碳纳米管改性氰酸酯树脂/碳纤维复合材料研究

采用多壁碳纳米管(MWNTs)为改性剂,对环氧树脂/双酚A型氰酸酯树脂体系进行增韧改性。以该改性体系制备了碳纳米管改性氰酸酯树脂/碳纤维复合材料。研究了MWNTs加入量对复合材料力学性能的影响,利用动态力学分析仪和扫描电子显微镜分别对该复合材料的耐热性及微观形貌进行了分析。结果表明,MWNTs的加入能明显地改善复合材料的耐热性和力学性能,当MWNTs的含量为1份和1.5份时,复合材料的层间剪切强度和弯曲强度分别提高约31%和23%。     

热塑性树脂改性氰酸酯树脂研究

采用热塑性树脂对双酚A型氰酸酯树脂（BADCy）进行增韧改性,根据改性BADCy的DSC曲线确定了改性BADCy的固化工艺。结果表明,热塑性树脂的加入对BADCy的固化行为影响较小,但能极大地提高BADCy的力学性能,当热塑性树脂质量分数为8％时,其弯曲强度和冲击强度分别从改性前的104．0MPa和6．0kJ／m^2提高到120．1MPa和14．2kJ／m^2,有效地增大了BADCy的韧性。     

BADCy/MMA半互穿网络的制备及性能表征

在加热熔融的氰酸酯树脂(BADCy)中加入甲基丙烯酸甲酯(MMA)单体(同步合成法)或MMA预聚体(异步合成法)并引发使其发生本体聚合,制备了具有半互穿聚合物网络结构的氰酸酯树脂/聚甲基丙烯酸甲酯(BADCy/MMA-SIPN),通过力学性能测试,红外及DSC分析研究了MMA含量对体系力学性能和热性能的影响。结果表明,互穿网絡的形成使氰酸酯树脂体系的力学性能和耐热性能都有较大的提高,冲击强度、弯曲强度及玻璃化温度分别提高了97.8%、58.6%和65℃。     

纳米SiO2改性BOZ/BMI/BADCy共聚物的制备及性能研究

研究了纳米SiO2含量对苯并恶嗪树脂(BOZ)/双马来酰亚胺(BMI)/双酚A型氰酸酯(BADCy)/纳米SiO2复合材料力学性能、热性能和吸水性能的影响。结果表明,当纳米SiO2质量分数为3%时,BOZ/BMI/BADCy/纳米SiO2复合材料具有较高的强度和良好的韧性,其缺口冲击强度和弯曲强度比BOZ/BMI/BADCy共聚物分别提高了11.6%和8.5%;同时,纳米SiO2质量分数为3%时BOZ/BMI/BADCy/纳米SiO2复合材料具有优异的耐热性,其初始热分解温度和最大热分解温度分别为343.2℃和430.3℃。     

氰酸酯/环氧树脂/碳纳米管复合材料的制备与性能研究

采用熔融浇铸法制备了氰酸酯/环氧树脂/多壁碳纳米管(MWCNTs)复合材料,通过导热系数测试、热重分析(TG)、扫描电子显微镜(SEM)对复合材料进行了分析和表征。结果表明:加入MWCNTs可以有效提高复合材料的导热性能,其中MWCNTs用量为3%的复合材料导热系数为0.35 W/(m·K),比纯树脂材料的导热系数提高了30%;MWCNTs的加入能够提高氰酸酯基复合材料的断裂韧性。     

多壁碳纳米管的表面改性及其在水性聚氨酯体系中的应用

采用自制的硅烷类改性剂(s-PEG)对经过酸氧化的多壁碳纳米管(MWNTs)进行表面改性处理,并通过共混法制备了MWNTs/水性聚氨酯(WPU)复合材料,研究了MWNTs的添加对复合材料性能的影响.结果表明,改性剂s-PEG成功地包覆于MWNTs表面,形成了s-PEG壳层,包覆率约为25％.改性MWNTs (s-PEG-MWNTs)的添加可以明显改善WPU复合材料的拉伸性能,当s-PEG-MWNTs的添加量为1％时,复合材料的拉伸强度和断裂伸长率比未添加MWNTs的材料分别提高了597％和152％.s-PEG-MWNTs在WPU基体中达到了良好的分散效果.此外,s-PEG-MWNTs的添加显著地增强了复合材料的导电性能.     

多壁碳纳米管在国产碳纤维增强环氧树脂复合材料中应用

研究了一种简易有效的多壁碳纳米管(MWNTs)分散入环氧树脂的方法,对树脂的工艺性进行试验研究;使用碳纤维复丝的力学性能来表征纤维/树脂界面性能和纤维强度转化效果,制备了含MWNTs的环氧树脂/碳纤维预浸料,并对使用此预浸料制备的复合材料单向板进行力学性能测试。结果表明,当MWNTs的用量为E–51的0.5%时,二者混合球磨8 h后配制的树脂溶液适用期大于24 h,黏度小于0.8 Pa·s,树脂浇铸体拉伸强度78 MPa,弯曲强度106 MPa,断裂伸长率4.3%;添加MWNTs之后纤维/树脂结合良好,复合材料单向板拉伸强度提升了7.2%,弯曲强度提升了9.73%,压缩强度提升了6.82%,层剪强度提升了11.54%。     

BADCy/PAN互穿网络的合成及表征

采用同步合成法和异步合成法分别制备双酚A型氰酸酯树脂/聚丙烯腈半互穿聚合物网络(BADCy/PAN-SIPN),研究了几种不同组分的SIPN体系.结果表明,BADCy/PAN-SIPN网络体系的形成对体系的力学性能和耐热性能都有较大的提高,当丙烯腈质量分数为15％时,SIPN体系的冲击强度提高了89.7％,弯曲强度提高...     

氰酸酯树脂及其碳纤维复合材料研究

E5 1环氧树脂改性双酚A型氰酸酯树脂 (BADCy)体系的力学和热性能的研究表明 ,5 % (质量分数 ,下同 )的E5 1环氧树脂可使BADCy的弯曲强度和冲击强度分别由原来的 95 .6MPa和 9.2 4kJ/m2 提高到 117.8MPa和12 .5 8kJ/m2 ,热变形温度仅下降 8℃。碳纤维 /BADCy复合材料的扫描电镜和力学性能测试结果表明 ,纤维的表面形态对界面粘结效果有较大影响 ,三种复合材料界面的粘结强弱顺序是T3 0 0 /BADCy >M 40 /BADCy >M 40J/BAD Cy。水煮 10 0h对三种碳纤维复合材料的弯曲性能影响不大 ,但对层间剪切强度的影响明显 ,其中M 40J/BADCy的层间剪切强度保持率只有 84.2 % ,而T3 0 0 /BADCy的强度保持率高达 92 .5 %。热冲击和紫外线辐照实验研究表明 ,-3 0℃ / 11h～ 15 0℃ / 11h的 2 0次热交变及总剂量为 1× 10 9J/m2 的紫外线照射对BADCy基碳纤维复合材料的力学性能影响很小 ,三种复合材料的弯曲强度、弯曲模量和层间剪切强度的保持率均大于 90 %。     

三种氰酸酯预聚物\聚砜树脂共混物的制备与性能研究

采用三种聚砜树脂(双酚A型聚砜PSF、聚醚砜PES、聚芳醚砜PPSU)为增韧树脂,分别与氰酸酯(BADCy)单体混合、预聚,制备出三种聚砜与氰酸酯预聚物的共混物。研究了共混树脂的剪切强度与聚砜树脂种类之间的关系。这表明三种共混树脂力学性能优异,最高使用温度分别为180℃、230℃和280℃。通过TG分析,表明三种共混树脂均为优异的耐高温材料,失重过程遵从BADCy自身的热氧化分解规律。     

Conductive chitosan/multi walled carbon nanotubes electrospun nanofiber feasibility

The current study focuses on the electrospinning of chitosan (CHT)/multi walled carbon nanotubes (MWNTs) composite nanofiber using a highly stable dispersion. The acetic acid (1–100%) and trifluoroacetic acid/dichloromethane (TFA/DCM 70: 30) was tested as solvent, and the TFA/DCM (70 : 30) is most preferred for fiber formation process with acceptable electrospinnability. Moreover, a new protocol was used to establish proper technique for preparation of electrospinning solution. FT-IR spectroscopy utilized to infer the extent of interaction between CHT polymer chain and MWNT filaments. A quite simple technique was employed to show the stability of electrospinning solution before nanofiber formation process. Scanning electronic microscope (SEM) was employed to show the influence of spinning parameters on surface morphology of electrospun fiber. Under optimized condition, homogeneous and beadfree CHT/MWNTs nanofibers and known physical characteristics were prepared. The formation of conducting nanofibers based on CHT nanocomposites can be considered as a significant improvement in electrospinning of CHT/CNT dispersion. The direct outcome of the current study includes the homogeneous CHT/MWNTs nanofibers with an average diameter of 275 nm and a conductivity of 9×10⁻⁵ S/cm. These results are extremely important for further investigation regarding biomedical applications.     

碳纳米管／环氧树脂复合体系研究

采用熔融混合法,利用超声分散制备了碳纳米管／环氧树脂纳米复合材料。研究了羟基化碳纳米管的添加量对复合材料的反应活性的影响;同时测试了碳纳米管／环氧树脂纳米复合材料的弯曲性能和电性能,并利用透射电镜对碳纳米管在复合材料中的微观结构进行了表征。结果表明：碳纳米管使复合材料的反应活性有所提高;当碳纳米管含量为1％时,碳纳米管／环氧树脂复合材料的弯曲强度和弯曲模量分别由纯体系的143．32MPa和3563．76MPa提高到155．79MPa和3690．45MPa,碳纳米管在环氧树脂基体中呈单根分散。碳纳米管使复合材料的体积电阻率和表面电阻率下降2个数量级。     

碳纳米管/聚丙烯腈导电纤维的结构与性能

使用浓硫酸和浓硝酸的混合溶液将多壁碳纳米管进行功能化处理后与聚丙烯腈(PAN)进行共混,采用湿法成形技术制备出了多壁碳纳米管/PAN导电纤维。采用扫描电镜、动态力学分析等手段对纤维的结构进行了分析,对纤维的物理机械性能及导电性能进行了测试。结果表明:添加碳纳米管5%时PAN纤维的强度、储存模量及玻璃化转变温度提高,断裂伸长率下降;添加经过功能化处理的碳纳米管可以有效地提高纤维的导电性能,当含量为5%时,电导率可达10-3S/cm。     

Effects of nanotube modification on the dielectric behaviors and mechanical properties of multiwall carbon nanotubes/epoxy composites

Multiwall carbon nanotubes (MWNTs) were modified by three methods, namely, oxidizing the tubes and opening both ends, filling the tubes with Ag, and grafting the tubes with hexamethylene diamine. Modified MWNTs/epoxy composites were prepared by melt‐mixing epoxy resin with the tubes. Transmission electron microscope images showed that the modified MWNTs can be dispersed in the epoxy matrix homogeneously. The dielectric behaviors and mechanical properties of the composites were investigated. The dielectric and mechanical properties of the modified MWNTs/epoxy composites were considerably improved compared with those of the epoxy matrix. The tensile strengths of the Ag‐filled, opened, and grafted MWNTs composites at the same filler content of 1.1 wt% were higher by ～30.5%, 35.6%, and 27.4%, respectively, than that of neat epoxy. The Izod notched impact strength of the grafted MWNTs/epoxy composite with filler content of 1.1 wt% was approximately four times higher than that of neat epoxy. A dielectric constant of ～150 of the composite with 1.1 wt% Ag‐filled nanotubes was observed in the low‐frequency range, which was ～40 times higher than that of the epoxy matrix. The proper modification of nanotubes provides a way to improve the properties of the polymer‐based composites. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Mechanical properties of carbon fiber reinforced bisphenol A dicyanate ester composites modified with multiwalled carbon nanotubes

A novel electrophoretic deposition (EPD) method was employed for grafting multiwalled carbon nanotubes (MWCNTs) on carbon fibers, which, after impregnation with bisphenol A dicyanate ester (BADCy), synergistically reinforced BADCy matrix composites (CNT‐C/BADCy). The effect of MWCNT presence on the mechanical properties of the composites was investigated. Composite tensile strength increased by 45.2% for an EPD duration of 2 min, while flexural strength exhibited a decreasing trend with EPD duration. Optical microscopy revealed that the existence of MWCNTs enhanced the fiber‐matrix interface while a large number of CNTs were observed to have pulled‐out from the matrix, a finding which explained the observed tensile strength increase in terms of energy dissipation by the specific toughening mechanism. The flexural strength decrease of the composites with CNTs as compared to specimens without nanotubes was found linked to the increased stress concentration in the BADCy matrix due to tube presence which weakens the adhesion between carbon fabrics. In a word, carbon nanotubes will enhance the micro interface and weaken the macro interface of the composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45100.     

Epoxy‐modified cyanate ester resin and its high‐modulus carbon‐fiber composites

Epoxy E51‐modified bisphenol A dicyanate (BADCy) and its high‐modulus carbon fiber (M40) reinforced composites were prepared in this research. The carbon‐fiber composites were prepared by autoclave molding. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy of BADCy‐E51 blend systems showed that polycyclotrimerization of BADCy primarily took place at low temperature. Epoxy group reacted with triazine ring group and produced oxazolidinone at high temperature. The data of mechanical properties, water absorption, and heat deflection temperature (HDT) of cured castings showed that the matrix system containing 95 wt% BADCy and 5 wt% E51 had optimum characteristics. Scanning electron microscopy (SEM) analysis of M40 fiber and the fracture surfaces of M40/BADCy‐E51 composite displayed that the adhesion between M40 fiber and BADCy was good though the surface of M40 was inert. The high retention of mechanical properties of M40/BADCy‐E51 composite after long‐term exposure to environmental conditions indicated that the M40/BADCy composite was suitable for space applications. POLYM. COMPOS., 27:402–409, 2006. © 2006 Society of Plastics Engineers     

Dispersion and mechanical properties of polypropylene/multiwall carbon nanotubes composites obtained via dynamic packing injection molding

In this article, polypropylene (PP)/multiwall carbon nanotubes (MWNTs) composites were prepared through dynamic packing injection molding, in which the oscillatory shear was exerted on the molten composite during packing and solidification stage of injection‐molding. A simultaneous increase of tensile strength and impact strength has been achieved for PP/MWNTs composites containing only 0.6 wt % MWNTs. Particularly, the impact strength was found increased by almost 50% at such low MWNTs content. These improvements in properties were attributed to uniform dispersion and possible orientation of nanotube induced by shear stress. It was suggested that the dynamic packing injection molding could provide much strong shear force for better dispersion of MWNTs in PP matrix, on one hand, but breakdown the aspect ratio of MWNTs, on the other. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1880–1886, 2007     

环氧化端羟基聚丁二烯改性氰酸酯树脂体系研究

采用环氧化端羟基聚丁二烯(EHTPB)对双酚A型二氰酸酯树脂(BADCy)进行增韧改性。运用差示扫描量热法分析改性体系的反应性,发现EHTPB对BADCy的固化反应有一定的催化作用。采用傅立叶变换红外光谱仪、扫描电子显微镜和广角X射线衍射仪等表征共混物的结构特征,研究增韧改性机理,并对固化产物进行热重分析和力学性能测试。结果表明,EHTPB能在不显著降低体系热稳定性的同时改善体系的韧性,使得改性树脂具有较好的综合性能。