Strong Fibers Research Articles

Hierarchical structure control in solution spinning for strong and multifunctional carbon nanotube fibers

Many strategies for manufacturing high-performance carbon nanotube (CNT) fibers have been reported in the past decade. Although spinning is an essential process regardless of the CNT pre-treatment method or fiber post-treatment route, little research has been carried out into the spinning process itself. During the formation of such fibers through the spinning, intra- and inter-bundle voids inevitably arise. The size and amount of these voids determines the macroscopic properties of fibers. Therefore, controlling the internal voids of fibers is key for enhancing their macroscopic properties. We systematically explore changes in the microstructures of fibers, especially inter- and intra-bundle voids in the solution spinning. Around the spinneret of the exit, extensional deformation by drawing is key for fiber orientation, and we find the minimum draw ratio (DR∗=4.5) for target orientation of the fiber. Moreover, by controlling the coagulation process, the shape of the fiber is made close to a circular shape, which drastically reduces voids in the fiber to 0.08 vol%. Consequently, the increase in packing density and orientation maximizes the fiber properties. The resulting fibers, which were highly oriented and exhibited a fine morphology, have the tensile strength of 5.0 ± 0.3 GPa, modulus of 302 ± 31 GPa, electrical conductivity of 11.2 ± 0.5 MS m−1, thermal conductivity of 398 ± 27 W m−1 K−1, and knot efficiency of 85 ± 11%. We believe that this systematic investigation of fiber formation provides useful insights into the development of high-performance multifunctional CNT fibers.

Evaluation of fiber compositions, strength indicators, and disintegration patterns of flushable sanitary products in relevance to what is flushable

ABSTRACT Sanitary products (SPs) such as toilet paper and moist wipes are marketed as flushable products (FPs). SP manufacturers, wastewater authorities, and governmental agencies describe FPs in their own terms, and cause confusion about what is safe to flush with respect to sewer operations. To identify sewer-safe FPs, 11 toilet paper (TP) and 39 flushable wipe (FW) samples that were collected from around the world were examined to assess critical links between their fiber compositions, strength indicators, and disintegration performance. The findings illustrate that products that are made of primarily wood-pulp fibers have low strength, disintegrate rapidly, and are safe flushables. In contrast, products that contain strong and synthetic fibers (e.g. polyester) exhibit high strength, disintegrate slowly, and pose significant risk of accumulation in sewer systems. Suggestions are offered for product improvement and for long-term sustainability of FPs and wastewater infrastructures.

Tough, Strong, and Conductive Graphene Fibers by Optimizing Surface Chemistry of Graphene Oxide Precursor

AbstractGraphene fibers with integrated mechanical and multifunctional properties are highly required for various potential applications. However, it remains a challenge to efficiently produce high‐performance graphene fibers because of the imperfect structures and harsh graphitization conditions. Herein, a scalable additive‐free wet‐spinning methodology is demonstrated for producing strong, tough, and conductive pristine graphene fibers by optimizing the surface chemistry of graphene oxide (GO) sheets and controlling their spinning and assembly behavior. Benefiting from GO with fewer surface terminations and low structural defects (f‐GO), the pristine f‐GO fibers possess a compact and ordered microstructure and strong interlayer interactions, giving a record high tensile strength of 791.7 MPa and high toughness of 24.0 MJ m−3 due to the stretching‐induced toughening behavior. After the mild chemical reduction, reduced f‐GO fibers inherit the optimized microstructure and present an outstanding tensile strength of 875.9 MPa and high toughness of 13.3 MJ m−3. Furthermore, the repairable structural defects on the f‐GO sheets allow the instant restoration of intrinsic conjugated structures, affording a superb electrical conductivity of 1.06 × 105 S m−1. Therefore, this study provides a facile, efficient, and scalable methodology for the fabrication of high‐performance and multifunctional graphene fibers and flexible wearable devices.

Coordinating chain crystallinity and orientation by tailoring electrical stretching for fabrication of super-tough and strong organic fibers

High-performance fibers generally require both plastic deformation resistance (strength) and high damage tolerance (toughness). Nevertheless, strength and toughness are inherently incompatible because of the unsatisfied supramolecular structure of polymer fibers. Herein, the principle of coordinating chain crystallinity and orientation by electrospinning technique is shown to resolve the conflict between super toughness and high strength. Using polyethylene terephthalate (PET) as the model system, chain crystallinity and alignment can be simultaneously and dynamically manipulated with polymer ultrafine fibers (UFFs) by precisely controlling the electrical stretching of a spinning jet. The obtained PET UFFs, characterized by loosely packed but highly aligned chain stacks, possessed a true strength of 853 MPa (similar to that of spider dragline silk), super toughness of 415 MJ/m3 (2.5 times higher than that of spider dragline silk), and extraordinary true strain of 210% (four times higher than that of spider dragline silk and exceeding that of highly elastic Spandex filaments). This facile strategy may offer a new paradigm for the development of advanced super-tough and robust materials.

Development and Utilization of Functional Kompetitive Allele-Specific PCR Markers for Key Genes Underpinning Fiber Length and Strength in Gossypium hirsutum L.

Fiber length (FL) and fiber strength (FS) are the important indicators of fiber quality in cotton. Longer and stronger fibers are preferred for manufacturing finer yarns in the textile industry. Functional markers (FMs) designed from polymorphic sites within gene sequences attributing to phenotypic variation are highly efficient when used for marker-assisted selection (MAS) in breeding superior varieties with longer FL and higher FS. The aims of this study were to develop FMs via kompetitive allele-specific PCR (KASP) assays and to validate the efficacy of the FMs for allele discrimination and the potential value in practice application. We used four single-nucleotide polymorphism markers and 360 cotton accessions and found that two FMs, namely, D11_24030087 and A07_72204443, could effectively differentiate accessions of different genotypes with higher consistency to phenotype. The appeared frequencies of varieties harbored Hap2 (elite alleles G and T) with longer FL (> the mean of accessions with non-elite allele, 28.50 mm) and higher FS (> the mean of accessions with non-elite allele, 29.06 cN•tex–1) were 100 and 72.7%, respectively, which was higher than that of varieties harbored only on a single elite allele (G or T, 77.9 or 61.9%), suggesting a favorable haplotype for selecting varieties with superior FL and FS. These FMs could be valuable for the high-throughput selection of superior materials by providing genotypic information in cotton breeding programs.

Electric field-assisted wet spinning to fabricate strong, tough, and continuous nanocellulose long fibers

Electric field-assisted wet spinning to fabricate strong, tough, and continuous nanocellulose long fibers

Polycrystalline morphology and mechanical strength of nanotube fibers

Correlating mechanical performance with mesoscale structure is fundamental for the design and optimization of light and strong fibers (or any composites), most promising being those from carbon nanotubes. In all forms of nanotube fiber production strategies, due to tubes’ mutual affinity, some degree of bundling into liquid crystal-like domains can be expected, causing heterogeneous load transfer within and outside these domains, and having a direct impact on the fiber strength. By employing large-scale coarse-grained simulations, we demonstrate that the strength s of nanotube fibers with characteristic domain size D scales as s ~ 1/D, while the degree of longitudinal/axial disorder within the domains (akin to a smectic ↔ nematic phase transition) can substantially mitigate this dependence.

Fracture energy for orthogonal cutting in unidirectional CFRP at different cutting directions

A unidirectional carbon fibre reinforced polymer (CFRP) laminate is a composite material made up of strong parallel carbon fibres incorporated in a polymer matrix such as epoxy to provide high stiffness and strength in the fibre direction of the laminate. Unfortunately, the interlaminar or intralaminar plane of this material has a low resistance to damages as the fracture toughness of a unidirectional CFRP laminate is related to the energy dissipation during the orthogonal cutting. The aim of this study is on cutting a unidirectional CFRP along the longitudinal or transverse directions, characterizing orthogonal cutting forces and the related fracture energy. Orthogonal cutting is performed using braised carbide tools for a range of cutting depth of 10-100 ³m with a rake angle of 30° to quantify the cutting forces and to observe the fracture mechanisms. The fibre orientations have a significant impact on surface bouncing-back. For some fibre orientations, the energy balance model is applicable, deducting the reasonable value of fracture toughness due to high normal force (F t). Fibre subsurface damage and cutting forces during cutting are found to be strongly influenced by the cutting depth. The input energy of cutting is released in form of new surface energy, fibre breakage, high bending energy, and chip fracture energy.

CHARACTERISATION AND SPECIFIC MARKERS EXPRESSION OF SOFT TISSUE SARCOMA: CASE REPORTS FOR THE DOG AT THE HO CHI MINH CITY VETERINARY CLINIC

Treatment failure in removing canine soft tissue tumors, a locally invasive mesenchymal neoplasm, may occur in between 7 and 75 percent of patients, with recurrence consistently associated with lower overall survival for the dog. This study was to classify the tumor examine the occurrence of cancers in dogs reported at the Ho Chi Minh Veterinary Clinic by integrating blood physiological and histopathological of patient samples. In this study, the percentage of tissue sarcoma in the dog was 1.5%. Histopathological analysis characteristics of the ear lobe tumors displayed a strong proliferation of rhabdoid cells, presence of leukocytes infiltrating around blood vessels, and vaginal tumors showed normal tumor cell density with a strong collagen fibers formation in fibroblast cells and no strong proliferation and ferocity of cells. In particular, immuno-histopathological analysis of biopsies sample from breast tumor showed an overexpressing of vimentin marker (68.1%) in cells which indicated status of malignant metastasis. The metastatic tumor cells in breast tumor might cause the change in blood biochemical parameters together with sepsis, thus the dog was not eligible for surgery. In general, histological examination and expression levels of markers can help determine the malignant status of tumors in dogs and should be included medical examination to limit local recurrence following surgical resection.

Mechanically Reinforced Silkworm Silk Fiber by Hot Stretching.

Silkworm silk, which is obtained from domesticated Bombyx mori (B. mori), can be produced in a large scale. However, the mechanical properties of silkworm silk are inferior to its counterpart, spider dragline silk. Therefore, researchers are continuously exploring approaches to reinforce silkworm silk. Herein, we report a facile and scalable hot stretching process to reinforce natural silk fibers obtained from silkworm cocoons. Experimental results show that the obtained hot-stretched silk fibers (HSSFs) retain the chemical components of the original silk fibers while being endowed with increased β-sheet nanocrystal content and crystalline orientation, leading to enhanced mechanical properties. Significantly, the average modulus of the HSSFs reaches 21.6 ± 2.8 GPa, which is about twice that of pristine silkworm silk fibers (11.0 ± 1.7 GPa). Besides, the tensile strength of the HSSFs reaches 0.77 ± 0.13 GPa, which is also obviously higher than that of the pristine silk (0.56 ± 0.08 GPa). The results show that the hot stretching treatment is effective and efficient for producing superstiff, strong, and tough silkworm silk fibers. We anticipate this approach may be also effective for reinforcing other natural or artificial polymer fibers or films containing abundant hydrogen bonds.

On the use of finite differences for vibration-based damage localization in laminated composite plates

Laminated composite materials are a staple of modern material development, with extremely strong fibers being combined with resins to form versatile and efficient engineering structures. However, the advancements in material development must be accompanied by equally advanced methods for damage detection, as these materials develop inherently unique failure modes. This thesis aims to further the study of the use of modal shapes and their spatial derivatives to damage localization in laminated composite rectangular plates. ANSYS® Parametric Design Language (APDL) is used to perform Finite Element simulations of plates with several damage scenarios and damage mechanics models. MATLAB® is used to postprocess these simulations results, namely by calculating the derivatives using the Finite Difference Method, applying three different Damage Detection Methods, including one that is being proposed here. To mimic experimental conditions and testing the resilience of the derivative orders, different noise levels are introduced in the results of the Finite Element simulations. A Quality Index is employed to quantitatively evaluate the solutions, mainly regarding the response to the introduced noise. The results show that the different Damage Detection Methods tested have comparable results in terms of quality. These results also show that the damage detectability is higher when the damaged areas coincide with high displacement/curvature areas of the mode shapes and that higher noise levels have a more noticeable negative impact when employing higher-order derivatives.

Experimental Investigation on Mechanical Properties of Carbon Nanotube-Reinforced Epoxy Composites for Automobile Application

Carbon nanotubes are established as a superior form of carbon. These have superior characteristics in terms of mechanical and chemical properties when compared to the other fibres available. High-strength fibres can be employed in a composite in a short form and mass-produced to fulfil high demands in composite applications. These composites can meet the strength requirements of nonstructural and structural components in a wide range of industries. Because of their light weight and excellent strength-to-weight ratio, these composites can be used in a wide range of applications. With Young’s modulus as high as 1 TPa and tensile strength up to 63 GPa, they are among the stiffest and strongest fibres. There is currently a lot of interest in using carbon nanotubes in a matrix to take advantage of these features. There have been a variety of polymer matrices used, and nanotube/ceramic and nanotube/metal composites are gaining popularity. The study of these materials is an ongoing process, as researchers and design engineers have yet to realize their full potential. Carbon nanotubes (CNTs) are used in this study to create the composite with the resin. The percentage of CNT used as a filler material in the composite is varied from 1 to 4 percent, with the best percentage chosen for optimal mechanical properties.

Manufacture of strong melt-spun fibers derived from α-1,3-glucan esters and determination of their crystal structures and crystalline elastic moduli

Melt-spun fibers derived from α-1,3-glucan esters were successfully manufactured without a plasticizer. Fibers derived from α-1,3-glucan butyrate had a tensile strength of over 1000 MPa. The crystalline structures of the α-1,3-glucan esters were determined as monoclinic systems by X-ray diffraction. The linear esters comprised threefold helices and the branched esters comprised five- or eightfold helices. The crystalline elastic moduli (El) parallel to the fiber axes were determined by time-resolved X-ray diffraction with tensile tests. Specifically, α-1,3-glucan propionate, α-1,3-glucan butyrate, and α-1,3-glucan valerate—which had threefold helices—had El values of 24.0, 12.4, and 4.2 GPa, respectively. In contrast, α-1,3-glucan 2-methyl valerate—which had a fivefold helix—had an El of 1.0 GPa. Therefore, the El decreased as the length of the side chain and the helix inclination increased. We concluded that El values of polysaccharide esters are not dependent on the glycosidic linkages, but rather on helix structures.

Methylcellulose-Cellulose Nanocrystal Composites for Optomechanically Tunable Hydrogels and Fibers.

Chemical modification of cellulose offers routes for structurally and functionally diverse biopolymer derivatives for numerous industrial applications. Among cellulose derivatives, cellulose ethers have found extensive use, such as emulsifiers, in food industries and biotechnology. Methylcellulose, one of the simplest cellulose derivatives, has been utilized for biomedical, construction materials and cell culture applications. Its improved water solubility, thermoresponsive gelation, and the ability to act as a matrix for various dopants also offer routes for cellulose-based functional materials. There has been a renewed interest in understanding the structural, mechanical, and optical properties of methylcellulose and its composites. This review focuses on the recent development in optically and mechanically tunable hydrogels derived from methylcellulose and methylcellulose–cellulose nanocrystal composites. We further discuss the application of the gels for preparing highly ductile and strong fibers. Finally, the emerging application of methylcellulose-based fibers as optical fibers and their application potentials are discussed.

Tiny yet tough: Maximizing the toughness of fiber-reinforced soft composites in the absence of a fiber-fracture mechanism

Tiny yet tough: Maximizing the toughness of fiber-reinforced soft composites in the absence of a fiber-fracture mechanism

Current Strategies for the Production of Sustainable Biopolymer Composites.

Rapid global population growth has led to an exponential increase in the use of disposable materials with a short life span that accumulate in landfills. The use of non-biodegradable materials causes severe damage to the environment worldwide. Polymers derived from agricultural residues, wood, or other fiber crops are fully biodegradable, creating the potential to be part of a sustainable circular economy. Ideally, natural fibers, such as the extremely strong fibers from hemp, can be combined with matrix materials such as the core or hurd from hemp or kenaf to produce a completely renewable biomaterial. However, these materials cannot always meet all of the performance attributes required, necessitating the creation of blends of petroleum-based and renewable material-based composites. This article reviews composites made from natural and biodegradable polymers, as well as the challenges encountered in their production and use.

Designing Materials and Processes for Strong Polyacrylonitrile Precursor Fibers.

Although polyacrylonitrile (PAN)-based carbon fibers have been successfully commercialized owing to their excellent material properties, their actual mechanical performance is still much lower than the theoretical values. Meanwhile, there is a growing demand for the use of superior carbon fibers. As such, many studies have been conducted to improve the mechanical performance of carbon fibers. Among the various approaches, designing a strong precursor fiber with a well-developed microstructure and morphology can constitute the most effective strategy to achieve superior performance. In this review, the efforts used to modulate materials, processing, and additives to deliver strong precursor fibers were thoroughly investigated. Our work demonstrates that the design of materials and processes is a fruitful pathway for the enhancement of the mechanical performance of carbon fibers.

Additive Timber Manufacturing: A Novel, Wood-Based Filament and Its Additive Robotic Fabrication Techniques for Large-Scale, Material-Efficient Construction.

Additive manufacturing (AM), as resource-efficient fabrication processes, could also be used in the dimensions of the construction industry, as a variety of experimental projects using concrete and steel demonstrate. In timber construction, currently few additive technologies have been developed having the potential to be used in large scale. Currently known AM processes use wood in pulverized form, losing its inherent structural and mechanical properties. This research proposes a new material that maintains a complete wood structure with continuous and strong fibers, and that can be fabricated from fast-growing locally harvested plants. We describe the material technology to create a solid and continuous filament made of willow twigs and investigate binding and robotic AM methods for flat, curved, lamination, and hollow layering geometric typologies. The resulting willow filament and composite material are characterized for structural capacity and fabrication constraints. We discuss our technology in comparison with veneer-based lamination, existing wood filament printing, and fiber-based AM in terms of fabrication, material capacity, and sustainability. We conclude by showing possible applications in the construction industry and future research possibilities.

Economic Valuation and Cultivation of Persimmons in Takengon City Central Aceh District

The persimmon fruit (Diospyros kaki) or Oriental persimmon is a complex plant that lives in the wild for hundreds of years growing in Indonesia in the highlands of at least 1000 above sea level; this plant turns out to function to resist erosion, landslides, and floods because of its strong roots and form fibers inside. The soil so that can withstand soil shifts that are suppressed by water. Besides stems, seeds, fruit from persimmon is also beneficial for health. However, some of this persimmon ecosystem has been cut down because its economic value is too low for the community. The purpose of this study is to determine the monetary value of the remaining persimmon ecosystem, determine what impacts humans feel when cutting down persimmon trees and determine alternative policies with the management of persimmon cultivation in the city of Takengon. This study used a survey method; sampling was selected by purposive sampling. The analysis used is the formula for total economic value (total economic value/TEV), willingness to accept (WTA). The results of this study indicate that the total monetary value of the persimmon ecosystem area in Takengon City is Rp. 27,175,000,000/ha/yr. The estimated economic value of the persimmon area is Rp.254.316 million/year.

Microstructure-Controlled Polyacrylonitrile/Graphene Fibers over 1 Gigapascal Strength.

Controlling the microstructures in fibers, such as crystalline structures and microvoids, is a crucial challenge for the development of mechanically strong graphene fibers (GFs). To date, although GFs graphitized at high temperatures have exhibited high tensile strength, GFs still have limited the ultimate mechanical strength owing to the presence due to the structural defects, including the imperfect alignment of graphitic crystallites and the presence of microsized voids. In this study, we significantly enhanced the mechanical strength of GF by controlling microstructures of fibers. GF was hybridized by incorporating polyacrylonitrile (PAN) in the graphene oxide (GO) dope solution. In addition, we controlled the orientation of the inner structure by applying a tensile force at 800 °C. The results suggest that PAN can act as a binder for graphene sheets and can facilitate the rearrangement of the fiber's microstructure. PAN was directionally carbonized between graphene sheets due to the catalytic effect of graphene. The resulting hybrid GFs successfully displayed a high strength of 1.10 GPa without undergoing graphitization at extremely high temperatures. We believe that controlling the alignment of nanoassembled structure is an efficient strategy for achieving the inherent performance characteristics of graphene at the level of multidimensional structures including films and fibers.