Polymerization of Dendritic Macromonomer and Preparation of its membrane for Permseparation

树状大分子侧链结构明确，对高选择性膜的超选择性起重要作用。我们用会聚法合成了树突状苯基乙炔单体，其外围基团为叔丁基、三甲基硅氧基或低聚二甲基硅氧烷。这些单体在乙炔末端单元用铑催化剂聚合，得到相应的聚苯乙炔衍生物，作为高聚合度的黄色粉末，例如DP=2.8 x 10^3，尽管它们的空间体积较大。单枝植物虽然具有空间体积，但却赋予了多枝植物高分子量的一些原因可以认为如下。末端乙炔从枝状簇中暴露出来，聚合过程有立体规则地进行，使侧链枝状簇得到合理的填充。该聚合物可溶于氯仿和四氢呋喃等常见有机溶剂，但不溶于醇类，其溶解度优于相应的零代聚苯乙炔衍生物。聚合物的广角x射线散射表明其为棒状分子的伪六边形晶格。平面间距随着周围硅基的生成或大小的增加而增大。结果表明，多树突植物具有良好的成膜能力，并对膜的透气性进行了测试。与相应的零代聚苯乙炔衍生物相比，聚树突的氧选择性表现出良好的性能。研究发现，多树突具有明确的树突状和棒状结构，有利于形成准选择性膜。

The well-defined side-chain structure of dendrimers is expected to play an important role on the permselectivity for highly selective membranes. We synthesized dendritic phenylacetylene monomers containing tert-butyl group, trimethylsilyl group, or oligodimethylsiloxane, as the peripheral group using the convergent approach. The monomers were polymerized with rhodium catalyst at the terminal acetylene unit to yield the corresponding poly(phenylacetylene) derivatives as yellow powders with a high degree of polymerization, e.g., DP=2.8 x 10^3, in spite of their steric bulkiness. Some reasons why the monodendrons gave the polydendrons with high molecular weight in spite of their steric bulkiness were probably considered as follows. The terminal acetylene was exposed from dendritic crowd, and the polymerization proceeded stereoregularly to give the reasonable packing of the side-chain dendrons. The polymers were soluble in common organic solvents, such as chloroform and tetrahydrofuran, but insoluble in alcohols, and the solubility of these polydendrons was better than that of the corresponding zero generation poly(phenylacetylene) derivatives. The wide angle X-ray scattering of the polymers suggested the pseudohexagonal lattice of rod-like molecules. The interplanar d spacing increased with increasing generation or size of the peripheral silyl group. The polydendrons indicated good membrane forming ability, and the gas permeability of the membrane was examined. The oxygen permselectivity of the polydendrons showed good performance in comparison with the corresponding zero generation of poly(phenylacetylene) derivatives. It was found that the well-defined dendritic and rod-like structure of the polydendrons was useful for pemselective membrane.