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功能型复合超微粒子的制备研究

Study on the Preparation of Functional Composite Superfine Particles

【作者】 罗付生

【导师】 李凤生; 宋洪昌;

【作者基本信息】 南京理工大学 , 材料学, 2002, 博士

【摘要】 通过使用过硫酸铵和偶氮二异丁脒盐酸盐作引发剂,利用乳液聚合法制备了粒径约为100nm,表面分别为负电性和正电性的PS(聚苯乙烯)乳胶粒。然后根据异相凝集-包埋法原理对具有不同表面电性的微米级的CaCO3和TiO2进行包埋复合,制得以无机粒子为核,有机粒子为壳层的包覆型有机—无机复合粒子。并分别讨论了溶液pH值条件和非离子表面活性剂对复合过程的影响。 根据机械力化学的原理,采用自行制备的微米级PS和PMMA(聚甲基丙稀酸甲酯)高聚物微球、金属粒子、纳米级的TiO2、炉料为原料粒子,通过采用自行研制的干式冲击设备和LG搅拌磨制得以高聚物微球、金属粒子为核,纳米TiO2、碳黑粒子等为包覆粒子的具有不同特殊功能的纳米/微米复合粒子。使用扫描电镜和光电子能谱对制得的复合微粒子进行表征,发现该方法可以使纳米TiO2粒子呈很好的分散状态复合在聚合物微球及金属粒子上,而且随着聚合物微球原料的不同,纳米TiO2粒子能在高聚物的表面的复合状态也不同。对复合炉料的研究表明,在炉料的表面发生了相应的机械化学反应,得到了宝贵的低增碳量、高熔点的特性,这对炉料品质的提高起到重要作用。对用LG搅拌磨和干式冲击法制备的复合粒子进行了比较,结果表明,用干式冲击法制得的复合粒子,子粒子分散性好,且分布均匀、所需处理时间短、复合效果较佳。本研究还讨论了干式冲击法中,母粒子的粒径均匀性对复合效果的影响。用扫描电镜、透射电镜、激光粒径测量仪、比表面仪、Zeta电势仪等对制得的复合粒子进行了表征。研究表明,采用异相凝集法和干式冲击法能够很好地制备有机—无机复合粒子。 利用分散聚合法制得了粒径约为3μm的聚苯乙烯种子微球,再通过溶胀、交联、种子乳液聚合及萃取处理,最后得到中空多孔的聚合微球,并讨论了其成孔机理和各博士论文功能型复合超微粒子的制备研究因素的影响。同时采用酸碱分步处理法制得纳米级P(st一MMA)多孔微球,分别使用电镜及比表面测量仪检测了其中空多孔形貌和表面孔径。通过实验证明制得的该两种多孔微球有很好的缓释效果。使用W/o反相微乳法和聚电解质的离子凝胶反应分别制得纳米级和亚微米级的壳聚糖微球,对制备的壳聚糖微球进行了型貌,粒径及比表面、孔径的表征。并以牛血清白蛋白(BSA)为模型药物进行了载药实验并进行了附载效率和体外释药速度测试,结果表明通过离子凝胶反应制备的壳聚糖微球有很好的缓释效果,可用于药物载体。并将通过水解法自行制得的纳米磁性铁粒子包埋在壳聚糖微球内,得到具有磁响应的壳聚糖微球药物载体,该载药微球有希用于人们迫切期望的靶向给药系统。

【Abstract】 With 2,2’ -azobis-2(amidineopropane) dihydrochloride (V5o) and ammonium persulphate (APS) being used as initiator, the cationic and anionic nanoparticles polystyrene (PS) latex were synthesized via emulsion polymerization respectively. Then by means of heterocoagulation and encapsulatin, on controlled condition the superfine powders of CaCO3 and TiO2 were coated with different nonaparticles Ps. The composite particles with core/shell structure were prepared by heating the composite particles above the glass transition temperature of PS. As predicted theoretically, the PS polymer spreaded over the surface of the titania particles to form composite particles with core-shell structure. The influence of pH value and non-ion surfactant in heterocoagulation was discussed. The property of the coated particles was characterized by SEM, and Zeta potential, particle size distribution of the particles before and after encapsulation was obtained by laser particle size analyzer.The mechanical modifying equipment was used to prepare compounded micro-spheres from PMMA particles and PS particles with metal particles and TiO2 nano-particles. The SEM was used to observe the images of particles and X-ray photoelectron spectroscopy (XPS) is used to obtain surface spectrum. Herein the TiO2 nano-particles can be dispersed on larger polymer particles and their surface morphology is different by using different polymer particles. Compare with the LG string method , encapsulated particles treated by dry impact method were well dispersed, processing time was shorter. The effect of size distribution of core particle was also discussed in dry impact method. SEM. particle size andZeta potential were used to characterize the properties of the composite particles.The polystyrene particles with 2.8 micrometer mean diameter were prepared by dispersion polymerization and hollow porous micro-sphere were prepared by extraction after seeding emulsion polymerization. Particles with multi-hollow structure were obtained and characterized by SEM, additionally the mechanism and factor about formation of porous structure were also discussed.To prepare the biodegradable nano-particles, reversed-phase micro-emulsion and ionotropic gelation methods were used. Two kinds of chitosan nano-particles were obtained and characterized by SEM, TEM. The nano-particles’ size distribution and specifical surface were determined. BSA is used as a model macromolecule drug and the in-vitro release rate of BSA from chitosan nano-particles are sustained. The experiment results show that chitosan nano-particles prepared could be used as carrier for the delivery of drugs. In the presence of magnetite nano-particles prepared in our experiment, chitosan particles warpped the magnetite nano-particles. The magnetic biodegradable drug carrier can be obtained by this method.

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