高强高模炭纤维

在各种不同性质的炭纤维材料中高强度高模量炭纤维材料占有特殊的地位,它们被划分为高强高模炭纤维。这类炭纤维无论在绝对值还是在比强度、比模量方面都超过了铝、钢和钛。在不同的结构材料中采用高强炭纤维材料     

现代体育器械的重要材料——炭纤维复合材料

炭纤维复合材料是上世纪50年代初应火箭、宇航及航空等尖端科学技术的需要而产生的,主要由炭纤维与树脂、金属、陶瓷等基体复合制成的结构材料.其比强度、比模量综合指标,在现有结构材料中是最高的.在密度、刚度、疲劳特性等有严格要求的领域及要求高温、化学稳定性高的场合,炭纤维复合材料均比传统材料颇具优势,现已被广泛应用于体育器械领域.本文通过具体的例证阐明了炭纤维复合材料在现代体育器械上的应用.     

微螺旋炭纤维手性复合吸波材料的研究

微螺旋炭纤维独特的螺旋手性结构赋予其优异的吸波性能,本文结合自身实验,综述了微螺旋炭纤维复合吸波材料的研究进展,并分析其吸波机理在螺旋手性结构引起的电磁波交叉极化,同时对发展更好的微螺旋炭纤维手性复合吸波材料提出了可行建议.     

新产品

具有世界最高强度水平的镁基炭纤维复合材料ＥＭ技术公司与京都大学的落合庄治郎教授等共同开发了镁与炭纤维的复合材料。此种复合材料是将在 30 0 0℃烧成的石墨化炭纤维与在 70 0～ 80 0℃熔融的镁 ,通过高压铸造法而进行复合。该材料的拉伸强度为 12 0 0ＭＰａ、模量为 5 70ＧＰａ ,密度为 2 .0ｇ/ｃｍ3 ,比铝轻 ,沿纤维方向的热膨胀系数为 0 ,热导率为 5 0 0Ｗ / (ｍ·Ｋ) ,比铜高 ,作为轻而又高强度的新材料 ,今后预期在飞机用材料和赛车等体育用品领域会有需求。另外 ,由于其导热性高、散热性好 ,在散热器等半导体基板或焊剂用具方面…     

文摘

<正>锂离子电池负极用纤维状炭材料[刊,中]/楠顶,黄正宏,康飞宇,等//新型炭材料,2015(1):1~11纤维状炭材料有各种尺度和形貌,由于成本和性能缺乏竞争力,制约其在锂离子电池负极材料中的应用。随着纳米技术的发展,一些改性后的新型炭纤维表现出良好的负极材料性能。文章综述了近年各种纤维状炭材料用作锂离子电池负极材料的国内外研究进展。依据纤维状炭材料的结构、性能及其研究思路,分别归纳了石墨纤维、炭纤维及具有各种     

化学浴法制备氢氧化镍@生物质炭纤维纳米复合材料及其电化学性能研究

以棉花在惰性气氛下高温处理得到的生物质炭纤维为载体,采用化学浴法原位制备氢氧化镍@生物质炭纤维纳米复合材料,并研究其作为超级电容器电极材料的电化学性能。借助X射线衍射和扫描电镜表征手段研究材料的结构和形貌。采用循环伏安、恒电流充放电及交流阻抗等电化学测试方法对材料的电化学性能进行分析。结果表明,氢氧化镍@生物质炭纤维复合材料中的氢氧化镍以纳米片层结构生长在生物质炭纤维表面,形成以氢氧化镍纳米片为壳、生物质炭纤维为核的核壳式结构;生物质炭纤维的引入能有效改善氢氧化镍的分散性,降低材料的电子转移阻力,进而提高氢氧化镍@生物质炭纤维复合材料的电化学性能。     

结构炭/炭复合材料力学性能及微观结构研究

采用四向编织、快速化学气相渗透致密化新工艺制备了炭／炭复合材料,其弯曲强度达３２０ＭＰａ。分析研究了这种材料的力学性能特征。利用ＳＥＭ和高分辨ＴＥＭ分析了基体炭、炭纤维／基体灰界面的精细结构,发现炭纤维呈单根被基体炭包围,基体现灰呈层片状,为二维有序的乱层石墨结构;在炭纤维与基体炭之间存在着过渡相,这一过渡相厚度的约几十纳米,随着与炭纤维之间距离的增大,它们之间形成的夹角由小变大,这一过渡相即为炭     

国内外聚醚醚酮开发应用进展

PEEK属特种高分子材料,可用作耐高温结构材料和电绝缘材料,也可与玻璃纤维或碳纤维复合制备增强材料,在航空航天、汽车、电子电气、运输、机械、医疗器械等领域应用广泛。本文综述了国内外PEEK产业发展现状及产品开发应用进展。     

炭纤维/环氧树脂结构吸波材料电磁特性研究

采用真空CVD炉分别在600,630,660℃对炭纤维进行了热处理,制备了3种不同的炭纤维,然后制备出炭纤维/环氧树脂结构吸波复合材料,最后采用波导法对材料的电磁特性进行了测试,并对其吸波性能进行了模拟。结果表明:炭纤维的热处理温度对材料的介电常数有较大影响。从实验中得出,通过控制炭纤维的热处理温度,可有效地调节炭纤维的介电常数,从而制备出具有良好的吸波性能的结构吸波材料。     

炭纤维复合炭分子筛的制备及其在气体分离和环保中的应用

本技术以短切炭纤维为原料,经化学、物理及等离子体表面处理等方法改性,随后加粘结剂复合成型为片状、柱状、蜂窝状的多孔坚硬材料,此类新材料具有开放式的大孔结构,可允许流体自由穿过;而且具有发达的微孔结构,较好的耐压、耐磨强度及良好的导电性和独特的表面性质。可以用于CO2的回收,NOx和SOx等酸性气体的脱除,从天然气中分离出CO2和H2S,印染行业中溶剂的回收,饮用水及废水的处理。炭纤维复合炭分子筛的制备及其在气体分离和环保中的应用     

Lyocell纤维原丝的性能对碳纤维强度的关联分析

运用灰色系统方法对新型纤维素原丝Lyocell纤维的性能与碳纤维强度之间的关系进行了关联分析，结果表明：Lyocell纤维的强度、纤度和断裂强力对碳纤维的强度有很大的影响，而对伸长和模量的影响较小。     

THE EFFECT OF PRECURSOR PROPERTIES ON THE STRENGTH OF CARBON FIBER

In this article, lyocell fiber is used as a precursor for carbon fiber. The mechanical properties of lyocell fiber and tenacity of carbon fiber from this precursor have been determined. Gray-relation analysis is used to investigate the relation between precursor's properties and the strength of the carbon fibers. The results suggested that the strength, force at breaking, and fineness of precursor have greater influence on the strength of carbon fibers than precursor's elongation, and modulus.     

Mechanical properties of carbon fiber/vinylester composites exposed to marine environments

The effects of seawater exposure on the mechanical properties of unidirectional T700 carbon fiber/vinylester (510A) composites have been examined. Carbon fibers with two different types of sizings (F and G) were studied. Dynamic mechanical analysis testing of the neat resin and a carbon/vinylester composite revealed similar viscoelastic responses and glass transition temperatures indicating same type of cured resin for both cases. An analysis of moisture absorption dynamics of the composites revealed Fickian behavior. The composites absorbed more moisture than the resin. The moisture up‐take in the composites is dominated by the fiber/matrix region. A comprehensive mechanical test program involving tension, compression, and shear tests was conducted on the composites at dry and saturated conditions. Composites with F‐sized carbon fibers displayed overall higher strengths than those with G‐sized fibers at both dry and moisture‐saturated conditions. Moisture absorption was found to have a moderate influence on most composite strengths, except for the in‐plane and interlaminar shear strengths, where reductions in the range of 10–16% occurred. POLYM. COMPOS., 35:1559–1569, 2014. © 2013 Society of Plastics Engineers     

Achievement of high surface charge in poly(vinylidene fluoride) fiber yarns through dipole orientation during fabrication

Electrospun fiber materials are of scientific interest for use in multiple application areas. Charged fiber structures show enhanced properties as desired for some of these applications. One factor influencing the charge on the fiber structure that has not been explored is fiber alignment. Electrospun fiber structures, such as membranes, typically consist of randomly oriented fibers. Structural properties of the membranes such as mechanical strength are known to be affected by the random orientation of the fibers. It is suspected that fiber orientation may also affect the charge capacity of charged fiber structures. A few approaches to form electrospun yarns have been reported. Some of these approaches can also cause fibers to preferentially align along the yarn axis instead of assembling into a random structure. In this work, a rotating metal cone was used to collect Poly(vinylidene fluoride) electrospun fibers from which stretched yarns were drawn and twisted into yarns. The alignment of the fibers in the yarns was controllable to a degree that allowed exploration of the effect of alignment on charge. Long continuous oriented or random yarns of relatively uniform thickness were produced at a rate of about 10 m/h. The yarns were polarized by methods of heating, stretching, and poling. The results show that the fiber yarn formation process endows more charges to the fibers compared to the normal fiber membrane electrospinning and post polarization. This provides a facile route for the preparation of enhanced charge-functionalized fiber structures for a wide range of applications.     

Precursors for Carbon and Graphlte Fibers

Abstract

Commercial production of carbon and graphite fiber products has been dominated by technology based on the thermal conversion of rayon and polyacrylonitrile fibers. In fact, a wide range of potentially useful and low-cost precursors exist. Most recently, pitch-based fibers have materialized as strong contenders for carbon fiber production. This study is a comprehensive analysis of carbon fiber precursors. It presents a data base for the development of a generalized theory for the prediction of formation of carbon fibers with high mechanical properties.     

PAN/PPG纤维预氧化及碳纤维结构和性能研究

采用聚丙二醇(PPG)与聚丙烯腈(PAN)共混制备的PAN/PPG原丝进行预氧化和碳化,利用SEM、FTIR、元素分析仪、力学性能测试等仪器和手段,研究了PPG的加入对预氧丝和碳丝的结构和性能的影响.研究发现:PPG的加入使PAN预氧丝的表面结构更加均匀,减少了碳纤维中的孔洞;同时还促进了纤维在预氧化和碳化过程中的氧化...     

新型碳纤维用原丝——高强高模Lyocell纤维纺丝工艺研究

采用天然高相对分子质量纤维素脱脂棉为原料 ,制备了高强高模纤维素纤维 ( L yocell纤维 ) ,并用此作为碳纤维原丝 ,成功制得了强度优于粘胶基碳纤维的 L yocell基碳纤维。考察了高相对分子质量纤维素的溶解特点 ,纺丝工艺对 L yocell纤维聚集态及性能的影响 ,比较了 L yocell纤维和粘胶原丝的表面及截面形态。实验表明 :高相对分子质量纤维素溶解的静溶胀时间和温度对其溶解有明显的影响 ;纺丝过程中 ,大的气隙长度对提高纤维的性能有利 ;随着凝固浴中 N -甲基吗啉 N -氧化物( NMMO )的浓度增加 ,纤维的强度和模量增加 ,当其在凝固浴中的质量分数达到 10 %时 ,强度模量最大 ,浓度继续增加 ,纤维的力学性能开始下降 ;拉伸比增加 ,L yocell纤维的强度模量增加 ,当拉伸比大于 3.0时 ,纤维的性能略有下降     

高温热处理后炭纤维表面微观形态

炭纤维的表面微观形态对其力学性能有很大影响，选择国产和日本东邦公司的炭纤维，对其进行高温热处理（1800～2500℃），研究了热处理温度对炭纤维力学性能、密度的影响。用SEM观察了热处理前后炭纤维的表面微观形态变化，讨论了表面缺陷产生的原因。     

A comparison of the mechanical properties of fibers spun from different carbon nanotubes

Spinnable carbon nanotube (CNT) arrays with different CNT structures have been synthesized using different growth methods and carbon sources, and long and stable fibers have been produced. Parameters of the nanotubes such as tube diameter, wall thickness, tube length and level of defects were found to play a more important role in the mechanical properties of the fibers than did the initial tube arrangement. To improve the fiber strength, as well as the modulus, the tubes must be long and have a small diameter and thin walls. The strongest fiber from double- and triple-walled CNTs is 1.23 GPa in strength, and 32% and 221% higher than those from CNTs with ∼6 and ∼15 walls (932 and 383 MPa), respectively. The fiber strength can be improved by 25%, up to 1.54 GPa, after poly(vinyl alcohol) infiltration with volume fraction of ∼20%. Our study also shows that C₂H₄ is superior to C₂H₂ as the carbon source for the growth of mainly double- and triple-walled CNTs, and therefore the spinning of high-strength fibers.     

Effect of the fabrication process on the microstructural evolution of carbon fibers and flexural property on C/SiC composites by the NITE method

Nano-infiltration and transient eutectic phase (NITE) SiC matrix composites are designed for application in aerospace propulsion systems, particularly in fasteners and thrusters. A variety of carbon fibers with different properties have been selected as reinforcements for SiC matrix composites. Carbon fibers are known to be stable at high temperatures; however, the effects of high applied pressure at high temperatures on the fiber microstructure evolution and mechanical properties are not well-known. As a scoping study for fabricating NITE C/SiC composites, the behaviors of various carbon fibers in SiC composites. Pitch-based fibers, namely, GRANOX XN-05 and YS-90A, and a polyacrylonitrile-based fiber, namely, TORAYCA T-300B, were selected for matrix reinforcement. The 3-point bending test results indicated pseudo-ductile behaviors in the cases of YS-90A and T-300B fiber reinforcements. Fracture resistance evaluation based on the single-notch bending test indicated that the YS-90A fiber reinforced composite afforded the highest fracture resistance among the three C/SiC composites. The microstructure evolution on YS-90A and T-300B fibers was limited to near the fiber surface. Therefore, YS-90A and T-300B carbon fibers are potential candidates for reinforcement in NITE C/SiC composites.