Yb2O3／TiO2纳米颗粒的制备及表征

采用溶胶-凝胶法制备了微量 Yb2O3掺杂纳米 TiO2颗粒,采用 XRD, TG-DTA, TEM等手段对试样经不同温度热处理后的结构相变、表面形貌、颗粒大小等特性进行了表征.实验表明温度不高于 400℃时,试样的颗粒粒径较小,粒径在 15 nm以下,比表面积大于 107.22 m2@ g-1, TiO2呈锐钛型;在 400℃以上, TiO2粒径迅速增大,微粒出现锐钛相与金红石相混晶结构;800℃时 TiO2微粒完全转化成金红石相.     

钴纳米颗粒的制备及其表征

采用简单的溶液还原方法，以聚乙烯吡咯烷酮（PVP，MW=58，000）作为高分子表面修饰剂，用水合肼（50％）作为还原剂，经回流处理，成功地制备出了分散性较好的钻纳米颗粒。利用XRD、TEM、SQUID等实验方法对产物的形貌、物相及磁性进行了表征。结果表明，产物为六方结构。其饱和磁化强度为153emu／g-1．62μB／Co，是体相材料的饱和磁矩的95％，其矫顽力为5174A·m^-1。此方法的优点在于反应条件温和、成本较低，重复性强、产率高且宜于控制。     

多功能壳聚糖基防油剂在防油纸中的研究进展

壳聚糖是制备纸张防油剂潜在的理想材料,但其价格高昂、吸湿性强,需通过改性赋予其"一剂多效"功能(如在防油的同时兼顾防水、抗菌或水蒸气阻隔等功能),以提高其工业应用价值.结合壳聚糖的防油机理,总结了壳聚糖基防油剂防油性能的影响因素,综述了近年来防水型、抗菌型和水蒸气阻隔型壳聚糖基防油剂的研究现状,并对壳聚糖基防油剂的未来发展方向进行了展望.     

Structural and magnetic characterization of norbornene-deuterated norbornene dicarboxylic acid diblock copolymers doped with iron oxide nanoparticles

A series of iron oxide doped norbornene (NOR)/deuterated norbornene dicarboxylic acid (NORCOOH) diblock copolymers were synthesized and characterized by X-ray photoelectron spectroscopy (XPS), small angle neutron scattering (SANS) and superconducting quantum interference device (SQUID) experiments. γ-Fe₂O₃ nanoparticles were synthesized within the microdomains of diblock copolymers with volume fractions of NOR/NORCOOH 0.64/0.36, 0.50/0.50 and 0.40/0.60. A spherical nanoparticle morphology was displayed in the polymer with 0.64/0.36 volume fraction. Polymers with 0.50/0.50 and 0.40/0.60 volume fractions exhibited interconnected metal oxide nanostructures. The observed changes in the shape and peak positions of the small-angle neutron scattering profiles of polymers after metal doping were related to the scattering from the metal oxide particles and to the possible deformed morphologies due to the strong interparticle interactions between metal particles, which may influence the polymer microphase separation. The combined scattering from both polymer domains and magnetic particles was depicted in SANS profiles of metal oxide doped polymers. γ-Fe₂O₃ containing block copolymers were superparamagnetic at room temperature. An increase in the blocking temperature (T_b) of interconnected nanoparticles was observed and was related to the interparticle interactions, which depends on the average distance (d) between particles and individual particle diameter (2R). The sample with volume fraction of 0.4/0.6 have the lowest d/(2R) ratio and exhibit the highest T_b at 115 K.     

Different effects of tri(acryloyloxyethyl) phosphate on the thermal degradation of photopolymerized epoxy acrylate and polyurethane acrylate films

Tri(acryloyloxyethyl) phosphate (TAEP) was blended in different ratios with epoxy acrylate EB600 and polyurethane acrylate EB270 to obtain a series of UV curable flame retardant resins. The thermal degradation mechanisms of their cured films in air were studied by thermogravimetric analysis, in situ Fourier‐transform infrared spectroscopy, and direct pyrolysis/mass spectrometry measurements. The results showed that the phosphate group in TAEP first degraded to form poly(phosphoric acid) before the degradation of EB600. Then, the formed poly(phosphoric acid) effectively promoted the conversion of EB600 to form char, which prevented the sample from further burning. However, urethane group in EB270 degraded simultaneously with phosphate group in TAEP, leading to not effectively increase the conversion of EB270 to char during the thermal degradation. It was thus found that the addition of TAEP more effectively improved the thermal stability, flame retardance, and the char yield during combustion of EB600 than those of EB270. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3130–3137, 2006     

SiO2·Bi2O3对NiZn铁氧体的烧结和磁性能的影响

本文采用溶胶-凝胶法制备NiZn铁氧体-SiO2·Bi2O3复合材料。结果表明:烧结过程中Bi2O3与SiO2形成非晶态玻璃相促进烧结,使瓷体烧结温度降至1030℃,并且瓷体的磁导率随非磁性玻璃相的增加显著减少。磁导率的变化主要是由于非磁性相的引入导致磁路隔断、退磁场增加以及铁氧体晶粒减小所致。加入适量非磁性相有助于改善瓷体的高频特性。     

氧化石墨烯/石蜡复合相变乳液的制备及对流传热特性

为提高石蜡相变乳液的传热性能，通过添加氧化石墨烯(GO)，制备了GO/石蜡复合相变乳液并对其相关性能进行了表征。搭建了流动阻力、对流换热试验台，对比研究了石蜡相变乳液及GO/石蜡复合相变乳液的流动阻力特性和对流换热特性，试验结果表明，由于GO的亲水性，复合相变乳液都表现出较好的稳定性。当GO的质量分数为0.01％、0.02％、0.03％时，复合相变乳液的热导率分别增加了20.01％、30.50％、35.18％。添加GO使乳液的流动阻力略有增加，直管段最大增加了6.70%，90°弯管处最大增加了13.20%；对流传热系数随着GO浓度的增加而增大，当GO浓度为0.03％时，对流传热系数最大提高了43.90％。     

PET/MFMB复合材料的力学性能、热性能的研究

用力学性能测定、DSC和熔体流动速率（MFR）测定法研究聚对苯二甲酸乙二酯／多功能母料（PET／MFMB）复合材料的力学性能和热性能。结果表明，当MFMB的含量为22％时，PET／MFMB复合材料的冲击强度、断裂伸长率分别出现极大值；复合材料中PET、PP的熔点比纯PET、纯PP的稍有降低，当PET／MFMB＝78／22时降低的幅度稍大；复合材料的MFR在PET／MFMB＝78／22时出现转变点。     

Production of nanoparticles of copper compounds by anodic dissolution of copper in organic solvents

The anodic behaviour of copper was investigated in ethanol solution containing LiClO₄, LiCl electrolyte and water. The type of electrolyte and the water content influences the mechanism of the anodic process and the formation of anodic products. In LiClO₄ electrolyte the dissolution of copper is related to the oxidation of Cu(I) to Cu(II). In solutions of LiCl the etching of copper begins with the creation of soluble complexes of Cu(I) with chloride ions and solvent molecules. At potentials above 0.4 V the formation of alkoxides was observed in both solutions, characterized by a yellow tint. On the other hand, above 0.8 V (i.e. above the equilibrium potential of alcohol oxidation) copper dissolution is accompanied by the formation of a blue colloidal suspension of Cu (II) copper salt. Anodic etching of copper in solutions containing 3% H₂O at potentials higher than 0.4 V leads to the formation of colloidal suspension of copper oxide nanoparticles.     

导电高分子PEDOT／PSS保护银纳米颗粒的制备与表征

利用导电高分子聚（3，4-二氧乙基噻吩）／聚（对苯乙烯磺酸）（PEDOT／PSS）作保护剂，制备了银纳米颗粒，用UV-Vis和TEM对其进行了表征．结果表明，选择合适量的PEDOT／PSS保护剂可以得到大小分布较窄银纳米颗粒．