CoS Nanosheets Coated with Dopamine-Derived Carbon Standing on Carbon Fiber Cloth as Binder-Free Anode for Li-ion Batteries

Cobalt sulphides attract much attention as anode materials for Li-ion batteries(LIBs).However,its poor conductivity,low initial column efficiency and large volume changes during cycling have hindered its further development.Herein,novel interlaced CoS nanosheets were firstly prepared on Carbon Fiber Cloth(CFC)by two hydrothermal reactions followed with carbon coating via carbonizing dopamine(CoS NS@C/CFC).As a freestanding anode,the nanosheet structure of CoS not only accommodates the volume variation,but also provides a large interface area to proceed the charge transfer reaction.In addition,CFC works as both a three-dimensional skeleton and an active substance which can further improve the areal capacity of the resulting electrode.Furthermore,the coated carbon combined with the CFC work as a 3D conductive network to facilitate the electron conduction.The obtained CoS NS@C/CFC,and the contrast sample prepared with the same procedure but without carbon coating(CoS NS/CFC),are characterized with XRD,SEM,TEM,XPS and electrochemical measurements.The results show that the CoS NS@C/CFC possesses much improved electrochemical performance due to the synergistic effect of nanosheet CoS,the coated carbon and the CFC substrate,exhibiting high initial columbic efficiency(~87%),high areal capacity(2.5 at 0.15 mA cm−2),excellent rate performance(1.6 at 2.73 mA cm−2)and improved cycle stability(87.5%capacity retention after 300 cycles).This work may provide a new route to explore freestanding anodes with high areal specific capacity for LIBs.

Novel sandwich structured glass fiber Cloth/Poly(ethylene oxide)-MXene composite electrolyte

Recently,poly(ethylene oxide)(PEO)-based solid polymer electrolytes have been attracting great attention,and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal batteries.In this article,a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal batteries.The PEO-based composite electrolyte is fabricated by hot-pressing PEO,LiTFSI and Ti_(3)C_(2)T_(x) MXene nanosheets into glass fiber cloth(GFC).The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties,good electrochemical stability,and high lithium-ion migration number,which indicates an obvious synergistic effect from the microscale GFC and the nanoscale MXene.Such as,the GFC@PEO-1 wt%MXene electrolyte shows a high tensile strength of 43.43 MPa and an impressive Young's modulus of 496 MPa,which are increased by 1205%and 6048%over those of PEO.Meanwhile,the ionic conductivity of GFC@PEO-1 wt%MXene at 60℃ reaches 5.01×10^(-2) S m^(-1),which is increased by around 200%compared with that of GFC@PEO electrolyte.In addition,the Li/Li symmetric battery based on GFC@PEO-1 wt%MXene electrolyte shows an excellent cycling stability over 800 h(0.3 mA cm^(-2),0.3 mAh cm^(-2)),which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt%MXene electrolyte with Li anode.Furthermore,the solid-state Li/LiFePO_(4) battery with GFC@PEO-1 wt%MXene as electrolyte demonstrates a high capacity of 110.2–166.1 mAh g^(-1) in a wide temperature range of 25–60C,and an excellent capacity retention rate.The developed sandwich structured GFC@PEO-1 wt%MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.

Adsorption onto Activated Carbon Fiber Cloth and Electrothermal Desorption of Volatile Organic Compound(VOCs):A Specific Review

A general research program, focusing on activated carbon fiber cloths （ACFC） and felt for environmental protection was performed. The objectives were multiple： （i） a better understanding of the adsorption mecha- nisms of these kinds of materials; （ii） the specification and optimization of new processes using these adsorbents; （iii） the modeling of the adsorption of organic pollutants using both the usual and original approaches; （iv） applications of ACFC in industrial processes. The general question was： how can activated carbon fiber cloths and felts be used in air treatment processes for the protection of environment. In order to provide an answer, different approaches were adopted. The materials （ACFC） were characterized in terms of macro structure and internal porosity. Specific studies were performed to get the air flow pattern through the fabrics. Head loss data were generated and modeled as a fi.mction of air velocity. The performances of ACF to remove volatile organic compounds （VOCs） were approached with the adsorption isotherms and breakthrough curves in various operating conditions. Regenera- tion by Joule effect shows a homogenous heating of adsorber modules with rolled or pleated layers. Examples of industrial developments were presented showing an interesting technology for the removal of VOCs, such as dichloromethane, benzene, isopropyl alcohol and toluene, alone or in a complex mixture.

Electrodeposited NiSe2 on carbon fiber cloth as a flexible electrode for high-performance supercapacitors

A flexible electrode of nickel diselenide/carbon fiber cloth(NiSe/CFC) is fabricated at room temperature by a simple and efficient electrodeposition method. Owing to NiSecharacter of nanostructure and high conductivity, the as-synthesized electrodes possess perfect pseudocapacitive property with high specific capacitance and excellent rate capability. In three-electrode system, the electrode specific capacitance of the NiSe/CFC electrode varies from 1058 F gto 996.3 F gat 2 A gto 10 A grespectively, which shows great rate capability. Moreover, the NiSeelectrode is assembled with an active carbon(AC) electrode to form an asymmetric supercapacitor with an extended potential window of 1.6 V. The asymmetric supercapacitor possesses an excellent energy density 32.7 Wh kgwith a power density 800 W kgat the current density of 1 A g. The nanosheet array on carbon fiber cloth with high flexibility, specific capacitance and rate capacitance render the NiSeto be regarded as the promising material for the high performance superconductor.

MnO2/Poly-L-lysine Co-decorated Carbon Fiber Cloth with Decreased Evaporation Enthalpy and Enhanced Photoabsorption/Antibacterial Performance for Solar-Enabled Anti-fouling Seawater Desalination

Solar-driven seawater evaporation is a potential strategy for mitigating global freshwater shortage,but its application is hindered by the photothermal membranes with high evaporation enthalpy,unsatisfactory photoabsorption,and easy contamination by microorganism.To solve these problems,herein we reported the design of manganese oxide/poly-L-lysine co-decorated carbon-fiber cloth(CFC)with decreased evaporation enthalpy and enhanced photoabsorption/antibacterial performance.Manganese oxide(MnO_(2))nanosheets(thickness:10-30 nm,diameter:400-450 nm)were grown in situ on the CFC surface by a hydrothermal method,and then the nanosheet surface was further decorated with poly-L-lysine(PLL)by the electrostatic adsorption.Co-decoration of MnO_(2)/PLL confers the conversion of hydrophobic CFC to superhydro-philic CFC/MnO_(2)/PLL,accompanied by the reduction of the evaporation enthalpy of bulk water to 2132.34 kJ kg-1 for CFC/MnO_(2)/PLL sample.Such CFC/MnO_(2)/PLL exhibits a strong photoabsorption in wide range(280-2500 nm)with an absorption efficiency of 97.8%,due to the light-trapping effects from hierarchical structures.Simultaneously,CFC/MnO_(2)/PLL has excellent antibacterial performance toward E.coli(99.1±0.2%)and S.aureus(98.2±0.5%)within 60 min in the dark,due to the electrostatic interaction between the bacterial cell membrane and PLL.Subsequently,CFC/MnO_(2)/PLL was hung between the seawater tank and empty tank to construct a hanging evaporator.Under 1.0 kW m^(-2)light irradiation,CFC/MnO_(2)/PLL shows a preeminent evaporation rate of 2.20 kg m^(-2)h^(-1).Importantly,when germy NaCl solution is evaporated,there is no solid-salt accumulation and bacteria contamination on CFC/MnO_(2)/PLL surface during the long-time test(12 h),conferring long-term anti-fouling seawater evaporation.Hence,this work provides new possibilities in the rational design of photothermal fabrics for solar-enabled efficient anti-fouling seawater desalination.

Vapor-phase hydrothermal growth of single crystalline NiS2 nanostructure film on carbon fiber cloth for electrocatalytic oxidation of alcohols to ketones and simultaneous H2 evolution

Electrocatalytic synthesis of value-added chemicals is attracting significant research attention owing to its mild reaction conditions, environmental benignity, and potentially scalable application to organic synthetic chemistry. Herein, we report the preparation of a single-crystalline NiS2 nanostructure film of N 50 nm thickness grown directly on a carbon fiber doth （NiSJCFC） by a facile vapor-phase hydrothermal （VPH） method. NiSJCFC as an electrocatalyst exhibits activity for both the oxygen evolution reaction （OER） and the hydrogen evolution reaction （HER） in alkaline media. Furthermore, a series of alcohols （2-propanol, 2-butanol, 2-pentanol, and cyclohexanol） were electrocatalytically converted to the corresponding ketones with high selectivity, efficienc and durability using the NiSJCFC electrode in alkaline media. In the presence of 0.45 M alcohol, a remarkably decreased overpotential （- 150 mV, vs. RHE） at the NiS2/CFC anode compared with that for water oxidation to generate O2, i.e., the OER, in alkaline media leads to significantly improved H2 generation. For instance, the H2 generation rate in the presence of 0.45 M 2-propanol is almost 1.2-times of that obtained for pure water splitting, but in a system that employs an applied voltage at least 280 mV lower than that required for water splitting to achieve the same current density （20 mA-crn-2）. Thus, our results demonstrate the applicability of our bifunctional non-precious-metal electrocatalyst for organic synthesis and simultaneous H2 production.

Growth of BiOBr/ZIF‑67 Nanocomposites on Carbon Fiber Cloth as Filter‑Membrane‑Shaped Photocatalyst for Degrading Pollutants in Flowing Wastewater

BiOBr-based nanocomposite photocatalysts are used for removing the organic pollutants,but their poor adsorption/photocatalytic performances and the low potential for recycling limit their application.To solve the issue,herein we report a large-area recyclable CFC/BiOBr/ZIF-67 filter-membrane-shaped photocatalyst prepared by in situ growth of BiOBr/ZIF-67 nanocomposites on carbon fiber cloth(CFC).Fabrication process is based on hydrothermal synthesis of BiOBr nanosheets(diameter 0.5–1μm)on carbon fiber cloth(as substrate material)and then a chemical bath route is used to grow ZIF-67 nanoparticles(diameter 300–600 nm)in situ on the surface of CFC/BiOBr.Resulted composite,CFC/BiOBr/ZIF-67,exhibits a high specific surface area(545.82 m^(2) g^(−1))and a wide photoabsorption,accompanied by an absorption edge(~620 nm).In dark condition,CFC/BiOBr/ZIF-67 adsorbs bisphenol A(BPA)and orange 7(AO7)within 60 min,respectively with 20.0% and 40.1% efficiency.This level of efficiencies are correspondingly 2.6 and 3.2 times more that of the bare CFC/BiOBr(7.6%for BPA and 12.4% for AO7).Under visible light irradiation,CFC/BiOBr/ZIF-67 can degrade 69.7% of BPA and 96.0% of AO7,in 120 min,which are,respectively,1.3 and 1.8 times higher than the absorption efficiency of bare CFC/BiOBr(53.2% for BPA,52.0% for AO7).When CFC/BiOBr/ZIF-67 is used as a filter membrane for photocatalytic removal of pollutants in flowing wastewater(AO7,rate:~1.5 L h^(−1)),92.2%of AO7 can be decomposed after 10 filtering cycles.This study suggests CFC/BiOBr/ZIF-67 as a novel highly functional,recyclable and environmental friendly photo-driven membrane filter for purification and recovery of flowing surface waste waters.

Optimizing the micropore-to-mesopore ratio of carbon-fiber-cloth creates record-high specific capacitance

The application of commercial carbon fiber cloth(CFC) in energy storage equipment is limited by its low specific capacitance and energy density. By a simple one-step activation treatment, the specific surface area of CFCs with porous structure can be increased considerably from 3.9 up to 875 m^2/g and the electrochemical properties of CFCs can be improved by three orders of magnitude(1324 mF/cm^2). Moreover,the hydrophobicity of CFCs can be transformed into superhydrophilicity. However, the electrochemical performance of CFCs does not show a positive correlation with specific surface area but have a strong relationship with the hierarchical pore distribution forged by the annealing treatment. Only moderate micropore and mesoporous ratio enables optimizing the electrochemical performance of CFCs.

Construction of n-TiO_(2)/p-Ag_(2)O Junction on Carbon Fiber Cloth with Vis-NIR Photoresponse as a Filter-Membrane-Shaped Photocatalyst

The development of effective and reusable photocatalysts with broad-spectra activity has attracted attention.Herein,we have constructed n-TiO_(2)/p-Ag_(2)O junction on carbon fiber(CF)cloth as an efficient and recyclable photocatalyst.With CF cloth as the substrate,TiO_(2) nanorods(length:1-2μm)are prepared by a hydrothermal process,and the in-situ growth of Ag_(2)O nanoparticles(10-20 nm)is then realized by chemical bath deposition route.The flexible CF/TiO_(2)/Ag_(2)O cloth(area:4×4 cm^(2))shows a broad and strong photo-absorption(200-1000 nm).Under the illumination of visible-light(λ>400 nm),CF/TiO_(2)/Ag_(2)O cloth can efficiently eliminate 99.2%rhodamine B(RhB),99.4%acid orange 7(AO7),87.6%bisphenol A(BPA),and 89.5%hexavalent chromium(Cr^(6+))in 100 min,superior to CF/Ag_(2)O cloth(83.5%RhB,60.0%AO7,31.2%BPA and 41.8%Cr^(6+)).In particular,under the NIR-light illumination(980 nm laser),CF/TiO_(2)/Ag_(2)O cloth can remove 70.9%AO7 and 60.0%Cr^(6+) in 100 min,which are significantly higher than those by CF/Ag_(2)O cloth(19.8%AO7 and 18.9%Cr^(6+)).In addition,CF/TiO_(2)/Ag_(2)O cloth(diameter:10 cm),as a filter-membrane,can effectively wipe off 94.4%flowing RhB solution(rate:~1 L h^(−1))at 6th filtering/degrading grade.Thus,CF/TiO_(2)/Ag_(2)O cloth can be used as a Vis-NIR-responded filter-membrane-shaped photocatalyst with high-efficiency for purifying wastewater.

Needle-like cobalt phosphide arrays grown on carbon fiber cloth as a binder-free electrode with enhanced lithium storage performance

Cobalt phosphide(CoP) is a promising anode candidate for lithium-ion batteries(LIBs) due to its high specific capacity and low working potential.However,the poor cycling stability and rate performance,caused by low electrical conductivity and huge volume variation,impede the further practical application of CoP anode materials.Herein,we report an integrated binder-free electrode featuring needle-like CoP arrays grown on carbon fiber cloth(CC) for efficient lithium storage.The as-prepared CoP/CC electrode integrates the advantages of 1 D needle-like CoP arrays for efficient electrolyte wettability and fast cha rge transpo rtation,and 3 D CC substrate for superior mechanical stability,flexibility and high conductivity.As a result,the CoP/CC electrode delivers an initial specific capacity of 1283 mAh/g and initial Coulombic effeciencies of 85.4%,which are much higher than that of conventional CoP electrode.Notably,the Co P/CC electrode shows outstanding cycling performance up to 400 cycles at 0.5 A/cm^(2) and excellent rate performance with a discharge capacity of 549 mAh/g even at 5 A/cm^(2).This work demonstrates the great potential of integrated CoP/CC hybrid as efficient bind-free and freestanding electrode for LIBs and future flexible electronic devices.

Boosting Capacitive Deionization Performance of Commercial Carbon Fibers Cloth via Structural Regulation Based on Catalytic-Etching Effect

Monolithic carbon electrodes with robust mechanical integrity and porous architecture are highly desired for capacitive deionization but remain challenging.Owing to the excellent mechanical strength and electroconductivity,commercial carbon fibers cloth demonstrates great potential as high-performance electrodes for ions storage.Despite this,its direct application on capacitive deionization is rarely reported in terms of limited pore structure and natural hydrophobicity.Herein,a powerful metal-organic framework-engaged structural regulation strategy is developed to boost the desalination properties of carbon fibers.The obtained porous carbon fibers features hierarchical porous structure and hydrophilic surface providing abundant ions-accessible sites,and continuous graphitized carbon core ensuring rapid electrons transport.The catalytic-etching mechanism involving oxidation of Co and subsequent carbonthermal reduction is proposed and highly relies on annealing temperature and holding time.When directly evaluated as a current collector-free capacitive deionization electrode,the porous carbon fibers demonstrates much superior desalination capability than pristine carbon fibers,and remarkable cyclic stability up to 20 h with negligible degeneration.Particularly,the PCF-1000 showcases the highest areal salt adsorption capacity of 0.037 mg cm^(−2) among carbon microfibers.Moreover,monolithic porous carbon fibers-carbon nanotubes with increased active sites and good structural integrity by in-situ growth of carbon nanotubes are further fabricated to enhance the desalination performance(0.051 mg cm^(−2)).This work demonstrates the great potential of carbon fibers in constructing high-efficient and robust monolithic electrode for capacitive deionization.

Deciphering the lithium storage chemistry in flexible carbon fiber-based self-supportive electrodes

Flexible carbon fiber cloth(CFC)is an important scaffold and/or current collector for active materials in the development of flexible self-supportive electrode materials(SSEMs),especially in lithium-ion batteries.However,during the intercalation of Li ions into the matrix of CFC(below 0.5 V vs.Li/Li+),the incompatibility in the capacity of the CFC,when used directly as an anode material or as a current collector for active materials,leads to difficulty in the estimation of its actual contribution.To address this issue,we prepared Ni_(5)P_(4)nanosheets on CFC(denoted CFC@Ni_(5)P_(4))and investigated the contribution of CFC in the CFC@Ni_(5)P_(4)by comparing to the powder Ni_(5)P_(4)nanosheets traditionally coated on a copper foil(CuF)(denoted P-Ni_(5)P_(4)).At a current density of 0.4 mA cm^(−2),the as-prepared CFC@Ni_(5)P_(4)showed an areal capacity of 7.38 mAh cm^(−2),which is significantly higher than that of the PNi_(5)P_(4)electrode.More importantly,theoretical studies revealed that the CFC has a high Li adsorption energy that contributes to the low Li-ion diffusion energy barrier of the Ni_(5)P_(4)due to the strong interaction between the CFC and Ni_(5)P_(4),leading to the superior Li-ion storage performance of the CFC@Ni_(5)P_(4)over the pristine Ni_(5)P_(4)sample.This present work unveils the underlying mechanism leading to the achievement of high performance in SSEMs.

High Oil-absorptive Composites Prepared from Non-woven Fiber and Sponges with 4-tert- butylstyrene-EPDM-divinylbenzene Graft Polymer

4-tert-butylstyrene-EPDM-divinylbenzene graft terpolymer (PBED) was prepared by graft cross-polymerization in toluene using BPO as an initiator. The gel-PBED and solPBED were isolated from extraction of tetrahydrofuran (THF), and then they were identified by IR spectroscopy. The maximum oil-absorptivity of gel-PBED produced from the optinum reaction conditions was 8 420% but its swelling rate was very low. The highest oil-absorptivity of photocrosslinked sol-PBED film was 5 800%. Although its oil absorbency was not as high as gel-PBED' s, swelling rate was higher than that of gelPBED and was suitable for commercial purpose. After swelling in oil, neither gel PBED nor photocrosslinked sol-PBED film having high oil-absorptivity had sufficient mechanical strength to be taken out of oil wholly. As is known, composite technique is one of the useful methods for reinforcing them. Fibers, sponges and non-woven cloths were used as reinforcers or supporters in this work. Oil-absorptivities and swelling kinetics were evaluated by method ASTM (F726 - 81 ) and an experimental equation. The mechanical properties and the morphologies of some composites were measured by tensile tester and SEM , respectively.

Effect of Cellulose Enzymes on Some Properties of Fibre Clothes

This study examined the effects of the enzyme cellulose on a few single jersey and interlock 100% flax t-shirts, two different styles of knit children’s clothes that differ in both their chemical and mechanical characteristics. Clothing samples were dyed using reactive colours and then subjected to normal acid cellulose enzyme treatment procedures. We evaluated some physical and mechanical features before and after cellulose treatments, then compared these characteristics. Its cellulose enzymatic processing enhances some mechanical properties of fibre knitwear, such as pilling resistance and retention of water. Some characteristics of fibre-knitted clothing, such as fabric weight, fabric thickness, fabric burst resistance, and seam tensile strength of T-shirt side seams, are reduced by cellulose enzyme treatment at a manageable rate. Compared to single-jersey all-fiber children’s T-shirts, interlocking 100% flax children’s T-shirts have a better effect of the enzyme cellulose treatment on the majority of physical and mechanical attributes.

基于CiteSpace的智能纺织服装产品研究进展

为揭示智能纺织服装的研究现状、热点和趋势,以CNKI数据库和WOS数据库中2012—2022年的相关文献为研究对象,采用CiteSpace可视化分析软件绘制知识图谱,分析智能纺织服装产品在国家、机构、作者方面的分布现状及合作情况,对研究热点和前沿趋势进行梳理。结果表明,2012—2022年,CNKI数据库发文量稳步上升,WOS数据库发文量快速增长且中国学者发文量较多;CNKI数据库研究合作强度较低且以东华大学和江南大学为主体;WOS数据库合作关系密切,研究集中度和合作强度大;CNKI数据库研究方向更注重应用和设计模式,WOS数据库则更注重电子元件制造和智能纤维与面料的开发;健康检测、变色肌理、仿生设计、生物材料、可穿戴应变等是目前智能纺织服装领域的前沿热点,电子元件制造、智能纤维及面料智能化研究是未来智能纺织服装领域研究的热点及趋势。

预应力CFRP布加固混凝土梁受弯试验

目的 研究不同加固方法下预应力碳纤维布加固混凝土梁的受弯性能,解决桥梁加固缺陷的问题。方法 制作了5根试验梁,其中一根为对比梁,不做任何加固处理,其余4根分别采用不同的锚固方式、不同的初始张拉力及不同的加固位置进行加固,通过控制变量,进行加载试验,分析其受弯性能的差异。结果 经加固后的试验梁承载能力与刚度明显增加,与对比梁相比,极限荷载分别提升了25%、22.06%、30.78%及36.76%;各试验梁达到屈服荷载时,经加固的试验梁挠度均小于对比梁产生的挠度,且模腔自锁式锚具锚固的试验梁挠度小于穿孔式自锁锚具锚固的试验梁挠度,相同锚固方法下初始张拉力较大的试验梁挠度要小于初始张拉力较小的试验梁挠度。结论 使用预应力碳纤维布加固混凝土梁能够有效提高混凝土梁的抗弯性能,提升效果与加固位置、锚固方式及初始张拉力大小有关。

浅谈建筑结构加固工艺

我国在基础建设快速发展的阶段,进一步加大了对基础设施建设的投入,从而加快了建筑业的发展,充分发挥国家科技力量的支撑作用,相继修建了各种类型的道路、桥梁、高楼、会展中心、重大水利工程等。由于受到自然灾害、空气影响等,这些建筑的结构往往出现过早老化的情况。据相关统计数据显示,全国城镇需要开展加固工作的民用建筑有30亿平方米,其中亟待修复加固处理的建筑有10亿平方米。如何对这些老旧建筑检测加固,需要进行研究探讨。

FRP布材增强钢筋混凝土桩水平承载性能研究

纤维增强复合材料(FRP)由于其轻质高强的优点被广泛应用于抗震加固、结构补强等实际工程中,但有关FRP增强混凝土桩水平承载性能的研究较少。为了研究不同FRP布材加固混凝土桩承载特性问题,通过室内模型试验对FRP布桩(普通钢筋混凝土桩身包裹FRP布材)的水平承载规律进行研究,探究了不同包裹层数、不同FRP布材类型、不同布材混合包裹对钢筋混凝土桩承载性能的影响。同时利用ABAQUS软件建立FRP布桩三维有限元模型,对每种工况进行数值模拟。结果表明,FRP布桩的水平承载性能随着包裹层数的增加而提升,提升效果与包裹层数之间并不存在正比例关系;不同布材类型的FRP布桩中,CFRP布对FRP布桩的水平承载性能提升效果最优;混合包裹(CFRP+GFRP)的提升效果要略优于包裹2层GFRP布。

碳纤维及碳纤维布混凝土抗冻性及能量耗散试验研究

为探究碳纤维增强方式对混凝土材料抗冻性能及能量耗散影响规律,利用纵波波速仪以及电液伺服压力机获取冻融循环作用(0,25,50,75,100次)后四种混凝土(素混凝土、碳纤维混凝土、碳纤维布混凝土、碳纤维及碳纤维布混凝土)的纵波波速及力学性能,分析碳纤维增强方式、冻融循环次数对试件相对动弹性模量、峰值应力、能量耗散及损伤度影响规律。结果表明:①相较于冻融循环0次素混凝土,冻融循环25,50,75,100次试件相对动弹性模量降幅分别为8.21%、18.33%、30.44%、45.89%,冻融循环次数的增加使试件相对动弹性模量降低,碳纤维及碳纤维布均能减缓试件相对动弹性模量降幅;②冻融循环次数的增加使四种不同混凝土试件峰值应力均呈降低趋势,碳纤维及碳纤维布不仅能够增强试件强度,还能够增强其抗冻性,且两者组合时对试件的提升效果最佳;③相较于未冻融试件,冻融循环25,50,75,100次时弹性变形能降幅分别为3.87%、7.63%、9.67%、12.70%,耗散能降幅分别为10.42%、21.97%、30.16%、41.60%,冻融作用会使试件内部产生损伤,降低试件储能、耗能效果;④三种碳纤维混凝土在达到峰值应力时对应机械损伤度值显著高于素混凝土对应机械损伤度值,碳纤维的增强作用能够有效提升混凝土材料吸能效果、延展性及抗冻性。

Kevlar纤维UD布的力学性能研究

研究树脂种类和含胶量对Kevlar纤维无纬(UD)布拉伸和层间剪切性能的影响规律。利用万能材料试验机测试不同比例的水性聚氨酯与水性丙烯酸酯共混树脂以及含胶量对Kevlar纤维UD布拉伸和层间剪切性能的影响规律。结果表明:随着丙烯酸树脂含量的增加,Kevlar纤维UD布的拉伸强度和层间剪切强度呈先增大后减小的趋势;水性聚氨酯树脂∶水性丙烯酸树脂比例为1∶2,Kevlar纤维UD布的拉伸强度和层间剪切强度最大。在一定范围内,Kevlar纤维UD布的拉伸强度和层间剪切强度随着含胶量的提高,呈先增大后减小的趋势,且树脂含量26%,Kevlar纤维UD布的拉伸强度和层间剪切强度达到最大值。