Synthesis and Structure Properties of Gradient-Modulus Star Copolymers

本项目的目的是研究梯度模量星星共聚物的新型合成和结构有序化。研究结果如下：1.以聚[异戊二烯（I）-嵌段-I/苯乙烯（S）-嵌段-S]锥形嵌段一元阴离子与二乙烯基苯（DVB）在苯中交联，制备了双模量星星共聚物。这些恒星的稀溶液性质的特点是静态和动态光散射（SLS和DLS）。苯分子的回转半径与斯托克斯半径之比（R_G/R_H）随臂数的增大而逐渐减小，并趋于1。甚至具有多臂的梯度模量星的行为也不像硬球，而是像软球，在良溶剂中，软球在边缘附近是可穿透的。动态光散射结果表明，即使在选择性溶剂中，梯度模量星也能形成单分子胶束.通过苯中的小角X射线散射和透射电子显微镜（TEM）测量研究了恒星的结构有序性。所有的星星样品在重叠阈值（C '）附近形成具有体心立方（BCC）结构的晶格。在臂数n<67的星星样品中，这种结构在体膜中转变为层状结构，在n=289的星星样品中，即使在体膜中，也表现出一种有趣的趋势，即球形结构保持在单分子胶束的尺度上.在C '附近，折射率模星形成了BCC结构的晶格。当这些星形结构在甲基丙烯酸甲酯（MMA）单体中形成立方晶格后，通过MMA单体的自由基聚合，将有序晶格永久锁定在固体基质中，从而构建了聚合物超结构。该技术是制备纳米聚合物超结构的最佳方法之一。

The aim of this project is to study the novel synthesis and structural ordering of gradient-modulus star copolymers. The results obtained are as follows.1. Gradient-modulus star copolymers were prepared by crosslinking poly[isoprene(I)-block-I/styrene(S)-block-S] tapered block monoanions with divinylbenzene(DVB) in benzene. The dilute-solution properties of these stars were characterized by static and dynamic light scattering (SLS and DLS). The ratio of radius of gyration over the Stokes radius (R_G/R_H) in benzene decreased gradually and approached unity as the arm number became large. Even gradient-modulus stars with multiarms behave not as near hard spheres but as soft spheres which were penetrable near the edge in a good solvent. It was found from the results of DLS that gradient-modulus stars formed unimolecular micelles even in selective solvent.2. Structural orderings of stars were investigated through the small-angle X-ray scattering in benzene and through the transmission electron microscopy (TEM) measurements. All of the star samples formed a lattice with a body-centered-cubic (BCC) structure near the overlap threshold (C'). In the star specimens with arm number n<67, this structure changed to the lamellae in the bulk film, in the star specimen with n=289, it showed an interesting tendency for the spherical structure to be maintained with the dimension of the unimolecular micelle even in the bulk film.3. Gradient-modulus stars formed a lattice with BCC structure near the C'. After these stars formed a cubic lattice in methyl methacrylate (MMA) monomer, the polymeric superstructures were constructed by locking permanently ordered lattice in a solid matrix by means of free-radical polymerization of MMA monomer. This technique is one of the best methods fir creating nanoscopic polymeric superstructures.