权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

SYNTHESIS OF DENDRIMERS BY SELF-CONDENSING GROUP TRANSFER POLYMERIZATION

自缩合基团转移聚合合成树枝状聚合物

基本信息

批准号：
08651042
负责人：
SAKAMOTO Kenkichi
金额：
$ 1.54万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

Dendrimers have recently received much attention as materials with novel physical properties. However, dendrimers are accessible only through multi-step syntheses that limit their availability. Recently, Frechet et al.has described self-condensing vinyl polymerization to produce dendrimer-like hyperbranched polystirene.In this research project, synthesis of hyperbranched polymethacrylates by the group transfer polymerization was carried out. Thus, 2- (2-methyl-1-triethylsiloxy-1-propenyloxy) ethyl methacrylate 1, which consisted of a methacrylate moiety and a ketene silyl acetal moiety, was prepared for the self-condensing polymerization of methacrylates. The polymerization of 1 was carried out in THF with fluoride ion as a catalyst. The resulting polymers were soluble in various organic solvents. Molecular weights of the polymers were about ten thousand estimated by GPC.The branched structure of the polymers was clearly characterized by ^1H and ^<13>C NMR spectroscopy.The ketene silyl acetal residues in the polymers were converted to various functional groups. Thus, water-soluble hyperbranched polymethacrylates were synthesized by introduction of ionic functional groups such as carboxylate anion and ammonium cation as the terminal groups of the polymers.These polymers behaved as unimolecular micelles ; they dissolved in water and incorporated organic molecules (guests) by hydrophobic interaction. Monitoring by UV-Vis and fluorescence spectroscopy revealed that the incorporation was controlled by the electrostatic force between the guests and the host polymers. The cavity size of the polymers depended on the change of their surface charge density. In fact, guest molecules were released when the charge of the polymers neutralized.

树枝状大分子作为一种具有新颖物理性质的材料，近年来受到了广泛的关注。然而，树枝状聚合物只能通过多步合成来获得，这限制了它们的可用性。近年来，Frechet等报道了乙烯基自缩合聚合制备树枝状超支化聚苯乙烯，本研究采用基团转移聚合法合成超支化聚甲基丙烯酸酯。因此，2-（2-甲基-1-三乙基甲硅烷氧基-1-丙烯氧基）乙基甲基丙烯酸酯1，它由一个甲基丙烯酸酯部分和一个烯酮甲硅烷基缩醛部分，制备用于甲基丙烯酸酯的自缩合聚合。1的聚合在THF中以氟离子为催化剂进行。所得聚合物可溶于各种有机溶剂中。用GPC测得聚合物的分子量约为1万，用~ 1H和~ 1C NMR谱表征了聚合物的支化结构<13>，聚合物中的乙烯酮基甲硅醇缩醛残基转化为各种官能团.通过引入羧酸根阴离子和铵离子等离子性官能团作为聚合物的端基，合成了水溶性超支化聚甲基丙烯酸酯，这些聚合物表现为单分子胶束，它们溶解于水，并通过疏水相互作用与有机分子（客体）结合。通过紫外-可见光谱和荧光光谱的监测表明，掺入由客体和主体聚合物之间的静电力控制。聚合物的空穴大小取决于其表面电荷密度的变化。事实上，当聚合物的电荷中和时，客体分子被释放。