RAFT聚合诱导自组装制备形貌可控的纳米颗粒

发布时间：2018-04-24 01:15

本文选题：RAFT异相聚合 + 星型高分子　；参考：《上海大学》2015年硕士论文

【摘要】：球形、纤维等多种聚合物纳米颗粒由于具有小尺寸、可多功能化及形貌可调等优点,在生物医药、催化剂、食品、分析检测及化学工业等诸多领域具有潜在的应用。两亲性嵌段共聚物在溶液中可以通过选择性溶剂、改变亲水和疏水段的链长、分子量、p H、盐浓度、单体种类和性质等来制备球状、棒状、层状、囊泡等形貌,这些纳米颗粒可应用于药物释放、催化等领域。在本文中,为了得到尺寸均匀、结构稳定、分子量和形貌可控的纳米颗粒,我们通过可逆加成断裂链转移(RAFT)异相聚合诱导自组装合成了多种双亲性高分子,并系统地研究了其动力学过程和影响形貌的各个因素,通过进一步功能化进行修饰得到了各种功能化的纳米颗粒。具体的研究内容和结果如下:1.星型高分子是一种具有多于三条链且有明确中心分枝点的聚合物,由于其结构规整、粘度低、比表面积大被广泛地用作药物输送、表面活性剂、反应器和催化剂等。本文选择聚N,N-二甲基丙烯酰胺(PDMA)作为高分子臂,合成了亲水的星型高分子,然后将合成的窄分布星型高分子作为大分子链转移剂(Macro-CTA)和纳米粒子的表面稳定剂,利用RAFT乳液聚合来进一步聚合苯乙烯。具体研究了星型高分子作为Macro-CTA和纳米粒子的表面稳定剂对乳液聚合动力学的影响。为了突出星型高分子作为Macro-CTA对反应的影响,我们选择了线型PDMA与苯乙烯进行乳液聚合与之进行对比;研究了固体含量和苯乙烯与Macro-CTA的质量比对所形成纳米颗粒形貌的影响。实验结果表明星型高分子调控苯乙烯的乳液聚合无诱导期,转化速率比传统线型高分子快,且通过增加固体含量发生了由球形到棒状的形貌转换。2.通过聚合诱导自组装能够在高固体含量条件下一步制备不同形貌的高分子颗粒,但通过该方法制得多功能化高分子颗粒的文献并不多。乙酰乙酸甲基丙烯酸乙二醇酯(AEMA)是一种含有β-酮酯官能团的单体,β-酮酯的存在,使该单体或其聚合物能够在一定条件下与羟胺或双羟胺发生反应,生成肟。另外,β-酮酯能与金属离子譬如银离子络合,然后在还原剂的还原下生成金属颗粒。通过实验得出AEMA单体在乙醇中是溶解的,而其高分子在乙醇中是不溶的,符合分散聚合体系的要求。因此本文选择了功能化单体AEMA作为憎溶剂链段和生物兼容性好的聚[聚(乙二醇)甲基醚甲基丙烯酸酯](PPEGMA)作为亲溶剂链段,通过RAFT分散聚合合成双亲性的高分子颗粒。在该课题中我们具体研究了AEMA在乙醇中分散聚合的动力学过程,并讨论了固体含量和PAEMA嵌段的聚合度对其形貌的影响。我们还通过设计实验研究了单体AEMA在RAFT分散聚合体系中合成的高分子RAFT不可控原因。然后我们将合成的高分子颗粒直接进行了一系列的功能化,合成了大小均一、结构稳定的功能化高分子颗粒。最后我们将AEMA作为功能单体与甲基丙烯酸苄酯(Bz MA)共聚,研究了该聚合的动力学和功能化等。实验结果表明,可以通过改变AEMA与PPEGMA的摩尔比和固体含量来控制高分子颗粒的粒径和形貌,而且直接将高分子颗粒进行下一步的功能化反应,转化效率高、稳定性好,有很大的应用潜能。3.水是一种经济、对环境友好的溶剂,但水分散聚合的研究并不多,主要是因为适合水分散聚合的单体种类比较少,因此发展出新的适合水分散聚合的体系对分散聚合的发展非常重要。在本课题中我们选择了一种带有酮的功能单体双丙酮丙烯酰胺(DAAM)进行水分散聚合,着重研究了聚合过程中的动力学,发现DAAM在聚合过程中转化效率高且完全。在研究高分子颗粒的形貌过程中,我们发现改变PDAAM嵌段长度和固体含量时,所形成的嵌段高分子纳米颗粒的形貌可以由球形转变为囊泡。当固体含量高于10%时,我们得到的囊泡粒径分散的很不均匀。为了制备大小均匀、稳定的囊泡,我们降低了引发剂与PDMA的比例,通过测试动态光散射(DLS)和透射电子显微镜(TEM)我们发现在相同的PDAAM嵌段长度和固体含量下,引发剂与PDMA的比例越低,得到的囊泡分散的越均匀。
[Abstract]:Spherical, fiber and other polymer nanoparticles have potential applications in many fields, such as biomedicine, catalyst, food, analysis detection and chemical industry, because of their small size, multifunction and adjustable morphologies. Two amphiphilic block copolymers can change the chain length of hydrophilic and hydrophobic segments in the solution by selective solvents. The molecular weight, P H, salt concentration, monomer type and properties are used to prepare spherical, rod, layered, vesicles, etc. these nanoparticles can be applied to drug release, catalysis and other fields. In this paper, in order to obtain nanoparticles with uniform size, stable structure, molecular weight and morphologies, we can reversibly add fracture chain transfer (RAFT) to the heterogeneous polymerization. A variety of amphiphilic polymers are synthesized by induction self-assembly, and the dynamic processes and various factors affecting the morphology are systematically studied. The functionalized nanoparticles are obtained by further functionalization. The specific content and results are as follows: the 1. star type high score is a kind of more than three chains and is clearly in the form. The polymer of the branching point is widely used as drug delivery, surfactant, reactor and catalyst, because of its regular structure, low viscosity and large surface area. In this paper, poly N, N- two methyl acrylamide (PDMA) was selected as the polymer arm to synthesize the hydrophilic star type high molecule, and then the synthetic narrow distribution star type polymer was used as the big fraction. The subchain transfer agent (Macro-CTA) and the surface stabilizer of nanoparticles are used to polymerize the styrene by RAFT emulsion polymerization. The effect of the star type polymer as the surface stabilizer of Macro-CTA and nanoparticles on the kinetics of emulsion polymerization is studied. In order to highlight the effect of the star type polymer on the reaction of the Macro-CTA, we choose to The influence of the solid content and the mass ratio of styrene to Macro-CTA on the morphology of the nanoparticles was studied. The experimental results showed that the star type polymer had no induction period for the emulsion polymerization of styrene, and the conversion rate was faster than that of the line type polymer, and the solid content was increased by the PDMA. The morphologies from spherical to rod like.2. can be prepared with different morphologies at a high solid content by polymerization induced self-assembly. However, there are few literature on the preparation of Polyfunctionalized polymer particles by this method. Acetoacetic acid methyl acrylate (AEMA) is a kind of functional group containing beta ketone ester (two). The presence of a monomer, beta ketone makes the monomer or its polymer react with hydroxylamine or hydroxylamine to produce oxime under certain conditions. In addition, the beta ketone can be complex with metal ions, such as silver ions, and then produce metal particles in the reduction of the reducing agent. Through experiments, the AEMA monomer is dissolved in ethanol and its polymer is in Ethanol is insoluble and conforms to the requirements of the dispersion polymerization system. Therefore, the functional monomer AEMA is selected as a hydrophobic chain segment and biocompatible poly (ethylene glycol) methyl ether methacrylate] (PPEGMA) as a pro solvent chain, and the amphiphilic polymer particles are synthesized by RAFT dispersion polymerization. The kinetic process of AEMA dispersion polymerization in ethanol was studied. The influence of the solid content and the degree of polymerization of the PAEMA block on its morphology was discussed. We also studied the uncontrollable cause of the polymer RAFT synthesized in the RAFT dispersion polymerization system by the design experiment. Then we made the synthesized polymer particles directly. A series of functionalization has been made to synthesize functional polymer particles with uniform size and stable structure. Finally, we have studied the kinetics and functionalization of AEMA as a functional monomer and benzyl methacrylate (Bz MA). The experimental results show that high fraction can be controlled by changing the molar ratio of AEMA to PPEGMA and the solid content. The particle size and morphology of the particles, and directly to the polymer particles in the next step of the functional reaction, high efficiency, good stability, and has great potential application potential.3. water is a kind of economic, environmentally friendly solvent, but water dispersion polymerization research is not much, mainly because the types of monomers suitable for water dispersion polymerization are relatively few, therefore hair The development of a new system suitable for water dispersion polymerization is very important for the development of dispersion polymerization. In this subject, we chose a functional monomer, double acetone acrylamide (DAAM) with ketone, for water dispersion polymerization, focusing on the kinetics in the polymerization process. It was found that DAAM was highly efficient and complete in the polymerization process. During the morphology of the subparticles, we found that when the length of PDAAM block and the solid content were changed, the morphology of the embedded polymer nanoparticles could be transformed from spherical to vesicles. When the solid content was higher than 10%, the size of the vesicles was very uneven. In order to prepare the uniform and stable vesicles, we reduced the lead. The ratio of hair agent to PDMA, by testing dynamic light scattering (DLS) and transmission electron microscopy (TEM), we found that under the same PDAAM block length and solid content, the lower the ratio of the initiator to PDMA, the more evenly distributed the vesicles were obtained.

【学位授予单位】：上海大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TQ317

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