si-Nb amorphous alloys for high frequency power applications

With the continuous shrinkage of the footprint of inductors and transformers in modern power supplies, higher flux, while still low-loss metallic replacements of traditional ferrite materials are becoming an intriguing alternative. One candidate replacement strategy is based on amorphous CoFeBSi soft-magnetic alloys, in their metallic glass form. Here the structural and magnetic properties of two different families of CoFeBSi-based soft magnetic alloys, prepared by arc-melting and subsequent melt spinning (rapid quenching) are presented, targeting potential applications at effective frequencies of 100 kHz and beyond. The nominal alloy compositions are Co67Fe4B11Si16Mo2 representing commercial Vitrovac and Co72-xFexB28-y (where B includes non-magnetic elements such as Boron, Silicon etc. x varies between 4 and 5 % and y is varied from 0 to 2 %) denoted Alloy #1 and prepared as a possible higher performance alternative, i.e. lower power loss and lower coercivity, to commercial Vitrovac. Room temperature magnetization measurements of the arc-melted alloys reveal that compared to Vitrovac, Alloy #1 already presents a ten-fold decrease in coercivity, with Hc ∼ 1.4 Am-1 and highest figure of merit of (Ms/Hc > 96). Upon melt-spinning the alloys into thin (< 30 μm) ribbons, the alloys are essentially amorphous when analyzed by XRD. Magnetization measurements of the melt-spun ribbons demonstrate that Alloy #1 possesses a coercivity of just 2 Am-1, which represents a significant improvement compared to melt-spun ribbons of Vitrovac (17 Am-1). A set of prototype transformers of approximately 10 turns of Alloy #1 ribbon exhibits systematically Hc < 10 Am-1 at 100 kHz, without a noticeable decrease in coupled flux and saturation.

High‐strength regenerated cellulose fibers spun from 1‐butyl‐3‐methylimidazolium chloride solutions

ABSTRACTHigh‐performance regenerated cellulose fibers were prepared from cellulose/1‐butyl‐3‐methylimidazolium chloride (BMIMCl) solutions via dry‐jet wet spinning. The spinnability of the solution was initially evaluated using the maximum winding speed of the solution spinning line under various ambient temperatures and relative humidities in the air gap. The subsequent spinning trials were conducted under various air gap conditions in a water coagulation bath. It was found that low temperature and low relative humidity in the air gap were important to obtain fibers with high tensile strength at a high draw ratio. From a 10 wt % cellulose/BMIMCl solution, regenerated fibers with tensile strength up to 886 MPa were prepared below 22 °C and relative humidity of 50%. High strengthening was also strongly linked with the fixation effect on fibers during washing and drying processes. Furthermore, an effective attempt to prepare higher performance fibers was conducted from a higher polymer concentration solution using a high molecular weight dissolving pulp. Eventually, fibers with a tensile strength of ∼1 GPa and Young's modulus over 35 GPa were prepared. These tensile properties were ranked at the highest level for regenerated cellulose fibers prepared by an ionic liquid–based process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45551.

Simultaneous optimization of electrical and thermal transport properties of Bi0.5Sb1.5Te3 thermoelectric alloy by twin boundary engineering

The strong interdependence between the Seebeck coefficient, the electrical and thermal conductivity makes it difficult to obtain a high thermoelectric figure of merit, ZT. It is of critical significance to design a novel structure that manages to decouple these parameters. Here, we combine a liquid state manipulation method for solidified Bi0.5Sb1.5Te3 alloy with subsequent melt spinning, ball milling, and spark plasma sintering processes, to construct dedicated microstructures containing plenty of 60° twin boundaries. These twin boundaries firstly scatter the very low-energy carriers and lead to an enhancement of the Seebeck coefficient. Secondly, they provide a considerable high carrier mobility, compensating the negative effect of the reduced hole concentration on the electrical conductivity. Thirdly, both experimental and calculated results demonstrate that the twin-boundary scattering dominates the conspicuous decrease of the lattice thermal conductivity. Consequently, the highest ZT value of 1.42 is achieved at 348K, which is 27% higher than that of the sample with less twin boundary treated without liquid state manipulation. The average ZT value from 300K to 400K reaches 1.34. Our particular sample processing methods enabling the twin-dominant microstructure is an efficient avenue to simultaneously optimize the thermoelectric parameters.

ChemInform Abstract: Structure and Permanent Magnet Properties of Zr1‐xRxFe10Si2 Alloys with R: Y, La, Ce, Pr and Sm.

Abstract(Zr0.7Ln0.3) 1.1Fe10Si2 (Ln: Y, Ce, Pr, Sm) alloys are prepared by arc melting and subsequent melt spinning.