碳纳米管-蒙脱土/环氧树脂复合材料的流变与固化特性

采用机械搅拌和离心分散的方法制备了多壁碳纳米管-有机蒙脱土/环氧树脂纳米复合材料。用X射线衍射和扫描电镜对复合材料的微观结构进行了分析和表征,研究了多壁碳纳米管含量对混杂体系流变性和固化特性的影响。结果表明,当有机蒙脱土含量为2%(质量分数,下同)时,蒙脱土在树脂体系中能够形成离散性结构,且与多壁碳纳米管形成一定程度的相互穿插结构。随着多壁碳纳米管含量的增加,混杂复合材料体系的黏度迅速上升,固化放热逐步降低。     

聚氨酯和蒙脱土协同增韧增强环氧树脂

采用聚合物互穿技术与原位插层聚合相结合的方法制备了有机蒙脱土修饰的环氧树脂/聚氨酯互穿网络纳米复合材料.傅立叶红外光谱,X射线衍射及透射电镜分析表明剥离或插层的蒙脱土片层表面羟基能与环氧树脂/聚氨酯基体发生交联反应,并且均匀分散在环氧树脂/聚氨酯基体中.力学性能测试结果表明聚氨酯,蒙脱土的加入同时增加了环氧树脂的拉伸强度和断裂韧性.扫描电镜分析表明聚氨酯和蒙脱土协同增韧增强环氧树脂的主要原因为剪切屈服和微裂纹增韧.     

多壁碳纳米管/聚醚砜环氧树脂复合材料的制备及力学性能

环氧树脂具有优异的热性能及力学性能,但本身脆性较大。为制备低成本、高性能的环氧树脂体系,使用聚醚砜（PES）和多壁碳纳米管（MWCNT）对环氧树脂进行增韧,制备了不同PES含量的PES-环氧树脂共混物,讨论了PES含量对环氧树脂力学性能的影响;采用熔融法,并配合使用机械搅拌、高剪切分散和超声分散制备了MWCNT/PES-环氧树脂复合材料,测试了其拉伸性能及断裂韧性,用SEM观察了MWCNT在树脂中的分散状态以及拉伸试样的断口形貌。结果表明：MWCNT的加入能够提高PES-环氧树脂体系的综合力学性能,且当MWCNT含量为0.7wt%时,树脂体系的综合力学性能最好;低PES含量下,小于1.0wt%的MWCNT的加入使材料力学性能超过用20.0wt%PES改性的环氧树脂;PES与MWCNT对环氧树脂具有协同增韧作用。     

酸酐固化环氧树脂-有机蒙脱土纳米复合材料的制备及性能研究

以甲基四氢酸酐为固化剂,对含羟基长链烷基季铵盐改性蒙脱土-环氧树脂纳米复合材料的制备进行了研究。通过TEM、SEM、TGA和DMA等对其微观结构、热性能和动态力学性能等进行表征和分析。TEM结果表明:有机蒙脱土以纳米片层分散在环氧树脂基体中,形成了纳米复合材料;有机蒙脱土含量3wt％时,环氧树脂被同时增韧增强:冲击强度提高87.8%,拉伸强度提高20.9%。纳米片层蒙脱土的加入同时也改善了环氧树脂的热稳定性和动态力学性能;有机蒙脱土含量5wt%时,热分解温度提高24.7℃,热变形温度提高了8.7℃;在T<T_g时,环氧树脂的储能模量提高42.86%,在T>T_g时,提高229.8%;相应玻璃化转变温度T_g提高14.7℃。      

有机蒙脱土改性R-122环氧树脂纳米复合材料的制备与性能

以钠基蒙脱土(Na-MMT)为原料,十六烷基三甲基溴化铵(CTAB)为插层剂,成功地制备出有机蒙脱土(OMMT),对其结构分析表明:蒙脱土的层间距由1.43nm增加到1.925～3.85nm。用该有机蒙脱土对R-122进行改性,成功制备了R-122复合材料,当有机蒙脱土的在树脂中添加的质量分数为4.0%时,冲击强度达到最大值21.2J/m,比纯树脂的提高了92.7%;扫描电镜分析表明:复合材料的断口呈复杂的层状分布,说明复合材料形成的新表面多,吸收的冲击能多;差示扫描热量分析表明,蒙脱土的加入使环氧树脂的耐热性得到进一步提高。利用有机蒙脱土对R-122树脂改性同时提高了韧性和耐热性,为R-122基高性能复合材料的制备提供了新的途径。     

二维和零维纳米材料协同增强的高性能纳米复合材料

将二维蒙脱土和零维纳米TiO_2共同复合到环氧树脂中,成功地制备出一种高性能有机蒙脱土/纳米TiO_2/环氧树脂复合材料。力学性能测试和热分析显示,该复合材料在拉伸模量、拉伸强度、弯曲模量、弯曲强度、缺口冲击强度、玻璃化转变温度、热分解温度上都明显优于纯环氧树脂,也优于有机蒙脱土/环氧树脂复合材料和纳米TiO_2/环氧树脂复合材料。XRD检测和透射电子显微镜观察显示,在有机蒙脱土/纳米TiO_2/环氧树脂复合材料中,蒙脱土被完全剥离为纳米单片,和纳米TiO_2交错分布于环氧树脂中。选择适宜的两种维度的纳米材料复合于聚合物中,是制备新型高性能复合材料的成功思路。     

悬浮聚合法制备纳米蒙脱土/聚合物( 苯乙烯-共聚-二乙烯基苯) 复合材料及性能

采用悬浮聚合法制备了纳米蒙脱土/聚合物(苯乙烯-共聚-二乙烯基苯) 复合材料。钠基蒙脱土(SMMT) 经十六烷基三甲基溴化铵(CTAB) 离子交换后获得有机蒙脱土(OMMT) 。采用XRD 和FTIR 分析表征了有机蒙脱土的结构与性能。通过XRD、TEM、SEM、和FTIR 对复合材料微观结构进行了表征; 通过热重分析仪( TG) 对复合材料的热稳定性能进行了研究。讨论了蒙脱土含量和交联剂用量对复合材料热稳定性能的影响。结果表明, 钠基蒙脱土的层间距为1. 48 nm , 经有机改性蒙脱土的层间距为2. 85 nm , 纳米蒙脱土/聚合物复合材料的层间距约为4 nm; 纯聚苯乙烯最大质量损失温度为399 ℃, 当蒙脱土含量为5 %、交联剂用量为10 %时, 纳米蒙脱土/聚合物最大质量损失温度提高到437 ℃。在实验条件下, 纳米蒙脱土/聚合物复合材料具有更好的热稳定性能。      

碳纳米管-有机化蒙脱土多维纳米界面构筑及其对环氧树脂的增韧机制

分别采用混酸、环氧树脂（EP）和硅烷偶联剂对碳纳米管（CNTs）进行功能化处理,用十八烷基三甲基氯化铵对蒙脱土（MMT）进行有机化处理,将具有一维纳米尺度的CNTs和二维纳米尺度的有机化蒙脱土（OMMT）复合引入EP酸酐固化体系,通过溶液共混法制备纳米OMMT/EP、CNTs/EP、CNTs-OMMT/EP复合材料。使用简支梁冲击试验仪测试三种复合材料的冲击强度,并利用SEM观察纳米复合材料的冲击断面形貌。实验结果表明,当OMMT的含量为4wt%时,纳米OMMT/EP复合材料的冲击强度比未掺杂纳米组分的EP提高了16.7%。经硅烷偶联剂处理后的CNTs（Si-CNTs）能与EP基体形成良好界面,当Si-CNTs的含量为0.9wt%时,纳米Si-CNTs/EP复合材料冲击强度比未掺杂纳米组分的EP提高了84.0%。当OMMT的含量为4wt%、Si-CNTs的含量为0.9wt%时,纳米Si-CNTs-OMMT/EP复合材料的冲击强度比未掺杂纳米组分的EP提高了135.4%。管状CNTs和片层结构OMMT对EP的韧性具有协同提高作用。     

脂肪族聚氨酯弹性体/蒙脱土复合材料的制备与性能

使用原位插层聚合法制备了一系列不同有机蒙脱土含量的基于异佛尔酮二异氰酸酯的脂肪族聚氨酯弹性体/蒙脱土纳米复合材料,通过X射线衍射(XRD)、差示扫描量热测试(DSC)、热重分析(TGA)等研究了有机蒙脱土含量对脂肪族聚氨酯弹性体结构与性能的影响。XRD结果表明,成功地合成了聚氨酯/蒙脱土插层型纳米复合材料。TGA结果表明,纳米复合材料的热稳定性随着有机蒙脱土含量的增加而提高。有机蒙脱土对聚氨酯基体有较好的增强和增韧作用,而当有机蒙脱土含量为7%时,纳米复合材料的力学性能最佳。     

活性炭/蒙脱土纳米复合材料的制备及吸附性能研究

以钠基蒙脱土为原料,用十六烷基三甲基溴化铵(HTMAB)制备有机蒙脱土.用自制的苯并噁嗪预聚体作插层剂,原位插层聚合制备出苯并噁嗪/蒙脱土纳米复合材料.经炭化、活化得到活性炭/有机蒙脱土纳米复合材料.经FT-IR、X射线衍射(XRD)和透射电镜(TEM)分析表明,蒙脱土片层在活性炭中已达到纳米级分散.研究其对小柴胡汤中总生物碱以及烟碱的静态吸附,试验结果表明平衡吸附数据基本符合Freundlich方程.     

Experimental fracture investigation of CNT/epoxy nanocomposite under mixed mode II/III loading conditions

For the first time, the brittle fracture of epoxy‐based nanocomposite reinforced with MWCNTs (multi‐walled carbon nanotubes) and subjected to mixed mode II/III loading conditions is investigated. This experimental investigation is carried out using a newly developed test configuration. Araldite LY 5052 epoxy, which is a resin frequently used in aerospace industry, is utilized to fabricate pure epoxy and nanocomposite test specimens with two different MWCNTs contents of 0.1 and 0.5 wt%. The obtained experimental results reveal that adding MWCNTs to epoxy resin up to 0.5 wt% improves the fracture toughness under pure mode II and pure mode III loading with an increasing trend. This is while the improvement under mixed mode II/III loading is reduced by adding nanotubes more than 0.1 wt%. To justify the variations of fracture toughness in terms of nanoparticles content, SEM (scanning electron microscopy) photographs of the fracture surfaces of the specimens in the vicinity of the initial crack front are prepared. Additional fracture mechanisms caused by adding carbon nanotubes are discussed in detail based on the provided SEM images.     

Fracture toughness and fatigue life of MWCNT/epoxy composites

The present work experimentally characterizes the mode-I fracture toughness and stress–life curve of multi-walled carbon nanotube-(MWCNT-)reinforced epoxy-matrix composites. The effects of carbon nanotube weight fraction and voids on the composite fracture toughness are studied. The average fracture toughness of 1 wt%- and 3 wt%-MWCNT/epoxy composites is 1.29 and 1.62 times of that of pure epoxy, respectively. The 0.5 wt%-MWCNT/epoxy composites’ fatigue lives are 10.5 and 9.3 times of the average fatigue life of neat epoxy, when they are subjected to cyclic loadings with stress amplitudes of 8.67 MPa and 11.56 MPa, respectively. The micrographs indicate that the separation and uniform distribution of MWCNTs in the matrix and the formation of voids significantly affect the fracture and fatigue behavior of MWCNT-reinforced composites.     

Fracture mechanisms of epoxy filled with ozone functionalized multi-wall carbon nanotubes

This work focused on the fracture mechanisms and reinforcing effects of ozone-treated multi-walled carbon nanotubes (MWCNTs) in epoxy matrix. Ozone functionalization of MWCNTs was found to be of help for a better dispersion and stronger interfacial bonding with epoxy matrix, which in turn improve the strength and fracture toughness of the resin. The MWCNT/epoxy composites showed complicated failure modes than the conventional fibrous composites, which have been quantitatively investigated and correlated with the fracture toughness of the nanocomposites studied.     

多壁巴基纸/环氧复合材料拉伸性能的影响因素

采用抽滤法制备了多壁碳纳米管(MWCNTs)纸(又称巴基纸), 研究了巴基纸增强不同环氧基体复合材料(巴基纸复合材料)的拉伸性能及其断口形貌, 分析了MWCNT含量、 树脂基体拉伸性能以及巴基纸与树脂的界面黏附作用对复合材料拉伸性能的影响。结果表明: 在MWCNT质量分数小于39.1%范围内, 增加碳纳米管含量, 可显著提高巴基纸/环氧复合材料的拉伸性能; 巴基纸/环氧复合材料的拉伸强度和模量与树脂基体的性能密切相关, 其拉伸破坏形式受基体的脆韧性影响显著; 相比较而言, 巴基纸与树脂间的黏附功对巴基纸/环氧复合材料拉伸性能的影响不明显。     

电场诱导多壁碳纳米管有序排列对多壁碳纳米管/环氧树脂复合材料性能的影响

采用交流（AC）电场诱导法制备了多壁碳纳米管（MWCNTs）均匀分散且定向有序排列的MWCNTs/环氧树脂复合材料。采用SEM、偏振拉曼光谱等研究了电场强度、MWCNTs含量、加电时间及温度（黏度）等因素对MWCNTs定向排列的影响,讨论了MWCNTs有序排列对MWCNTs/环氧树脂复合材料电学和力学性能的影响。结果表明：MWCNTs沿电场方向有序排列;MWCNTs/环氧树脂复合材料施加AC电场后的拉曼强度明显高于未施加电场的情况;当MWCNTs含量从0wt%增加到0.025wt%时,MWCNTs/环氧树脂复合材料导电率从2.3×10^-12 S/cm增加到1.3×10^-8 S/cm,增加了约4个数量级;MWCNTs含量为2.5wt%时,MWCNTs/环氧树脂复合材料拉伸强度提高了26.3%。     

Mode I interlaminar fracture behavior and mechanical properties of CFRPs with nanoclay-filled epoxy matrix

The mechanical properties and fracture behavior of nanocomposites and carbon fiber composites (CFRPs) containing organoclay in the epoxy matrix have been investigated. Morphological studies using TEM and XRD revealed that the clay particles within the epoxy resin were intercalated or orderly exfoliated. The organoclay brought about a significant improvement in flexural modulus, especially in the first few wt% of loading, and the improvement of flexural modulus was at the expense of a reduction in flexural strength. The quasi-static fracture toughness increased, whereas the impact fracture toughness dropped sharply with increasing the clay content.Flexural properties of CFRPs containing organoclay modified epoxy matrix generally followed the trend similar to the epoxy nanocomposite although the variation was much smaller for the CFRPs. Both the initiation and propagation values of mode I interlaminar fracture toughness of CFRP composites increased with increasing clay concentration. In particular, the propagation fracture toughness almost doubled with 7 wt% clay loading. A strong correlation was established between the fracture toughness of organoclay-modified epoxy matrix and the CFRP composite interlaminar fracture toughness.     

Mechanical properties of carbon fiber/fullerene-dispersed epoxy composites

This study examined the effect of fullerene dispersion on the mechanical properties of carbon-fiber reinforced epoxy matrix composites (CFRPs). Mechanical properties such as tension, compression, open-hole compression, comparession after impact (CAI), binding, short beam shear, and interlaminar fracture toughness were evaluated for [0]₈, [90]₁₆, [45/0/?45/90]_2S laminates. Tension and compression strengths increased 2–12% by dispersing 0.5% of fullerene into the matrix resin. Furthermore, interlaminar fracture toughness of the composite was improved by about 60%. It was revealed that a small amount of fullerene (0.1–1 wt.%) increased the failure strain of epoxy resin itself, thereby improving the CFRP strength.     

Multiscale carbon fibre–reinforced polymer (CFRP) composites containing carbon nanotubes with tailored interfaces

Pristine and functionalized multiwalled carbon nanotubes (MWCNTs) with tailored interfaces were efficiently dispersed in an epoxy matrix using a three‐roll mill and further reinforced with carbon fibres. 1.3‐Dipolar cycloaddition of azomethine ylides was used for the chemical modification of MWCNTs by a solvent‐free approach. The influence of different loadings and types of MWCNTs on the final properties of the epoxy matrix was studied. Moreover, the most promising formulations were selected for manufacturing of prepreg sheets. The transversal tensile properties and the interlaminar fracture toughness under mode I loading (G_IC) of multiscale carbon fibre–reinforced polymer (CFRP) composites were characterized. The results point out that it is not straightforward to transfer the remarkable intrinsic properties of MWCNTs to the composite level, although an overall positive trend was found. Double cantilever beam experiments showed that G_IC of CFRP composites was improved 44% at ultralow content of functionalized MWCNTs (0.043 wt%).     

Effect of acid and TETA modification on mechanical properties of MWCNTs/epoxy composites

Acid treatment and triethylene-tetramine (TETA) modification of multi-walled carbon nanotubes (MWCNTs) purposing to attain better dispersibility and stronger interfacial bonding between MWCNTs and epoxy matrix have been carried out in this paper. The epoxy and MWCNTs/epoxy composites were produced by cast molding method. Stress–strain curves show that TETA-MWCNTs/epoxy hold the greatest toughness of all samples with 0.5 wt.% nanoparticles. The Young’s modulus of TETA-MWCNTs/epoxy has a significant increase about 38% compared to the neat epoxy, while the Young’s modulus of unmodified MWCNTs/epoxy or acid-modified MWCNTs/epoxy has a bit of decrease. Tensile and impact strength tests reflect that TETA-MWCNTs reinforced epoxy composites have an obvious improvement of tensile strength about 30% and an enhancement of impact strength over 34% compared to the pure epoxy composites with only 0.5 wt.% loading of TETA-MWCNTs. Scanning electron microscopy images of fractured surface of MWCNTs/epoxy indicate homogeneous dispersibility of TETA-MWCNTs and strong interfacial adhesion between the TETA-MWCNTs and the epoxy in the MWCNTs/epoxy composite.