【作者】 刘晓青；

【导师】 邓建平；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2010， 硕士

【摘要】 本文首先合成了五种带有不同芳香类取代基的炔丙酰胺单体[HC≡CCH2NHCOR,R for M1：C6H4CH3；M2：C6H4CH2CH3；M3：C6H4(CH2)2CH3；M4：C6H4(CH2)3CH3；M5：C6H4C(CH3)3],这些单体在Rh催化剂[(nbd)Rh+B-(C6H5)4]的催化作用下进行配位聚合,得到了分子量适中的聚合物,这些聚合物的产率能达到90%-95%,并且顺式含量均大于95%。Poly(1)-poly(3)的在350nm处有UV-vis吸收峰,表明这三种聚合物可能形成了螺旋结构,但需要得到进一步实验证明。而poly(4)and poly(5)在300nm-500nm这个范围内没有UV-vis吸收峰,表明这两种聚合物在测试条件下没有形成螺旋结构。由于手性单体M6的均聚物在一定条件下可以形成稳定的螺旋结构,因此利用单体M6与M2共聚,所得共聚物能表现出很强的CD信号,并且随着单体组分的变化,CD信号有明显的变化,这表明相邻侧基之间的空间位阻以及协同效应对螺旋结构的形成有一定的影响。另外,在Rh催化剂[(nbd)Rh+B-(C6H5)4]的催化作用下,一种手性炔丙酰胺类单体在五种不同极性的溶剂(甲苯、三氯甲烷、四氢呋喃、二氯甲烷以及N,N-二甲基甲酰胺)中聚合,均可得到产率较高的聚合物。在这五种溶剂中对这些聚合物进行圆二色谱(CD)测试,发现聚合物分别在这五种溶剂中都可以形成稳定的螺旋结构,并且能表现出光学活性,即使在强极性溶剂DMF中都可以得到稳定的螺旋结构。这五种聚合物在同一溶剂中其CD和UV-vis谱图吸收峰的强度强度随分子量增大而增强；同一种聚合物在不同溶剂中的CD和UV-vis谱图吸收峰的强度变化规律与溶剂极性有关,即吸收峰的强度随溶剂极性的增大而减小。然后,本文还合成了一种新型的具有光学活性的核／壳纳米粒子,这种核／壳纳米粒子的核层是具有光学活性的取代乙炔螺旋聚合物,壳层为乙烯基聚合物。在同一体系中通过配位聚合及自由基聚合得到这种核／壳纳米粒子,且核层与壳层在多官能团单体的作用下交联,得到核／壳以化学键交联的核壳纳米粒子。这一课题不仅使配位聚合和自由基聚合在同一体系中发生,同时还使一种材料具备了光学活性与纳米这两种特性。更多还原

【Abstract】 Five achiral N-propargylamide monomers with various phenyl-based substitutents, [HC=CCH2NHCOR, R for M1:C6H4CH3; M2:C6H4CH2CH3; M3:C6H4(CH2)2CH3; M4: C6H4(CH2)3CH3; M5:C6H4C(CH3)3], were synthesized and polymerized with a rhodium catalyst, (nbd)Rh+B-(C6H5)4 (nbd= 2,5-norbornadiene). The corresponding five homopolymers were obtained in high yields of 90-95%and with moderate molecular weights (Mn≥10000). All the polymers possessed high cis contents (≥95%). Poly(1)-poly(3) exhibited UV-vis absorption peaks at approx.350 nm, which indicates that the three polymers formed helical conformations, while no UV-vis absorption peaks could be observed in poly(4) and poly(5) in the wavelength range of 320-500 nm, demonstrating that these two polymers could not adopt helical structures under the examined conditions. To confirm the helical structures formed in poly(1)-poly(3), a chiral monomer, M6, was utilized to copolymerize with M2, which was used as the representative for M1-M3. M6 was utilized since its polymer could form stable helices under suited conditions. The resulting copolymers exhibited remarkable CD effects, however, the maximum wavelength in the copolymers varied remarkably, mainly depending on the composition of the copolymers. It is concluded that in the formation of ordered helical conformations, the substitutents of varied bulk led to different steric repulsion and varied synergic effects among the neighboring pendent groups.In order to explore the effects of solvents on the polymerization of propargylamide, polymerization of M7 was carried out with Rh catalyst in various solvents with different polarity, including toluene (C7H8), chloroform (CHCl3), tetrahydrofuran (THF), methylene dichloride (CH2Cl2), and dimethylformamide (DMF). The obtaining polymers can reach high yields. According to the CD and UV-vis spectroscopy, the polymers can adopt helical conformation and present optical activity in these five solvents, even in DMF with high polarity. With an increase in the molecular weight of polymers, the CD signals and UV-vis absorptions of the five polymers in the same solvents increased. As the polarity of solvents increased, the the CD signals and UV-vis absorptions of one polymer in the five solvents have a decrease.A novel methodology is reported about preparing a new class of core/shell nanoparticles. The nanoparticles consist of a unique core (composed of an optically active helical-substituted polyacetylene) and a shell (composed of a vinyl polymer) and thus exhibit optical activities. Such nanoparticles were synthesized by combining aqueous catalytic microemulsion polymerization and free radical polymerization in one specific system. The shell and core could be further cross-linked for improving the properties of particles by using multifunctionalmolecule. The investigations are of high importance not only in polymer chemistry due to the combination of catalytic polymerization and free radical polymerization in one system but also in materials due to the integration of "chirality" and "nano" concepts in one single material.更多还原