超声辅助湿法合成纳米HA及MWNT/HA复合材料

以Ca(NO3)2·4H2O、(NH4)2HPO4和NH3·H2O为原料,在超声波辅助下,湿法合成了羟基磷灰石,用FTIR、XRD和TEM对产物进行了分析,结果表明:合成的羟基磷灰石为纳米级纺缍状晶体,不用烧结即具有较高晶化度,且为单一的羟基磷灰石晶相。以此制备条件为基础,采用原位合成的方法制备了多壁碳纳米管/羟基磷灰石复合材料,FTIR、XRD和TEM的分析结果表明:碳纳米管能较好的分散于羟基磷灰石基体中,部分碳纳米管表面可被反应生成的羟基磷灰石所包覆,二者之间有着较好的相容性,可作为一种新型的生物复合材料应用。     

碳纳米管/羟基磷灰石生物复合涂层的制备与微观结构研究

采用电泳沉积的方法在钛板表面制备了碳纳米管/羟基磷灰石复合涂层。XRD研究发现,复合涂层的成分主要是羟基磷灰石和碳纳米管;IR研究发现,复合涂层中含有羟基、磷酸根等官能团;SEM研究发现,复合涂层均匀致密,碳纳米管与羟基磷灰石颗粒混合均匀,且碳纳米管的表面已被1层羟基磷灰石薄膜均匀包覆。随着碳纳米管含量从20%增加到40%,复合涂层的致密度逐渐提高,其表面质量逐渐改善。     

含镉羟基磷灰石的形成及其稳定性

采用液相共沉淀方法合成了不同镉摩尔含量X_Cd(即: Cd/(Ca+Cd))的镉羟基磷灰石. 通过XRD, FT-IR, FE-SEM, TG-DTG-DSC-MS和TCLP对产物的组成、形貌、热稳定性及化学稳定性进行了探讨. 结果表明, 随着X_Cd的增加, Cd²⁺进入到羟基磷灰石的晶格中依次形成Ca_3.9(Ca_4.7Cd_0.7)(PO₄)₆(OH)_1.8, Ca_3.8(Ca_4.1Cd_0.73)(PO₄_₆(OH)_1.8, Ca_3.6(Ca_4.5Cd_0.76)(PO₄)₆(OH)_1.6和Cd₅(PO₄)₃OH; 这些产物在500℃以下均可稳定存在, 且热稳定性随着X_Cd的增加明显提高; 毒性浸出结果显示, Cd²⁺能够进入到羟基磷灰石的晶格中, 但产物的化学稳定性不高.     

纳米羟基磷灰石/聚碳酸酯复合生物材料Ⅰ:制备及表征

使用硬脂酸对羟基磷灰石表面进行改性,制备了纳米羟基磷灰石/聚碳酸酯(n-HA/PC)复合生物材料,利用透射电子显微镜(TEM) 、红外光谱(FTIR) 、X射线衍射(XRD)、扫描电子显微镜(SEM)等对羟基磷灰石和复合生物材料微观组成结构进行了表征。结果表明: 弱结晶结构的纳米羟基磷灰石经表面改性后,硬脂酸通过离子键吸附在其表面,形成有效的有机包覆层;与聚碳酸酯复合时,通过氢键与聚合物结合,改善了n-HA与PC聚合物的界面相容性;制备的n-HA/PC复合材料与自然骨力学性能相匹配。      

纳米羟基磷灰石丝素蛋白仿生矿化材料的制备研究

以Ca(NO₃)₂与Na₃PO₄为无机相的前驱体,将丝素蛋白直接溶于Ca(NO₃)₂溶液中,不经过脱盐处理,直接滴入Na₃PO₄溶液中反应,在37℃下丝素蛋白和羟基磷灰石晶体之间相互作用,仿生合成了纳米羟基磷灰石(n-HA)丝素蛋白(SF)生物矿化材料.用FTIR、XRD、XPS和SEM进行表征.结果表明,羟基磷灰石和丝素蛋白两相间具有较强的化学键合,矿化材料中无机相包含少量碳酸根,为缺钙类骨羟基磷灰石并且呈现一定的长轴取向性,说明丝素蛋白大分子对羟基磷灰石晶体的成核和生长起着模板和调控作用.矿化物颗粒尺寸在50~200nm之间,其抗压强度为32.21MPa,可作为非承重部位骨组织缺损修复材料.     

碳纳米管-超细铜粉复合粉体的制备

采用混酸纯化法在碳纳米管表面引入羟基、羧基等基团, 在此基础上, 用SnCl_2·2H₂O溶液对碳纳米管进行敏化处理. 处理过的碳纳米管均匀地分散在水溶液中, 形成碳纳米管悬浮液. 在这种碳纳米管悬浮液中加入五水硫酸铜, 先后用葡萄糖和甲醛对铜实施还原, 原位制备了碳纳米管-超细铜粉复合粉体. SEM和TEM结果表明, 碳纳米管均匀地分散在超细铜粉中, 并且与铜颗粒形成较牢固的结合.     

α-Ni(OH)2/SiO2核壳以及α-Ni(OH)2空心微球的制备及表征

采用以正硅酸乙酯(TEOS)水解为基础的硅溶胶种子生长法制备了粒径约为270nm的近单分散二氧化硅球型颗粒.采用一种新的溶液生长法,以氢氟酸作为溶液中镍离子配位剂,加入氨水调节溶液pH值的同时作为镍离子补充配位剂,60℃水浴条件下在已制得SiO2微球表面均匀包覆α-Ni(OH)₂得到Ni(OH)₂/SiO₂核壳结构,Ni(OH)₂壳层厚度约为35nm.结合多步包覆法提高Ni(OH)₂壳层厚度,三次包覆后壳层厚度达到约100nm,四次包覆后约为140nm.采用20wt％的强碱NaOH溶液对三次包覆后的Ni(OH)₂/SiO₂核壳结构进行处理,得到了壳层厚度约为95nm的α-Ni(OH)₂空心微球.空心微球具有较大的比表面积为141.06m²/g.     

碳纳米管取向对HA/CNTs复合材料力学性能的影响

以碳纳米管为增韧材料,用原位合成法制备了羟基磷灰石/碳纳米管复合粉体,通过氮气保护热压烧结制备了羟基磷灰石/碳纳米管复合材料,并对其进行了XRD、FT-IR、SEM、致密度、抗弯强度及断裂韧性测试,同时探索了碳纳米管取向对材料力学性能的影响.结果表明,复合材料中碳纳米管择优分布在热压面内;碳纳米管取向对材料的力学性能有较大影响,随θ(材料表面与热压方向的夹角)的增大,材料的力学性能提高,垂直于热压面的方向最差,平行于热压面的方向最好.     

羟基磷灰石合成及高温稳定性的研究

以Ca(NO₃)₂·4H₂O和(NH₃)₂HPO₄为原料,用沉淀法合成羟基磷灰石(HA)。在合成过程中添加明胶,考察明胶对HA成核、生长、粉末形态及热稳定性的影响。研究表明:当明胶加入量超过4wt％时,将阻碍HA的成核和生长;加4wt％明胶合成的粉末,经900℃煅烧,其平均颗粒尺寸为40nm,明显小于未加明胶的HA粉末,但热稳定性较差;在1000℃煅烧便有部分羟基磷灰石分解,生成β-磷酸钙。此β-磷酸钙煅烧至1500℃呈熔融态,仍没有相变为α-磷酸钙,具有很好的热稳定性。     

微孔致孔剂对钙磷陶瓷表面类骨磷灰石形成的研究

钙磷陶瓷表面类骨磷灰石层的形成对瓷诱导新骨生成起非常重要的作用. 本文利用体外模拟装置首次研究了微孔致孔剂对新工艺制备的含CO₃^2-的双相HA/β-TCP多孔陶瓷表面类?骨磷灰石形成的影响. 结果表明, 该陶瓷因CO₃^2-的掺入, 导致类骨磷灰石晶体的形成时间大大缩短(从14天缩短至6天). 此外还有缺钙羟基磷灰石晶体?的生成. 并且微孔致孔剂以聚乙烯醇缩丁醛(PVB)优于硬脂酸(SA)粉末, 它更有?利于类骨磷灰石的形成. 在同时加入PVB作微孔致孔剂时, 类骨磷灰石晶体的形成情况随PVB加入量的增大而越来越好. 综合其相关性能来看, PVB的加入量以m_钙磷粉:m _致孔剂=1:0.3为宜. 微孔致孔剂的优化有利于该陶瓷材料骨诱导性的提高.     

Studying the growth of carbon nanotubes on carbon fibers surface under different catalysts and electrochemical treatment conditions

A special electrochemical anodic oxidation (EAO) method was applied to modify the surface of carbon fibers (CFs) with fatty alcohol polyoxyethylene ether phosphate (O₃P), triethanolamine (TEA), fatty alcohol polyoxyethylene ether ammonium phosphate (O₃PNH₄), and ammonium bicarbonate (NH₄HCO₃) used as the electrolyte respectively. Then different catalysts, including Ni, Co, and Cu, were used to catalyze the growth of carbon nanotubes (CNTs) on the surface of CFs. The variation regulation of structure and property of CNTs on CFs surface was investigated by different methods. The results showed that the optimal effect of surface modification of CFs was achieved when O₃PNH₄ served as an electrolyte and the optimal electrochemical treatment intensity (ETI) was 100C/g. Also, with temperature variety, there are different microstructure changes for CNTs that adopt different catalysts. Through the experiment, a uniform catalyst coating was obtained on the surface of CFs after reduction process, which laid the foundation for the growth of uniform and regular CNTs.     

碳纳米管-TiB2陶瓷基复合材料的制备与性能研究

研究了用热压烧结(HP)方法制备TiB2-xwt%CNTs-5wt%Ni(x=0.1、0.3、0.5、1、4)复合材料的工艺条件、力学性能和微观结构.用XRD研究了其相组成,用SEM观察了复合材料的断口形貌和裂纹扩展.研究表明碳纳米管的加入使复合材料的硬度、弯曲强度和断裂韧性得到明显的提高,并且在碳纳米管含量为0.5wt%左右时,复合材料的硬度达到20.5GPa,弯曲强度为496MPa,断裂韧性达7.25MPa·m1/2;断口形貌分析表明碳纳米管主要分布于TiB2颗粒的晶界处,复合材料的增韧机制主要是碳纳米管的拔出机制和桥联机制.     

用单壁纳米碳管制备葡萄糖生物传感器的研究

以单壁纳米碳管为代表材料,对利用纳米碳管制备葡萄糖生物传感器中纳米碳管的作用和纳米碳管修饰电极的方法、酶的固定化方法及电极种类等因素对传感器性能的影响进行了研究.研究结果表明,纳米碳管的加入能有效地改善传感器的电化学性能,利用二茂铁和单壁纳米碳管共同修饰电极所制得的传感器的性能要好于仅用单壁纳米碳管修饰电极制得的传感器.在酶的固定化方法中,戊二醛交联法要略好于明胶包埋法;而利用铂电极制备出的生物传感器对葡萄糖的响应电流要明显高于利用金电极和玻碳电极制备出的生物传感器.这些结论对于开发纳米碳管在生物传感领域及生命科学相关领域的应用有参考价值.     

Effect of a multiscale reinforcement by carbon fiber surface treatment with graphene oxide/carbon nanotubes on the mechanical properties of reinforced carbon/carbon composites

An effective carbon fiber/graphene oxide/carbon nanotubes (CF-GO-CNTs) multiscale reinforcement was prepared by co-grafting carbon nanotubes (CNTs) and graphene oxide (GO) onto the carbon fiber surface. The effects of surface modification on the properties of carbon fiber (CF) and the resulting composites was investigated systematically. The GO and CNTs were chemically grafted on the carbon fiber surface as a uniform coating, which could significantly increase the polar functional groups and surface energy of carbon fiber. In addition, the GO and CNTs co-grafted on the carbon fiber surface could improve interlaminar shear strength of the resulting composites by 48.12% and the interfacial shear strength of the resulting composites by 83.39%. The presence of GO and CNTs could significantly enhance both the area and wettability of fiber surface, leading to great increase in the mechanical properties of GO/CNTs/carbon fiber reinforced composites.     

碳纳米管-ZrB2-SiC陶瓷基复合材料的制备与性能研究

研究了用热压烧结方法制备的不同碳纳米管(CNTs)含量的ZrB₂-SiC- xwt% CNTs (x=0、1.0、2.5、4.0) 复合材料的工艺条件、力学性能和微观结构. 用TEM观察了试样的微观结构, 用SEM观察了试样断口形貌和裂纹扩展情况, 并对其强韧化机制进行了分析. 研究表明, 碳纳米管主要分布沉积在ZrB2颗粒内部, 形成内晶型结构, 在CNTs含量为2.5%时, 相对密度、维氏硬度和弯曲强度分别为99.6%、21.7GPa和542MPa, 断裂韧性达到6.10MPa·m^1/2. 碳纳米管加入后材料致密性提高、晶粒细化,所形成的内晶型结构是材料强度和韧性得以提高的原因.     

Facile synthesis of boron nitride coating on carbon nanotubes

Boron nitride (BN) coating on the surface of carbon nanotubes (CNTs) was synthesized by the direct reaction of NaBH₄ and NH₄Cl in the temperature range of 500–600 °C. X-ray diffraction, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) confirm the formation of BN coating. It is revealed that the BN coating follows the shape of CNTS without damaging the surface of CNTs, and the elements B and N distribute homogenously along the whole CNTs without chemical bonds between carbon and BN layers. Besides, the oxidation resistance of the CNTs improved a lot after being coated with BN.     

Features of nanostructured coatings obtained by laser deposition of carbon nanotubes

The effect of carbon nanotubes (CNTs) on the surface mechanical strength and transparency of various soft optical materials for the UV and IR spectral range, semiconductors, metals, and plastics has been studied. The prospects of using laser surface processing and applying field-oriented CNTs are demonstrated. It is established that the laser deposition of CNTs leads to a two- to tenfold increase in the surface strength and a 2–10% modification of the optical transmission spectrum of materials.     

A Phase‐Separation Route to Synthesize Porous CNTs with Excellent Stability for Na+ Storage

Porous carbon nanotubes (CNTs) are obtained by removing MoO₂ nanoparticles from MoO₂@C core@shell nanofibers which are synthesized by phase‐segregation via a single‐needle electrospinning method. The specific surface area of porous CNTs is 502.9 m² g^?1, and many oxygen‐containing functional groups (C? OH, C?O) are present. As anodes for sodium‐ion batteries, the porous CNT electrode displays excellent rate performance and cycling stability (110 mA h g^?1 after 1200 cycles at 5 A g^?1). Those high properties can be attributed to the porous structure and surface modification to steadily store Na⁺ with high capacity. The work provides a facile and broadly applicable way to fabricate the porous CNTs and their composites for batteries, catalysts, and fuel cells.     

Plasma treatment as a method for functionalising and improving dispersion of carbon nanotubes in epoxy resins

This study reports on the results of plasma-treated carbon nanotubes (CNTs) in the presence of oxygen and ammonia which can be scaled up for relatively large quantities of nanomaterials. The plasma treatment has been shown to change the surface chemistry and energy as well as the morphology of the carbon nanotubes. X-ray photoelectron spectroscopy analysis shows increases in oxygen and nitrogen groups on the oxygen- and ammonia-treated CNTs, respectively. Titration of the enhanced oxygen plasma-treated CNTs reveals an increased presence of carboxylic acid groups at 2.97 wt% whilst bulk density decreases from 151 kg/m³ for untreated carbon nanotubes to 76 kg/m³ after the enhanced oxygen treatment. The free surface energy has also been shown to increase from 33.70 up to 53.72 mJ/m² determined using a capillary rise technique. The plasma-treated carbon nanotubes have been mixed in epoxy and have shown an improvement in dispersion, which was quantitatively evaluated using an optical coherence tomography (OCT) technique shown to be suitable for nanocomposite characterisation. This research has demonstrated that it is possible to surface functionalise large quantities of carbon nanotubes in a single process, and that this process improves the dispersion of the carbon nanotubes in epoxy.