ZnO纳米棒提高碳纤维增强树脂基复合材料界面性能

碳纤维增强树脂基复合材料因其高的比强度和比模量,在航空航天等领域被广泛地应用。目前,碳纤维与树脂的界面性能是制约复合材料性能的关键因素。通过简单的水热法,在碳纤维表面合成了ZnO纳米棒阵列。在不同的生长时间下,制备了具有不同长度的ZnO纳米棒。ZnO纳米棒改性之后树脂对碳纤维的浸润性能明显提高。同时,复合材料的界面剪切强度得到明显提升,最大增幅达到了28.4%。通过扫描电子显微镜观测了单丝拔出后碳纤维的表面形貌,结果表明:改性碳纤维单丝拔出后表面粗糙而且残留了断裂的树脂基体,进一步证明碳纤维表面生长ZnO纳米棒之后界面强度得到改善。     

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%。     

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。     

ZnO纳米棒水热法生长与表征

采用两步法在FTO导电玻璃衬底上制备ZnO纳米棒,首先利用浸渍-提拉法在FTO导电玻璃衬底上制备ZnO晶种层,然后把有ZnO晶种层的FTO衬底放入盛有生长溶液的反应釜中利用水热法制备ZnO纳米棒.研究了生长溶液的浓度、生长温度和生长时间对所制备的对ZnO纳米棒阵列的微结构和光致发光性能的影响,利用X射线衍射(XRD)、扫描电子显微镜(SEM)和光致发光谱(PL)研究了ZnO样品的结构、形貌和光学性质.实验结果表明:所制备的ZnO纳米棒呈现六方纤锌矿结构,沿(002)晶面择优取向生长,纳米棒的平均直径约为100 nm,长度约为2.5 μm.所制备的ZnO纳米棒在390 nm附近具有很强的紫外发光峰和在550 nm附近有较弱的宽绿光发光峰.     

芳纶纤维增强树脂基复合材料的界面粘结性能研究

为了改善芳纶纤维增强树脂基复合材料的界面粘结性能,从树脂基体入手,依据相似相容原理和芳纶的结构特点,合成出新型热固性树脂(AFR–T)用作芳纶复合材料的基体,以未经表面处理的芳纶作增强材料,采用热压成型法制备了AFR–T/芳纶纤维复合材料,并通过测定溶度参数、接触角、线膨胀系数、层间剪切强度(ILSS)和横向拉伸强度等方法研究了复合材料的界面粘结性能。结果表明,AFR–T树脂浇注体与芳纶的溶度参数相近,AFR–T树脂溶液在芳纶纸表面的接触角为36.9°,小于环氧树脂(EP)溶液与芳纶纸的接触角(53.2°),说明AFR–T树脂对芳纶的浸润性优于EP;AFR–T/芳纶纤维复合材料的ILSS和横向拉伸强度为73.0 MPa和25.3 MPa,分别比EP/芳纶纤维复合材料提高了25.9%和32.5%,这表明AFR–T树脂与芳纶纤维之间的浸润性和界面粘结性能较好。     

TiO_2/ZnO双层电子传输层的制备及光电化学性能

首先在氟掺杂的氧化锡导电玻璃(FTO)上水热生长一层TiO_2纳米棒阵列薄膜,然后通过旋涂法旋涂ZnO籽晶层后水热法生长ZnO纳米棒得到TiO_2/ZnO纳米棒阵列薄膜。通过XRD、SEM、PL、UV-Vis和电化学工作站等对单层TiO_2纳米棒和TiO_2/ZnO纳米棒的结构、表面形貌、荧光性能、光吸收强度以及光电化学性质进行表征。结果表明,随着水热生长ZnO时间的增长,ZnO纳米棒密度增加; ZnO纳米棒的生长时间不同使其荧光强度不同,TiO_2/Zn O纳米棒的荧光强度与单层TiO_2纳米棒相比有着微小的减弱,没有明显的衍射峰; TiO_2/ZnO纳米棒复合材料比单层TiO_2的光吸收强度高,提高其光学性能,但是吸光区域都在紫外光区域;在标准模拟太阳光照射下,TiO_2/Zn O纳米棒的光电流为0. 002 m A,单层TiO_2纳米棒的光电流为0. 006 m A,复合薄膜的电流有着明显的变化。     

纳米SiO2对EP／国产芳纶Ⅲ纤维复合材料性能的影响

选择纳米SiO2作为增强材料改性环氧树脂(EP)基体,与国产芳纶Ⅲ纤维缠绕成复合材料。研究了不同含量的纳米SiO2对EP基体拉伸性能和冲击性能的影响;通过NOL环复合材料剪切强度测试和纤维缠绕Φ150mm容器水压爆破实验,研究了不同含量纳米SiO2对EP/国产芳纶Ⅲ纤维复合材料层间剪切强度和纤维强度转化率的影响。结果表明,EP基体中纳米SiO2质量分数为3%时,对基体拉伸和冲击性能均有显著改善,拉伸强度和冲击强度分别提高28.8%和22.6%,EP/国产芳纶Ⅲ纤维复合材料的层间剪切强度达到最大值,比未改性配方高出约56.8%;Φ150mm容器水压爆破结果表明,纳米SiO的加入使纤维强度转化率平均提高7%以上。     

芳纶纤维等离子体接枝改性处理研究

采用等离子体接枝对芳纶纤维表面进行改性处理,采用XPS、浸润性、界面剪切强度对等离子体接枝处理前后的表面组成、复合材料界面粘接性能等进行了研究,结果表明:等离子体接枝处理可以有效地提高芳纶纤维表面的极性官能团,增加与基体树脂-环氧树脂的浸润性,进而提高芳纶/环氧复合材料的界面粘接强度.     

对位芳香族聚酰胺纤维及其增强复合材料的发展

介绍了对位芳香族聚酰胺纤维(对位芳纶)特别是聚对苯二甲酰对苯二胺纤维的国内外发展情况,包括纤维品种、产量、性能和该类纤维作为先进复合材料骨架的发展情况。指出我国发展包括芳纶Ⅲ在内的对位芳纶产业的必要性和紧迫性,以及芳纶表面改性、树脂基体及增强复合材料的研究重点和方向。     

硬脂酸对纳米ZnO填充聚丙烯流变和结晶行为的影响

为了给纳米ZnO/聚丙烯(PP)复合材料的加工及性能优化提供理论依据,采用熔融共混的方式制备纳米ZnO/PP复合材料,通过扫描电子显微镜(SEM)、旋转流变仪、差示扫描量热仪(DSC)以及X射线衍射仪(XRD)对纳米ZnO/PP复合材料的结构与性能进行表征,以研究硬脂酸加入前后对复合材料的微观结构、流变性能及结晶行为的影响。结果表明,当纳米ZnO质量分数低于5%时,粒子分散良好,复合材料熔体的复数黏度随纳米ZnO质量分数的增大而减小,但是当纳米ZnO质量分数高于10%后,纳米粒子发生团聚,体系黏度上升。硬脂酸的加入增强了ZnO纳米粒子与PP基体的界面作用,也改善了ZnO纳米粒子的分散性。纳米ZnO质量分数小于5%时,对PP结晶没有明显影响,但是当纳米粒子团聚后对PP起异相成核作用。硬脂酸的加入可以有效抑制复合材料中的PP在升温过程中β晶向α晶的转变。ZnO纳米粒子的团聚对β晶的形成起抑制作用。     

Interfacial studies on the surface modified aramid fiber reinforced epoxy composites

In this work, solutions of rare earth modifier (RES) and epoxy chloropropane (ECP) grafting modification method were used for the surface treatment of aramid fiber. The effect of chemical treatment on aramid fiber has been studied in a composite system. The surface characteristics of aramid fibers were characterized by Fourier transform infrared spectroscopy (FTIR). The interfacial properties of aramid/epoxy composites were investigated by means of the single fiber pull‐out tests. The mechanical properties of the aramid/epoxy composites were studied by interlaminar shear strength (ILSS). As a result, it was found that RES surface treatment is superior to ECP grafting treatment in promoting the interfacial adhesion between aramid fiber and epoxy matrix, resulting in the improved mechanical properties of the composites. Meanwhile, the tensile strengths of single fibers were almost not affected by RES treatment. This was probably due to the presence of reactive functional groups on the aramid fiber surface, leading to an increment of interfacial binding force between fibers and matrix in a composite system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4165–4170, 2006     

Effect of ultrasound on wettability between aramid fibers and epoxy resin

Good wetting of reinforced fiber by resin was a main factor in the improvement of the interface adhesion of their composites. Ultrasound with a frequency of 20 kHz was used to improve the wettability between aramid fibers and epoxy resin during the winding process of the composites. The effects of ultrasound on the viscosity and surface tension of epoxy resin and on the surface characteristics of aramid fibers were investigated. The wettability of aramid fibers and treated epoxy resin under different conditions and of aramid fibers and epoxy resin under ultrasonic online treatment were compared. The results indicated that the main action of ultrasound was to force epoxy resin to impregnate aramid fibers, in addition to the influence of ultrasound on the properties of epoxy resin and aramid fibers. The results of microdebond testing showed that the interfacial shear strength (IFSS) of aramid/epoxy composites could be 26% higher than that of untreated composites because of the improved wettability between aramid fibers and epoxy resin subjected to ultrasonic online treatment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

RETRACTED ARTICLE: Surface modification of aramid fibers with novel chemical approach

Friedel–Crafts Reaction as a simple and convenient approach to the surface modification of aramid fiber was introduced in this paper. Epoxy chloropropane was chosen as the treatment reagent to modify aramid fibers surface via Graft reaction. After the modification, the interfacial properties of aramid/epoxy composites were investigated by the single fiber pull-out test (SFP), and the mechanical properties of aramid fibers were investigated by the tensile strength test. The results showed that the interfacial shear strength (IFSS) value of aramid/epoxy composites was enhanced by about 50%, and the tensile strength of aramid fibers had no obvious damage. The crystalline state of aramid fibers was determined by X-ray diffraction instrument (XRD), and the results showed that there were not any distinct crystal type varieties. The surface elements of aramid fibers were determined by X-ray photoelectron spectroscopy (XPS), the analysis of which showed that the oxygen/carbon ratio of aramid fiber surface increased obviously. The possible changes of the chemical structure of aramid fibers were investigated via Fourier transform infrared spectrum (FTIR), and the analysis of which showed that the epoxy functional groups were grafted into the molecule structure of aramid fibers. The surface morphology of aramid fibers was analyzed by Scanning electron microscope (SEM), and the SEM results showed that the physical structure of aramid fibers was not etched or damaged obviously. The surface energy of aramid fibers was investigated via the dynamic capillary method, and the results showed that the surface energy was enhanced by 31.5%, and then the wettability degree of aramid fiber surface was enhanced obviously too. All of the results indicated that this novel chemical modification approach not only can improve the interfacial bonding strength of aramid/epoxy composites remarkably, but also have no negative influence on the intrinsic tensile strength of aramid fibers.     

Effect of rare earth elements surface treatment on tensile properties of aramid fiber‐reinforced epoxy composites

Solutions of rare earth modifier (RES) and epoxy chloropropane (ECP) grafting modification method were used for the surface treatment of aramid fiber. Tensile properties of both the aramid/epoxy composites and single fibers were tested. The effects of RES concentration on tensile properties of aramid/epoxy composites were investigated in detail to explore an optimum amount of rare earth elements in solution for modifying aramid fiber. The fracture surface morphologies of tensile specimens were observed and analyzed with the aid of SEM. The experimental results show that rare earth treatment is superior to ECP grafting treatment in promoting interfacial adhesion between the aramid fiber and epoxy matrix. Meanwhile, the tensile strengths of single fibers were almost not affected by RES treatment. The optimum performance is obtained when the content of rare earth elements is 0.5 wt %. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1037–1041, 2004     

低温氨气等离子体对芳纶表面的改性

采用氨气等离子体对芳纶表面进行改性,用X-射线光电子能谱、场发射扫描电子显微镜、力学性能测试等手段对改性前后纤维表面的元素组成、形貌及其拉伸强度进行表征,并进一步通过微脱黏方法分析了等离子体处理条件对芳纶/环氧树脂复合材料界面黏结强度的影响。结果表明:芳纶经表面改性后,其表面极性官能团、表面粗糙度均有所增加,同时与环氧树脂基体的界面黏结强度明显增加。     

Surface ammonification of the mutual‐irradiated aramid fibers in 1,4‐dichlorobutane for improving interfacial properties with epoxy resin

The mutual irradiated aramid fibers in 1,4‐dichlorobutane was ammoniated by ammonia/alcohol solution, in an attempt to improve the interfacial properties between aramid fibers and epoxy matrix. Scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS), and single fiber tensile testing were carried out to investigate the functionalization process of aramid fibers and the interfacial properties of the composites. Experimental results showed that the fiber surface elements content changed obviously as well as the roughness through the radiation and chemical reaction. The surface energy and IFSS of aramid fibers increased distinctly after the ammonification, respectively. The amino groups generated by ammonification enhanced the interfacial adhesion of composites effectively by participating in the epoxy resin curing. Moreover, benefited by the appropriate radiation, the tensile strength of aramid fibers was not affected at all. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44924.     

Surface modification of aramid fibers with γ‐ray radiation for improving interfacial bonding strength with epoxy resin

Co⁶⁰ γ‐ray radiation as a simple and convenient method for surface modification of Armos aramid fibers was introduced in this article. Two kinds of gas mediums, N₂ and air, were chosen to modify aramid fiber surface by γ‐ray irradiation. After fiber surface treatment, the interlaminar shear strength values of aramid/epoxy composites were enhanced by about 17.7 and 15.8%, respectively. Surface elements of aramid fibers were determined by XPS, the analysis of which showed that the ratio of oxygen/carbon was increased. The crystalline state of aramid fibers was determined by X‐ray diffraction instrument. The surface topography of fibers was analyzed by atomic force microscopy and scanning electron microscope. The degree of surface roughness and the wettability of fiber surface were both enhanced by γ‐ray radiation. The results indicated that γ‐ray irradiation technique, which is a suitable way of batch process for industrialization, can significantly improve the surface properties of aramid fibers reinforced epoxy resin matrix composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Adhesive joints between carbon fiber and aluminum foam reinforced by surface‐treated aramid fibers

Short aramid fibers have been successfully used to reinforce the interface adhesive property between carbon fiber/epoxy composites and aluminum foam, and to form aramid‐fiber “composite adhesive joints.” In this study, to further improve the reinforcing effect of the aramid‐fiber‐reinforced adhesive joints, aramid fibers were ultrasonic treated to conduct different surface conditions. Critical energy release rate of the carbon fiber/aluminum foam sandwich beams with as‐received and treated interfacial aramid fibers were measured to study the influence of the surface treatment on aramid fibers. It was found that reinforcements in critical energy release rate were achieved for all samples with treated aramid fiber as measured under double cantilever beam condition. The interfacial characteristics of the short aramid fibers with different surface condition were investigated and discussed based on scanning electron microscopy observations. It is suggested that advanced bonding between aramid fibers and epoxy resin was conducted after surface treatment, and more energy was therefore absorbed through fiber bridging during crack opening and extension process. POLYM. COMPOS., 36:192–197, 2015. © 2014 Society of Plastics Engineers