碳纤维研究领域技术制高点-上浆剂

综述并分析了聚丙烯腈基碳纤维用上浆剂种类、制备方法和上浆工艺以及上浆剂对复合材料层间剪切强度、弯曲强度和耐湿热性能影响的重要性。指出碳纤维上浆剂研发的滞后已成为制约我国碳纤维进一步发展的重要因素,尽快开展系列碳纤维专用上浆剂的研制是解决国产碳纤维应用工艺性能问题的有效途径。     

不同种类碳纤维上浆剂的研究

实验并讨论了几种不同类型上浆剂对碳纤维复合材料的影响。分别从乳液稳定性、复合材料力学性能、表面形貌和冲击断面形貌进行考察,结果表明：聚丙烯醇乳液上浆剂稳定性好,经其处理后的碳纤维复合材料力学性能优异,其界面结合能力强。     

碳纤维热塑性树脂上浆剂及其对复合材料界面的影响

研究一种适用于碳纤维增强热塑性树脂的水性乳液上浆剂。考察了上浆剂的粒度、浸润性、贮存稳定性、耐酸碱稳定性、热稳定性以及上浆后碳纤维的毛丝率;并通过实验对上浆处理前后碳纤维表面形貌的观察和单丝界面剪切强度的分析。结果表明,聚氨酯质量分数为1%和乳化剂质量分数为0.8%的上浆剂,粒径小、分散均匀和具有良好的稳定性,经上浆处理后的碳纤维与树脂基体的界面剪切强度从40.2 MPa提高到了51.9 MPa。     

上浆量对碳纤维应用性能的影响

介绍了上浆量对碳纤维应用性能影响的最新研究情况，综述了上浆量对碳纤维成型过程中的工艺性能以及复合材料的力学性能的影响，阐述了上浆量对碳纤维界面性能的影响机制，指出针对特定材料体系，存在一个能够使界面结合性能最强的最佳上浆量。     

碳纳米材料在碳纤维上浆剂中的应用

简述了碳纤维上浆剂的分类及作用,重点介绍了碳纳米材料在碳纤维上浆剂中的应用,包括碳纤维上浆剂中碳纳米材料对上浆剂稳定性、碳纤维表面特性及碳纤维复合材料界面性能的作用。碳纤维上浆剂可分为溶剂型、乳液型、水溶性上浆剂,采用上浆法可以通过碳纤维上浆工序直接将碳纳米材料引入碳纤维表面。通过对上浆剂中的碳纳米材料进行改性,引入带同种电荷的官能团,可降低上浆剂乳胶粒子的团聚,提高上浆剂的稳定性,增加碳纤维表面粗糙度和改变碳纤维表面化学组成,增强碳纤维复合材料界面的物理锚定作用与化学键合作用,提高碳纤维复合材料的界面性能。指出通过化学键将改性碳纳米材料接枝到上浆剂主浆料分子上,可以缓解碳纳米材料的团聚,使碳纳米材料更均匀地包裹在碳纤维表面,进一步改善碳纤维表面特性和复合材料界面性能,这是未来碳纳米材料上浆剂研究的重要方向之一。     

碳纤维上浆改性及其增强聚合物材料研究进展

介绍了针对不同树脂基体制备碳纤维(CF)上浆剂的方法,并探讨CF上浆改性对CF增强聚合物基复合材料(CFRPC)界面性能及力学性能的影响。根据不同树脂基体类型综述了CF表面上浆后增强环氧树脂、聚酰胺、聚碳酸酯、聚醚砜及聚酰亚胺等聚合物材料的力学性能和界面粘结强度的变化情况。最后指出,针对不同树脂基体开发专用上浆剂,在CF生产过程中采用专用上浆剂对CF进行上浆处理,以实现CF生产完成后即可制备界面性能和力学性能优异的CFRPC,是CF上浆改性研究的未来发展方向。     

自乳化环氧上浆剂对碳纤维复合材料性能影响

以过硫酸铵为催化剂,用不同相对分子质量聚乙二醇(PEG400、800、1000、1500、2000、4000、6000)与氢化双酚A环氧进行加成聚合反应,滴加去离子水制得改性环氧乳液。分别从乳液稳定性、化学结构、耐热性和复合材料表面以及断面形貌和力学性能表征上浆剂乳液及其复合材料性能。结果表明:PEG2000改性环氧乳液上浆剂稳定性与耐温性好,平均粒径0.866μm,经其处理后碳纤维复合材料的力学性能优异,界面结合能力强。     

聚丙烯腈基碳纤维用环氧树脂上浆剂的比较

用两种环氧树脂上浆剂对国产聚丙烯腈基碳纤维进行上浆,测试和比较了两种环氧树脂上浆剂对聚丙烯腈(PAN)基碳纤维耐磨性、与水接触角、表面能等性能以及拉伸强度、伸长率、层间剪切强度(ILSS)等力学性能的影响。上浆剂中主体成分环氧树脂相对分子质量不是影响碳纤维层间剪切强度的决定性因素。     

碳纤维用水性乳液上浆剂的研究现状

简述了碳纤维用水性乳液上浆剂的制备、应用和性能表征手段的研究现状.介绍了相似相容和界面层理论在上浆剂主剂树脂选择方面的应用,说明了乳化剂、固化剂和纳米材料等原料的添加对上浆剂性能的影响,阐述了上浆剂乳液制备中自乳化法和相转乳化法的选择方法,以及表面处理和上浆处理工艺及工艺参数的优化方法.总结了应用于上浆剂乳液、上浆纤维...     

碳纤维表面处理和上浆剂的研究进展

复合材料的界面特性与其宏观力学性能密切相关:界面层的厚度和模量决定了界面处应力的传递,界面层的化学组成也会间接影响界面粘结强度,因此研究复合材料界面层组成及性能的影响因素是十分必要的。因此,碳纤维自身的表面物理、化学性质和碳纤维表面涂覆的上浆剂成为了重要考虑因素。本文结合日本东丽关于碳纤维表面处理、上浆剂种类及上浆工艺的专利及其它文献,综述了表面处理方法和上浆剂种类对界面粘结性能的影响。     

Tensile properties of carbon filled liquid crystal polymer composites

Electrically and thermally conductive resins can be produced by adding carbon fillers. Mechanical properties such as tensile modulus, ultimate tensile strength, and strain at ultimate tensile strength are vital to the composite performance in fuel cell bipolar plate applications. This research focused on performing compounding runs followed by injection molding and tensile testing of carbon filled Vectra A950RX liquid crystal polymer composites. The four carbon fillers investigated included an electrically conductive carbon black, thermocarb synthetic graphite particles, and two carbon fibers (Fortafil 243 and Panex 30). For each different filler type, resins were produced and tested that contained varying amounts of these single carbon fillers. The carbon fiber samples exhibited superior tensile properties, with a large increase in tensile modulus over the base polymer, and very low drop in the ultimate tensile strength as the filler volume fraction was increased. The strain at the ultimate tensile strength was least affected by the addition of the Panex carbon fiber but was significantly affected by the Fortafil carbon fiber. In general, composites containing synthetic graphite did not perform as well as carbon fiber composites. Carbon black composites exhibited poor tensile properties. POLYM. COMPOS., 29:15–21, 2008. © 2007 Society of Plastics Engineers     

基于蜻蜓翅脉结构的连续碳纤维增强树脂基复合材料仿生设计与增材制造

以具有轻质高强优异性能的蜻蜓翅脉结构为设计灵感，在分析翅脉网格结构抗冲击原理的基础上，设计了传统和仿生两类对比结构。采用熔融挤出3D打印机成功制备了具有不同结构的连续碳纤维增强聚乳酸复合材料试样，并对不同结构复合材料试样的拉伸性能和抗冲击性能进行了测试和对比分析。研究分析结果表明：由于拉伸力方向上的连续碳纤维含量相对较少，限制了仿生结构复合材料抗拉强度的提高，但仿生结构的平均抗拉强度为传统结构的1.18倍；当仿生结构复合材料试样受到冲击力时，其内部六边形结构的连接角度会发生变化，从而极大消耗冲击能量，同时具有六边形网格结构的连续碳纤维可以有效阻碍裂纹的扩展，因此仿生结构的平均冲击韧性可以达到传统结构的2.46倍；仿生蜻蜓翅脉结构可以显著提高增材制造复合材料的综合力学性能，且对于抗冲击性能的提高具体突出效果。连续碳纤维增强树脂基复合材料的有效可行的仿生蜻蜓翅脉结构设计和增材制造，可极大扩展其在高冲击载荷领域中的相应应用。     

Investigations on the performances of treated jute/Kenaf hybrid natural fiber reinforced epoxy composite

Natural fiber composite laminates are nowadays used in structural application such as aerospace, automobile and in sports goods because of their high strength to weight ratio and renewability. Hence the study of mechanical behaviors of natural fiber composites is very important in using these composite laminates for such specific applications. This project aims at identifying the mechanical properties of hybrid natural Jute/Kenaf fiber. The major drawbacks in natural fiber are its Resin incompatibility. Surface treatment of fiber is made to improve the interfacial bonding between the fiber and resin and to reduce the moisture absorption. Laminates are fabricated using Hand lay-up technique. Mechanical properties such as tensile, flexural, and Impact test for jute/kenaf hybrid laminates were obtained. Specimen preparation and Mechanical property testing were carried out as per ASTM standards. Micro structures of the different layer of hybrid specimens are scanned by the Scanning Electron Microscope.     

Research and application prospect of short carbon fiber reinforced ceramic composites

With the advantage of high temperature resistance, low expansion, low density and excellent thermal stability, carbon fiber reinforced ceramic composites have a very wide range of applications in aerospace, military, energy, chemical industries and transportation. Short carbon fiber reinforced ceramic composites are characterized by simple processes, low manufacturing costs, short preparation times and automated production, can be used in fields such as friction materials and thermal protection system. This paper reviews the current status and recent advances in research on homogenization techniques, mechanical properties, thermal properties and frictional properties of short carbon fiber reinforce ceramic composites. Different processing routes for short carbon fiber reinforced ceramic composites, including reactive melt infiltration (RMI), hot pressing (HP), spark plasma sintering (SPS) and pressureless sintering, the advantages and drawbacks of each method are briefly discussed. The future development direction of low-cost manufacturing short carbon fiber reinforced ceramic composites is prospected.     

Understanding the relation between structural and mechanical properties of electrospun fiber mesh through uniaxial tensile testing

Polymeric electrospun fibers have the potential to be utilized for a variety of applications such as tissue engineering, filtration, and textiles, owing to their high surface area per unit mass. However, these applications have some form of dependency on the mechanical properties of fiber meshes. Therefore, the current study is aimed at understanding the mechanical behavior of electrospun fiber systems at different length scales in order to establish a correlation between their structure and mechanical properties. Micro‐/nano‐fiber meshes of polystyrene were fabricated by the process of electrospinning and were subjected to uniaxial tensile testing. High‐resolution imaging during tensile testing revealed the macroscopic and microscopic structural evolution of these fibers. Further, the dependence of tensile strength, % elongation, and toughness of fiber meshes on the orientation of the fibers were also experimentally observed. The continuum mechanics simulation studies of fiber meshes with different orientations corroborated well with these experimental studies. Comprehensively, these studies demonstrated the changes in mechanical behavior of electrospun fiber meshes owing to the reorientation and alignment of fibers in meshes at microscopic and macroscopic length scale during tensile testing. Such study can be extrapolate for the design and fabrication of load‐bearing tissues scaffolds, and filtration devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45012.     

Biopitch-based general purpose carbon fibers: Processing and properties

Eucalyptus tar pitches are generated on a large scale in Brazil as by-products of the charcoal manufacturing industry. They present a macromolecular structure constituted mainly of phenolic, guaiacyl, and siringyl units common to lignin. The low aromaticity (60-70%), high O/C atomic ratios (0.20-0.27%), and large molar mass distribution are peculiar features which make biopitches behave far differently from fossil pitches. In the present work, eucalyptus tar pitches are evaluated as precursors of general purpose carbon fibers (GPCF) through a four-step process: pitch pre-treatment and melt spinning, and fiber stabilization and carbonization. Homogeneous isotropic fibers with a diameter of 27 μm were obtained. The fibers had an apparent density of 1.84 g/cm³, an electrical resistivity of 2 × 10⁻⁴ Ω m, a tensile strength of 130 MPa, and a tensile modulus of 14 GPa. Although the tensile properties advise against using the produced fibers as structural reinforcement, other properties give rise to different potential applications, as for example in the manufacture of activated carbon fibers or felts for electrical insulation.     

Biopolyamide hybrid composites for high performance applications

This study focuses on the performance characteristics of wood/short carbon fiber hybrid biopolyamide11 (PA11) composites. The composites were produced by melt‐compounding of the fibers with the polyamide via extrusion and injection molding. The results showed that mechanical properties, such as tensile and flexural strength and modulus of the wood fiber composites were significantly higher than the PA11 and hybridization with carbon fiber further enhanced the performance properties, as well as the thermal resistance of the composites. Compared to wood fiber composites (30% wood fiber), hybridization with carbon fiber (10% wood fiber and 20% carbon fiber) increased the tensile and flexural modulus by 168% and 142%, respectively. Izod impact strength of the hybrid composites exhibited a good improvement compared to wood fiber composites. Thermal properties and resistance to water absorption of the composites were improved by hybridization with carbon fiber. In overall, the study indicated that the developed hybrid composites are promising candidates for high performance applications, where high stiffness and thermal resistance are required. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43595.     

Investigation on promotion effect of oxidative stabilization for pitch-based fiber by co-carbonization of coal tar pitch and atmospheric residual

As a pivotal step in the preparation of carbon fiber, oxidative stabilization not only plays a crucial role in maintaining fibrous morphology but also contributes significantly to enhance mechanical properties of resultant carbon fiber. Due to high activation energy of pitch molecules reaction with oxygen and the sluggish diffusion of oxygen within the fiber, the improvement of oxidative stabilization efficiency faces significant challenges. Atmospheric residual (AR) has a high and easily oxidized aliphatic structure. Spinnable pitch is synthesized by co-carbonization of coal tar pitch (CTP) and AR at a ratio of 3:1 in this work. Its methylene bridge bond ratio is 4.45% and have an appropriate amount aliphatic structure, which makes pitch molecular more linear and naphthenic. Excessive addition of AR is detrimental to spinning performance. The most optimal oxidative stabilization temperature of as-spun fiber was 280°C, which is lower than that of fiber produced by CTP alone (300°C), displaying a higher oxidative stabilization efficiency. The obtained pitch-based carbon fiber shows excellent mechanical properties with tensile strength of 999.0 ± 80.1 MPa and Young's modulus of 57.7 ± 3.5 GPa. The co-carbonization by two different substances has been applied in manufacturing carbon fiber, providing a facile approach to accelerate the oxidative stabilization of pitch fiber.     

Glass Fiber-Reinforced Composites: From Formulation to Application

Glass fiber-reinforced composite materials are attractive because their properties can be tailored to meet the specific needs of a variety of applications. The mechanical and thermal properties of a composite generally follow the rule of mixtures. As glass fiber is the major component at 70–75% by weight (50–60% by volume), selection of the correct glass product is critical. Glass fiber reinforcement is available in many forms, including continuous rovings, chopped fibers, fabrics, and nonwoven mats. In addition to form, selection of a reinforcement product involves choosing a glass type, chemistry on the glass (sizing) filament diameter, and tex. Glass formulation or type governs mechanical, thermal, and corrosion properties, whereas sizing protects the glass during handling and gives compatibility with the resin system. Filament diameter and strand tex are chosen to balance physical properties and manufacturing efficiency. A significant amount of tensile strength, up to 50%, may be lost from a pristine single filament to a multi-filament roving. To minimize this degradation, the utmost care and consistency must be exercised in the fiber forming process. This, coupled with selection of a high-performance glass formulation, enables use of composites in highly demanding applications, such as pressure vessels and ballistic armor.     

Preferred orientation of chopped fibers in polymer-based composites processed by selective laser sintering and fused deposition modeling: Effects on mechanical properties

The orientation of reinforcing fibers in polymer-based composites greatly affects their mechanical features. It is known that different orientations of continuous fibers in the stacked layers of a laminate play a crucial role in providing an isotropic mechanical behavior, while the alignment of chopped fibers in injection molding of composites results in a degree of anisotropy. Recent additive manufacturing techniques have offered a way of controlling the fiber orientation. This article aims to investigate the effect of fiber orientation on the mechanical properties of polyamide/carbon fiber composites processed by fused deposition modeling and selective laser sintering. Tensile samples which had different fibers and layer interface with respect to the sample axis (and therefore to the tensile load) were produced. Tensile tests were performed at different strain rates; the tensile properties and the fracture surface morphology were correlated with the processing method and the sample microstructure. The best strength and stiffness were observed when the fibers and the layer interfaces were parallel to the sample axis.