碳纤维湿法缠绕用高模量高韧性环氧树脂基体

设计了一系列针对碳纤维湿法缠绕的环氧树脂基体,测试了树脂浇注体及其复合材料的力学性能和热机械性能,研究了树脂基体对碳纤维复合材料界面性能的影响.试验结果表明,对韧性树脂体系,树脂基体的模量是发挥纤维强度的关键因素,模量的提升将大幅提高复合材料的综合性能.经复配和优化的树脂体系兼具高模量和高韧性,其T700碳纤维复合材料NOL环拉伸强度达到2480MPa,T800碳纤维复合材料NOL环拉伸强度达到2780MPa,玻璃化温度(Tg)超过200℃,具有优异的界面性能和耐热性能.     

湿法缠绕成型T700碳纤维/氰酸酯树脂复合材料力学性能研究

研究了湿法缠绕成型的T700碳纤维/氰酸酯树脂复合材料NOL环及单向板力学性能。测试了树脂配方的粘度-温度特性,T700碳纤维/氰酸酯树脂复合材料NOL环的拉伸及剪切性能,采用SEM对NOL环拉伸试样破坏形貌进行了观察。测试了T700碳纤维/氰酸酯树脂单向板复合材料的常温拉伸性能、弯曲性能、层间剪切性能和高温弯曲性能。结果表明,树脂配方在25℃下的粘度为800 cps,可以直接在室温条件下用于复合材料湿法缠绕成型,并具有充分的使用期。NOL环的拉伸强度为2220 MPa,剪切强度为56. 8 MPa,树脂基体对碳纤维具有良好的浸润性,能够较好地发挥出碳纤维的高强度特性。T700碳纤维氰酸酯树脂单向板复合材料的高温力学性能优异,200℃下弯曲强度保留率高达60. 4%,250℃下弯曲强度保留率高达45. 0%。     

碳纤维缠绕成型用环氧树脂体系研究

以甲基四氢苯酐、聚己内酯三醇和DMP-30制备了改性甲基四氢苯酐G920。将双酚A环氧树脂CYD-128、聚氨酯改性环氧树脂CYD-133、1,4-丁二醇二缩水甘油醚CYD-622和G920混合制得浇注体及碳纤维复合材料NOL环。采用粘度和力学性能测试、示差扫描量热分析、热重分析及扫描电镜分析对材料的性能进行了研究。结果表明,该树脂体系的粘度和适用期满足湿法缠绕成型工艺要求,浇铸体具有优异的耐热性能与力学性能,其制备的T-700碳纤维复合材料NOL环拉伸强度达到2 500 MPa,层间剪切强度达到69.9 MPa,具有优异的界面性能和强度保持率,适合T-700碳纤维的湿法缠绕成型。     

纤维直径及浸润剂对高强度玻璃纤维及其复合材料性能的影响

高强度玻璃纤维是一种力学性能优异的特种玻璃纤维,是高性能复合材料三大增强纤维(碳纤维、芳纶纤维、高强度玻璃纤维)之一.本文研究了不同直径系列及不同增强环氧型浸润剂系列对400孔高强度玻璃纤维及其复合材料性能的影响关系.通过原丝拉伸断裂强力、及NOL环拉伸、剪切强度的对比发现,①JA型浸润剂在拉丝工艺匹配和复合材料性能方面均明显优于FE-5浸润剂;②纤维直径在9～13μm范围内变化时对高强度玻璃纤维复合材料的性能没有影响.     

碳纤维／环氧树脂在橡胶内衬表面的全缠绕工艺设计

根据橡胶内衬碳纤维全缠绕压力气瓶的技术指标,依据网格理论对缠绕层和缠绕张力进行详细的理论设计计算,确定缠绕参数和工艺.选用的环氧树脂体系力学性能优异,其黏度满足缠绕成型工艺要求,同时复合材料NOL环的断面形貌表明该树脂体系与T800碳纤维界面结合良好.对缠绕成型的压力气瓶进行试验,检测表明.水压爆破试验和疲劳试验结果均满足复合材料气瓶的设计要求.     

碳纤维复丝拉伸性能测试影响因素研究

碳纤维作为增强材料使用时,其复合材料的力学性能很大程度上取决于碳纤维本身的力学性能,因此准确表征碳纤维的拉伸强度、拉伸模量等力学性能对其后续研究、生产和应用具有重要作用。根据标准GB/T 3362—2017、ASTM D4018—17以及ISO 10618:2004(E)中的规定,并结合实验室碳纤维拉伸测试积累的数据结果,测定T300B、T700SC及T800HB 3种碳纤维浸胶复丝的拉伸强度、拉伸模量及断裂伸长率,确定最佳测试条件。结果表明:在2 mm/min及5 mm/min的拉伸速率下,T300B、T700SC及T800HB碳纤维复丝拉伸强度和拉伸模量测试值接近真实值;应变区间为0.3%～0.6%时测出的拉伸模量值接近T300B、T700SC及T800HB碳纤维复丝的真实值。     

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℃。     

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。     

碳纤维湿法缠绕用环氧树脂基体研究

以TDE-85树脂和AFG-90树脂为主体树脂,混合芳香胺为固化剂,研究了一种适合于碳纤维复合材料湿法缠绕成型的树脂配方。结果表明,该树脂的黏度低(＜550 mPa·s)、适用期长,其浇铸体具有优异的力学性能,其拉伸强度为107 MPa,拉伸模量为4．09 GPa,弯曲强度为161 MPa,弯曲模量为3．88 GPa,断裂伸长率超过6%。用其制备的T-700碳纤维缠绕复合材料界面粘接好,NOL环层间剪切强度达到66．8 MPa,拉伸强度达到2．44 GPa。     

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%。     

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.     

Study on the mechanical properties and microstructure of high-performance carbon fiber/epoxy composites

A high-toughness epoxy has been prepared using carboxyl-terminated butadiene acrylonitrile (CTBN) as a toughening agent to modify the AG-80 epoxy resin. High-performance carbon fiber/epoxy (CF/EP) composites are fabricated using the CTBN-toughened epoxy resin as the matrix and two types of CF, namely, T800SC and T800HB, as reinforcement. The mechanical properties of the matrix, surface properties of the CFs, tensile properties, and fracture morphologies of the composites are systematically investigated to elucidate the key factors influencing interfacial bonding in high-performance CF/EP composites. The results reveal that the most significant improvement in toughness is achieved when the CTBN content is 6.90 wt.% in the epoxy resin. Owing to the high content of polar functional groups and excellent surface wettability of T800SC, the T800SC/EP composite exhibits superior mechanical properties compared with the T800HB/EP composite.     

The effect of silica (SiO2) nanoparticles and ammonia/ethylene plasma treatment on the interfacial and mechanical properties of carbon-fiber-reinforced epoxy composites

A nanoparticle dispersion is known to enhance the mechanical properties of a variety of polymers and resins. In this work, the effects of silica (SiO₂) nanoparticle loading (0–2 wt%) and ammonia/ethylene plasma-treated fibers on the interfacial and mechanical properties of carbon fiber–epoxy composites were characterized. Single fiber composite (SFC) tests were performed to determine the fiber/resin interfacial shear strength (IFSS). Tensile tests on pure epoxy resin specimens were also performed to quantify mechanical property changes with silica content. The results indicated that up to 2% SiO₂ nanoparticle loading had only a little effect on the mechanical properties. For untreated fibers, the IFSS was comparable for all epoxy resins. With ethylene/ammonia plasma treated fibers, specimens exhibited a substantial increase in IFSS by 2 to 3 times, independent of SiO₂ loading. The highest IFSS value obtained was 146 MPa for plasma-treated fibers. Interaction between the fiber sizing and plasma treatment may be a critical factor in this IFSS increase. The results suggest that the fiber/epoxy interface is not affected by the incorporation of up to 2% SiO₂ nanoparticles. Furthermore, the fiber surface modification through plasma treatment is an effective method to improve and control adhesion between fiber and resin.     

臭氧处理对碳纤维表面及其复合材料性能的影响

利用X射线光电子能谱(XPS)研究了碳纤维经臭氧(O3)氧化处理后表面元素组成及表面官能团的变化，结果发现，O3表面处理主要增加了碳纤维表面上的羟基或醚基官能团；研究了表面O3氧化处理对复合材料力学性能的影响，结果表明，碳纤维经O3氧化处理后明显改善了碳纤维与环氧树脂间的界面粘结，其复合材料的层间剪切强度明显提高。     

多面体低聚倍半硅氧烷在环氧树脂改性中的应用进展

综述了近几年多面体低聚倍半硅氧烷(POSS)在环氧树脂改性中的应用。POSS单独修饰环氧树脂,可提高其力学性能及热稳定性能;POSS协同9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物等功能性分子一起修饰环氧树脂,可增强其阻燃性能;POSS与碳纳米管、石墨烯等纳米材料共同修饰环氧树脂,可提高纳米材料在环氧树脂中的分散性,改善纳米复合材料的导电能力和黏结强度等性能;POSS与纤维共同修饰环氧树脂,可有效增强纤维与环氧树脂间的界面性能。最后展望了POSS修饰改性环氧树脂的未来方向:开发更简易的引入方式,引入更多样的官能分子,协同多种纳米材料修饰环氧树脂。     

Characterization of the interphase in carbon fiber/polymer composites using a nanoscale dynamic mechanical imaging technique

The interphase of fiber reinforced polymer composites is a narrow region around the fiber, and the mechanical performance of a composite strongly depends on the properties of the interphase. The interphase of carbon fiber reinforced polymer composites (CFRPs) is difficult to quantitatively characterize because of its nanometer dimension. To solve this problem, we present a nanomechanical imaging technique for mapping the dynamic mechanical property around the interphase region in CFRPs, and for providing nanoscale information of the interfacial dimension. The experimental results show that this method can determine the width and topography of the interphase with nanoscale lateral resolution, based on the storage modulus profile on the cross section of the composite. The average interphase thicknesses of a T300 carbon fiber/epoxy resin composite and a T700 carbon fiber/bismaleimide resin composite are 118 nm and 163 nm, respectively, and the size of interphase is uneven in width and “river-like”, which is consistent with the surface topography of the carbon fibers. Furthermore, the effect of water-aging on the interphase of the T300/epoxy composite was analyzed using the in situ imaging technique. An increase in the interphase width and interface debonding were revealed, implying a degradation in the interphase region.     

Enzyme‐mediated surface modification of jute and its influence on the properties of jute/epoxy composites

Surface modification of jute fibers is necessary to improve the adhesion and interfacial compatibility between fibers and resin matrix before using fibers in polymer composites. In this study, dodecyl gallate (DG) was enzymatically grafted onto the jute fiber by laccase to endow the fiber with hydrophobicity. A hand lay‐up technique was then adopted to prepare jute/epoxy composites. Contact angle and wetting time measurements showed that the surface hydrophobicity of the jute fabric was increased after the enzymatic graft modification. The water absorption and thickness swelling of the DG‐grafted jute fabric/epoxy composite were lower than those of the other composites. The tensile and dynamic mechanical properties of the jute/epoxy composites were enhanced by the surface modification. Scanning electron microscopy images revealed stronger fiber–matrix adhesion in composites with modified fibers. Therefore, the enzymatic graft modification increased the fiber–matrix interface area. The fiber–matrix adhesion was enhanced, and the mechanical properties of the composites were improved. POLYM. COMPOS., 38:1327–1334, 2017. © 2015 Society of Plastics Engineers     

Modification of the carbon fiber surface with a copper coating for composite materials with epoxy

Surface treatment of carbon fibers is essential to provide adequate interfacial interaction, and strength in carbon fiber/epoxy composites. The electrodeposition of a metallic copper coating on the carbon fiber surface has been examined as an alternative method to improve carbon fiber-epoxy interfacial properties. The wettability of the carbon fiber by the epoxy resin was improved as a result of copper electrodeposition. As a consequence, the adhesion between the carbon fiber and epoxy was also greatly improved by the surface electrolytic treatment used. The electrodeposition conditions affected significantly both wettability and adhesion phenomena. The electrolytic current had a strong effect on the interface performance. It was found that there was an intermediate electrolytic current, within the range used, which promoted better wetting and composite strength, compared with conventionally surface-oxidized carbon fibers.     

碳纤维复合材料发动机壳体用高性能树脂基体的研制

在综合考虑树脂黏度、力学性能、耐热性能的基础上。开发了适用于碳纤维复合材料火箭发动机壳体温法缠绕成型工艺用耐高温和韧性环氧树脂基体。用差示扫描式量热法(DSC)、傅里叶红外光谱FT—IR等分析技术对该韧性树脂基体的固化反应动力学参数、树脂基体固化物的性能和复合材料的性能进行了系统的研究。结果表明，该韧性树脂基体黏度低，适用期长，韧性好，与碳纤维界面粘接强度高，所制得的复合材料火箭发动机壳体纤维强度转化率高。为今后相关方面的研究指明了方向。