共查询到19条相似文献,搜索用时 187 毫秒
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通过悬浮聚合技术合成了以聚苯乙烯为壁材、以石蜡为芯材的储能微球,研究了壁膜的选择及包覆程度。结果表明:聚苯乙烯很适合作为石蜡储能微球的壁膜,合成的石蜡聚苯乙烯微球包覆完整。 相似文献
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采用无皂乳液聚合法制备了单分散亚微米级聚苯乙烯微球。考查了偶联剂的种类和用量对聚苯乙烯微球形貌、粒径、粒径分布及溶解性能的影响。结果表明:采用N,N-亚甲基双丙烯酰胺为偶联剂制备的聚苯乙烯微球为亚微米级,并且呈现单分散性;增加偶联剂的用量,聚苯乙烯微球的粒径先减小后增大,单分散指数变大。FT-IR谱图表明合成了聚苯乙烯微球。 相似文献
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用沉积表面反应法制备了以聚苯乙烯为核、Mn-Fe氧化物为壳的磁性核-壳微球. 考察了锰含量对核-壳球磁性的影响,分别采用烧结法和溶剂萃取法去除核-壳球内的聚苯乙烯以制取中空微球. 讨论了烧结温度与所形成的中空微球比表面积的关系,考察了溶剂萃取法去除聚苯乙烯的效果,比较了两者所形成的中空微球的性能. 结果表明,烧结法所得微球性能优于溶剂萃取法所得微球. 探讨了烧结法形成中空磁性球的最佳条件,在400℃下煅烧核-壳微球可以得到饱和磁化强度为68.66 emu/g、比表面积为27.8438 m2/g的含锰铁氧化物磁性中空微球. 相似文献
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聚苯乙烯单分散交联纳米微球的制备和表征 总被引:2,自引:0,他引:2
以苯乙烯为单体,二乙烯基苯为交联剂、过硫酸钾为引发剂,甲基丙烯酸为稳定剂,通过无皂乳液聚合反应,合成0粒径均匀分布的聚苯乙烯高分子微球.聚苯乙烯纳米微球由于其特定的尺寸和形貌,具有其他材料所不具备的特殊功能.采用无皂乳液聚合法制备了具有单分散性的亚微米级聚苯乙烯球,考察了聚合体系单体对微球粒径的影响.通过研究聚合物微球的自组装工艺,选出最佳条件并制备具有三维有序结构的光子材料.结果表明不同半径的聚苯乙烯微球在白光照射下会显现出不同颜色.可作为填料放到涂料中. 相似文献
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Synthesis of aluminum methylcyclohexylphosphinate and its use as flame retardant for epoxy resin 下载免费PDF全文
A novel aluminum phosphinate—aluminum methylcyclohexylphosphinate (Al(MHP))—was synthesized by reacting n‐butyl methylphosphonite with cyclohexene, followed by reacting with anhydrous AlCl3. The products were characterized with gas chromatography, Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance, phosphorus nuclear magnetic resonance, X‐ray fluorescent spectroscopy, and thermogravimetric (TG) analyses. After blending with epoxy resin (EP), flame retardancy was estimated with the use of limited oxygen index (LOI) and UL‐94 test, and thermal stability was investigated using TG analysis. The morphologies and composition of the char obtained after being heated at 300 °C for 20 min followed by 500 °C for 3 min in the muffle furnace were characterized by scanning electron microscopy (SEM) with energy‐dispersive X‐ray (EDX) analysis. Results showed that Al(MHP) is an efficient flame retardant for EP, and Al(MHP)/EP can pass UL‐94V‐0 rating with an LOI of 28.8% by adding 15 wt.% of Al(MHP). TG results showed that the presence of Al(MHP) in EP increases the char yield and depresses the thermal decomposition. SEM‐EDX analysis showed that the char obtained at 300 °C is coherent and consists of P‐rich components; at higher temperature (500 °C), the char becomes tiny and loose and phosphorus element is released into gas. Compared with neat EP, composites have lower water absorption. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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John P. Bullivant Shan Zhao Brad J. Willenberg Bettina Kozissnik Christopher D. Batich Jon Dobson 《International journal of molecular sciences》2013,14(9):17501-17510
Feraheme, is a recently FDA-cleared superparamagnetic iron oxide nanoparticle (SPION)-based MRI contrast agent that is also employed in the treatment of iron deficiency anemia. Feraheme nanoparticles have a hydrodynamic diameter of 30 nm and consist of iron oxide crystallites complexed with a low molecular weight, semi-synthetic carbohydrate. These features are attractive for other potential biomedical applications such as magnetic fluid hyperthermia (MFH), since the carboxylated polymer coating affords functionalization of the particle surface and the size allows for accumulation in highly vascularized tumors via the enhanced permeability and retention effect. This work presents morphological and magnetic characterization of Feraheme by transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDX), and superconducting quantum interference device (SQUID) magnetometry. Additionally, the results of an initial evaluation of the suitability of Feraheme for MFH applications are described, and the data indicate the particles possess promising properties for this application. 相似文献
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Fe3O4 magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl3·6H2O and FeCl2·4H2O with addition of ammonium hydroxide. The conditions for the preparation of Fe3O4 magnetic nanoparticles were optimized, and Fe3O4 magnetic nanoparticles obtained were characterized systematically by means of transmission electron microscope (TEM), dynamic laser scattering analyzer (DLS) and X-ray diffraction (XRD). The results revealed that the magnetic nanoparticles were cubic shaped and dispersive, with narrow size distribution and average diameter of 11.4nm. It was found that the homogeneous variation of pH value in the solution via the control on the dropping rate of aqueous ammonia played a critical role in size distribution. The magnetic response of the product in the magnetic field was also analyzed and evaluated carefully. A 32.6 mT magnetic field which is produced by four ferromagnets was found to be sufficient to excite the dipole moments of 0.05g Fe3O4 powder 2cm far away from the ferromagnets. In conclusion, the Fe3O4 magnetic nanoparticles with excellent properties were competent for the magnetic carriers of targeted-drug in future application. 相似文献
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通过甲基亚膦酸单丁酯与环己烯的自由基加成,然后与氢氧化钠以及硫酸镁和硫酸锌成盐制备得到一种可熔融的烷基次膦酸复盐阻燃剂-甲基环己基次膦酸锌镁[MgZn(MHP)]。采用红外光谱(FTIR)、核磁氢谱(~1H NMR)以及X射线荧光光谱(XRF)等技术表征了目标产物,并通过熔融共混法制备MgZn(MHP)-PBT阻燃复合材料。添加质量分数为20%的MgZn(MHP)可使PBT的极限氧指数(LOI)由17. 7%提高至28. 2%,垂直燃烧测试达到UL94 V-0级别。微形量热测试表明MgZn(MHP)对PBT的热释放速率(HRR)抑制作用明显。热分解动力学结果表明,20%MgZn(MHP)-PBT复合材料在初始阶段的活化能比纯PBT的要低,而平均活化能则高于纯PBT。 相似文献
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《分离科学与技术》2012,47(5):996-1020
Abstract The feasibility of a magnetic separator device for ex‐vivo blood detoxification was studied. This blood detoxification approach entails administering functionalized magnetic microspheres (FMMSs) into a patient's body by transdermal injection to capture and remove toxins from the blood using highly specific receptors attached to the surface of the FMMSs. These toxin‐loaded FMMSs are then removed from the body using extracorporeal blood circulation through a specially designed magnetic separator, based on high gradient magnetic separation principles. The performance of the magnetic separator, in terms of its collection efficiency (CE) of the FMMSs, was evaluated theoretically using a streamline analysis of a 2‐D model. The effects of blood velocity (1 to 20 cm/s), magnetic field strength (0.1 to 2.0 T), wire size (0.125 to 2.0 mm in radii), separator unit size at a fixed ratio of tube to wire diameter of one, tube length (2.0 to 20 cm), wire material (nickel, SS 430 and wairauite), and magnetic material comprising the FMMSs (iron, typical magnetite and weaker magnetite) on the CE were evaluated. Provided that the blood velocity was below 2 cm/s, CEs >80% could be attained under reasonable conditions, like when using FMMSs 400 nm in diameter and containing 60 wt% magnetite in a magnetic field of 0.5 T using a magnetic separator with 0.5 mm radii wire (at a fixed ratio of tube to wire diameter of close to one) that was 10 cm in length (same as the tube) and made of SS 430. CEs of between 30% and 80% could also be attained at blood velocities up to 20 cm/s without compromising the magnetic separator design. The magnetic separator performance improved by reducing the size of the unit with tubes and wires of equal radii, increasing the applied magnetic field strength, utilizing magnetic materials with the highest magnetizations, and increasing the length of the unit. Overall, the results from this study delineated the physically realistic conditions that make ex vivo blood detoxification possible with this magnetic separator device. 相似文献
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磁性导向柔红霉素白蛋白微球的研究 总被引:7,自引:0,他引:7
:采用乳化交联技术将磁性超微粒子及柔红霉素包埋于白蛋白内 ,化学交联固化后制得柔红霉素磁性白蛋白微球。该微球呈球形 ,平均粒径为 2 32 μm ,大小分布均匀 ,在 0 0 5T磁场中具强磁响应性 ,在水中分散性好。磁性微球载药量为 11 2 6 % (mg/mg) ,包封率为 75 0 % ;临界相对湿度CRH =81 6 %。含药微球在体外 12h释放完全 ,具一定的缓释作用。体内外磁定位实验表明 ,DNR磁性白蛋白微球制剂可浓集于靶区。稳定性考察表明所制微球稳定性良好。 相似文献
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Fe3O4 magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl3-6H2O and FeCl2-4H2O with addition of ammonium hydroxide. The conditions for the preparation of Fe3O4 magnetic nanoparticles were optimized, and Fe3O4 magnetic nanoparticles obtained were characterized systematically by means of transmission electron microscope (TEM), dynamic laser scattering analyzer (DLS) and X-ray diffraction (XRD). The results revealed that the magnetic nanoparticles were cubic shaped and dispersive, with narrow size distribution and average diameter of 11.4 nm. It was found that the homogeneous variation of pH value in the solution via the control on the dropping rate of aqueous ammonia played a critical role in size distribution. The magnetic response of the product in the magnetic field was also analyzed and evaluated carefully. A 32.6 mT magnetic field which is produced by four ferromagnets was found to be sufficient to excite the dipole moments of 0.05 g Fe3O4 powder 2 cm far away from the ferromagnets. In conclusion, the Fe3O4 magnetic nanoparticles with excellent properties were competent for the magnetic carders of targeted-drug in future application. 相似文献
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为了实现对钢铁行业微细颗粒的超低排放,提出磁性纤维提高对 Fe基细颗粒物的捕集。 基于计算流体力学?离散相模型CFD-DPM对比研究了传统纤维、磁性纤维直径对Fe基细颗粒捕集效率以及过滤阻力的影响。结果表明:当风速为0.10 m/s时,对于直径为35~45 μm范围的纤维,直径的增大能够明显增加过滤阻力。对于粒径小于2.5 μm的颗粒,磁性纤维直径的增加对捕集效率提高的影响相对较小,当颗粒粒径大于2.5 μm时,增大纤维直径能够显著提高捕集效率。风速处于0.01~0.05 m/s范围时,增大纤维直径对提高磁性纤维捕集效率作用明显;当风速为0.08~0.10 m/s时,纤维直径变化对捕集效率的影响较小。磁性纤维质量因子随纤维直径增大而下降。 相似文献