【作者】 雷军；

【导师】 戴红莲；

【作者基本信息】 武汉理工大学 ， 材料学， 2009， 硕士

【摘要】 本论文针对现有磁性微球存在的磁性物质含量低、粒度不均一、表面缺乏活性功能基团、生物相容性差等缺点,选择钡铁氧体粒子和聚氨酯（PU）为研究对象,制备出了一种结合了BaFe₁₂O₁₉的X光显影性和PU高分子的高弹性、优良的生物相容性等优点的BaFe₁₂O₁₉/PU磁性复合微球,并对合成微球进行了表面改性,获得了表面氨基化、高磁性物质含量、粒度均一的磁性复合微球。研究了微米、纳米BaFe₁₂O₁₉磁性粒子的合成及表面改性,优化了复合微球的制备工艺,对微球的理化性能进行了表征,对改性微球吸附性能进行了初步探讨。确定了复合微球中磁性组分的制备工艺:采用自燃烧法合成BaFe₁₂O₁₉微粒,粒子为片状结构,平均粒径约1μm;以适量乙二醇和聚乙烯醇混合溶液为新助剂,采用柠檬酸盐溶胶凝胶法,利用快速升温和预烧热处理工艺,合成了球形BaFe₁₂O₁₉纳米粒子,粒子粒径为30-50 nm。微米、纳米BaFe₁₂O₁₉粒子均有较大的饱和磁化强度。讨论了磁性粒子种类、搅拌速度等对微球包覆率、磁性能、形貌等的影响。本研究结合扫描电子显微镜（SEM）观察了微球的表面和内部形貌,红外光谱仪（IR）表征了微球的化学结构,热重分析仪分析了微球磁性无机物的含量即包覆率,振动样品磁强计（VSM）分析了微球的磁性能,紫外吸收光谱分析了微球的吸附量。结果表明:纳米BaFe₁₂O₁₉/PU磁性复合微球的包覆率20.06%要高于微米BaFe₁₂O₁₉/PU磁性复合微球的包覆率14.02%,粒子越小,磁性越强,包覆率越大;磁性复合微球在一定的粒径范围内,磁性物质的包覆量随着粒径的增大而增大,采用中速搅拌合成微球磁性物质含较高、粒度均一、球形度好;Nano-BaFe₁₂O₁₉/PU复合微球的饱和磁化强度（7.50emu/g）高于Micro-BaFe₁₂O₁₉/PU复合微球的饱和磁化强度（6.33 emu/g）;微球经表面改性后成功接枝上了活性功能基团-NH₂,吸附实验研究表明,每1g微球吸附95 mg的卵磷脂,微球单位质量的吸附量较大,吸附率ω=72.24%,达到了良好的吸附效果。更多还原

【Abstract】 At present,magnetic microspheres have many defects,such as low content of magnetic substance,broad distribution of particles size,lack of active functional groups on surface,bad biocompatibility and so on.In this study,Ba-ferrite particles and PU were chosen to prepare BaFe₁₂O₁₉/PU magnetic composite microspheres combining with X-ray radioparency and high magnetic response of BaFe₁₂O₁₉ and excellent elasitisity,good biocompability of PU polymer.After surface modification, the microspheres obtained aminated surface,high magnetic contents and narrow size-distribution.The paper focused on preparation and surface modification of micro- and nano- BaFe₁₂O₁₉ particles,the optimal technological conditions for preparation,physic-chemical properties and adsorptive Capacities of the composite microspheres.An appropriate preparation technology for magnetic composite microspheres was established.BaFe₁₂O₁₉ powder with flake structure and 1μm of average size was prepared by self-combustion method.Spherical nano-BaFe₁₂O₁₉ particles were synthesized by using citrate sol-gel method combined with rapid warming and pre-heat treatment process,glycol and PVA were utilized as auxiliaries.The average size of nano-BaFe₁₂O₁₉ particles was 30-50 nm.Both of micro-BaFe₁₂O₁₉ and nano-BaFe₁₂O₁₉ had high saturation magnetization.In this paper,the influence of magnetic particles’ size and stirring rate on the coating rate,magnetic properties and structure of microspheres were studied.The sutructure of microsphere was observed by SEM.The chemical constitution of microsphere was tested by FT-IR.The content of magnetic inorganic and magnetic properties of microspheres were analyzed by TG and VSM respectively.The adsorption quantity of microspheres was investigated by UV absorption spectra.The results showed that the coating rate of nano-BaFe₁₂O₁₉/PU magnetic composite microspheres was more than that of micro-BaFe₁₂O₁₉/PU ones.The magnetic properties and coating rate of microspheres increased with its particle size decreasing.When the size of magnetic particles kept in some range,coating rate of microspheres increased with its average size increasing.Magnetic microspheres had high purity,narrow particle size distribution and perfect sphere when medium stirring rate was adopted.Compared with micro-BaFe₁₂O₁₉/PU,nano-BaFe₁₂O₁₉/PU microspheres had high saturation magnetization.After surface modification,-NH₂ was grafted on the surface of microspheres.From adsoption experimet,we found that per gram microsphere could adsorb 95 mg lecithin,and the adsoption rate was 72.24%.更多还原