热疗用葡聚糖磁流体的升温特性研究

用不同浓度的葡聚糖40000和20000水溶液制备纳米铁氧体磁流体,检测磁流体在交变磁场中的升温情况,计算升温速率和特异性吸收值(SAR值)。结果显示,磁流体在磁场中的升温速率与铁氧体的浓度和磁场强度成正线性相关。磁场强度一定时,磁流体的SAR值与铁氧体浓度成负线性相关;铁氧体浓度一定时,磁流体的SAR值与磁场强度成正线性相关。磁流体的升温速率和SAR值与葡聚糖相对分子质量和浓度无关。瘤内及瘤周注射24.16 mg/0.2 mL磁流体在55 kHz,20kA/m磁场中作用10 min,移值瘤中心的平均升温速率为1.5°C/min,温度可以达到并维持在46°C左右,而注射相同体积生理盐水的移植瘤,温度几乎没有变化。     

Fe3O4水基磁流体的制备及其分散性能研究

采用共沉淀法制备了纯Fe3O4纳米粒子,分别用高氯酸、四甲基羟胺和油酸/十二烷基苯磺酸钠为表面活性剂对其进行表面处理后分散在水中,得到了3种水基磁流体,对这3种磁流体的浓度及稳定性进行了测定。实验结果显示:酸性、碱性和中性水基磁流体中Fe3O4的浓度分别为4.8%、5.8%和8.1%,其中中性水基磁流体中粒子的分散性能最佳;经过离心后,3种水基磁流体中的粒子均产生了沉降,且酸性和碱性磁流体中的粒子比中性磁流体中的粒子沉降的多。在此基础上,对影响粒子分散稳定性的机理进行了初步探讨。     

聚乙烯醇分散水基磁流体的研制

将Fe^2＋和Fe^3＋均匀地分散在聚乙烯醇高分子溶液中，用化学共沉淀法进行原位反应，制得聚乙烯醇分散水基磁流体。用Gouy磁天平、透射电镜、X射衍射仪和纳米粒度与电位分析仪对磁流体和铁氧体进行测试与分析。研究发现，磁流体中的磁性粒子粒径为10nm以下，磁流体具有超顺磁性，聚乙烯醇（PVA）高分子线团包裹着Fe3O4磁性粒子，形成十分稳定的分散体系。     

水基NiFe_2O_4磁流体在无磁场时的沉降稳定性

为研究水基NiFe_2O_4磁流体在不施加磁场时沉降稳定性的影响因素,先采用两步法制备该磁流体样品。其中,纳米粒子为纳米NiFe_2O_4粉体,载液为RO反渗透膜处理水,分散剂包括十二烷基苯磺酸钠、十二烷基硫酸钠、油酸钠、聚乙二醇、十六烷基三甲基溴化铵、油酸和硬脂酸等。在重力场下,研究分散剂种类、质量分数和纳米粒子质量分数对磁流体沉降稳定性的影响,并测量部分磁流体样品的零场黏度,以得到使该磁流体稳定性和流动性较好的制备方法。然后参考以上方法,制备以CoFe_2O_4和Fe_3O_4为纳米粒子的磁流体。并通过与NiFe_2O_4磁流体进行对比,研究水基NiFe_2O_4磁流体在重力场下的热稳定性。实验表明,当分散剂分别为油酸、十二烷基苯磺酸钠和十二烷基硫酸钠,其质量分数分别为4.0%~4.6%、3.4%~3.7%和1.5%~1.7%,且NiFe_2O_4纳米粒子质量分数为1.9%时,这种磁流体的沉降稳定性和流动性能达到较好效果,并且水基NiFe_2O_4磁流体相比其他磁流体具有良好的热稳定性。     

稀土Dy~(3+)改性铁氧体磁流体磁性粒子的制备及性能测试

研究稀土铁氧体表面改性,采用化学共沉淀法制备了稀土铁氧体磁流体,并用古埃磁天平、透射电子显微镜、X射线衍射仪等对其进行了性能测试。同时探讨了稀土铁氧体磁性粒子的形成机理及表面活性剂对磁流体基本性质的影响;然后,系统地研究了当温度80℃,时间180 m in,表面活性剂用量比0.25,碱过量比0.6时稀土材料Dy3+的加入对铁氧体磁流体性能的影响,并对其进行了理论分析和探讨。     

新型磁性材料--Co-B磁流体的制备

用硼氢化纳还原氯化钴无水乙醇溶液制备得到纳米钴硼合金粒子,选用烃类化合物Na（AOT）2为表面活性剂,甲基硅油为载液制备得到饱和磁化强度为 80 mT,具有强抗氧化性的磁流体.透射电镜（TEM）表征合金粒子的晶型及大小,古埃磁天平法表征磁流体的磁性和稳定性,并分析了实验条件对制备的影响.     

Pickering乳液的制备及稳定性研究

Pickering乳液是一种由固体粒子取代有机表面活性剂稳定乳液体系的新式乳液。采用St?be法,以无水乙醇作共溶剂,用氨作催化剂,分解正硅酸乙酯(TEOS)制备纳米固体SiO_2粒子,然后用纳米固体SiO_2粒子作稳定剂,制备三氯甲烷/水的Pickering乳液。考察了纳米固体SiO_2粒子加入量、油水体积比、氢氧化钠溶液浓度对Pickering乳液稳定性的影响。结果表明:当纳米固体SiO_2粒子加入量为0.035g、油水体积比为1:350、氢氧化钠溶液浓度为0.01mol·L~(-1)时,制备的乳液稳定性最好。     

三表面活性剂磁流体的制备及性能研究

用化学沉淀法制备Fe3O4纳米粒子，以十二烷基磺酸钠，蓖麻油，油酸钠为分散剂，制备水基Fe3O4磁流体，研究了搅拌时间对磁流体的磁性能的影响，表面活性剂用量对磁流体的沉降稳定性的影响，并对其原因进行分析。     

葡聚糖-Fe3O4磁性纳米粒子在小鼠体内的分布

采用水热法制备葡聚糖-Fe3O4磁性纳米粒子,并建立原子吸收法测定葡聚糖-Fe3O4磁性纳米粒子生物样品定量分析方法,研究其体内分布。小鼠的心、肝、脾、肺、肾中低、中、高3种浓度加样回收率为98.80%~100.41%,日内精密度RSD均小于3%,日间精密度RSD均小于5%,经尾静脉给药后葡聚糖-Fe3O4主要被肝脏摄取。     

壳聚糖包裹磁流体的制备及其物性表征

采用共沉淀法制备纳米Fe3O4磁粒子,经离心分离后利用超声分散将纳米磁粒子弥散于壳聚糖溶液中形成了具有高度生物兼容性的壳聚糖包裹磁流体。利用XRD、TEM、红外光谱和磁天平对产物进行物性表征。探讨了壳聚糖质量、反应温度、超声分散时间和pH值对产物磁性的影响,结果表明:在反应温度为45℃,超声时间为55 min,pH值大于9,壳聚糖质量为0.15 g的条件下,制备的磁粒子约为15 nm左右,磁化饱和强度38.4 mT,抗氧化性高的壳聚糖包裹磁流体。该磁流体可作为X射线造影剂、靶向药物载体。     

Core‐shell structured ferrite‐silsesquioxane‐epoxy nanocomposites: Composite homogeneity and mechanical and magnetic properties

Epoxy‐based composites of ferrite nanoparticles (50 nm) with 3‐glycidoxypropyl‐ (GPTMS), aminopropyl‐ (APTMS), or methyl‐silsesquioxane (MTMS) coatings are reported. The GPTMS coatings (30‐nm thick) allowed uniform particle dispersion in the epoxy and prevented sedimentation of the nanoparticles, whereas the APTMS‐coated particles formed agglomerates, leading to particle sedimentation. The particles with the thinnest coating (MTMS – 3 nm) agglomerated in the composites without sedimentation. The composites based on GPTMS‐coated particles showed higher fracture toughness than the composites based on MTMS‐coated particles. The uniformity and thickness of the coatings were related to alcohol composition of the coating media. Coating removal by a novel ultrasonic etching allowed precise determination of the effective ferrite content in the coated nanoparticles. A markedly lower coercivity for nanoparticles without coatings as compared with the nanoparticles with thicker coatings was observed. The saturation magnetization and the coercivity of the composites were independent of coating and casting procedures. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

水热法合成锰锌铁氧体纳米球包覆的碳纳米管磁性材料的研究

用水热法分别在160℃和220℃下反应5 h制备了锰锌铁氧体纳米球包覆的碳纳米管复合材料。用X射线衍射分析样品的物相,用高分辨透射电镜和电子衍射分析样品的形貌和结构,用振动样品磁强计表征磁性能。结果表明：锰锌铁氧体为球形,粒径约为13 nm。磁滞回线结果表明：复合材料粒子的饱和磁化强度为10.92 em u/g,剩磁为4.25 em u/g,矫顽力为381.43O e。     

Synthesis of dextran‐metaxalone conjugates and study on their control drug release behaviors

Metaxalone (Met), a drug for treatment of pain and stiffness due to muscle injuries, was covalently linked to dextran via a chloroacetyl chloride spacer. The average molecular weights of dextran are 20,000 (D₂₀₀₀₀) and 40,000 (D₄₀₀₀₀), respectively, and the procedure of chemical modification for dextrans was conducted by a two‐step protocol: (1) synthesis of N‐chloroacetyl‐metaxalone; (2) synthesis of D₂₀₀₀₀‐Met and D₄₀₀₀₀‐Met. The controlled drug release studies were performed in buffer solutions with pH values of 1.1, 7.4, and 10.0. The results demonstrate that, under the same condition, the rate of release for D₂₀₀₀₀‐Met is slower than that of D₄₀₀₀₀‐Met, and more amount of Met can be detected releasing from polymer‐drug conjugate at the presence of α‐chymotrypsin in a buffer solution with pH = 8.0. It was also found that these novel polymer‐drug conjugates can effectively improve the Met's pharmacokinetics, and can increase its half‐life period. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and electrorheological properties of polyaniline‐coated barium titanate composite particles

Polyaniline‐coated barium titanate composite particles were synthesized by surface grafting polymerization, in which five silane coupling agents with different terminal groups were used. The structure of composite particles was characterized by SEM, XRD, FTIR, and TGA, and the electrorheological properties were tested by rotational rheometer. The results show that polyaniline was coated on the surface of barium titanate particles to form the shell‐core structure. The yield stress of the electrorheological fluids based on polyaniline‐coated barium titanate composite particles is higher than that of polyaniline and barium titanate. Compared with PANI‐based electrorheological fluids (ERFs), the composite particles‐based ERFs have lower field‐off viscosity due to the molecular interaction. The yield stress of the ERFs, as well as density of the composite particles, was affected by the groups at terminal of silane coupling agents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of magnetic poly(glycidyl methacrylate) microspheres by emulsion polymerization in the presence of sterically stabilized iron oxide nanoparticles

With the aim to synthesize water‐dispersible superparamagnetic nanoparticles, iron oxide was precipitated in aqueous solution of dextran, (carboxymethyl) dextran (CM‐dextran), (DEAE‐dextran), or D ‐mannose. Glycidyl methacrylate (GMA) was emulsion‐polymerized in the presence of the nanoparticles and the effect of iron oxide modification on the product properties was investigated. The main factors affecting the morphology, size, and size distribution of the latex particles are the type and concentration of emulsifier (Disponil AES 60, Tween 20, Triton X‐100) and initiator [ammonium persulfate (APS) and 4,4′‐azobis(4‐cyanovaleric acid) (ACVA)]. Disponil AES 60 and ACVA are the preferred emulsifier and initiator, respectively, because oxirane groups hydrolyzed during the APS‐initiated polymerization. Up to some 5 wt % of iron was found in poly(glycidyl methacrylate) (PGMA) microspheres obtained by emulsion polymerization in the presence of dextran‐coated iron oxide and emulsified with Disponil AES 60. The size of magnetic PGMA microspheres could be controlled in the range ? 70–400 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4348–4357, 2006     

Sedimentation-resistant electrorheological fluids based on PVAL-coated microballoons

Sedimentation is often a problem in electrorheological (ER) fluids featuring solid particles suspended in a low-density hydrocarbon oil. This problem was addressed by synthesizing particles comprising silica microballoons coated with PVAL using a salt-induced coacervation process. The ER performance of the fluids based on these particles was equivalent to prototypical commercial fluids, both with respect to current leakage and shear stress under steady simple shear flow. For comparing diverse fluids as to these practical characteristics, a dimensionless ER effectiveness number, Er, was proposed: Er = σγ˙/EJ where σ is the shear stress, γ˙ is the electric field, and J is the current. The resulting uniform coatings were also found to impart a degree of resistance to breakage. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:539–547, 1997     

水性聚氨酯包覆RDX的影响因素研究

以环氧有机硅复合改性的水性聚氨酯(WPU)作为黑索今(RDX)包覆剂,研究了包覆温度、WPU用量、RDX粒度及表面活性剂种类和用量对包覆后RDX机械感度、热感度和流散性的影响,并通过撞击感度测试、5s延滞期爆发点测试和金相显微镜晶型观测分析确定了较佳的包覆工艺条件。结果表明,包覆温度40℃、WPU质量分数2.0%、RDX粒度200～300目和阳离子表面活性剂质量分数0.5%～1.0%时,包覆后的RDX颗粒形状圆滑,感度较低,颗粒间包覆剂残留较少,流散性良好。     

Preparation and radar wave absorbing characterization of bicomponent fibers with infrared camouflage

Sheath‐core bicomponent fibers were prepared by a general melt‐spinning method with polypropylene chips and various particles. The melt‐spun fibers were characterized by DSC and mass specific electrical resistance (MSER) apparatus. The electromagnetic constant was measured using a network analyzer and the absorbing wave effect was evaluated by an arch method. The results of the DSC thermogram indicated that the crystallinity of polypropylene containing particles in the core‐part slightly increased first and then kept steadily with the particles content increase. Nanoparticles in the sheath‐part did not make the crystallinity of fibers change markedly. The MSER of fibers rapidly decreased with the metal particles input. The complex permeability of fibers with Ba/Mn‐Zn ferrite was improved compared with that of fiber with single Mn‐Zn ferrite and the complex permittivity of fiber containing the 20 wt % Ba/Mn‐Zn ferrite increased with the increasing bronze content. The fibers filled with the Ba/Mn‐Zn ferrite and bronze particles had good radar absorbing effect. The input of Al particles in the sheath‐part of the fibers showed a limited effect on the radar wave absorbing properties of the fibers. The lowest infrared emissivity of the fibers including 15 wt % Al particles in sheath‐part reached 0.62. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2180–2186, 2007