机械混炼过程对天然橡胶/有机蒙脱土纳米复合材料结构的影响

采用机械混炼插层法制备天然橡胶(NR)/有机蒙脱土(OMMT)纳米复合材料,研究混炼过程对复合材料结构的影响。结果表明,剪切作用越强并不越有利于大分子链的插层,当辊距为3 mm时,适当增加薄通的次数,有益于分子链插入蒙脱土层间。当薄通次数达到40次时,可形成剥离型的纳米复合材料。且在共混过程中加入偶联剂,可使得蒙脱土与橡胶间的化学交联的比例提高,从而改善复合材料的物理机械性能和热氧老化性能。     

改性多壁碳纳米管/聚乳酸复合材料的研究

制备了改性多壁碳纳米管/聚乳酸复合材料,研究了改性多壁碳纳米管对聚乳酸的增强作用.通过拉曼光谱分析、热重分析证实了多壁碳纳米管酸化酯化反应的发生.通过溶液法制备了聚乳酸/改性多壁碳纳米管复合物.考察了聚乳酸和改性多壁碳纳米管复合体系的相容性.扫描电镜分析结果说明了聚乳酸和改性多壁碳纳米管复合物相容性的变化.随着改性多壁碳纳米管在复合物中含量的增加,体系的分散效果也越好,相容性也有提高.实验结果表明,在聚乳酸材料中添加改性碳纳米管材料到一定值对,可以提高材料的力学性能,且当改性碳纳米管添加量达到1.5％的时候材料力学性能达到了一个最大值,拉伸强度可达120.4MPa.     

填充碳纳米管/石墨的复合型电磁波屏蔽膜

介绍一种填充碳纳米管/石墨的复合型电磁波屏蔽膜的组成、制备及其耐老化性能,实验发现：当碳纳米管/石墨的配比为1/7～1/2、有机聚合物/导电填料的配比为29.6/70.4～32.4/67.6时,该屏蔽膜具有最佳的电性能、屏蔽性能和加工性能,且在一定条件下具有负的温度系数。用多层结构模型讨论了该屏蔽膜的导电性,并与铜、镍蒸发膜的屏蔽特性进行了比较。     

对乙酰氨基酚在碳纳米管粉末微电极上的电化学行为

对乙酰氨基酚;碳纳米管;粉末微电极;示差脉冲伏安法     

碳纳米管粉末微电极技术研究超氧自由基的电产生及化学性质

将多壁碳纳米管填充在粉末微电极尖端的小孔里制成碳纳米管粉末微电极,研究氧单电子还原产生超氧自由基的电化学行为.在二甲亚砜(DMSO)介质中,该电极反应是一个近乎可逆的还原/氧化过程,峰电位差(ΔEp)120mV,并显示出良好的稳态伏安曲线.根据极化曲线算得该电极反应的异相电荷传递速率常数ks=9.8×10-3cm/s.此外,还研究了超氧自由基的氧化性和碱性,并对相关反应过程作了讨论.     

高分子量聚苯胺/碳纳米管复合材料的合成与表征

在导电聚合物中,聚苯胺（PANI）因其导电性能优良,环境稳定性好,合成工艺简单,原料成本低廉等优点,被认为是最有可能实际应用的导电聚合物．然而用传统方法合成的聚苯胺由于其分子量小,分子链中存在缺陷而使其导电性能和力学性能大大降低,从而限制了其实际应用．而高分子量聚苯胺的导电性能和力学性能比一般聚苯胺有较大的提高．     

尼龙6/碳纳米管纳米复合材料自由体积特性的正电子湮没研究

采用正电子湮没寿命谱技术研究了尼龙6/碳纳米管纳米复合材料的自由体积特性。实验结果发现碳纳米管对纳米复合材料的自由体积孔洞尺寸影响甚微,而自由体积孔洞数目和相对自由体积分数均随碳纳米管含量的增加而明显减小。导致这种减小的原因可能来自两方面,其一是由于碳纳米管和基质聚合物间的相互作用限制了高分子链段运动;其二是碳纳米管填充增强了尼龙6基体结晶性能。此外,力学性能研究表明,碳纳米管在复合材料中较均匀的分散和较好的界面接触可以提高材料的力学强度,而自由体积分数的减小则使材料的韧性变差。     

玻璃纤维对碳纳米管填充聚合物/热塑性聚氨酯共混体系导电性能的影响

研究了表面带有环氧基团的玻璃纤维(GF)对聚丙烯(PP)/热塑性聚氨酯(TPU)/多壁碳纳米管(MWCNT)、 聚甲基丙烯酸甲酯(PMMA)/TPU/MWCNT和聚乳酸(PLA)/TPU/MWCNT体系导电性能的影响. 研究结果表明, 未添加GF时, 由于MWCNTs选择性地分布在TPU分散相中, PP/TPU/MWCNT, PMMA/TPU/MWCNT和PLA/TPU/MWCNT材料的导电性能很差; 加入20%的GF使3个体系的电阻率均大幅度下降, 最高下降约13个数量级, 表明填充GF是一种具有普适性的改善以TPU为分散相的共混体系导电性能的有效方法. GF使体系电阻率降低的机理主要是形成了TPU包覆GF结构, 该结构可以看作长径比较高的导电棒, 可以有效协助导电通路的构建; 同时GF还起到了体积占位的作用, 提高了体系中导电组分在基体中的有效浓度.     

磷化钴/多壁碳纳米管的制备及电催化性能研究

不断增加的能源需求和环境污染危机推动了替代高效能源转换和储存技术的广泛研究。电催化分解水具有潜在的应用前景,其可以利用电能获得清洁无污染的氢能。鉴于此,本论文通过不同浓度KOH浸泡超声的多壁碳纳米管(MWNT_S)作为基底,CoCl₂溶液为反应液,运用水热与固体磷化法得到负载有CoP的多壁碳纳米管材料。通过X-射线粉末衍射仪(XRD)、冷场发射扫描电子显微镜(SEM)、比表面及孔隙度分析(BET)对复合材料的晶型、形貌和比表面积进行了分析;通过电化学工作站对其相关电学性能进行了测试。实验结果表明在浓度为1 mol·L^-1 KOH浸泡的碳纳米管吸附的CoP含量最高(CoP-MWNTS-1.0),且电催化性能最佳,其在10 mA·cm²的电流密度下过电势为196 mV,Tafel斜率为231.07 mV/dec。     

碳纳米管/五氧化二钒空心球的制备及其电化学性能研究

采用溶剂热法制备了碳纳米管穿插的分级结构五氧化二钒空心球（VOC_x）. 使用XRD、SEM、循环伏安曲线和充放电曲线研究了不同碳纳米管量对产物结构、形貌和电化学性能的影响. 结果表明,碳纳米管的加入明显改善了VOC的倍率特性. 碳纳米管含量为7.1%时,0.5 A·g^-1电流密度下,其比电容达到346 F·g^-1,8 A·g^-1电流密度时,其电容保持率可达75%. 与活性炭组装成混合电容器,在功率密度为700 W·kg^-1时,能量密度达12.6 Wh·kg^-1.     

Insights into the Payne Effect of Carbon Black Filled Styrene-butadiene Rubber Compounds

As a widely used reinforcing filler of rubber, carbon black(CB) often enhances the nonlinear Payne effect and its mechanism still remains controversial. We adopt simultaneous measurement of rheological and electrical behaviors for styrene-butadiene rubber(SBR)/CB compounds and CB gel(CBG) during large deformation/recovery to investigate the contribution of conductive CB network evolution to the Payne effect of the compounds. In the highly filled compounds, the frequency dependence of their strain softening behavior is much more remarkable than that of their CB network breakdown during loading, while during unloading the unrecoverable filler network hardly affects the complete recovery of modulus, both revealing that their Payne effect should be dominated by the disentanglement of SBR matrix. Furthermore,the bound rubber adjacent to CB particles can accelerate the reconstruction of continuous CB network and improve the reversibility of Payne effect. This may provide new insights into the effect of filler network, bound rubber, and free rubber on the Payne effect of CB filled SBR compounds.     

磺化石墨烯/天然橡胶复合材料的性能研究

以磺化石墨烯为填料,将其填充到天然胶乳中,混合均匀后共沉淀,采用传统橡胶加工方法制备了天然橡胶复合材料。对磺化石墨烯的结构和形貌进行了表征,测定了硫化胶的力学性能、耐磨性能、透气性能和导热性能。研究结果表明:磺化石墨烯表面含有丰富的活性官能团,为少层片状结构,硫化胶的力学性能、耐磨性得到了提高,而透气性和导热性有所下降。当石墨烯添加量为2.0%(wt)时,复合材料的拉伸强度最大为27.06MPa;磨耗体积仅为0.08cm~3;导热系数最小为0.42W/(m·K);透气量最低,为1.98×10~(-4)cm~3/(m~2·d·Pa)。     

Processing and Characterization of Polypropylene Filled with Multiwalled Carbon Nanotube and Clay Hybrid Nanocomposites

Nanocomposites reinforced with hybrid fillers of carbon nanotubes (CNTs) and clays were developed, aiming at enhancing the dispersion of nanofillers with balanced mechanical properties while lowering the cost of the final product. Polypropylene-based nanocomposites were prepared by the master batch dilution technique with varying combinations of CNTs and clays as fillers by using commercially available highly concentrated master batches of polypropylene/organoclays and polypropylene/multiwalled carbon nanotubes using high-shear twin-screw extrusion. Their mechanical and morphological properties were then evaluated. It was shown that the addition of hybrid filler to polypropylene enhanced the ductility and flexural properties of nanocomposites, confirming the synergistic effect of nanofillers as a multifunctional fillers. The novelty of this work lies in the synergy arising from the combination of two nanofillers with unique dimensions and aspect ratios as well as different dispersion characteristics, which have not been specifically considered previously.     

碳纤维三向织物/环氧树脂复合材料的制备与力学性能

选择不同纱线间距[即二经(纬)纱之间的中心距]尺寸的碳纤维三向织物,采用热压成型技术制备了碳纤维三向织物/环氧树脂复合材料.研究了纱线间距及样品裁剪角度等对力学性能的影响,并与碳纤维二向织物/环氧树脂复合材料的力学性能进行对比.结果表明,随着纱线间距尺寸从2 mm增加到6 mm,0°方向断裂强度从221. 7 MPa下降到148. 1 MPa,撕裂强力从1000 N下降到600 N; 90°方向断裂强度从50. 0MPa下降到22. 1 MPa,撕裂强力从330 N下降到100 N;顶破强力从424 N下降到216 N.这些力学性能的逐渐降低是单位面积的碳纤维增强体含量减少和织物的孔洞增大共同作用的结果.纱线间距为2 mm的碳纤维三向织物复合材料在0°(以纬纱为基准),30°,45°,60°和90°方向的断裂强度分别为221. 7,48. 5,44. 3,227. 7和50. 0 MPa,即断裂强度在0°和60°方向大于在30°,45°及90°方向.由三向织物的编织原理可知,0°与60°方向完全相同,因此其断裂强度相似,且样品中有一组纱线与外加载荷平行,对形变破坏具有一定的约束作用,而...     

炭化处理高烧失量硅藻土及对天然橡胶的性能补强

通过缺氧条件下煅烧富含有机质的内蒙硅藻土制备了一种含炭的硅藻土,并将这种炭化硅藻土代替部分炭黑用于天然橡胶的补强.采用红外光谱、X射线衍射、热分析、扫描电子显微镜、能谱和万能材料试验机对炭化硅藻土进行结构表征和力学性能测试.结果表明,于600℃进行2h的缺氧锻烧处理后,硅藻土中的有机质已经转化为无定形碳紧密吸附于硅藻土...     

Analysis of Single-Walled Carbon Nanotubes Using a Chemical Bond Element Model

A three dimensional nano-scale finite element model (FEM), called the chemical bond element model, is proposed for the simulation of mechanical properties of single-walled carbon nanotubes (SWCNTs) based upon molecular mechanics method. Chemical bonds between carbon atoms are modeled by chemical bond elements. The constants of a sub-stiffness matrix are determined by using a linkage between molecular mechanics and continuum mechanics. In order to evaluate the correctness and performance of the proposed model, simulation was done to determine the influence of nanotube wall thickness, radius and length on the elastic modulus (Young's modulus and shear modulus) of SWCNTs. The simulation results show that the choice of wall thickness significantly affects the Young's modulus and shear modulus. The force field constants is also very important, because the elastic modulus is sensitive to force field constants and the elastic properties of SWCNT are related to the radii of the tubes. The contribution of length to elastic modulus is insignificant and can be ignored. In comparison with the Young's modulus and shear modulus reported in the literature, the presented results agree very well with the corresponding theoretical results and many experimental measurements. Furthermore, if the force constants are properly chosen, the present method could be conveniently used to predict the mechanical behavior of other single-walled nanotubes such as boron nitride nanotubes. The results demonstrate the value of the proposed model as a valuable tool in the study of mechanical behaviors of carbon nanotubes and in the analysis of nanotube-based equipments.     

Enhanced Physical and Mechanical Properties of Nitrile-Butadiene Rubber Composites with N-Cetylpyridinium Bromide-Carbon Black

The physical and mechanical properties of nitrile–butadiene rubber (NBR) composites with N-cetylpyridinium bromide-carbon black (CPB-CB) were investigated. Addition of 5 parts per hundred rubber (phr) of CPB-CB into NBR improved the tensile strength by 124%, vulcanization rate by 41%, shore hardness by 15%, and decreased the volumetric wear by 7% compared to those of the base rubber-CB composite.     

碳纳米管的化学修饰以及作为润滑油添加剂的摩擦学性能研究

采用硫酸和硝酸混合酸对催化裂解法(CVD法)制备的多壁碳纳米管(MWNNTs)进行纯化,然后运用硬脂酸对碳纳米管进行表面修饰,并研究了硬脂酸修饰后的碳纳米管的表面状况以及作为润滑油添加剂的摩擦学行为．实验结果表明,在硫酸催化剂作用下,通过酯化反应碳纳米管能够被硬脂酸包覆,并且硬脂酸修饰的碳纳米管作为润滑油添加剂能够显著提高基础油的减摩抗磨性能,当添加量为0．15％左右时,润滑油的减摩抗磨性能最佳,与基础油相比可以使摩擦系数下降10％左右,磨损量下降30％～60％．     

改性纳米炭黑/聚氨酯复合物的制备及表征

利用有机硅偶联剂改性的纳米炭黑和聚氨酯制备了纳米炭黑/聚氨酯复合物. 采用红外光谱、透射电镜、流变学及力学性能等测试方法对纳米粒子及其聚氨酯复合物进行了表征. 红外光谱表明, 纳米粒子的存在使聚氨酯的氢键结构发生了改变. 适量改性纳米炭黑粒子明显提高了聚氨酯的拉伸强度和断裂伸长率等力学性能. 流变学测试结果表明, 溶液中改性纳米炭黑粒子与聚氨酯分子间存在明显的相互作用.     

多孔基体负载的碳纳米管复合膜制备及其气体渗透性能

采用改进的浮动催化法在多孔Al2O3基体上制备了垂直取向的碳纳米管阵列, 并用旋转喷涂法将聚苯乙烯填充于碳纳米管的空隙, 进一步将其制备成复合碳纳米管膜, 研究了H2和CO2单组分在碳纳米管复合膜中的渗透性能, 实验结果表明, H2/CO2的理想分离系数随着复合膜中碳管管径的减小而增大, 在管径较小的复合膜中, 气体渗透分离系数高于努森扩散限制, 达到6.25, 具有一定的分离效果. 两种气体在复合膜中的渗透率随着渗透温度的增加而减小.