两种T700碳纤维表面特性及其复合材料界面性能

分别用扫描电子显微镜(SEM)、X射线光电子能谱(XPS)以及接触角测量仪分析了国产MT700C碳纤维和东丽T700SC两种碳纤维的表面微结构、表面化学特性以及与树脂的浸润性,并对其环氧树脂复合材料MT700C/603和T700SC/603在干态和湿态下的界面性能进行了研究。结果表明,MT700C碳纤维表面O/C比和活性碳原子含量比T700SC碳纤维高,并且表面具有明显的沟槽,因此MT700C与树脂的浸润性好于T700SC碳纤维,可以与603树脂形成具有良好界面粘结的MT700C/603复合材料。在室温干态条件下,MT700C/603复合材料的层间剪切强度(ILSS)大于T700SC/603复合材料。但是在湿热老化环境中,T700SC/603复合材料最终的剪切强度保留率大于MT700C/603复合材料。     

国产高性能碳纤维组织结构表征与性能分析

本文采用SEM、XRD、Ram an及XPS等测试技术对国产GCF、日本Toray公司T300及美国AKZO公司HTA5131碳纤维的表面形貌、组织结构及化学组成进行了表征,分析了材料的微观组织结构与宏观性能的关系。研究结果发现,国产GCF横截面与T300相似,而表面形貌与进口碳纤维略有差别;国产GCF石墨层间距离为0.34901nm,叠层厚度为1.46nm,表面微晶尺寸为4.44nm,表明国产碳纤维微观结构比较规整,具有与T300相当的弹性模量,但表面微晶尺寸较大,不利于纤维强度的提高。GCF表面含氧官能团含量为42.55%,高于HTA5131,而低于T300,可以与树脂基体形成较强的界面作用。     

碳纤维/TDE85环氧树脂复合材料界面性能的研究

高性能碳纤维增强树脂基复合材料因其轻质、高强、高模量等优势,已在航空航天等领域广泛应用,增强体与树脂基体之间的界面结合状况对其性能有很大影响,因此对界面进行研究具有非常重要的意义。本文分别研究了T800、CCF300、T300三种碳纤维增强TDE85环氧树脂复合材料的界面性能。运用XPS对碳纤维和单纤维复合材料试样的表面化学成分进行了表征,XPS结果表明,与树脂复合后,碳纤维表面官能团的含量、结构及化学环境都发生了明显的变化,界面产生了较强的物理和化学作用。利用DCT21测量仪测试碳纤维与环氧树脂TDE85的接触角,分析了纤维与树脂的润湿性,实验结果显示纤维与树脂的润湿性良好。在此基础上,通过微滴脱粘方法测量纤维与树脂的界面剪切强度,以表征其界面粘结性能。微滴脱粘的实验结果显示,T800/TDE85体系的IFSS值高达79.7MPa,比T300/TDE85、CCF30/TDE850体系分别高21%、24%。     

低成本中温固化湿法缠绕用树脂基体及其国产碳纤维复合材料

针对国产T700碳纤维、中温固化及湿法缠绕的特点,制备了一种适合国产T700碳纤维湿法缠绕用的低成本树脂基体,研究了树脂基体热性能、力学性能、使用期和成本,测试了该树脂基体与国产T700碳纤维制备的复合材料的力学性能。结果表明:该树脂体系耐热性良好且力学性能优异,适宜中温固化,粘度和使用期满足湿法缠绕工艺要求,成本降低超过65%;该树脂基体与国产T700碳纤维制备的复合材料力学性能优异,0°拉伸强度为1988.15 MPa,0°压缩强度为821.02 MPa,弯曲强度为1839.94 MPa,剪切强度为89.51 MPa。     

国产T800S级碳纤维表面特性对复合材料界面性能影响研究

对两种国产T800S级碳纤维与进口T800S碳纤维表面特性及其复合材料界面性能的关联性进行了研究。通过扫描电镜（SEM）与原子力显微镜（AFM）对三种碳纤维的表面形貌与粗糙度进行了表征;采用X射线光电子能谱（XPS）对三种碳纤维表面化学官能团比例进行了分峰计算;通过碳纤维表面静态接触角对纤维表面浸润性进行了分析。制备并表征了碳纤维NOL环与单向复合材料的力学性能与微观破坏形貌,通过对比分析确定了影响复合材料界面性能的关键性因素,对复合材料界面性能的进一步提升具有指导意义。     

基于NOL环的高性能纤维与环氧树脂的匹配性研究

纤维与树脂的界面对复合材料的整体力学性能有着显著的影响。基于NOL环的宏观力学测试一般被用来反映复合材料的界面粘结性能,因此适用于评价纤维与树脂之间的宏观力学性能匹配性。为了探究高性能碳纤维T700SC、T800HB及高强玻璃纤维与环氧树脂的宏观力学性能匹配性,本研究首先根据GB/T 1458—2008国家标准制备NOL环试样,再借助NOL环的拉伸和层间剪切强度测试分析了高性能纤维与环氧树脂不同匹配组合宏观力学性能差异的原因,并寻找出最佳匹配组合。结果表明:玻璃纤维与环氧树脂的界面存在最佳的粘结强度,而且不同粘结强度导致拉伸强度和破坏机理不同,而碳纤维复合材料界面性能较差,容易分层破坏;T800HB与环氧树脂的宏观力学匹配性优于T700SC,环氧树脂力学性能、碳纤维的表面微观结构与性质以及环氧树脂与碳纤维之间的相互作用关系是影响界面粘结性能的根本原因。该研究在高性能纤维单向复合材料的材料选择与设计方面具有现实意义。     

国产高性能碳纤维复合材料界面性能研究

对国产MT300-3K、JHT300-3K和东丽T300-3K碳纤维表面微观形貌及其环氧树脂基复合材料界面性能进行对比研究,SEM结果表明,三者表面微观形貌一致;单纤维拔出对比试验表明,国产MT300-3K与东丽T300-3K碳纤维界面剪切强度相当,略大于国产JHT300-3K碳纤维;单向板弯曲强度、层间剪切强度及破坏面微观形貌分析表明,三种T300-3K级碳纤维与环氧树脂基体的匹配性好,界面粘接强度相当。     

活性碳纳米管对T700 CF/环氧树脂复合材料性能影响

本文通过对多壁碳纳米管进行酸化、酰氯化和氨基化处理,然后与活性稀释剂进行预反应,制备出了一种具有反应活性的碳纳米管。将0.5wt%的活性碳纳米管分散到环氧树脂中,通过湿法缠绕工艺制备出T700碳纤维/环氧树脂多尺度复合材料NOL环。实验结果表明,活性碳纳米管的加入能够显著降低树脂的表面能而对黏度影响不大;同时复合材料NOL环的拉伸强度、模量、断裂伸长率和层间剪切强度分别提高了8.9%、12.2%、1.8%和17.0%;树脂与纤维的界面黏结得到明显改善;复合材料玻璃化转变温度提高了16℃。     

碳纤维表面电化学氧化的研究

主要采用电化学氧化法对聚丙烯腈(PAN)基碳纤维进行连续氧化处理,利用扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和动态力学热分析(DMTA)对碳纤维表面处理效果进行了研究。SEM表面形貌研究结果表明,碳纤维经电化学氧化处理后,其表面的粗糙度和比表面积增大。XPS表面化学分析表明,经电化学氧化处理后的碳纤维表面羟基含量提高55％,活性碳原子数增加18％。DMTA谱图表明经电化学氧化处理的碳纤维增强树脂基复合材料(CFRP)其玻璃化温度(Tg)提高5℃、损耗角正切(tanδ)较未处理的降低30％。定量计算出的界面黏结参数A和α与CHRP的层间剪切强度(ILSS)所反映的碳纤维与树脂间界面黏结效果是一致的。研究结果表明,采用适当的处理条件可使CFRP的ILSS提高20％以上。     

国产T700S碳纤维增强复合材料压力容器的成型工艺

分别采用扫描电子显微镜、傅立叶变换红外光谱仪对国产T700S碳纤维表面形貌及表面涂层进行了表征,通过NOL环实验对两种树脂体系进行优选,找到了一种与国产T700S碳纤维匹配性较好的树脂体系,然后设计正交试验,对影响?150 mm复合材料压力容器成型的因素设置了不同的水平,通过正交试验比较,最终确定缠绕张力为40~50 N﹑封头补强方式为碳布补强环补强﹑胶槽温度55~60℃、刮胶板和滚胶筒间隙0.15~0.20 mm、缠绕后处理方式为玻璃布带环向/螺旋向各缠绕1层时,制作的复合材料压力容器特性指数最高(37.5 km),可作为国产T700S碳纤维进一步工程化应用的参考。     

Interfacial improvement of carbon fiber/epoxy composites using a simple process for depositing commercially functionalized carbon nanotubes on the fibers

An aqueous suspension deposition method was used to coat the sized carbon fibers T700SC and T300B with commercially carboxylic acid-functionalized and hydroxyl-functionalized carbon nanotubes (CNTs). The CNTs on the fiber surfaces were expected to improve the interfacial strength between the fibers and the epoxy. The factors affecting the deposition, especially the fiber sizing, were studied. According to single fiber-composite fragmentation tests, the deposition process results in improved fiber/matrix interfacial adhesion. Using carboxylic acid-functionalized CNTs, the interfacial shear strength was increased 43% for the T700SC composite and 12% for the T300B composite. The relationship between surface functional groups of the CNTs and the interfacial improvement was discussed. The interfacial reinforcing mechanism was explored by analyzing the surface morphology of the carbon fibers, the wettability between the carbon fibers and the epoxy resin, the chemical bonding between the fiber sizing and the CNTs, and fractographic observation of cross-sections of the composites. Results indicate that interfacial friction, chemical bonding and resin toughening are responsible for the interfacial improvement of nanostructured carbon fiber/epoxy composites. The mechanical properties of the CNT-deposited composite laminate were further measured to confirm the effectiveness of this strategy.     

Effect of Atmospheric Plasma Treatment on Carbon Fiber/Epoxy Interfacial Adhesion

In this work the effect of atmospheric plasma treatment on carbon fiber has been studied. The carbon fibers were treated for 1, 3 and 5 min with a He/O₂ dielectric barrier discharge atmospheric pressure plasma. The fiber surface morphology, surface chemical composition and interfacial shear strength between the carbon fiber and epoxy resin were investigated using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and the single fiber composite fragmentation test. Compared to untreated carbon fibers, the plasma treated fiber surfaces exhibited surface morphological and surface composition changes. The fiber surfaces were found to be roughened, the oxygen content on the fiber surfaces increased, and the interfacial shear strength (IFSS) improved after the atmospheric pressure plasma treatment. The fiber strength showed no significant changes after the plasma treatment.     

Surface modification of ultra-high strength polyethylene fibers for enhanced adhesion to epoxy resins using intense pulsed high-power ion beam

The effects of intense pulsed high power ion beam (HPIB) treatment of ultra-high strength polyethylene (UHSPE) fibers on the fiber/epoxy resin interface strength were studied. For this study, argon ions were used to treat Spectra? 1000 (UHSPE) fibers in vacuum. Chemical and topographical changes of the fiber surfaces were characterized using Fourier transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), dynamic wettability measurements, and scanning electron microscopy (SEM). The fiber/epoxy resin interfacial shear strength (IFSS) was evaluated by the single fiber pull-out test. The FTIR-ATR and XPS data indicate that oxygen was incorporated onto the fiber surface as a result of the HPIB treatment. The wettability data indicate that the fibers became more polar after HPIB treatment and also more wettable. Although the total surface energy increased only slightly after treatment, the dispersive component decreased significantly while the acid-base component increased by a similar amount. SEM photomicrographs revealed that the surface roughness of the fibers increased following the HPIB treatment. The single fiber pull-out test results indicate that HPIB treatment significantly improved the IFSS of UHSPE fibers with epoxy resin. This enhancement in IFSS is attributed to increased roughness of the fiber surface resulting in mechanical bonding and in increased interface area, increased polar nature and wettability, and an improvement in the acid-base component of the surface energy after the HPIB treatment.     

T700碳纤维/环氧树脂复合材料热降解实验研究

针对T700碳纤维增强环氧树脂复合材料的热降解行为以及回收所得碳纤维的力学性能进行了研究。研究结果表明,碳纤维的存在增加了环氧树脂降解时所需的活化能,热降解反应的温度、时间和气氛等因素对环氧树脂基体降解效果以及回收碳纤维力学性能均有影响。在空气条件下500℃处理30 min后碳纤维表面没有残留物,但其回收纤维的拉伸强度保留率仅为77.6%。通过首先在氮气气氛高温短时热处理,再在空气气氛下450℃进行30 min热降解的两步法处理后,碳纤维表面残炭得到去除,回收碳纤维的拉伸强度保留率达到了90.4%,由其制备单向复合材料的层间剪切强度保留率可达到75.8%。     

高性能碳纤维表面特性及其对浸润性能的影响

以4种不同型号的高性能碳纤维T700、UTS50、T800和IM7为研究对象,采用扫描电子显微镜和原子力显微镜对碳纤维直径、表面形貌和粗糙度进行表征,通过表面/界面张力仪对纤维表面能和树脂体系的表面张力进行分析,利用旋转流变仪对树脂体系的粘度进行测试。最后对碳纤维与不同温度和不同丙酮质量分数的618环氧树脂浸润性能进行测试,以分析纤维表面性能、温度和溶剂质量分数对碳纤维浸润性能的影响。结果表明,升高温度或提高溶剂质量分数有利于降低树脂体系的表面张力和粘度,从而有效改善碳纤维的浸润性能。纤维直径、表面粗糙度和表面能对碳纤维的浸润性能均有一定影响,其中纤维直径是影响浸润速率的主导因素,表面能和表面粗糙度对浸润质量的影响更加显著。     

Improvement of adhesion of Kevlar fiber to epoxy by chemical modification

Kevlar 149 fibers were surface-modified by chlorosulfonation and subsequent reaction of -SO₂O with some reagents (e.g. glycine, water, ethylenediamine, and 2-butanol) to improve the adhesion to epoxy resin. The mechanical properties and surface topography of the modified fibers were investigated at different reaction times and reagent concentrations. The surface functional groups introduced into the surface of the fibers were identified by X-ray photoelectron spectroscopy (XPS) and static secondary ion mass spectroscopy (SIMS). The interfacial shear strength (IFSS) between the fibers and epoxy resin was measured by the microbond test. The results showed that the IFSS was markedly improved (by a factor of 2.25) by the chlorosulfonation/glycine treatment and that the fiber strength was not affected. Scanning electron microscopy (SEM) was also used to study the surface topography of fibers pulled from the epoxy resin. Furthermore, energy dispersive X-ray (EDX) spectroscopy was used to qualitatively examine the amount of sulfur in the fiber surfaces and in the fracture surfaces of fibers from microbond pull-out specimens. The results of EDX examination were consistent with a change of the fracture mode from the interface between the fiber and the epoxy resin to a location within the fiber and/or epoxy resin as observed by SEM.     

Novel application of chitosan: ameliorative effect of homogeneous and floccular chitosan on the interfacial property of carbon fiber/epoxy resin composites

A novel homogeneous floccular chitosan was directly grafted onto carbon fiber surface by a simple and controllable method. Scanning electron microscopy (SEM), single fiber strengths and interlaminar shear strength (ILSS) have been applied to characterize the fiber and the interface bonding. Compared with raw carbon fibers, the chitosan-treated ones demonstrate significant increases in the surface roughness and wettability. Particularly, about 21.21% increase in the mechanical properties of composites was obtained, which is attributed to good adhesion between functional carbon fiber and resin matrix in the interlaminar regions, as revealed by fracture surfaces.     

杂环芳纶表面ZnO纳米界面相的构筑及其界面强化作用

为了改善杂环芳纶(F3)与环氧树脂黏结性差以及不耐紫外辐射的缺点,首先对纤维进行功能化预处理,然后通过溶胶-凝胶法和水热法分别在芳纶表面生长了氧化锌纳米颗粒和氧化锌纳米线界面层。采用X成、形貌、与环氧树脂的黏结性以及抗紫外性能进行了研究。结果表明:纳米颗粒状和纳米线形态的ZnO纳米界面相能够显著提高纤维与树脂基体的黏结性能,与未处理的纤维相比,单纤维复合材料的界面剪切强度分别提高了14.1%和27.0%;同时ZnO的破坏,经过168 h紫外辐射试验后,纤维强度保持率从79.1%提高到96.7%。