氧化石墨烯改性碳纤维/环氧树脂复合材料的湿热性能及微观形貌

采用湿法预浸技术和模压工艺制备了氧化石墨烯(GO)改性碳纤维/环氧树脂(CF/EP)复合材料,研究了 GO在室温干态及湿热处理后对CF/EP复合材料动态热力学性能和层间剪切性能的影响,并通过微观形貌分析了复合材料的改性机制.结果表明,当GO添加量分别为0.5％和0.8％时,GO-CF/EP复合材料的玻璃化转变温度(Tg...     

氧化石墨烯-碳纳米管复合膜层间增韧碳纤维/环氧树脂复合材料

碳纤维增强树脂基复合材料层合板结构的层间性能一直是材料的性能短板,本文利用氧化石墨烯(GO)和碳纳米管(CNT)设计制备了具有一定渗透性和树脂浸润性的复合膜,采用层间增韧方法,制备了GO-CNT复合膜改性碳纤维/环氧树脂(CF/EP)复合材料,通过张开型Ⅰ型层间断裂韧性(G_ⅠC)与滑移型Ⅱ型层间断裂韧性(G_ⅡC)对GO-CNT-CF/EP复合材料的层间韧性进行了研究,并结合复合材料的破坏微观形貌和损伤/破坏特征分析了GO-CNT复合膜对复合材料的层间增韧效果及增韧机制。结果表明：GO与CNT质量比为3∶7时制备的复合膜具有良好的成膜工艺性和树脂浸润性,EP与GO-CNT复合膜的接触角远低于其与纯GO膜的接触角,并且GO与CNT结构中的羟基、羧基、环氧基等含氧基团增加了它们与EP的物理亲和性和化学作用,有利于复合材料层间GO-CNT/EP微区结构的强韧化。GO-CNT复合膜对复合材料的张开型层间断裂韧性G_ⅠC没有增强效果,甚至复合材料的G_ⅠC值还发生了轻微下降。而GO-CNT复合膜对复合材料的滑移型层...     

氧化石墨烯改性不同表面性质的碳纤维/环氧树脂复合材料的微观形貌与动态热力学性能

通过模压成型，采用氧化石墨烯(GO)对四种碳纤维(CCF300、T700、CCF800、CCM40J)织物/环氧树脂(CF/EP)复合材料进行改性，通过复合材料的微观形貌、动态热力学性能等研究了GO对四种不同表面性质的CF/EP复合材料的改性效果。研究表明，添加GO后，GO/EP对四种CF的浸润性均比EP明显提高，纤维与GO/EP间的界面黏接比与EP基体间的黏接明显改善；CF/EP复合材料的破坏主要发生在CF与EP的界面，而GO的存在使GO-CF/EP复合材料的破坏由CF与EP基体的界面向GO/EP区域过渡。CF表面的氧碳比和沟槽均显著影响复合材料的玻璃化转变温度(T_g)，具有最高表面氧碳比的GO-CCF300/EP复合材料表现出最高的T_g，但沟槽更丰富的CCM40J和CCF300碳纤维对CF/EP复合材料的T_g表现出更好的GO改性效果。      

丁基橡胶/还原氧化石墨烯复合材料的制备及性能

采用水合肼(HH)为还原剂制备还原氧化石墨烯(rGO),以rGO作为增强填料,丁基胶乳为基体,通过改进的超声胶乳混合和原位还原工艺,制备了力学性能优异的丁基橡胶(IIR)/rGO复合材料。结果表明,在IIR基体中添加较低含量rGO时,rGO显示完全剥离和均匀分散的状态;rGO由于具有较高的比表面积,可以提高其与IIR基体之间的界面相互作用,使得IIR/rGO复合材料的拉伸强度和断裂伸长率共同增大;对比纯IIR,IIR/rGO复合材料的储能模量增加、损耗因子减小,具有更好的阻尼性能和热稳定性。     

全湿热场下碳纤维/环氧树脂复合材料层间剪切强度

针对T700/TR1219B碳纤维/环氧树脂复合材料,在不同湿/热/力耦合条件下进行层间剪切实验,对比分析性能衰减规律,通过峰值力纳米力学模量成像技术定量表征界面尺寸变化,并结合微观断口形貌分析探究湿热损伤机制.结果表明,T700/TR1219B的层间剪切性能受湿、热场影响显著,当吸湿率为2％时,层间剪切强度从原样的7...     

石墨烯改性环氧树脂/碳纤维复合材料拉伸性能的研究

通过H2SO4/HNO3混酸酸化石墨烯,并用硅烷偶联剂KH-560接枝酸化的石墨烯,然后将处理好的石墨烯均匀的分散在环氧树脂中,制备高性能的环氧树脂/碳纤维复合材料。通过红外光谱(FTIR)、热失重(TG)、透射电子显微镜(TEM)等分析方法对处理的石墨烯的表面官能团及表面形貌进行表征,用DCW-7拉伸试验机对所制得的复合材料进行测量。结果表明:酸化的石墨烯表面成功地接枝上了一定量的硅烷偶联剂KH-560,在树脂体系中添加2%的硅烷偶联剂KH-560处理的石墨烯的复合材料的拉伸强度提高了10.7%,断裂强力提高了10.4%。     

ZnS/还原氧化石墨烯复合材料的制备及光催化性能

水热法一步合成ZnS/还原氧化石墨烯（ZnS/RGO）复合材料,通过XRD、FTIR、Raman、SEM分析溶剂（乙醇、水）对ZnS/RGO复合材料形貌和结构的影响。结果表明,以乙醇为溶剂制备的ZnS颗粒尺寸小、均匀分散在石墨烯片层上,在形成ZnS纳米颗粒的同时将氧化石墨烯（GO）还原成石墨烯。对亚甲基蓝（MB）的光催化结果显示,ZnS/RGO复合材料具有优异的光催化性能,其光催化速率是纯ZnS颗粒的3.7倍,石墨烯作为优良光生电子的传输通道和收集体能够降低光生电子-空穴对的重新结合率,极大提高了ZnS/RGO复合材料的光催化性能。      

电泳沉积氧化石墨烯的碳纤维表面改性及其增强环氧树脂复合材料界面性能

采用超声辅助电泳沉积法,以异丙醇作为溶剂,在连续碳纤维(CF)表面沉积一层氧化石墨烯(GO),对CF表面进行改性。再经200℃高温处理来增强(GO)与CF之间的黏合性,从而增加CF/环氧树脂(EP)复合材料的界面结合强度。利用SEM和AFM对改性前后CF的表面形貌及微观结构变化进行了表征,通过XPS对改性前后CF表面官能团的变化进行了检测。结果表明,在CF表面沉积GO并经200℃处理后,有效地部分还原了GO(RGO),填补或桥联了CF表面缺陷,使改性后CF的拉伸强度提高了34.58%。同时,高温处理使RGO与CF之间生成牢固的化学键,从而提高了RGO与CF之间的结合强度,最终使RGO-CF/EP复合材料的界面剪切强度(IFSS)提高了69.9%。      

碳纤维-氧化石墨烯/环氧树脂复合材料的制备及表征

采用改进的Hummers法制备了五种具有不同氧化程度的氧化石墨烯（GO）。借助元素分析、X射线光电子能谱及FTIR红外光谱测试对所制备GO的组成及结构衍变进行了表征。利用光学显微镜对不同GO在固化剂异佛尔酮二胺（IPDA）中的分散状态进行观察,并将分散效果最佳的GO试样用于改性碳纤维/环氧树脂（CF/EP）复合材料。结果表明,随着氧化剂用量及反应时间的增加,GO的氧化程度也随之增加。在氧化程度较低时,GO表面官能团主要以羰基、羧基和酚羟基为主。随着氧化程度的不断提高,GO表面官能团主要为醚、环氧和醇羟基结构。GO在IPDA中的分散状态与其氧化程度密切相关,氧化程度最低和最高的GO均出现明显的聚集现象。另外,GO表面在分散过程中可被IPDA化学改性。在EP基体中加入分散效果最佳的GO（0.2wt%）后,与CF/EP复合材料相比,CF-GO/EP复合材料的弯曲强度、层间剪切强度和Ⅱ型层间断裂韧性分别提高了14%、17%和14%。     

氧化石墨烯的尺寸对碳纤维/环氧树脂湿热界面性能的影响

通过Hummers法获得两种尺寸的氧化石墨烯(GO),利用模压成型制备GO改性碳纤维增强环氧树脂复合材料(GO/CF/EP),并对复合材料进行湿热处理,利用层间剪切性能、动态热机械性能和微观形貌分析室温干态和湿热处理后复合材料的改性效果。结果表明：GO对复合材料的层间剪切强度和玻璃化转变温度均具有良好的改善作用;室温干态时两种尺寸GO对复合材料层间剪切强度的改善效果基本相同;随GO含量增加,小尺寸GO使复合材料的湿热层间剪切强度下降更快,GO含量为0.1%(质量分数,下同)时对复合材料的层间剪切性能改善作用较好,而GO含量为0.2%时对复合材料的玻璃化转变温度改善更好。随GO含量增加,GO-EP复合树脂基体的放热峰向低温移动,小尺寸GO使复合树脂的凝胶时间变短。微观形貌分析表明,GO的存在有利于增加复合材料破坏时的裂纹扩散路径,从而更有助于材料耗散裂纹尖端能量。     

碳纤维/聚苯硫醚热塑性复合材料电阻焊接工艺

本文针对航空器结构用碳纤维/聚苯硫醚(CF/PPS)复合材料为研究对象，开展电阻焊接工艺研究；利用CF/PPS复合材料混编织物作为电阻元件，成功制备了CF/PPS复合材料层板电阻焊接接头；重点利用Taguchi方法和方差分析获取CF/PPS复合材料层板电阻焊接最佳工艺参数(电流为12 A，压力为1.5 MPa，时间为30 min)及各参数对焊接接头剪切强度的贡献(电流为83.37%，压力为9.55%，时间为6.02%)。最佳焊接工艺参数焊接的接头单搭接剪切强度约为17.88 MPa；同时，对最佳参数焊接试样(H-LSS)和较低剪切强度试样(L-LSS)的焊接接头截面和剪切失效断口形貌进行了观察和分析。结果表明:H-LSS试样的焊缝区域树脂填充和浸润良好，且主要剪切失效形式为层间剪切失效，即为纤维与树脂基体脱黏及CF/PPS织物复合材料断裂混合失效；L-LSS试样的焊缝区域树脂填充和浸润较差，存在较多空隙，且剪切失效形式为焊缝界面脱黏失效。      

Interlaminar fracture morphology of carbon fibre/PEEK composites

The interlaminar fracture morphology of a carbon fibre/poly(ether-ether-ketone) composite (Aromatic Polymer Composite, APC-2) has been examined. The techniques used included scanning electron microscopy on fracture surfaces and on polished and etched sections. Two types of interlaminar fracture are observed: stable and unstable fracture. Both fracture surfaces exhibit microductility but it is more extensive for stable fracture. The fracture surfaces are not planar but have surface roughness. Fibre breakage and peeling are also observed and a quantitative examination enables the fracture energy contributions from the various processes to be calculated. The use of an etching technique reveals the spherulite texture and the presence of a deformation zone which extends into the bulk of the composite from the fracture surface. The extent of this zone is greater in the stable fracture region than in the unstable region and its presence indicates that the volume of composite which can be brought into the energy absorbing process extends well beyond the interlaminar region. The size of the zone has also been calculated using the fracture energy contributions and there is moderate agreement between calculated and observed zone size. Patterns of microductility on the fracture surface are seen to be due to spherulite texture, however the spherulite boundaries do not influence the fracture path.     

氧化石墨烯改性玄武岩纤维及其增强环氧树脂复合材料性能

为了改善玄武岩纤维/环氧树脂复合材料的界面性能,通过偶联剂对氧化石墨烯进行改性,并将改性后的氧化石墨烯引入到上浆剂中对玄武岩纤维进行表面涂覆改性,同时制备了氧化石墨烯-玄武岩纤维/环氧树脂复合材料.采用FTIR表征了氧化石墨烯的改性效果;运用SEM分析了改性上浆剂处理对玄武岩纤维表面及复合材料断口形貌的影响和作用机制.结果表明:偶联剂成功接枝到氧化石墨烯表面;玄武岩纤维经氧化石墨烯改性的上浆剂处理后,表面粗糙度及活性官能团含量增加,氧化石墨烯-玄武岩纤维/环氧树脂界面处的机械齿合作用及化学键合作用增强,界面黏结强度得到改善,玄武岩纤维的断裂强力提高了30.8%,氧化石墨烯-玄武岩纤维/环氧树脂复合材料的层间剪切强度提高了10.6%.     

Interlaminar reinforcement of glass fiber/epoxy composites with graphene nanoplatelets

This work investigated the ability of graphene nanoplatelets (GnPs) to improve the interlaminar mechanical properties of glass-reinforced multilayer composites. A novel method was developed for the inclusion of GnPs into the interlaminar regions of plain-weave, glass fabric fiber-reinforced/epoxy polymer composites processed with vacuum assisted resin transfer molding. Flexural tests showed a 29% improvement in flexural strength with the addition of only 0.25 wt% GnP. At the same concentration, mode-I fracture toughness testing revealed a 25% improvement. Additionally, low-velocity drop weight impact testing showed improved energy absorption capability with increasing concentration of GnPs. Ultrasonic C-scans and dye penetration inspection of the impact- and back-sides of the specimens qualitatively support these results. Finally, the impact damage area was quantified from the C-scan data. These results showed that the impact-side damage area decreased with increasing concentration of GnP, while the back-side damage area increased.     

Interlaminar properties of carbon fiber composites with halloysite nanotube-toughened epoxy matrix

Halloysite nanotubes (HNTs), which are geometrically similar to multi-walled carbon nanotubes, can improve the impact strength of epoxy substantially, according to our previous work [1]. Using a HNT-toughened epoxy as the matrix, a set of hybrid composites was prepared with carbon fiber-woven fabrics. The interlaminar properties of the composites were investigated by a short-beam shear test, a double-cantilever-beam test and an end-notched flexure test. The results showed that the addition of HNTs to the composites improved the interlaminar shear strength and the fracture resistance under Mode I and Mode II loadings greatly. The morphological study of the hybrid composites revealed that HNTs were non-uniformly dispersed in the epoxy matrix, forming a unique microstructure with a large number of HNT-rich composite particles enveloped by a continuous epoxy-rich phase. A study of the fracture mechanism uncovered the important role of this special morphology during the fracturing of the hybrid composites.     

Greatly enhanced cryogenic mechanical properties of short carbon fiber/polyethersulfone composites by graphene oxide coating

In order to employ polyethersulfone (PES) in cryogenic engineering field, its cryogenic mechanical performance should be examined and should also be improved to meet the high requirement for cryogenic engineering application. In this work, pure PES, graphene oxide (GO)/PES, short carbon fiber (SCF)/PES, GO/SCF/PES and GO-coated SCF/PES composites are prepared using the extrusion compounding and injection molding techniques. The tensile and flexural properties of these composites are systematically investigated at a typical cryogenic temperature (77 K). It is shown that the cryogenic mechanical properties are enhanced by the addition of GO, SCFs and coated-SCFs. In particular, the GO-coated SCF/PES composites display the greatly enhanced cryogenic mechanical properties with the highest values compared to other PES composites. In addition, it is exhibited that the cryogenic mechanical properties at 77 K of PES and its composites are far higher than those at room temperature (RT).     

还原氧化石墨烯/天然橡胶-丁腈橡胶复合材料的制备与性能

采用水合肼还原氧化石墨烯（GO）制备了还原氧化石墨烯（RGO）,以RGO作为分散介质加入到天然橡胶（NR）和丁腈橡胶（NBR）基体中,通过乳液共混法制备了RGO/NR-NBR复合材料。采用FTIR、Raman、XRD及SEM等手段表征了RGO的结构和形貌,测试结果表明,水合肼还原GO效果较好,基本除去含氧官能团,同时RGO还保留了GO的片层结构。RGO/NR-NBR复合材料的SEM测试结果显示,纳米尺寸的RGO均匀分散在橡胶基体中,且复合材料的拉伸断面粗糙程度显著增加。RGO/NR-NBR复合材料的硫化性能测试结果表明,随RGO的含量增加,复合材料的交联密度、最大扭矩及扭矩差均增大。RGO/NR-NBR复合材料的力学性能随RGO含量的增加而提高,当RGO含量为3.0%时,材料的拉伸强度、100%定伸强度和邵氏硬度分别提高了65.7%、90.3%和21.1%,断裂伸长率降低了13.1%。