Oxide Composite Fibers Research Articles

Highly Efficient Polystyrene/Metal Oxide Fiber Composites for Passive Radiative Cooling

Passive radiative cooling has garnered significant attention in energy‐saving applications as it is an effective way to cool to temperatures below ambient without external energy input. Successful cooling performances can be achieved by carefully selecting metal oxides with narrow absorption bands that lie entirely within the atmospheric window of 8−13 μm, thereby allowing radiative transfer between terrestrial objects and outer space. Highly scalable, metal oxide‐doped fibers made from recyclable polystyrene herein are proposed and demonstrated. The material exhibits nearly 100% reflectivity in the visible and near‐infrared (IR) range, and under direct solar irradiation, the material can cool by up to 22.3 °C below the ambient temperature without energy input due to strong emissivity in the atmospheric window. This cooling persists despite nonideal atmospheric conditions and convective/conductive heat exchange. Microsized fiber‐based radiative cooling is reported for the first time. Unlike film‐based passive radiative cooling materials, fibers are relatively simple to manufacture, flexible, lightweight, and low in cost. Therefore, such a material may be suitable for large‐scale applications such as buildings to supplement air conditioning or as a wearable fabric to promote subambient cooling for the wearer.

Electrospinning fabricated novel poly (ethylene glycol)/graphene oxide composite phase-change nano-fibers with good shape stability for thermal regulation

In this study, novel poly (ethylene glycol)/graphene oxide (PEG/GO) composite phase-change fibers (PCFs) were developed by using PEG as the phase change ingredient, GO as the thermally conductive filler, and PVP as the fiber matrix through electrospinning to enhance the thermal properties of shape-stabilized PCFs. Results indicated that PEG was grafted with GO by self-assembly among the functional groups. PVP was dispersed in the mixture to ensure nano-fiber formation. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images revealed that the diameters of the composite PCFs decreased due to GO addition. The addition amount of GO is 0.5 wt% can prepare the composite PCFs with a homogeneous and smooth surface. DSC results demonstrated that the composite PCMs possess good phase-change behavior, fast thermal-response rates, and excellent thermal reliability. The largest melting/crystallization enthalpy of the prepared composite PCFs with 0.5 wt% GO addition was 103.6 J g−1 and 101.1 J g−1. More importantly, after 100 DSC thermal cycles, there was no obvious change for phase-change enthalpy. The thermal conductivity of the composite PCFs can reach 0.5668 W/(m·K), indicating the thermal conductivity of composite PCFs increased significantly with the GO addition. Moreover, the composite PCFs possess excellent thermal-regulated performance, leakage resistance, and shape stability. Hence, the fabricated composite PCFs possess good comprehensive properties that can be used widely in thermo-regulated systems.

Dry Spinning of Continuous Graphene Oxide/TPU Composite Fibers with Excellent Strength and Toughness

Graphene fiber has broad application prospects in aerospace, biomedical and other fields because of its excellent mechanical properties. In this paper, graphene oxide (GO) and thermoplastic polyurethane (TPU) composite fibers have been prepared by two comparable methods including wet spinning and dry spinning. The fibers obtained by dry spinning show better strength and toughness compared with wet spinning. Further research results show that the dry spinning process can effectively control the internal microstructure of the fiber, improve the internal stress distribution and load transfer efficiency, then realize the optimization of its macro mechanical properties. This study will provide useful guidance for the optimization strategy of internal microstructure and the improvement of preparation process of graphene fiber.

Physicochemical and histochemical characteristics of bovine longissimus lumborum muscle defected as muscular steatosis (massive adipocyte infiltration)

To understand muscular steatosis observed in beef carcasses, physicochemical and histochemical characteristics were compared between abnormal (massive fatty replaced) and normal regions of beef striploin. Fat content in the abnormal region (48.02%) was approximately twice than that in the normal region (22.01%). However, fatty acids did not show significant (P > 0.05) differences in their compositions between the two regions. Tenderness was significantly (P < 0.05) higher in the abnormal region. However, other meat quality traits were not significantly (P > 0.05) different between the two regions. Massive accumulation of adipocytes was accompanied by muscle fiber atrophy regardless of muscle fiber types. Without a change in total muscle fiber density, oxidative fiber composition was significantly increased, whereas glycolytic fiber composition was decreased (P < 0.05). These findings suggest that adipogenic transdifferentiation and muscle fiber type switching can occur within the muscle due to muscular steatosis.

Resveratrol improves meat quality, muscular antioxidant capacity, lipid metabolism and fiber type composition of intrauterine growth retarded pigs

This study investigated whether resveratrol could improve meat quality, muscular antioxidant capacity, lipid metabolism and fiber type composition of intrauterine growth retarded pigs. Thirty-six pairs of male normal birth weight and intrauterine growth retardation (IUGR) piglets were orally fed with 80 mg resveratrol/kg body weight/d or vehicle during the sucking period (7–21 d). Then the offspring were fed with a basal diet containing 300 mg resveratrol/kg or a basal diet from weaning to slaughter (150 d). The IUGR-impaired meat quality (luminance and yellowness) was associated with muscular oxidative stress via increased Keap1 protein level, fat accumulation, and higher MyHC IIb gene expression. Expectedly, resveratrol increased glutathione peroxidase activity and MyHC I gene expression, reduced protein carbonyl and malondialdehyde contents, enhanced fatty acid oxidation via upregulated PPARα and targeted genes expression, and thereby improving drip loss and yellowness. Results indicate that resveratrol improved meat quality of IUGR pigs through enhancing antioxidant capacity, increasing oxidative fiber composition, and suppressing lipid accumulation.

Novel prepreg manufacturing process for oxide fiber composites

A novel pre-impregnated fiber-preform (prepreg) manufacturing process for Nextel™610/ Al2O3-ZrO2 oxide fiber composites (OFC) was developed, using glycerol containing slurries.. It provides a simple and cost-effective way of producing OFC and lead to mean flexural strengths of up to 392 MPa. The use of glycerol in the slurry lead to reproducible and storable prepregs. The correlations between slurries with different glycerol contents and varying values of relative humidity during conditioning were investigated. By subjecting prepregs containing 16 wt% or 26 wt% slurries to different drying conditions, their suitability for accelerated drying methods was investigated. The storability of prepregs was studied under various storing conditions for at least four weeks. Sorption and desorption behavior of these slurries were investigated by Dynamic Vapor Sorption (DVS).. A glycerol content of 26 wt% proved to be favorable, because it provides a reproducible and robust process and enables ready-for-use prepregs only 15 min after infiltration.

Oxide composite fibers with quasiplastic components and composites with brittle matrices on their basis

By the internal crystallization method oxide composite fibers containing high-strength sapphire and hexaaluminates of calcium, lanthanum or barium are obtained. The presence of “weak” planes in the layered structure of hexaaluminates provides cracks inhibition. The dependences of the ultimate strain (strength) of the fibers of these compositions on the length are obtained. The positive effect of such fibers was evaluated on composites with brittle matrices of recrystallized molybdenum and nickel-aluminum intermetallic. The fracture toughness of composite materials with such fibers significantly exceeds the fracture toughness of composites with sapphire fibers. The composites were tested in the temperature range of 20– 1400 °C and showed non-brittle behavior under load, and their strength and fracture toughness correspond to the requirements for structural materials of this kind. The structure of fibers and composites was also studied by electron microscopy.

Development of a wearable infrared shield based on a polyurethane\u2013antimony tin oxide composite fiber

Here, we investigate a wearable-based IR and thermal stealth structure that effectively blocks IR and thermal radiation from a human body or device using a polyurethane–antimony tin oxide (PU–ATO) composite fiber. The aging time of the ATO sol prepared by a sol–gel method, and the concentration of ATO with respect to that of the PU matrix were optimized to prepare PU–ATO composite fibers that simultaneously have an appropriate mechanical strength (strength of ~4 MPa and strain of ~340%) and IR- and thermal radiation-shielding properties with ~98% IR light, as determined by Fourier transform IR spectroscopic studies. The fabricated PU–ATO composite fiber showed stable IR- and thermal radiation-shielding properties even when exposed to ten cycles of repeated temperature changes of −20 and +80 °C and long-term temperature changes for 30 days. In addition, the surface of the PU–ATO composite fiber was rendered hydrophobic to prevent the distortion of the IR and thermal radiation due to the wetting of the PU–ATO composite fiber with absorbed water. The PU–ATO composite fiber-based textile proposed herein can be applied in wearable IR- and thermal radiation-shielding technologies to shield IR signals generated by objects of diverse and complex shapes.

Properties of Polyhexamethylenediamine/Graphene Oxide Composite Fiber Membranes Prepared by Electrospinning

Properties of Polyhexamethylenediamine/Graphene Oxide Composite Fiber Membranes Prepared by Electrospinning

Surface-Functionalized Poly(Ether Sulfone) Composite Hollow Fiber Membranes with Improved Biocompatibility and Uremic Toxins Clearance for Bioartificial Kidney Application.

Bioartificial kidney (BAK) is attracting the focus of the research community. In this study, the efficacy of surface-functionalized poly(ether sulfone)-TPGS-graphene oxide composite hollow fiber membranes as a promising material for the single extracorporeal unit for BAK application was evaluated. The cytotoxicity was examined using human primary renal proximal tubular epithelial cells (hPTCs), and the removal of uremic toxins (urea, creatinine, phosphate, and lysozyme) from the toxin-spiked goat blood was measured. The surface-functionalized polymer composite membranes acted as a biocompatible material for attachment and proliferation of hPTCs, which was confirmed by microscopy studies, proliferation, and activity assays. The functional activity of these renal cells over this biocompatible membrane was also maintained. Remarkably, the functionalized composite membranes showed removal of urea (46.4 ± 3.5%), creatinine (52.2 ± 3.9%), phosphate (35.5 ± 2.7%), and lysozyme (11.2 ± 0.8%) from the toxin-spiked goat blood. Therefore, these obtained results showed that the surface-functionalized poly(ether sulfone)-TPGS-graphene oxide composite hollow fiber membranes are suitable for BAK application.

Heat-Killed Bifidobacterium breve B-3 Enhances Muscle Functions: Possible Involvement of Increases in Muscle Mass and Mitochondrial Biogenesis.

A previous clinical study on pre-obesity subjects revealed that Bifidobacterium breve B-3 shows anti-obesity effects and possibly increases muscle mass. Here, we investigated the effects of B-3 on muscle function, such as muscle strength and metabolism, and some signaling pathways in skeletal muscle. Male rodents were orally administered live B-3 (B-3L) or heat-killed B-3 (B-3HK) for 4 weeks. We found that administration of B-3 to rats tended to increase muscle mass and affect muscle metabolism, with stronger effects in the B-3HK group than in the B-3L group. B-3HK significantly increased muscle mass and activated Akt in the rat soleus. With regard to muscle metabolism, B-3HK significantly increased phosphorylated AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α and cytochrome c oxidase (CCO) gene expression in the rat soleus, suggesting an effect on the AMPK-PGC1α-mitochondrial biogenesis pathway. Furthermore, B-3HK promoted oxidative muscle fiber composition in the gastrocnemius. We also observed a significantly higher level of murine grip strength in the B-3HK group than in the control group. These findings suggest the potential of heat-killed B-3 in promoting muscle hypertrophy and modifying metabolic functions, possibly through the Akt and AMPK pathways, respectively.

Efficient removal of 2,4-dichlorophenol from contaminated water and alleviation of membrane fouling by high flux polysulfone-iron oxide/graphene oxide composite hollow fiber membranes

Phenolic compounds are the harmful water contaminants, which severely affect living beings. Therefore, it is essential to remove the phenolic compounds, e.g., 2,4-dichlorophenol (2,4-DCP) from water sources. In this study, polysulfone-iron oxide/graphene oxide composite hollow fiber membranes were fabricated, which showed oxygen-enriched functional groups and improved hydrophilicity. With 0.5 wt.% iron oxide/graphene oxide nanohybrid in polysulfone hollow fiber membranes, remarkably high pure water flux was measured (339.8 ± 9.9 L/m2h). The improved antifouling property was achieved with a flux recovery of 95.8 %. The 2,4-DCP separation efficiency was measured to be 96.5 ± 1.6 % and 70.5 ± 2.1 % from the contaminated lab water and lake water, respectively. The separation efficiency of the composite membranes remained almost the same at the 5th filtration cycle. These results indicated that the polysulfone-iron oxide/graphene oxide composite hollow fiber membranes are promising in the efficient removal of the harmful 2,4-DCP from water sources.

Preparation, Stability and Local Piezoelectrical Properties of P(VDF-TrFE)/Graphene Oxide Composite Fibers

The unprecedented attributes such as biocompatibility and flexibility of macromolecular piezoelectric polymer has triggered an immense interested in scientific society for their potential exploitation in implantable electronic devices. In the present article, a theoretical and experimental investigation is done to explore the polarization behavior of composite fibers based on copolymer poly-trifluoroethylene P(VDF-TrFE) and graphene oxide (GO) with varying composition of the components is explored for its possible application in bioelectronic devices. Electromechanical properties of the PVDF/GO nanofibers were investigated using piezoresponse force microscopy (PFM) method. The switching behavior, charge states, and piezoelectric response of the fibers were found to depend on the concentration of GO up to 20%. Theoretical models of PVDF chains, interacting with Graphene/GO layers has been used to explore the evolution of piezoresponse in the composite fibers. In order to compute piezoelectric coefficients, the behavior of composite in electrical fields has been modeled using software HyperChem. The experimental results are qualitatively correlated with a computed theoretical model.

Highly aligned and geometrically structured poly(glycerol sebacate)-polyethylene oxide composite fiber matrices towards bioscaffolding applications.

The biocompatible and biodegradable polymer poly(glycerol sebacate), or PGS, is a rubber-like material that finds use in several biomedical applications. PGS is often cast into a mold to form desired structures; alternatively, blending PGS with other reinforcing polymers produces viscous solutions that can be spun into non-woven fibrous scaffolds. For tissue scaffolding applications, ordered fibrous matrices are advantageous and have been shown to promote cell orientation and proliferation by contact guidance, providing topographical cues for the seeded cells. The development of techniques for easily producing aligned fibrous matrices is therefore a priority. PGS nanofibers have been fabricated successfully using electrospinning techniques. For producing PGS microfibers, we introduce the electro-less STRAND (Substrate Translation and Rotation for Aligned Nanofiber Deposition) process as an alternative to electrospinning. STRAND provides superior control of fiber properties including diameter, alignment, spacing, and therefore deposition density by mechanically drawing polymer fibers from solution. The goal in using this method is the simple production of aligned PGS fiber matrices for retinal tissue scaffolding.

Fabrication and performance of wool keratin–functionalized graphene oxide composite fibers

The objective of this study is to reduce environmental pollution caused by waste wool and to enable it to be recycled. L-Cysteine was used to dissolve wool in an aqueous solution for the extraction of keratin. Furthermore, the reconstruction of keratin was attempted by dissolving wool keratin in Na2CO3/NaHCO3 buffer with various contents of polyethylene glycol (PEG)–functionalized graphene oxide (PEG-g-GO). Then, the regenerated keratin/PEG-g-GO composite fibers were wet-spun to form a series of composite fibers. Fourier-transform infrared spectroscopy, XPS analysis, Raman spectroscopy, and thermogravimetric analysis were used to characterize the structure and properties of the composite. The results show that PEG was successfully grafted onto the GO. PEG-g-GO had a good interfacial effect with the keratin matrix in composite fibers without any agglomeration, apart from dispersing evenly. With the addition of PEG-g-GO, the crystallinity and the tensile strength and elongation at break of the composite fiber increased, and it induced more β-sheet secondary conformation within the keratin matrix. When the quality fraction of PEG-g-GO was 0.20%, the tensile strength of the composite fibers reached a maximum (157 ± 40 MPa) and the breaking elongation reached a maximum of 3.9%, which was approximately 168% and 89% higher than that of the pure keratin fibers, respectively. More importantly, the entire process is green and of low cost, which not only reduces environmental pollution but also improves resource utilization.

Near-net shape manufacture process for oxide fiber composites (OFC)

Abstract A novel, vacuum-assisted single-step slurry infiltration process (SIP) for the manufacturing of OFCs (Oxide Fiber Composites) was developed. It provides a simple and cost-effective way to infiltrate near-net shape fiber preforms, such as radial braided fiber architectures. NextelTM 610 fabrics were infiltrated with an alumina-zirconia slurry in order to obtain NextelTM 610/Al2O3-ZrO2 composites, which were investigated by SEM and three-point-bending tests. Vacuum pressures varying from 50 mbar to 700 mbar were tested for the SIP as well as varying solid contents between 50 wt.% to 71 wt.% and different aids (manual support by Teflon roller, pressure infiltration) during the initial infiltration. As advancement of the SIP, a double-step infiltration process (DIP) was developed, to ensure a more homogeneous infiltration of the fiber bundles. A comparison of microstructure and mechanical properties of the OFCs manufactured by SIP and DIP with OFCs manufactured by a prepreg process was made. To demonstrate the feasibility of the developed DIP process for complex fiber preforms, a burner nozzle was fabricated by infiltrating a radial braided preform.

Получение, структура и механические свойства оксидных композитных волокон для композитов с хрупкой матрицей.

Получение, структура и механические свойства оксидных композитных волокон для композитов с хрупкой матрицей.

Electrospun poly(vinylidene fluoride)-zinc oxide hierarchical composite fiber membrane as piezoelectric acoustoelectric nanogenerator

Nanogenerators which efficiently convert mechanical forces, vibrations and sound to electrical energy have attracted much attention and showed potential application as sustainable energy source for powering miniature devices. In this work, we fabricated a piezoelectric acoustoelectric nanogenerator using poly(vinylidene fluoride)-zinc oxide composite fiber membrane with hierarchical microstructure by electrospinning and hydrothermal techniques. The prepared PVDF–ZnO acoustoelectric nanogenerator (PVDF–ZnOANG) was able to generate voltage and current output of 1.12 V and 1.6 μA with a power density output of 0.2 μW cm−2 (50 μW cm−3) in optimized sound condition (140 Hz, 116 dB). Under the optimized sound condition, the electric energy generated by the prepared PVDF–ZnOANG could charge a capacitor up to 1.3 V in 3 min. The PVDF–ZnOANG generated higher voltage output under sound of low frequency and high sound pressure level and therefore might be a promising power source for noise energy harvesting.

Boosting Lithium Storage Properties of MOF Derivatives through a Wet-Spinning Assembled Fiber Strategy.

Graphene composite fibers are of great importance in constructing electrode materials with high flexibility and conductivity for energy storage and electronic devices. Integration of multifunctional metal-organic frameworks (MOFs) into graphene fiber scaffolds enables novel functions and enhanced physical/chemical properties. The close-packed and aligned graphene sheets along with the porous MOF-derived structures can achieve excellent lithium storage performance through synergetic effects. In this work, a facile and general strategy is demonstrated for the preparation of MOF/graphene oxide (GO) fibers, which serve as precursors for the subsequent preparation of porous metal oxide/reduced graphene oxide (rGO) composite fibers. The obtained composites, for example, porous Fe2 O3 /rGO and Co3 O4 /rGO fibers, possess unique features of MOF-derived porous structures and excellent electrical conductivity. When tested as anode materials for lithium-ion batteries in coin cells, the MOF/GO fiber-derived porous metal oxide/rGO composite fibers exhibited high specific capacity, excellent rate capability and cycling performance. Moreover, a flexible fiber battery was fabricated based on the Fe2 O3 /rGO composite fiber, which demonstrates its potential application for flexible electronic devices.

The combined effect of formulation and pH on properties of polyethylene oxide composite fiber containing egg albumen protein

The aim of this work was to elucidate the influence of egg white albumen (EA) protein loaded on the electrospinning of PEO solutions under different concentrations and pHs conditions. Properties of the electrospun fiber mats, such as morphology, thermal properties, and wettability were analyzed. In addition, rheological behavior of the polymer solutions was measured to explain the electrospinnability for fiber formation. The rheological results showed that the addition of EA protein affects the molecular entanglement required to electrospin PEO, being able to incorporate up to 75wt% EA protein. The diameter of most of the PEO/EA fibers was in the range of 200–400nm. When comparing the effect of concentration and pH of the electrospinning solution, the morphology of the fibers was found to be mainly affected by the second one. FTIR analysis of the blend fibers confirmed the presence of the protein and revealed that the secondary structure changed with pH. From a thermodynamic point of view, the EA protein and PEO showed a high degree of mutual incompatibility. The presence of EA protein influenced PEO polymer thermal behavior, lowering its melting point and decreasing the quantity of PEO crystallites. All the PEO/EA electrospun fiber mats showed rapid water absorption, which increased as PEO concentration became higher, and similarly, when lowering protein concentration.