【作者】 张亮；

【导师】 白如科；

【作者基本信息】 中国科学技术大学 ， 高分子化学与物理， 2009， 硕士

【摘要】 含POSS聚合物的优异性能近期引起了人们的广泛兴趣,例如在耐热阻燃、耐磨损、提高与材料相容性、增强有机半导体材料的发光效率等领域有着大量的报道。利用POSS自身固有的低表面能、排斥体积大等性质,将其引入两亲性聚合物体系做为疏水链段的研究报道相对来说还比较少,特别是对含POSS两亲性聚合物的本体、界面或水溶剂组装行为研究还很不完善,需要对其深入研究。众所周知,在高分子科学领域研究的一个重要概念就是聚合物结构决定性能,因此设计合成具有精确结构的含POSS两亲性聚合物是深入的研究其相关性能的前提和基础。在本论文中,我们主要合成了两种结构明确的含POSS两亲性单体及其聚合物以及一种含一个POSS基团的新型两亲性聚合物。一.以POSS-NH₂和PEO-CHO一步缩合形成的希夫碱为反应中间体,还原后得到的PEO-NH-POSS与丙烯酰氯反应得到聚合基团为丙烯酰胺结构,亲水基团为二缩三乙二醇单甲醚,疏水基团为POSS的两亲性单体,通过核磁和渗透凝胶色谱对单体及其聚合物进行分析表征。二.合成了亲水基团为羧基,疏水基团为POSS的两亲性苯乙烯单体衍生物,通过核磁对其结构进行表征,用红外光谱对单体离子键形成-断裂过程进行了跟踪表征,并初步研究了单体的聚合行为,得到了一种新型的含POSS聚合物。三.我们利用活性自由基聚合方法合成了POSS基团在PS和PEO之间的两亲性聚合物。在大分子引发剂存在下,苯乙烯在110 oC下进行ATRP聚合,经过核磁和渗透凝胶色谱对聚合物结构、分子量、分子量分布等进行表征,结果证明聚合是活性可控单分散的;通过透射电镜和扫描电镜对含POSS的两亲性聚合物在水溶液中进行组装结果观察表征,得到了具有复杂内部结构的多孔囊泡,并系统研究了组装溶剂、PS的链长对组装形貌的影响,最后从膜最低弹性能和POSS位阻带来的长弛豫时间过长这两个角度,对多孔结构可能的形成机理进行分析。更多还原

【Abstract】 Recently, POSS containing polymers have attracted considerable research interest due to their versatile applications in heat resistance, flame retardance, abrasion resistance, solubility enhancement and field of organic semiconductors. However, the POSS cage has been neglected in application of amphiphilic polymers as hydrophobic chain by using its intrinsic low surface energy and the comparable dimensions to the linear polymers, especially for the self-assembly of POSS containing polymers in bulk, interface and water. It is well known that material properties depending on its molecular structure are the basic principle in the field of polymer science. Therefore, the design and synthesis of well defined amphiphilic POSS containing polymers are the precondition and foundation of its related properties and applications. In our works, two types of amphiphilic POSS containing monomer and its polymers with specific structure, as well as another novel polymer with one POSS at the junction point of two blocks, were synthesized.First, the monomer with triethylene glycol monomethyl ether as hydrophilic group and POSS group as hydrophobic group was synthesized via the reaction of acryloyl chloride and the key intermediate PEO-NH-POSS; such intermediate was obtained through one-pot approach including the condensation of POSS-NH₂ with PEO-CHO and reduction of the resulting Schiff base with NaBH₄ without separation. The monomers and its polymers were characterized by ¹H NMR spectroscopy and GPC respectively.Second, we designed a novel styrene derivative monomer with a carboxyl as hydrophilic group and POSS group as hydrophobic group, which was different from the above mentioned. The structure was determined by ¹H NMR and the formation and cleavage of ion-bond were traced by FTIR. In addition, the initial polymerization study was made and yielded a novel amphiphilic polymer.Third, we presented a strategy for the synthesis of well-defined amphiphilic block copolymers containing a POSS moiety at the junction point of a polystyrene chain and a poly （ethylene oxide） chain via controlled/living free-radical polymerization. In presence of the macroinitiator, the atom transfer radical polymerization of styrene was conducted at 110 oC, and the structure, molecular weight and the polydispersity of the polymers were characterized by ¹H NMR spectroscopy and GPC. The polymerization results demonstrate that the process bears all the characteristics of controlled/living free-radical polymerization, the amphiphilic block copolymers have efficiently been obtained with controlled molecular weight and low polydispersity. The result of self-assembly shows that the amphiphilic block copolymers can form compound porous vesicles in aqueous solution characterized by TEM and SEM. The influence of solvent and the length of hydrophobic chain for the self-assembly process were investigated carefully. Moreover, the possible mechanism for the formation of the porous vesicles was proposed according to the minimization of the elastic energy and the long-lived intermediate caused by POSS.更多还原