Fiber-reinforced composites are ideal materials for lightweight design in fields such as aerospace, building, and electric vehicles. However, their performance improvement is significantly constrained by an insufficient understanding of the complex morphology, orientation, and distribution of the fibers within these materials. The previous methods, including micro-computed-tomography and simplified structural modeling, are incapable of obtaining both universally applicable and high-fidelity models of fiber reinforcement structure. We provide a novel simulation approach that establishing a comprehensive and systematic simulation covering the entire process from raw fibers to the final reinforcement structure. In this paper, A multi-scale Monte Carlo simulation is developed for the initial stage in the entire manufacturing process: the formation of fiber layers from raw fibers. The model integrates three scales-fiber, tuft, and fiber layer-while accounting for the inherent randomness in morphology, orientation, size, and spatial distribution both of fiber and tuft. It successfully achieved a high-fidelity reproduction of the apparent morphology of the fiber layer under varying fiber types and processing parameters. Moreover, the model accurately predicts the influence of process parameters on the lengthwise unevenness of fiber layer for cotton, viscose, and polyester fibers, confirming its validity. This work not only provides a crucial starting point for the precise prediction of the fiber reinforcement structure in composites, but also lays an important modeling foundation for the comprehensive prediction of 'design-manufacture-performance' of fiber-reinforced composites.

The contact morphology and model can effectively characterize the complex morphology between the yarn and the abrasive. A contact model of the yarn-abrasive is constructed using the surface morphology of the abrasive. We compare the effects of abrasive distribution, particle size, and contact model on the contact area and stress to determine the applicable abrasive distribution and contact model for the yarn-abrasive contact. According to the adhesive parameters, the Hertz contact model provides a more accurate framework for characterizing yarn-abrasive interactions under these experimental conditions. The particle size of abrasives has a considerable effect on their contact area and stress; conversely, the distribution of abrasives has no impact. From the anti-abrasion properties of the yarn, we can select the standard particle size as the abrasive size and use the Hertz contact model to calculate the contact stress between the yarn and the abrasive more reliably.

The batt is the first semiproduct in the yarn spinning process, and its longitudinal mass unevenness significantly affects the properties of the spun yarn. Therefore, establishing a theoretical model for batt unevenness is crucial for accurately predicting and controlling yarn quality. However, previous models only address cross-sectional unevenness and are not applicable to unevenness along the commonly used segment length (i.e. 1 m). Furthermore, these models are semiempirical and no longer valid because of the progress in both equipment and technology for yarn spinning. In this paper, we first derive an expression for batt unevenness caused by the random positional distribution of tufts—the constituent elements of the batt—that is valid for arbitrary segment lengths. Second, an improved expression is developed by incorporating tuft mass randomness via variance addition. Then, using MATLAB and the Monte Carlo method, the randomness of tuft number and mass was simulated to obtain the unevenness and mass variation of the batt. Finally, data from experiments with cotton, viscose, and polyester fibers for segment lengths ranging from 30 to 300 mm and from previous literature for a segment length of 1 m were used to verify the proposed expression and simulation method. Results show highly consistent trends between measured and predicted batt unevenness, with correlation coefficients exceeding 0.92 for cotton, exceeding 0.91 for viscose, and exceeding 0.94 for polyester, strongly confirming their effectiveness. This research provides a basis for predicting batt and yarn properties, and offers guidance for designing optimum process parameters in yarn production.

Valorization of non-cellulosic polysaccharides is crucial for enhancing the economic competitiveness of biorefinery processes. In this study, a mixture of boric acid and sodium hydroxide was employed to efficiently extract hemicellulose from holocellulose switchgrass. Borate-assisted alkaline extraction resulted in a higher xylan content (59.5 %) compared to conventional alkaline extraction. The hemicellulose fractions derived from the borate-alkaline treatment exhibited a higher molecular weight (Mw = 51.2 kDa) and a relatively lower degree of polydispersity (1.28), indicating improved structural stability. The presence of borate had a protective effect against chain scission, preserving glucuronic acid residues and increasing galactose content. Additionally, borate improved hemicellulose purity, with up to 74.1 % of the extracted hemicellulose being suitable for further enzymatic applications. Extended extraction time further enhanced hemicellulose recovery, reaching 97.9 % under NaOH/boric acid conditions while maintaining structural integrity, as confirmed by SEM, FTIR and 2D HSQC NMR analyses. These findings provide insights into the role of borate in optimizing hemicellulose extraction and improving its potential for bioconversion processes.

Staple yarn is the basic element of most textiles, and the breakage mechanism of staple yarn has always been a topic of focus in the textiles field. Fiber tension in staple yarn, caused by twisting, forms the basis for exploring its breakage mechanism. In this paper, a numerical model is proposed to simulate the fiber tension in staple yarn, considering fiber properties, staple yarn parameters, and the shrinkage of fibers during twisting. To ensure the reliability of the model, several typical and commonly used staple yarns were analyzed to validate the simulated results. The results show that the fiber tension in staple yarn is related to its fiber properties and linear density. Meanwhile, the mean absolute percentage error of the numerical model is only around 5%–8%. The correlation coefficient R between the simulated results and the tested results is 0.99, proving that the model has very good accuracy and applicability. This model would provide a basis for further research on the breakage mechanism of staple yarn.

Background: Transient flow characteristics of airflow in restricted annular nozzles remain underexplored. Objective: This research aims to elucidate the transient dynamics of airflow during vortex spinning. Method: Five nozzle configurations with distinct structural parameters (detailed in Section 3.1) were analyzed using 3D dynamic grid numerical simulations and theoretical methods. Results and findings: circle The airflow field exhibits intrinsic instability, characterized by turbulence, eddy formation, and backflow dissipation. circle Case 2 (spiral surface angle: 30 degrees; jet holes: 5 x & Oslash;0.5 mm; cone angle: 10 degrees) achieved peak tangential velocity, enhancing fiber wrapping and twisting. circle Optimizing airflow paths streamlines the nozzle's inner profile and selectively amplifies tangential airflow, improving fiber wrapping. Implications: Understanding transient flow enables: (i) Airflow path optimization for reduced resistance, (ii) Smoother inner nozzle surfaces, (iii) Minimized yarn friction and tension fluctuations,thereby improving spinning efficiency and yarn quality.

Loop yarn is a typical fancy yarn composed of three strands and differs significantly from conventional yarn. The loop yarn also suffers from friction and wear during use and processing. To create a unique fuzzing effect, loop yarn is usually sanded by rubbing against an abrasive. The frictional force and coefficient can only roughly reflect the frictional effect between yarn and abrasive, and it is challenging to represent the amount of contact between the two at the microscopic level. A Hertz contact model is first established to evaluate the contact between the loop yarn and the abrasive. This paper derives the calculation formula for the contact number and area between the loop yarn and the abrasive. The calculation results indicate that as the mesh of the abrasive increases, the frictional force and coefficient decrease, the contact number between the loop yarn and the abrasive gradually increases, the contact area first increases and then tends to stabilize, and the contact force and stress decrease and stabilize. The ratio of the fiber distribution force to its contact area can be used as an evaluation index for fiber wear resistance. The product of the square root of contact number, abrasive particle radius, and friction index can provide feedback on friction performance.

In recent years, conductive gel materials have attracted extensive attention in the field of flexible electronics because of their excellent elasticity. When constructed as gel fibers, they can adapt to greater deformation, be woven, and be assembled with fabrics to make wearable smart devices without compromising comfort. However, gel fibers reported often exhibit insufficient mechanical properties and poor adaptability to different environment. Herein, a super-stretchable ionic conductive gel fiber is reported. It is formed via a solvent-free templateassisted strategy, with a polyacrylamide (PAM) - TEMPO-mediated oxidized cellulose nanofibrils (TOCNF) double-network as main structure. The influence of each component content was analyzed. The addition of TOCNF significantly toughens the fiber (breaking strength, strain and toughness of 3.55 MPa, 1715.66 % and 4.75 MJ/m3, respectively) and provides larger channels for ion transport. The synergistic effect of lithium chloride (LiCl) and glycerin in system endows the fiber with properties of anti-dehydrating, anti-freezing, and good ionic conductivity (0.128 S/m). When used as a wearable strain sensor, the gel fiber has good linear response (sensitivity gauge factor of 0.8128) in the strain range of 0-300 %, which can accurately and stably sense human body movement, such as finger bending, wrist activities, walking and running in real time.

In this study, a novel bleaching method for ramie cellulose fibers with low oxidative damage was developed by utilizing the properties of sodium percarbonate contained in tea saponin, which slowly releases hydrogen peroxide in the catalytic oxidation system of N-hydroxyphthalimide (NHPI). First, the bleaching process was optimized using response surface design, followed by comparison and characterization of fiber properties prepared under different bleaching systems. Finally, the energy consumption, water consumption, and toxicity of the NHPI/tea saponin system were evaluated. The results demonstrated that fibers bleached by catalytic oxidation with the NHPI method (COBM-N) exhibited a 170 % increase in whiteness and a 5.16 % improvement in breaking tenacity compared with degummed ramie fiber, while the specific work of rupture (SWR) decreased by only 2.4 %. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR) analyses revealed that non-cellulosic substances in raw cellulose fibers were further removed after bleaching. X-ray diffraction (XRD) analysis showed that fiber crystallinity was closely related to SWR. The crystallinity of degummed ramie fibers, COBM-N fibers, and oxidation-bleached fibers without NHPI (OBM) was determined to be 89.92 %, 89.13 %, and 88.26 %, respectively. Furthermore, the SWR of these fibers also decreased sequentially. Selective oxidation of cellulose fibers at the C6 position was confirmed by 13C nuclear magnetic resonance (NMR) analysis. Raman mapping analysis showed that the intensity of the absorption peak at 1604 cm-1 decreased after bleaching, confirming that colored groups were removed by oxidation. Life Cycle Assessment (LCA) indicated that, compared with the sucrose octaacetate (SOA) system, the NHPI/tea saponin system reduced energy consumption by about 37.84 % and water consumption by 35.80 %, with a lower environmental impact.

In the early stage, we established a tuft disentanglement model considering the interaction between fibers. In the disentanglement model, the fiber was assumed to be a multi-rigid chain model, with only friction between fibers. However, this model can only simulate the frictional mechanical response of fibers under a single carding action without evaluating the carding results. This paper applies the disentanglement model to the taker-in part of the carding machine, where one end of the tufts is continuously carded as the other end is gripped. Also, the effect of the carding parameters, such as the gauge between the feed roller and the taker-in and the speed of the taker-in, on disentanglement was studied based on the carding results, which are evaluated by the weight percentage of carded tufts. The simulation results showed that the higher taker-in speed and the smaller gauge can reduce the weight percentage of tufts after carding, which means better carding results. Similar trends were observed in the experiments, which verified the rationality of the simulation of tuft disentanglement for the taker-in part. Future work would apply the model to emphasize the frictional mechanical behaviors of fibrous materials involving fiber interactions given a specific scene during spinning.

Drafting is a critical process in spinning that attenuates slivers or strands into yarn and influences the final yarn quality. Roller pressure is key to controlling fiber movement within the strand during drafting. However, previous studies have mainly concentrated on roller pressure in non-twisted strands, leaving the effects on twisted strands unexplored. This study develops a geometric model to analyze the roller pressure distribution in twisted strands during drafting and establishes a mechanical calculation model for further analysis. A thin-film pressure sensor was used to measure the pressure distribution and validate the calculation model. The results indicated that the maximum deviation between the calculated and measured values was 9.58%, confirming the accuracy of the model in predicting pressure distribution on twisted strands held by the roller nip. Additionally, this study investigates how linear density and twist factor influence strand compression properties. Increasing strand linear density promotes uniform pressure distribution, while a higher twist factor leads to stress concentration and elevated compressive stress. Understanding roller pressure distribution is essential for accurately predicting fiber interactions and movement during drafting, ultimately aiding in yarn quality assessment.

Fancy yarn is a type of strand with a unique structure, and its appearance differs from conventional yarn. Wearing tests were conducted on loop yarn. The calculation method for the tensile force of worn loop yarn was established by integrating the calculation methods of tensile force for ply yarn and loop yarn to control the tensile force of loop yarn accurately during wearing. Its accuracy in calculating the tensile force of worn loop yarn was verified. As the wear continued, the loop yarn became fuzzy and had broken yarn, and the tensile force of the component yarn continued to decrease. By comparing the calculated and measured tensile force of worn loop yarn, it is found that the revised calculation formula for tensile force can predict the tensile force of worn loop yarn, and this method is more accurate than other previous methods. Therefore, the revised formula for the tensile force applies to calculate the tensile force of worn loop yarn, and it can also be used for tension adjustment in the fuzzing process of loop yarn.

Improving the uniformity of phase separation in wet spinning is crucial for enhancing fiber properties. Different from traditional wet spinning methods, in this approach, the calcium source is homogeneously dispersed in the alginate spinning solution as nano-calcium carbonate. The release of calcium ions and in-situ crosslinking are regulated by adjusting the pH of the coagulation bath, thereby enhancing crosslinking uniformity. Morphology and distribution of calcium ions analysis revealed that the radial structure of the in-situ crosslinking spinning fibers is denser and more uniform, with a higher calcium ion concentration indicating a stronger degree of crosslinking. Tensile tests demonstrated that the fracture strength of in-situ crosslinking spun fibers without drawing is twice than that of traditional wet spinning fibers. This method offers a novel approach for the fabrication of wet-spun fibers with a uniform radial structure and high strength.

The structural coloration arising from the orderly arrangement of nanoparticles has garnered significant interest. Cellulose nanocrystals (CNCs) represent a form of liquid crystal capable of self-assembling into cholesteric configurations as their concentration increases. The distinct morphology and surface functionalities of CNCs give rise to diverse self-assembly architectures. Nonetheless, the challenge persists in fabricating successive fibrous materials that exhibit long-range ordered structures while maintaining processable mechanical characteristics. Herein, a precursor spinning solution was injected into microtubules via a syringe pump and introduced into a coagulation bath containing Ca2+ ions at a regulated flow rate, resulting in multi-scale filaments composed of CNC and alginate. Experimental evaluations and computational modeling reveal that enhanced cross-linking interactions between oxalic acid-derived CNCs and calcium ions significantly improve the tensile properties of the resulting filaments, achieving a maximum tensile strength of approximately 140 MPa. The innovative topological configuration of the filaments endows them with coordinability and polarization-based encryption capabilities, positioning them as promising candidates for advanced textile applications aimed at directed signal transmission or identification.

Natural fiber reinforced composites possess the advantages of lightweight, degradability and excellent mechanical properties. The primary objective of this work was to investigate the effect of the distribution of reinforcing fibers and the matrix within the composite on the performance of composites. The biomass-based composites were prepared by hot-pressing the fabrics woven by core-spun yarn that produced from flax noil fibers and Polylactic Acid (PLA) fibers, utilizing the thermo-plasticity of PLA fibers. The core-spun yarns were constructed with a core-sheath structure, in which the core yarn was a flax/PLA blended yarn and the sheath part was PLA staple fibers. The special structure effectively improved the hairiness, evenness and weave-ability of the yarn. The properties of the composites were improved by controlling the distribution of PLA and flax fiber in the core and sheath of the core0-spun yarn in order to improve the distribution of the reinforcing fibers and matrix. The biomass-based composites presented the excellent tensile properties (breaking strength of 32 MPa, elongation of 14.3 %), tearing properties (tearing energy of 95.71 KJ/m2) and dynamic thermo-mechanical properties (storage modulus of 1953 MPa at 35 degrees C temperature, loss factor of 0.285), when the blending ratio of PLA and flax fiber within the core yarn was 80:20. In addition, the composites showed superior environmental friendliness, with a biodegradability of 52.1 % within 180 days. These biomass-based composites developed in this work display admirable potential applications for automobile interiors, sporting equipment, packaging materials, etc.

Aqueous Zinc-ion batteries have been a promising candidate for large-scale energy storage system benefiting from its economic, high safety and energy density. Whereas, the issues of Zn anode that surrounding dendrite growth, side reaction and corrosion have hindered it from further practical application. To circumvent these problems, we propose an organic/inorganic functional Janus separator based on commercial glass fiber (GF) membrane, effectively inhibiting the growth of Zn dendrite and enhancing the reversibility of Zn anode. The functional layer with dense and tiny pore, can restricts ion diffusion, and the filler of Graphene oxide- Titanium dioxide (GO-TiO2) could induce the Zn2+ epitaxial deposition. The Zn symmetric cell with the modified separator runs over 2000 h stably at a density of 1 mA cm-2 (1800 h, 2 mA cm- 2). Even at a higher density of 5 mA cm- 2, it also shows an ultralong lifespan of over 600 h. When assembled into Zn//MnO2 full cell, the modified separator shows higher capacity (initial capacity of 112.1 mAh g- 1) and capacity retention (60.57 % after 500 cycles at 1C) than GF (97.1 mAh g- 1, 48.4 %). Furthermore, the full cell with the modified separator possesses more excellent rate performance. This novel modification strategy of separator opens up more possibilities for high-performance aqueous Zn-ion batteries.

In the authors’ previous work, slub yarn was simulated by randomly determining the fiber position with the Monte Carlo method according to the draft principle of ring-spun slub yarn. In this paper, the total torque of each micro-element yarn was calculated by considering the contribution of fiber bending, twisting and stretching to the torque of yarn body. The micro-element yarn is a regular ring-spun yarn. The twist of each micro-element yarn can be calculated according to the equal torque between micro-element yarns and the conservation law of twists. The twist curve along the yarn axis also can be obtained. The simulation values of the slub twist and base twist can be obtained by calculating the average twist of the slub apparent segment and that of the base apparent segment, respectively. The twist angle and diameters of the slub and base apparent segments of the spun slub yarn were measured using scanning electron microscopy images, enabling determination of the measured values for both slub twist and base twist. The average error rate of the simulated value compared with the measured value for slub twist was 7.654%, while for base twist, it was 7.745%. The relationships between slub length, base length, slub multiple, design twist, and both slub twist and base twist were investigated. The correlation coefficient ( R) of the simulated and measured values was generally above 0.9, and the trend of the two was consistent. The work presented in this paper provides a basis for the development of virtual spinning technology.

The performance of blended yarns is affected by the distribution of component fibers within blended yarn and the blending uniformity. However, there is a lack of comprehensive and quantitative investigations on the relationship between them. In this paper, various specifications for two-component blended yarns were prepared, and the main factors affecting blending uniformity were analyzed. Then the yarn blending irregularity and yarn performance, including tenacity, tenacity coefficient of variation, extension and yarn unevenness were tested. Finally, Pearson correlation analysis and linear regression were performed between blending irregularity and each yarn performance to characterize the influence of blending uniformity on yarn performance quantitatively. The results show that the blending irregularity is effectively improved by uniform feeding of slivers, and increasing the passage of sliver blending. The blending irregularity has no significant influence on the relationship between twist factor and yarn performance. The blending irregularity has the most positive and highest effect on tenacity coefficient of variation, followed by tenacity and unevenness in third place, and the Pearson correlation coefficient ( P) were all above 0.5, and the linear regression coefficient was above 10−3, but the breaking extension was weakest and negatively correlated with blending irregularity. Except for breaking extension, the effect of blending irregularities on yarn performance becomes more obvious when there are large differences in fiber linear density and fiber length. This paper reveals the relationship between blending uniformity and yarn performance, to provide a basis for theoretical research on the properties of blended yarns.

The morphology parameters of slub yarn include slub length, base length, the length of the transitional segment, slub multiple, slub linear density, base linear density, and average linear density of slub yarn. These parameters have an impact on the appearance of both slub yarn and its fabric. This paper aims to predict the morphology parameters of spun slub yarn by utilizing the model proposed in Part 1 for ring-spun slub yarns. Once the slub generation mode was known, slub yarn could be simulated with the morphology parameters. The simulated slub fabric was obtained by arranging the simulated slub yarn in the warp and weft directions. According to our study, the prediction accuracy of each morphology parameter was over 80% by comparing the simulated parameters with the measured ones of spun slub yarn. The CV (coefficient of variation) of the slub segment number per unit area was utilized to assess the distribution of slubs in the simulated fabric. This research can facilitate the development of slub yarn and its fabric, providing guidance for technicians to enhance production technology.

Roller drafting, a key mechanical operation for attenuating slivers to a desired thickness, holds critical significance in the spinning processes of the textile industry. Within the drafting stage of spinning, the motion state of fibers is influenced by their intrinsic characteristics, the force applied, and the distribution of both fast-moving and slow-moving fibers. This research focused on man-made fibers, which are isometric, and studied their distributions in the roller drafting zone. In addition, the cut-off weighting method was incorporated to measure the fiber distributions in the drafting zone, the impact of drafting parameters on fiber distribution was discussed, and the associated fiber distribution curves were generated. Findings reveal that fiber distributions are highly affected by factors such as the fiber length, roller-setting, and draft ratio. Conversely, the input sliver linear density and doubling number exhibited negligible influence on the fiber distribution. The total fiber distribution curve appeared as a dichotomy, including a horizontal line and an oblique line. This study also presented a second-order regression model and a deduction model to predict the distribution of isometric fibers in the roller drafting zone.