表面处理对PA6/CF复合材料力学性能与破坏形态的影响

通过碳纤维(CF)表面官能团的酰氯化,利用酰氯作为己内酰胺阴离子聚合的活化剂,成功地制备了表面接枝尼龙6(PA6)的CF。研究了表面己内酰胺稳定化并阴离子接枝PA6的CF对PA6／CF复合材料力争性能与破坏形态的影响。结果表明,表面接枝PA6后的PA6／CF复合材料界面相互匹配,改善了复合材料界面的相互作用,提高了复合材料的剪切强度,复合材料剪切破坏呈部分非界面脱粘破坏。     

碳纳米管含量对聚酰亚胺/碳纤维复合材料性能的影响

以聚酰亚胺(PI)为基体、碳纤维(CF)和碳纳米管(CNTs)为复合增强体,采用热模压工艺制备了不同CNTs含量的PI/CF/CNTs复合材料。采用电子拉力机、动态热机械分析仪和热重分析仪研究了PI/CF/CNTs复合材料的力学性能、动态力学性能和热稳定性。结果表明,与未加CNTs的PI/CF复合材料相比,CNTs含量为PI质量的0.2%时,PI/CF/CNTs复合材料具有最佳的常温力学性能,其中常温拉伸强度提高19.5%,常温弯曲强度提高20.6%,常温层间剪切强度提高14.7%,玻璃化转变温度则由357℃提高到451℃;CNTs含量为PI质量的0.05%时,PI/CF/CNTs复合材料具有最佳的高温力学性能,其中400℃拉伸强度提高15.8%,400℃弯曲强度提高9.6%,400℃层间剪切强度提高12.8%。CNTs的添加对PI/CF/CNTs复合材料的热稳定性几乎没有影响。     

炭纤维表面处理对CF／PMR—15复合材料力学性能的影响

研究了炭纤维表面不同处理方法对复合材料力学性能的影响,采用等离子体和等离子体接枝技术对炭纤维表面进行处理后,CF／PMR－15复合材料的界面剪切强度与层间剪切强度均有所提高,随着界面状态的改善,界面剪切强度提高的幅度比层间剪切强度提高的大,本文为指导炭纤维的表面处理,评价处理效果,进一步预报复合材料的宏观性能打下了基础。     

γ-射线辐照碳纤维对其复合材料力学性能的影响

利用高能射线(60Coγ-射线)辐照接枝技术对碳纤维(CF)表面进行处理。对辐照处理前后的CF分别利用SEM观察其复合材料层间剪切断口;比较了吸收剂量对碳纤维增强环氧树脂复合材料层间剪切强度(ILSS)的影响。结果表明:辐照处理后的,碳纤维增强环氧树脂复合材料的界面明显得到改善,辐照接枝技术在一定的剂量范围内能够有效地提高复合材料的ILSS,但是过大的辐照剂量和接枝率不利于复合材料的界面改性。     

表面处理对碳纤维/聚苯硫醚复合材料性能的影响

以碳纤维(CF)平纹织物、聚苯硫醚(PPS)纤维为原材料,通过混杂铺丝及热压的方法制备出CF/PPS热塑性复合材料。研究了不同表面处理方法对CF表面官能团、碳(C)与氧(O)元素含量比、单丝拔出强度及复合材料两相浸润性、界面性能、力学性能等的影响。结果表明:丙酮处理可以有效去除CF的上浆剂,利于PPS熔体在CF之间的均匀分散与浸渍,在一定程度上提升了CF/PPS复合材料的力学性能;硝酸溶液处理可以增加CF平纹织物表面的O/C摩尔比,且CF表面轴向产生缺陷和沟壑;CF与PPS之间的界面剪切强度随硝酸处理时间的增加而明显增加,但CF/PPS复合材料的力学性能呈现先增加后降低的趋势;通过表面处理改善CF与PPS之间的浸润性以及界面相互作用力,可以提升CF/PPS复合材料的力学性能。     

潜伏型上浆剂对CF与MAPP树脂界面作用的影响

本文制备了三种不同潜伏型交联剂含量的上浆剂,DH1.5%、DH3.0%和DH6.0%,通过处理上浆提高碳纤维(CF)与马来酸酐接枝聚丙烯(MAPP)树脂之间的界面作用。利用微脱粘实验表征复合材料的界面剪切强度(IFSS),并利用傅里叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)表征界面增强作用。结果表明:随着上浆剂中潜伏型交联剂含量的增加,复合材料的IFSS值也随之增加,当使用DH6.0%处理CF时,IFSS值达到7.42 MPa,相较于不做处理的CF/MAPP复合材料提高了204.1%。从FTIR和SEM的结果可知界面性能的提高是由于潜伏型交联剂会在复合材料界面处与CF、MAPP发生化学键合作用。     

短切炭纤维增强热塑性树脂—PA1010复合材料的研究

本工作采用熔融混料热模压成型工艺制备短切炭纤维增强热塑性树脂SCFR-TP—PA1010复合材料。着重研究了复合材料的各种力学性能、热性能及CF与基体间的界面状态、CF含量、复合工艺对材料性能的影响以及CF经表面处理后其性能及复合材料层间剪切强度ILSS的变化。并对复合材料剪切断裂机制进行了初步探讨。我们发现复合材料中CF的增强作用明显,CF含量以20～30％(重量)为最佳。CF经氧化处理后,强度和模量均有所降低,但纤维与基体的粘结作用增强。电聚合涂层处理则随单体——溶剂——电解质体系的不同而有不同结果。复合材料浸水后ILSS降低,虽经干燥处理亦不能完全恢复。剪切断口电镜分析发现剪切断裂有三种方式,其主要机制是微裂纹的扩展导致界面脱胶和基体开裂。     

γ-射线辐照对碳纤维及其复合材料力学性能的影响

以60Coγ-射线为辐照源对碳纤维(CF)表面进行处理,利用扫描电子显微镜(SEM)观察经辐照处理后的碳纤维单丝表面及其与环氧树脂制备的复合材料试样的层间剪切断口;通过层间剪切强度比较了吸收剂量对其复合材料层间剪切强度(ILSS)的影响,并根据GB/T3362—1982标准比较了辐照前后碳纤维复丝拉伸强度的变化。结果表明:辐照处理后的碳纤维增强环氧树脂复合材料的界面明显得到改善,在一定的吸收剂量范围内能够有效地提高复合材料的ILSS,但是过大的辐照剂量和接枝率不利于复合材料的界面改性;当辐照剂量小于250kGy时,碳纤维的复丝拉伸强度有所提高。     

石墨和碳纤维改性聚酰亚胺复合材料的导热性能

以石墨、碳纤维(CF)、聚酰亚胺(PI)三元复合材料为研究对象,考察了CF体积含量对PI三元复合材料导热性能的影响,并采用了拟二元体系模型探讨了石墨和CF填充PI复合材料的协同效应。结果表明,CF的加入可以提高复合材料的力学性能：拉伸强度呈现先升高后降低的趋势,当CF含量为11.8 %（体积分数,下同）时,拉伸强度可达66.37 MPa;弯曲强度随着CF体积含量的增而增加,当CF含量为24.6 %时,弯曲强度可达103.3 MPa。复合材料热导率呈非线性增长,表明石墨和CF间存在协同效应;当CF含量为34.1 %时,环境扫描电子显微镜分析表明,CF与石墨能很好地搭接,增大了传热面积,复合材料热导率可达0.512 W/(m·K),约是其计算值的2倍。     

聚吡咯层对碳纤维/环氧树脂复合材料界面粘结性能的影响

以三氯化铁为氧化剂,采用吡咯液相沉积聚合方法制备聚吡咯-碳纤维(PPy-CF),然后与环氧树脂(EP)复合,制得PPy-CF/EP复合材料,并对其进行拉伸性能测试,研究了聚合温度对PPy-CF/EP复合材料界面剪切强度(IFSS)的影响。结果表明:在CF表面吡咯沉积聚合最佳工艺条件为聚合温度70℃,时间30min,经过吡咯沉积聚合改性后,得到的PPy-CF/EP复合材料的IFSS有所提高;最佳条件下制得的PPy-CF/EP复合材料的IFSS是CF/EP复合材料的1.24倍;在PPy-CF中,PPy与CF之间无化学键作用,PPy-CF/EP复合材料的IFSS与PPy-CF表面含氧基团和粗糙度有关;吡咯化学沉积聚合改性是一种提高纤维与树脂界面粘结性能的有效方法。     

粘胶基碳纤维连续式电化学氧化表面处理(Ⅱ)碳纤维增强复合材料的界面

本文用短支梁三点弯曲法及Fragment法测定了连续式电氧化处理粘胶基碳纤维与酚醛树脂及环氧树脂复合材料界面粘合性 ,并用SEM观察了其界面的形貌。结果表明 :在本试验范围内经电化学氧化处理可以使粘胶基碳纤维 /酚醛树脂复合材料界面的粘合强度提高25 % ,而粘胶基碳纤维 /环氧树脂复合材料界面的粘合强度可提高100 %。这可能是由于环氧树脂可与碳纤维表面的官能团形成化学键的原因。     

High improvement of interfacial and mechanical properties in reinforced PP composite by grafting polyethyleneimine modified carboxylic multi-walled carbon nanotubes on short carbon fiber

The properties of carbon fiber reinforced polymer composites (CFRPs) will benefit greatly from improving interfacial performance. In this study, the interfacial properties of the PEI-CNT-CF/PP composite was improved by coating polyethyleneimine (PEI) modified carboxylic multi-walled carbon nanotubes (CNTs) in aqueous solution (PEI-CNT) onto the surface of the CF (PEI-CNT-CF) to form a network structure. The network formation changed the chemical characteristics and compatibility of CF surface by introducing amine (imine) groups, and could induce transcrystallization (TC) at interface of composite. These positive factors led to a 24.6% increasement in the interfacial shear strength (IFSS) of PEI-CNT-CF/PP, and further resulted in 16.2% and 5.3% improvement in tensile and flexural strength, respectively. SEM images of the fracture surface demonstrated a significant improvement in the interfacial adhesion between PEI-CNT-CF and PP resin. These results indicated that the PEI-CNT was a great choice to strengthen the interface of CF/PP system.     

Effect of surface treatment on the tribological performance of carbon fiber reinforced thermoplastic polyimide composites

The effect of rare earth solution (RES) surface treatment of carbon fibers (CFs) on the tensile strength and tribological properties of CF‐reinforced polyimide (CF/PI) composite was investigated. Experimental results revealed that the tensile strength of RES‐treated CFs reinforced PI composite was improved by about 19% compared with that of untreated composite, while 7% improvement was achieved by air oxidation. Compared with the untreated and air‐oxidated CF/PI composite, the RES‐treated composite had the lowest friction coefficient and specific wear rate under given applied load and reciprocating sliding frequency. RES treatment effectively improved the interfacial adhesion between CFs and PI. The strong interfacial adhesion of the composite made CFs not easy to detach from the PI matrix and prevented the rubbing‐off of PI, and accordingly improved the friction and wear properties of the composite. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Effect of silane‐coupling agents on interfacial properties of CF/PI composites

In this article, to form a structure‐controlled interface, carbon fiber (CF) surfaces were first activated by plasma technique and then hydroxylated by LiAlH₄ treatment, and then were reacted with a suit of silane‐coupling agents terminated with desired functional groups to form thin films, which further reacted with polyimide (PI) resin to generate a strong adhesion interface. The morphology, structure, and composition of CF surfaces before and after treatment were investigated by atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and X‐ray photoelectron spectroscopy (XPS), respectively. The results of FTIR and XPS analysis showed that silane‐coupling agents were successfully chemisorbed onto the CF surfaces by the hydrolysis and condensation reactions. The interfacial shear strength of the CF/PI microcomposites was evaluated by the microbond technique. The results showed that the types of the interfacial functional groups, especially the vinyl end groups in vinyltriethoxysilane (VS), which can react with PI resin, had very significant influence on the improvement of the interfacial adhesion properties of composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effects of polyhedral oligomeric silsesquioxane coatings on the interface and impact properties of carbon‐fiber/polyarylacetylene composites

Two kinds of polyhedral oligomeric silsesquioxane (POSS) coatings were used for the modification of the interface in carbon fiber (CF) reinforced polyarylacetylene (PAA) matrix composites. The effects of the organic–inorganic hybrid POSS coatings on the properties of the composites were studied with short‐beam‐bending, microdebonding, and impact tests. The interlaminar shear strength and interfacial shear strength showed that the POSS coatings resulted in an interfacial property improvement for the CF/PAA composites in comparison with the untreated ones. The impact‐test results implied that the impact properties of the POSS‐coating‐treated composites were improved. The stiffness of the interface created by the POSS coatings was larger than that of the fiber and matrix in the CF/PAA composites according to the force‐modulation‐mode atomic force microscopy test results. The rigid POSS interlayer in the composites enhanced the interfacial mechanical properties with a simultaneous improvement of the impact properties; this was an interesting phenomenon in the composite‐interface modification. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5202–5211, 2006     

树脂基复合材料界面结合的研究Ⅱ:界面优化及界面横晶的研究

分析了树脂基复合材料受力状况下对界面结合的要求,着重介绍了微量冲击和临界纤维断裂长度分析两种检测树脂基复合材料界面剪切强度的方法及其研究成果.通过对单丝纤维断点周围基体树脂形态的分析,提出了一种判断优化界面的方法.     

Interfacial improvement of carbon fiber-reinforced methylphenylsilicone resin composites with sizing agent containing functionalized carbon nanotubes

A liquid sizing agent containing multiwall carbon nanotubes (MWCNTs) was prepared for carbon fiber (CF) reinforced methylphenylsilicone resin (MPSR) composite applications. In order to improve the dispersion of MWCNTs in the sizing agent and interfacial adhesion between CF and MPSR, MWCNTs and CF were functioned by the chemical modification with tetraethylenepentamine (TEPA) used as a MPSR curing agents. The CF before and after the sizing treatment-reinforced MPSR composites were prepared by a compression molding method. The microstructures, interfacial properties, and impact toughness of CF were systematically investigated. Experimental results revealed that a thin layer of MPSR coating containing functionalized MWCNTs (MWCNT-TEPA) was uniformly grafted onto the surface of CF. The sized CF-reinforced MPSR composite showed simultaneously remarkable enhancement in the interlaminar shear strength and impact toughness. Meanwhile, the tensile strength of CF had no obvious decrease after sizing treatment. In addition, the interfacial reinforcing and toughening mechanisms were also discussed. We believe that the facile and effective method in preparing multifunctional fibers provides a novel interface design strategy of carbon fiber composites for different applications.     

芳纶纤维/AFR树脂复合材料界面粘结性能的研究

为了改善芳纶纤维复合材料的界面粘结性能,合成了一种新型树脂(AFR)作为基体,以未经任何表面处理的芳纶纤维作增强材料,制备了芳纶纤维/AFR复合材料。采用测定表面能、接触角、层间剪切强度、横向拉伸性能和扫描电镜观察形貌等方法,从宏观和微观等方面研究了芳纶纤维/AFR复合材料的界面粘结性能。结果表明,AFR树脂与芳纶纤维有相近的表面能,AFR树脂溶液与芳纶纤维的接触角为42.8°,而环氧树脂(EP)与芳纶纤维的接触角为68°,说明AFR树脂对芳纶纤维的润湿性优于EP树脂;芳纶/AFR复合材料的层间剪切强度、横向拉伸强度和纵向拉伸强度分别为74.64MPa、25.34MPa和2256MPa,比芳纶/EP复合材料的相应强度分别提高了28.7%、32.5%和13.4%,其复合材料破坏面的形貌也说明芳纶纤维与AFR树脂之间的界面粘结性能较好。     

CF/纳米SiO_2改性树脂复合材料界面性能研究

本文以纳米SiO2改性树脂作为树脂基体,以连续碳纤维作为增强体制备复合材料,研究了纳米SiO2掺入树脂中百分含量对树脂基体与增强体之间的界面性能的影响。通过对树脂基体与增强体纤维浸润性、微脱粘、层间剪切强度和扫描电子显微镜,对复合材料界面性能测试和表征。结果表明,随着纳米SiO2含量的增加,常温下,基体树脂和增强体纤维浸润性能下降,单丝纤维与树脂微球的界面剪切强度和复合材料单向板层间剪切强度在某一含量范围均有所提高。