Improvement of compression performance of fiber reinforced polymer（繊維強化複合材料の圧縮特性の向上）

信州大学(Shinshu university)博士（工学）ThesisRUAN FANGTAO. Improvement of compression performance of fiber reinforced polymer（繊維強化複合材料の圧縮特性の向上）. 信州大学, 2015, 博士論文. 博士（工学）, 甲第646号, 平成28年03月20日授与.doctoral thesi

Mechanical Enhancement of UHMWPE Fibers by Coating with Carbon Nanoparticles

Fiber-reinforced plastic (FRP) is composed of reinforced fibers and matrix resin, and has high specific strength and low-density materials. Because of the orientation of the fibers within them, FRPs are prone to buckling damage when under compression along the axial direction of the fiber, especially flexible organic ones. The compressive performance of FRP is largely dependent on fiber properties. the buckling load of FRP will increase with the increasing of fiber's. In this study, we developed a way to improve the compressive and bending strength of ultra-high molecular weight polyethylene (UHMWPE) fibers. Carbon nanotubes (CNTs) and vapor-grown carbon fibers (VGCFs) were coated on the surface of UHMWPE fibers by pyrrole vapor deposition. The transverse compressive strength and bending strength of single UHMWPE fibers were determined by microcompression and single fiber bending measurements, respectively. The experiment result showed that coating UHMWPE fibers with CNTs and VGCFs increased both their transverse compressive strength and bending strength. It is excepted that the improved fiber would applied in FRP for better compressive performance.ArticleFIBERS AND POLYMERS. 15(4):723-728 (2014)journal articl

Mechanical enhancement of UHMWPE fibers by coating with carbon nanoparticles

Fiber-reinforced plastic (FRP) is composed of reinforced fibers and matrix resin, and has high specific strength and low-density materials. Because of the orientation of the fibers within them, FRPs are prone to buckling damage when under compression along the axial direction of the fiber, especially flexible organic ones. The compressive performance of FRP is largely dependent on fiber properties. the buckling load of FRP will increase with the increasing of fiber's. In this study, we developed a way to improve the compressive and bending strength of ultra-high molecular weight polyethylene (UHMWPE) fibers. Carbon nanotubes (CNTs) and vapor-grown carbon fibers (VGCFs) were coated on the surface of UHMWPE fibers by pyrrole vapor deposition. The transverse compressive strength and bending strength of single UHMWPE fibers were determined by microcompression and single fiber bending measurements, respectively. The experiment result showed that coating UHMWPE fibers with CNTs and VGCFs increased both their transverse compressive strength and bending strength. It is excepted that the improved fiber would applied in FRP for better compressive performance.ArticleFIBERS AND POLYMERS. 15(4):723-728 (2014)journal articl

Właściwości pochłaniania fal elektromagnetycznych tkaniny bawełnianej z powłoką z nanorurek węglowych

In order to endow cotton fabric with the electromagnetic shielding property while preserving comfort and softness, carbon nanotubes (CNTs) were coated onto NaOH pretreated fabrics via a binder-free dip-coating approach. Scanning electron microscopy (SEM) and Infrared spectroscopy were utilised to investigate the surface morphology and modification of the CNT functionalised fabrics. The effects of the number of dip-coatings, the concentration of carbon nanotubes, and the impregnation temperature on electrical conductivity, electromagnetic (EM) shielding effectiveness (SE), and wave absorbing efficiency of cotton fabrics were evaluated, respectively. The SE value of the CNT functionalised cotton fabrics increased with the dip-coating time and reached 16.5 dB after CNT dip-coating ten times, which indicates that 97.76% of the electromagnetic wave was shielded. Meanwhile, by adding layers of stacking fabrics, the SE of CNT coated fabrics was further improved to 26.4 dB. The shielding mechanism was also studied by comparing its reflection and absorption behaviour, which demonstrates that 65.7% of the electromagnetic wave was absorbed.Aby nadać tkaninie bawełnianej właściwości ekranowania elektromagnetycznego przy jednoczesnym zachowaniu komfortu i miękkości, najpierw zastosowano obróbkę tkaniny z zastosowaniem NaOH, a następnie nałożono na nią powłokę z nanorurek węglowych (CNT). Za pomocą skaningowej mikroskopii elektronowej (SEM) i spektroskopii w podczerwieni zbadano morfologię powierzchni tkanin funkcjonalizowanych CNT. Oceniono wpływ liczby powłok zanurzeniowych, stężenia nanorurek węglowych i temperatury impregnacji na przewodność elektryczną, skuteczność ekranowania elektromagnetycznego (EM) (SE) oraz efektywność pochłaniania fal przez tkaniny bawełniane. Stwierdzono, że wartość SE funkcjonalizowanych tkanin bawełnianych CNT wzrastała wraz z czasem powlekania zanurzeniowego i osiągnęła 16.5 dB po dziesięciokrotnym powlekaniu zanurzeniowym CNT, co wskazało, że 97.76% fali elektromagnetycznej było ekranowane. Poprzez dodanie warstw tkanin, współczynnik SE tkanin powlekanych CNT został dodatkowo poprawiony do 26,4 dB. Zbadano również mechanizm ekranowania, porównując jego właściwości odbijania oraz pochłaniania i stwierdzono, że 65.7% fali elektromagnetycznej zostało zaabsorbowane

Green synthesized clavate-shaped ZnO modified silk fabric with aging resistance and outstanding antibacterial and UV-shielding properties

Silk, a popular luxury textile with many years of history, is easy to embrittle and adsorb bacteria when stored for a long time or exposed to sunlight, which affects its service life. To improve the silk fabrics with excellent antibacterial activity, washing and aging durability, and UV shielding, multifunctional silk fabrics were designed and fabricated via a green finishing approach. Here, we proposed a simple strategy to fabricate silk fabrics with multi-functions via coating clavate-shaped ZnO nanoparticles (ZF-silk fabrics) by dipping and pressing for cycles. The scanning electron microscope (SEM), fourier transform infrared (FTIR), ultraviolet visible spectrophotometry (UV–Vis), and X-ray diffraction (XRD) were used to analyze the structure and properties of fabricated ZF-silk fabrics. Compared with raw silk fabric, the fabricated ZF-silk fabrics represented excellent UV shielding, good tensile strength, and superior antibacterial activity. Notably, the ZF-silk fabrics had good washing stability and aging resistance. In addition, the ZF-silk fabrics possessed superior antibacterial activity before and after aging treatment (under UV radiation for 72 h). Therefore, the durable and multifunctional ZF-silk fabrics indicate great potential for achieving to realize a long service life of the fabrics

Effect of Chemical Treatment on Rice Straw Fiber Surface and Properties of Straw/Polylactic Acid Composites

In this work, rice straw fibers were modified using NaOH, KBM-403, and tetraethyl orthosilicate (TEOS), and the changes in the surface groups of the straw fibers before and after the modification were analyzed by infrared testing. Straw/polylactic composite were prepared by hot pressing, and the effects of the modifiers used on the properties of these blends were studied by conducting mechanical and thermal performance tests. The results showed that the tensile strength of the straw fiber composites modified by NaOH and KBM-403 increased by 20% and 21.2%, respectively, compared with that of the unmodified composite, whereas the tensile strength of the TEOS-modified fiber did not increase significantly. The flexural strengths of the composites increased by 10.2%, 11.1%, and 13.2%. The impact strength increased by 38.5%, 7.6%, and 7.6%. The results of thermal analysis show that initial and maximum thermal decomposition temperatures of the composite materials increased, indicating that the modified composite materials had a higher thermal stability. These blends are a kind of potential material for structural applications such as interiors, drywell and partitions for furniture

Tuning In‐Plane Wicking Properties of Hydrophilic Fibrous Membranes Using Hydrophobic Fibrous Cover Layers

Abstract This study elucidates the effect of thin porous hydrophobic covering layers on the in‐plane wicking properties of a hydrophilic fibrous membrane. Polyacrylonitrile (PAN) fibrous membrane is used as the hydrophilic membrane model and poly(vinylidene fluoride‐hexafluoropropylene) (PVDF‐HFP) fibrous membranes as hydrophobic covers, both prepared by electrospinning. The vertical wicking height is measured to express the in‐plane wicking properties. The results show that the PVDF‐HFP fibrous layer profoundly impacted the in‐plane wicking properties. When the PVDF‐HFP layer is 5.00–7.05 µm in thickness, the PVDF‐HFP/PAN composite membranes show a directional water transport property. The wicking height is higher than the other composite membranes with either a thinner PVDF‐HFP layer (7.05 µm), which stops water permeation from both sides. Such a trend happened no matter whether the PVDF‐HFP layer covered one or both PAN membrane sides. The composite membranes with a PVDF‐HFP layer thicker than 7.05 µm show the smallest wicking height. By changing PVDF‐HFP layer thickness, the wicking height can be adjusted by 50–110%. Such thickness‐dependent wicking capability is novel, having not been reported in the previous literature. It comes from the combined action of hydrophobic and hydrophilic surfaces on water. The tunable wicking properties combined with the water‐absorbing and transport properties enabled the PVDF‐HFP/PAN fibrous membranes to exhibit different functions. They offer opportunities to develop novel “smart” membranes for various applications

Near-Instantaneously Self-Healing Coating toward Stable and Durable Electromagnetic Interference Shielding

10.1007/s40820-021-00709-0Nano-Micro Letters13119