Polymer Fibers Research Articles

Effect of Hemp and Sheep Wool Reinforcements on Mechanical and Acoustic Properties in Natural Fibre Polymer Composite using Vacuum Bag Moulding Process

Effect of Hemp and Sheep Wool Reinforcements on Mechanical and Acoustic Properties in Natural Fibre Polymer Composite using Vacuum Bag Moulding Process

Photoinduced bending in bimorph optical fibers

Optomechanical materials directly generate work from light through physical deformation upon illumination. Here, we report an optical fiber-based optomechanical actuator that undergoes bending when illuminated by actinic light. A model for light-induced bending curvature as a function of geometrical and material properties was developed to aid in design. Polymer fibers were fabricated and filled directly during the draw with a molten azobenzene derivative. Upon illumination, photoactivated motion is observed and quantified with an optical lever beam approach.

Optimization of microwave-produced coal-derived char insulation foam using response surface methodology

A new char-based insulation foam (CIF) is developed using coal-derived pyrolysis char (PC) and lignin, a paper and pulp industry byproduct. In this study, CIF is prepared by adopting the microwave method and Response Surface Methodology (RSM) is utilized to optimize predictions about the properties such as thermal conductivity, foam texture, compressive strength, and pore distribution of CIF. The three independent variables including percent char content, lignin/char ratio, and foaming agent/polyol ratio are considered in the RSM methodology. The face-centered central composite design is selected to obtain 17 test runs. Optimization of the predicted responses is performed to find the recipe considering a composite desirability function. Confirmatory test results show agreement between the predicted and observed values, with the percent error ranging from 0.00 % to 11.35 %, thereby confirming the accuracy of the prediction equations. The optimized CIF exhibits a thermal conductivity of 0.0633 W/m.K and a compressive strength of 695 kPa making it comparable to or better than traditional building insulation products such as fiber insulation, polymer composite, particle board, and ceramic glass foam. Therefore, this new CIF has the potential to be used as an energy-saving insulation material for building envelopes.

Electrospinning of polyetherketoneketone fibers: The effect of fabrication regime on the morphology, physico-chemical and biological characteristics

Electrospinning is a unique technology based on the fabrication of polymer fibers from the solution under an applied electric field. Electrospun membranes are applied in various fields, starting from filter technologies to tissue engineering. Polyalyletherketones (PAEK) is a family of synthetic bioinert polymers characterized by outstanding mechanical performance, high chemical stability, and biocompatibility. In the present study, the effect of electrospinning parameters (collector-to-tip distance, applied voltage, spinning solution flow rate and polymer concentration in the spinning solution) on the morphology of the fabricated polyetherketoneketone (PEKK) membranes as well as their crystal structure, chemical stability and biocompatibility was investigated. Based on 108 combinations of the electrospinning parameters, it was found that minimum concentration of PEKK in the spinning solution in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) required for the fibers’ formation is 4 wt %, while the applied voltage providing fibers without defects was found at 20 kV. It was demonstrated that the tested electrospinning regimes allow to fabricate the membranes with average fiber diameter from 0.76 ± 0.29 to 1.46 ± 0.60 μm and porosity from 87 ± 1 to 92 ± 1 %. It was found that electrospinning process has no effect on the chemical structure of PEKK macromolecules. Electrospinning parameters had no effect on crystal structure of PEKK in the fabricated membranes, which was found to be amorphous. The fabricated membranes demonstrated high Young modulus (above 150 MPa) and elongation over 170 %, were stable in strong alkali and acid solutions and biocompatible towards mouse embryonic fibroblasts.

Study of Ultra-High Performance Concrete Mechanical Behavior under High Temperatures.

The main concern with concrete at high temperatures is loss of strength and explosive spalling, which are more pronounced in high-strength concretes, such as Ultra-High Performance Concrete (UHPC). The use of polymeric fibers in the mixture helps control chipping, increasing porosity and reducing internal water vapor pressure, but their addition can impact its mechanical properties and workability. This study evaluated the physical and mechanical properties of UHPC with metallic and PVA fibers under high temperatures using a 23 central composite factorial design. The consistency of fresh UHPC and the compressive strength and elasticity modulus of hardened UHPC were measured. Above 300 °C, both compressive strength and elasticity modulus decreased drastically. Although the addition of PVA fibers reduced fluidity, it decreased the loss of compressive strength after exposure to high temperatures. The response surface indicates that the ideal mixture-1.65% steel fiber and 0.50% PVA fiber-achieved the highest compressive strength, both at room temperature and at high temperatures. However, PVA fibers did not protect UHPC against explosive spalling at the levels used in this research.

Analysis and Optimization of Delamination Factor for Microwaved Cured Pineapple Leaf Fiber Polymer Composite through ANOVA Analysis

Analysis and Optimization of Delamination Factor for Microwaved Cured Pineapple Leaf Fiber Polymer Composite through ANOVA Analysis

Cleaner and Sustainable Production of Core-Sheath Polymer Fibres.

The amalgamation of sustainable practises throughout the fabrication process with advanced material engineering holds promise not only for eco-conscious manufacturing but also for promoting technological advancements in versatile material design and application. Moreover, technological innovation serves as a catalyst for sustainability initiatives, driving innovation and enabling the adoption of greener practises across industries. This study investigates redefining the production protocol of pressure spinning to produce core-sheath polymer fibres, deepening sustainable practises. It aims to explore innovative approaches such as modifying spinning parameters, optimising polymer solvent configurations and understanding fluid behaviour to curtail material wastage and maintain minimal energy consumption without compromising production efficiency. Utilising Polyvinylpyrrolidone (PVP) for the core and Polyethylene oxide (PEO) for the sheath, production rates of up to 64 g/h were achieved with a fibre diameter range of 3.2 ± 1.7 µm to 4.6 ± 2.0 µm. Energy consumption per mass of fibres produced showed a decreasing trend overall with increasing applied gas pressure. These findings highlight the potential for the efficient and scalable production of core-sheath fibres with applications in various advanced materials fields.

The Effects of Pulsed Electrospinning Process Variables on the Size of Polymer Fibers Established with a 23 Factorial Design.

In the present study, the influence of the electrical parameters of the pulsed electrospinning process, such as the electrical voltage, the frequency of pulses, and the pulse duration, on the structure of obtained nonwovens was determined for the first time. It was found that all the parameters studied strongly influence the average diameter of the obtained fibers and that the pulsed electrospinning process carried out under specific conditions makes it possible to obtain, among other things, bimodal nonwovens. A 23 factorial design was used to determine how the selected electrical parameters of the pulsed electrospinning process affect the structure of the resulting electrospun mats. It is shown, among other things, that by appropriately selecting the parameters of the electrospinning process, the thickness of fibers can be controlled, resulting in nonwovens with a desired morphology.

Mechanical properties and ductility improvement mechanisms of fiber-reinforced biomimetic mineralized composites using sea sand

Biomimetic mineralized composites (BMC) is an emerging green cementing material. However, the application of BMC is limited by brittle failure. This study proposes novel fiber-reinforced biomimetic mineralized composites (FRBMC) with excellent ductility based on the coupling method of fiber reinforcement and biomimetic chemically induced calcium carbonate precipitation (BCICP). Three typical fibers, including polymer fibers (polypropylene fiber, PF), mineral fibers (basalt fiber, BF), and plant fibers (coir fiber, CF), were used to explore the feasibility of application in FRBMC. Accordingly, mechanical properties, pore structures, and microscopic characteristics were assessed through unconfined compressive strength (UCS) test, mercury intrusion porosimetry (MIP) tests, and scanning electron microscopy (SEM). The results show that fiber induces a transition from brittle to ductile failure modes in BMC. PF exhibits the most notable enhancement in residual strength and peak strain, while BF leads to the highest compressive strength. CF can effectively enhance energy absorption after reaching peak stress. Moreover, FRBMC with CF contains a higher quantity of minute pores, while BF can reduce the porosity of FRBMC. The calcium carbonate crystals effectively cement fibers and sand particles, enhancing the ductility of FRBMC through forming various cementing structures. This study investigates the synergistic effect of BCICP and fiber reinforcement, providing valuable guidance for potential practical applications of FRBMC.

Polybenzimidazole-Reinforced Terphenylene Anion Exchange Water Electrolysis Membranes.

Anion exchange membrane water electrolysis (AEMWE) for hydrogen production combines the advantages of proton exchange membrane water electrolysis and alkaline water electrolysis. Several strategies have been adopted to improve the performance of AEMWE and to obtain membranes with high hydroxide ion conductivity, low gas permeation, and high durability. In this work AEMs reinforced with poly[2,2'-(p-oxydiphenylene)-5,5'-benzimidazole] (PBIO) polymer fibres have been developed. A fibre web of PBIO prepared by electrospinning was impregnated into the poly(terphenylene) mTPN ionomer. The membranes are strengthened by the formation of a strong surface interaction between the reinforcement and the ionomer and by the expansion of the reinforcement over the membrane thickness. The hydroxide ion conductivity, thermal stability, dimensional swelling, mechanical properties, and hydrogen crossover of the reinforced membranes were compared with the characteristics of the non-reinforced counterpart. The incorporation of PBIO nanofibre reinforcement into the membrane reduced hydrogen crossover and improved tensile properties, without affecting hydroxide conductivity. PBIO-reinforced mTPN membrane was assessed in a PGM-free 5 cm2 AEMWE single cell using NiFe oxide anode and NiMo cathode catalysts, at a cell temperature of 50 °C and with 1 M KOH fed to the anode. The performance of the cell increased continuously over the 260 hours test period, reaching 2.06 V at 1.0 A cm-2.

Nonlinear finite element damage analysis of laminated shells by Carrera Unified Formulation

The paper presents a comprehensive study on the nonlinear finite element analysis of laminated shells, employing the Carrera Unified Formulation (CUF) in conjunction with a progressive damage model developed by Tita et al. (2008). This research focuses on accurately predicting the behavior of laminated composite structures under progressive damage. The model accounts for both polymer matrix and fiber failures, and the numerical implementation and simulations are performed using MATLAB. The study validates the proposed framework by comparing the numerical results with experimental data, demonstrating a good agreement and thus confirming the model’s capability to capture the nonlinear behavior of laminated shells during damage progression. The research also highlights the importance of the CUF in providing a versatile approach to finite element analysis, allowing for different families of elements and, thickness expansions and use of failure criteria that consider out of plane stresses, which can be particularly useful for a more detailed and physically consistent analysis of damage in composite materials.

Seaweed Superheroes: Cystoseira barbata-Incorporated Electrospun Fibers for Lead Ion Sequestration.

The efficient removal of lead ions at low concentrations is paramount in combating the significant threat posed by water pollution resulting from industrial activities and population growth. In this study, electrospun C. barbata/PAN fibers were developed to efficiently remove lead(II) ions from water. The morphology, structure, and mechanical properties of the fibers were examined, highlighting that the augmentation of the surface area through the conversion of C. barbata into the polymer fibers facilitates increased metal bonding sites during sorption. C. barbata/PAN fibers exhibited superior characteristics, including higher surface area, smaller pore size, and increased pore volume, compared to powdered C. barbata. The effects of factors such as shaking time, algae percentage, sorbent amount, pH, metal concentration, and temperature on Pb(II) sorption were investigated by the batch method. At an initial ion concentration of 100 μg L-1 and pH 4.0, C. barbata (5 wt %)/PAN fiber demonstrated a notable sorption efficiency of 89-90% (270 μg/g) after 60 min. The equilibrium data align with the Freundlich and Dubinin-Radushkevich isotherm models, whereas the pseudo-second-order kinetic model provides the most suitable description. The characterization of fibers after sorption revealed that carboxyl, hydroxyl, and sulfonyl groups play an active role in Pb(II) sorption.

Performance of Self-healing Cementitious Mortar with PVA Fiber and SAP

Although concrete materials generally exhibit outstanding mechanical properties, it is susceptible against crack formation. It has been reported that narrow cracks (≤ 150 µm) could be naturally sealed in the cement matrix by externally supplied water-induced hydration. However, the crack width of larger than 150 µm is difficult to be sealed without using additional self-healing admixture. In this study, the self-healing cementitious mortar was successfully developed by using a combination of polyvinyl alcohol (PVA) fiber and superabsorbent polymer (SAP), aiming to heal the wide cracks. Although the mechanical properties were slightly reduced, it shows outstanding self-healing performance by using the dual admixtures. A self-healing rate of 60% was observed in the control sample with an initial crack width of 300 µm, while a self-healing rate of nearly 100% was confirmed with suitable SAP and PVA. In addition, it was confirmed that lower hydration degree of self-healing mortar in early stage contributes to the enhanced self-healing performance of developed composite system by internally supplied water from SAP.

Polyphenol assisted assembly of prussian blue analogs nanocrystals decorated 3D GO functional microspheres for polymer fiber bifunctional membrane with high oil-water emulsion permeability and powerful photocatalytic self-cleaning ability

Due to the intricate components of wastewater and physical stacking of graphene oxide (GO), the current GO membranes exhibit the fatal defects of low porosity and poor anti-fouling ability. Herein, a three dimensional (3D) FeCo-PBA@GO functional microsphere was constructed via anchoring GO nanosheets onto hard template of 3D polymethyl methacrylate (PMMA) microsphere driven by hydrogen bond and van der Waals force. On this basis, the Prussian blue analogs nanocrystals (FeCo-PBA) grew in situ on such functional microsphere and further assembled onto porous polyacrylonitrile (PAN) fiber mat through the tannic acid assisted spraying technique, resulting in highly permeable and photocatalytic self-cleaning FeCo-PBA@GO/PAN fibrous composite membrane. Interestingly, the unique 3D nanostructure of FeCo-PBA@GO microsphere arranging on membrane surface effectively prevented the dense physical stacking of GO nanosheets and increased the oil repellence property, thereby regulating the water channel and breaking through permeability limitation of membrane. As a result, the composite membrane exhibited superior separation fluxes (˃3029 L m−2 h−1) for different oil/water (O/W) emulsions, with rejection rate above 99.0 %. Owing to rich active sites and enhanced electron/mass transport property of FeCo-PBA functional layer, the composite membrane could effectively degrade various dyes by peroxymonosulfate (PMS) activation, with the degradation efficiency of 93.1–96.9 % within 40 min and demonstrated favorable antifouling and photocatalytic self-cleaning ability after cycling separation of O/W emulsion. In addition, the generated multiple reactive oxygen species and photocatalytic mechanism were proposed. This work provides a versatile pathway to prepare multifunctional GO advanced membranes for large-scale treatment of complex emulsified oily wastewater.

Electrochemical Characterization of Non-Aqueous and Aqueous Gel Polymer Electrolytes for Zinc-Ion Fiber Batteries

The increasing miniaturization of integrated circuits has enabled a wide variety of new applications for embedded sensors and smart devices. Miniaturization of their power sources, however, has lagged in comparison. There are many challenges to devising a space-conscious battery, including the power density, mechanical stability, and chemical safety. Batteries made in fiber formats are of interest for use in wearable electronics. Recent studies have shown the feasibility of Li-ion battery chemistries in drawn polymer fibers via thermally induced phase separation (TIPS)1,2 but key performance gaps in safety and reliability of these fiber batteries remain.In addition to Li-ion, zinc-manganese dioxide (Zn-MnO2) chemistries are particularly good candidates for fiber format batteries due to their relatively low raw material cost, low reactivity, and tolerance of environmental contaminants such as water. Our work has focused on two Zn-MnO2 gel polymer electrolyte (GPE) cell formats: one non-aqueous polyvinylidene fluoride (PVDF) based gel polymer electrolyte, the other an aqueous polyvinyl alcohol (PVA) based GPE. In this work, we synthesize, characterize, and compare these two electrolyte formats head-to-head in both Zn-Zn symmetric cells and Zn-MnO2 full cells.After the GPEs were synthesized, thermo-gravimetric analysis was used to characterize the gels and evaluate the feasibility of drawing the GPE of interest into fibers. We synthesized zinc salt containing PVDF-based GPEs and characterized them in ionic blocking cells via electrochemical impedance spectroscopy (EIS), achieving conductivities of 1.8 mS/cm2. We also assembled Zn-Zn symmetric cells, investigated key performance characteristics such as the transport number and the electrochemical stability window, and stably cycled them for over 500 hours at 0.5 mA/cm2. Lastly, we assembled Zn-MnO2 full cells to confirm the battery performance.

One-Step Fabrication of Semi-Transparent Nanofibrous Lithium-Ion Battery

Flexibility and transparency of batteries greatly expand their application and offer new opportunities to electronic devices making them foldable, bendable, and not obstracting. Herein was proposed a facile and beneficial strategy to solve “hot” issues of such type of batteries by providing a uniform and stable framework for bendable, portable and semi-transparent "all-in-one" lithium-ion batteries (LIBs). The “all-in-one” flexible LIB was fabricated by one-stage electrospinning of PEO and PVDF-HFP-based precursor solution loaded with active materials. The electrochemical performance of the anode and cathode membranes was investigated in lithium half cells. To improve the electron-conductivity, CNTs were introduced inside the nanofibers in anode and cathode parts. The nanofibers containing active materials were successfully fabricated with the use of pre-synthesized nanosized LFP/C and graphite powders and loading them into the electrospinning solutions of the cathode and anode, respectively. The use of the same polymer to produce all three parts of the battery (anode, separator and cathode), as well as optimized electrospinning conditions, made it possible to obtain all-in-one flexible solo membrane. The concept was based on the application of nanofibers containing pre-synthesized active materials without carbonization, sintering or any other post-treatment. The developed “all-in-one” membrane assembled within copper and nickel meshes acting as anodic and cathodic current collectors demonstrated semi-transparency as can be seen from the figure. It is enabled by the swollen polymer fibers network, which provides transparent substrate for nano-sized particles of active materials. Additionally, the thin metallic mesh used as current collectors could maintain the overall transparency of the cell. Alternatively ITO glass and/or membrane with high content of CNT were used as a current collectors to provideimproved transparency and flexibility. Acknowledgment This research is funded by the Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. BR21882402) Figure 1

A Comprehensive Review of Recent Developments on the Natural Fiber Reinforced Polymer Matrix Composites for Automotive and Sports Application: Materials, Processes and Properties

Now a days, the world has been evolving and adapting to advance technology; as a result, the development and expansion of Composite materials have been growing day by day.. Natural fibres are a feasible and eco-friendly alternative to synthetic fibres for polymer composite reinforcing. Materials are attractive because they are economical, environmentally friendly, abundant in nature, and have mechanical properties[60]. Natural fibres are given first priority above all other types of fibres due to their appealing qualities include biodegradability, minimum cost, environmental friendliness, high strength-to-weight ratio in engineering goods, and low health risks. An overview of recent trends in physio mechanical characteristics, thermal properties, morphological behaviour, surface treatment, design optimisation with the ANOVA technique, the effect of Mercerization and SEM analysis, microstructural interfacial adhesion, and the various methodologies used to measure these properties. Keywords: Natural fiber polymer composites, Physio mechanical properties, SEM Analysis, Thermal properties, ANOVA technique, Applications.

Investigation on the flexural behavior of high‐strength fiber‐reinforced concrete

AbstractThe present research investigated the flexural behavior of high‐strength fiber‐reinforced concrete (HSFRC) with six different types of fiber: hooked‐end and crimped steel fibers, chopped and pultruded glass fibers; monofilament and twisted polymeric fibers. An extensive experimental program with 108 specimens for 3‐point bending tests was carried out and the parameters analyzed were the fiber content (0.50%, 0.75% and 1.00% in volume), the fiber type and the compressive strength of the concrete (60 and 90 MPa). Statistical analyses were performed and showed that regardless of the fiber material, increasing the amount of fibers added to concrete increases residual strength and toughness. Limit of proportionality is not affected by the addition of fibers, while postcracking behavior, on the other hand, is controlled by the fibers. Increasing the compressive strength of the concrete matrix affect mainly the limit proportionality of all mixes and the postcracking behavior of the concrete reinforced with hooked‐end steel fibers. The classification of HSFRC and the conditions required for HSFRC for use in structural applications according to the fib Model Code 2010 were also discussed, and it was verified that such conditions are not consistent with the experimental results and should be revised for high‐strength fiber‐reinforced concrete.

Analysis of thermomechanical and dynamic characteristics of treated saccharum munja fiber polymer composite

Analysis of thermomechanical and dynamic characteristics of treated saccharum munja fiber polymer composite

Study on the promotion multiple of blood flow velocity on human epidermal microcirculation of volcanic rock polymer fiber seamless knitted fabric

Abstract As a material that can release infrared rays, volcanic rock polymer fibers can be used in textiles to improve human microcirculation, which is helpful to relieve chronic inflammatory diseases such as perishoulder arthritis. In this article, there are two different kinds of exterior yarns. Volcanic rock blended polyester, volcanic rock blended polyamide, polyester and polyamide are chosen as the material type of exterior yarn Ⅰ, whereas the material type of exterior yarn II is conductive polyamide yarn. The exterior yarn feed ratio of exterior yarn Ⅰ and exterior yarn II is designed as 8:0, 7:1 and 6:2 when weft plain stitch, 1 + 1 mock rib and 1 + 3 mock rib are used as the knitted structure of the fabric. According to the three-factor four-level orthogonal experimental design method, the sample protocol was established, and 16 knitted sample fabrics were produced. Then, the promotion multiple of blood flow velocity on human epidermal microcirculation of each sample was tested and analyzed. The results show that the promotion multiple of blood flow velocity on human epidermal microcirculation of the fabrics woven by volcanic rock polymer fibers is better than that of the blank control group, and the difference between fabrics with different volcanic rock polymer fibers is small. The higher the proportion of exterior yarn Ⅰ is, the better the promotion multiple of blood flow velocity on human epidermal microcirculation of fabric will be. The effect of knitted structure on the promotion multiple of blood flow velocity on human epidermal microcirculation of fabrics is not obvious. This study provides reference for the design of medical or health textiles for chronic inflammatory diseases.