Mechanical,electrical, and thermal expansion properties of carbon nanotube-based silver and silver-palladium alloy composites

The mechanical, electrical, and thermal expansion properties of carbon nanotube（CNT）-based silver and silver–palladium（10：1, w/w） alloy nanocomposites are reported. To tailor the properties of silver, CNTs were incorporated into a silver matrix by a modified molecular level-mixing process. CNTs interact weakly with silver because of their non-reactive nature and lack of mutual solubility. Therefore, palladium was utilized as an alloying element to improve interfacial adhesion. Comparative microstructural characterizations and property evaluations of the nanocomposites were performed. The structural characterizations revealed that decorated type-CNTs were dispersed, embedded, and anchored into the silver matrix. The experimental results indicated that the modification of the silver and silver–palladium nanocomposite with CNT resulted in increases in the hardness and Young＇s modulus along with concomitant decreases in the electrical conductivity and the coefficient of thermal expansion（CTE）. The hardness and Young＇s modulus of the nanocomposites were increased by 30%？40% whereas the CTE was decreased to 50%-60% of the CTE of silver. The significantly improved CTE and the mechanical properties of the CNT-reinforced silver and silver–palladium nanocomposites are correlated with the intriguing properties of CNTs and with good interfacial adhesion between the CNTs and silver as a result of the fabrication process and the contact action of palladium as an alloying element.     

Effects of various fillers on sintering,microstructures and properties of Ca-Ba-Al-B-Si-O glass/ceramic composites简

Low-temperature sintering and properties of LTCC （low temperature co-fired ceramics） materials based on CaO-BaO-Al2O3-B2O3-SiO2 glass and various fillers such as Al2O3, silica glass, christobalite, AlN, ZrO2, MgO-SiO2, TiO2 were investigated. The results show that densification, crystallization, microstructures and dielectric properties of the composites are found to strongly depend on the type of filler. The densification process of glass/ceramic composites with various fillers is mainly from 600 ℃ to 925 ℃, and the initial compacting temperature of samples is 600 ℃. The initial rapid densification of samples starts at its glass softening temperature. LTCC compositions containing Al2O3, silica glass, AlN and MgO-SiO2 fillers start to have the crystallization peaks at 890, 903, 869 and 844 ℃, respectively. The crystallization peaks are believed as correlated to the crystallization of CaAl2SiO8, β-SiO2, Ca2Al2SiO7 and β-SiO2. The composite ceramic with Al2O3, silica glass and TiO2 ceramic have a better dense structure and better smooth fracture surface. Sample for Al2O3 has the lowest dielectric loss tanδ value of 0.00091, whereas the sample for MgO.SiO, has the highest dielectric loss tanδ value of 0.02576. The sample for TiO2 has the highest dielectric constant value of 14.46, whereas the sample for AIN has the lowest dielectric constant value of 4.61.     

Fabrication and adsorption property of novel adsorbent for potential application to wastewater with Fe（Ⅲ） ions

The spherical macroporous cellulose（SMC） was fabricated using medical absorbent cotton as raw material and nano CaCO3 as porogenic agents.And then,the phenylglycine was grafted onto the SMC to obtain the novel spherical macroporous cellulose derivative adsorbent（PSMC）.FT-IR and scanning electron microscope（SEM） were employed to characterize the adsorbents and Fe3＋ ions served as model solute to evaluate the adsorption property of the adsorbents.The experimental results show that the amount of porogenic agents and the value of pH have obvious influence on adsorption capacity of the adsorbents.The data of adsorption kinetic and isotherm display that the adsorbents possess excellent equilibrium adsorption capacity（348.94 mg/g） and have a bright prospect and considerable potential in the treatment of Fe3＋ ions in wastewater.     

纳米自组装大孔催化剂对催化裂化柴油的加氢催化性能

采用二次纳米自组装方法制备出具有大孔道的催化剂0106、1227,两种纳米自组装催化剂在30～100 nm孔径分布分别占11％、28％。纳米自组装催化剂具有低堆积密度和高金属含量等特点。在10 mL固定床微型反应器中,以镇海炼化的催化裂化柴油为原料,在温度360℃、压力7 M Pa、氢油体积比为600∶1、体积空速为1．5 h-1条件下,考察了两种纳米自组装催化剂的初活性评价,并与现有工业催化剂作对比。结果表明,两种纳米自组装催化剂0106、1227可使催化裂化柴油的含硫质量分数从12400μg/g分别最低降到483、283μg/g ,最高脱硫率分别为96．10％、97．71％;将含氮质量分数从1507μg/g分别最低降到35．7、14．0μg/g ,最高脱氮率分别为97．63％和99.00％;其最高芳烃饱和率分别为67．99％和68．88％;而参比催化剂仅可使催化裂化柴油的含硫质量分数从12400μg/g最低降到537μg/g ,最高脱硫率为94．57％;将含氮质量分数从1507μg/g最低降到64．6μg/g ,最高脱氮率为95．54％;其最高芳烃饱和率为65．65％。     

PVDF-HFP基复合微孔聚合物电解质膜的制备与改性

为了提高聚偏氟乙烯-六氟丙烯(PVDF-HFP)基电解质的离子电导率和机械强度,采用倒相法,制备出复合聚偏氟乙烯-六氟丙烯基电解质PVDF-HFP-Si O2.复合电解质的形貌、结构和电化学性能分别用SEM、XRD和交流阻抗法进行了表征.结果表明:纳米Si O2的加入增强了聚合物的拉伸强度,同时有效降低了聚合物的结晶度.PVDF-HFP-Si O2分解电压为5.1V,离子迁移数为0.81,聚合物电解质的电导率(25℃)为4.84×10-3S·cm-1.     

聚硫堇/纳米金修饰电极对NO2-的电催化氧化及分析应用

研究了一种基于聚硫堇/纳米金复合材料修饰电极对NO2-的电催化氧化。相对于裸玻碳电极,聚硫堇-纳米金协同催化效应使NO2-的氧化电流增强,过电位降低。详细讨论了聚合膜的厚度、纳米金吸附时间、pH缓冲介质、pH值以及干扰离子对NO2-氧化电流的影响。在最优实验条件下,测得NO2-的线性范围为3.0×10^-6～1.0×10^-3 mol/L,检测限为1.0×10^-6 mol/L。该修饰电极具有灵敏度高、稳定性和重现性好、抗干扰能力强的特点,可用于实际样品中NO2-含量的测定,结果满意。     

液相沉积法制备氧化锡隔热树脂膜的研究

当今世界以节能减排为主题的低碳经济发展潮流中,包括汽车玻璃和建筑玻璃的隔热贴膜节能技术受到了越来越多的关注.本文采用液相沉积法制备纳米二氧化锡聚丙烯酸酯隔热有机膜.首先选择有利于产生异相沉积的前驱体溶液浓度及pH值,配制浓度为2mM~10mM的低浓度四氯化锡溶液,盐酸浓度选择0.1M~0.4M;选取甲基丙稀酸甲酯34.5%~90%、丙烯酸丁酯10%~35.5%、甲基丙稀酸0~30%、偶氮二异丁腈0.1%~0.3%,制备聚丙烯酸酯薄膜;将制得的聚丙烯酸酯薄膜放入氯化锡溶液中,控制反应温度为40℃~80℃,反应时间为6h~18h,将薄膜拿出,洗涤、干燥得纳米氧化锡有机隔热薄膜.通过XRD分析及SEM观察,氧化锡均匀沉积在有机薄膜表面,具有较好的隔热性能.     

聚乙二醇水溶液中纳米钯微波合成与表征

为防止纳米粒子发生团聚现象和沉降现象,在聚乙二醇的存在下,不加还原剂,微波辐射氯化钯水溶液,合成了纳米钯粒子。采用紫外可见吸收光谱、X射线衍射、透射电镜等技术对钯粒子的形貌进行了研究,考察了微波时间和聚乙二醇用量对纳米钯粒子形态的影响。结果表明,m（ PEG400）：m（ PdCl2）＝30时,微波功率300 W下反应30 min,得到单分散的纳米钯粒子,尺寸在10 nm左右。而且纳米钯的存在降低了基体聚乙二醇400的热稳定性。     

纳米金修饰的微柱型微流控芯片用于循环肿瘤细胞检测

设计并制作了微柱型聚二甲基硅氧烷(PDMS)微流控芯片,并在通道表面组装纳米金,固定上皮细胞粘附因子(EpCAM)抗体后用于循环肿瘤细胞(Circulating Tumor Cell,CTC)检测。结果表明,纳米金成功组装在γ-氨丙基三乙氧基硅烷硅烷化的PDMS微柱表面,EpCAM抗体功能化的微流控芯片能有效捕获全血中的模型CTCs,当流速小于40μL/min时,捕获效率大于90%。建立一种简单廉价、捕获效率高的CTCs检测新方法,有望为全血中CTCs的分离提供新的策略。     

表面活性剂对球形二氧化硅制备的影响

以正硅酸乙酯为硅源,氨水调节体系pH值,采用沉淀法制备二氧化硅微球。考察了聚乙二醇、曲拉通X-100、吐温-80等非离子表面活性剂对二氧化硅微球形貌的影响,通过扫描电子显微镜(SEM)和透射电子显微镜(TEM)以及X射线衍射对其进行表征。结果表明,表面活性剂的种类不同,加入量不同,可制备出粒径范围在80~600nm左右的光滑的二氧化硅微球。