【作者】 周康；

【导师】 邓建平；

【作者基本信息】 北京化工大学 ， 化学， 2010， 硕士

【摘要】 空心/多孔聚合物微球和螺旋大分子由于它们各自独特的结构、性能及潜在的应用前景而受到广泛的关注,将螺旋大分子接枝到空心/多孔交联聚合物微球上,一方面为解决螺旋聚合物的应用难题提供思路,另一方面也可实现聚合物微球的功能化,赋予聚合物微球很高的光学活性,从而拓宽聚合物微球的应用范围。结合螺旋大分子的特殊性能,尤其是光学拆分、不对称催化方面的性能,该类空心/多孔微球有望在手性分离、药物可控释放、手性催化及光学材料领域得到应用。本文设计设计合成了带有碳碳双键功能侧基的螺旋大分子,利用其作为大分子单体分别采用模板法和两步种子溶胀聚合法成功制备了接枝有螺旋大分子的空心聚合物和多孔结构的聚合物微球,考察了它们的手性识别和手性分离性能,主要工作如下：通过共聚反应设计合成了一系列带有C=C功能侧基的聚炔丙酰胺聚合物(OAHP),聚合产率高(≥95%),分子量适中(10000-17000),分子量分布略宽(2.63-4.79)。利用红外和核磁表征出了分子链中的C=C功能侧基。利用紫外.可见光谱(UV-vis)和圆二色光谱(CD)表征了聚合物的二级结构,结果显示,共聚物(1-co-2),共聚物(1-co-3),共聚物(4-co-3)均能形成螺旋构象,并具有很强的光学活性,共聚物的二级结构受共聚物组分的影响明显。由马来酸酐(MAH)和醋酸乙烯酯(VAC)分散聚合得到的聚合物微球(PMV),并以之作为模板,加入一定量的螺旋大分子单体OAHP,MAH,二乙烯基苯(DVB)为共聚单体,引发剂AIBN,升温聚合制备了核壳结构微球。用丙酮洗去PMV模板,得到接枝有螺旋大分子的空心微球(CPMD-g-OAHP)。利用红外、SEM和TEM对空心微球进行了表征,结果证明空心微球上成功得接枝上了螺旋大分子,微球的大小和壳层厚度可控。将CPMD-g-OAHP空心微球分散在THF中进行测试紫外光谱和圆二色谱(CD),结果显示微球具有很强的光学活性。考察了CPMD-g-OAHP空心微球对酒石酸、苯丙氨酸和苯乙胺的手性识别能力,结果显示微球对苯乙胺的手性识别能力明显,表现为优先吸附R型苯乙胺。微球能对外消旋苯乙胺进行有效拆分,分离液ee值达到28%。利用分散聚合法制备了聚苯乙烯微球PS,并以此作为种子,与溶胀剂和单体、交联剂、OAHP乳化液经二步溶胀,升温聚合制备了接枝有螺旋大分子多孔交联微球PSD-g-OAHP。利用红外、SEM和TEM对多孔微球的组成和微观结构进行了表征。更多还原

【Abstract】 Hollow/porous polymeric micro/nanospheres and helical polymers have recently attracted considerable attention due to their unique properties. By grafting helical chain to polymeric microspheres, it can not only help to resolve the application problem of helical polymer, but also achieve the functional modification of polymeric microspheres. Combining with the special properties of helical polymers, in particular the optical resolution and asymmetric catalysis properties, such hollow/ porous microspheres is expected to find lots of applications, such as chiral separation, controlled release, chiral catalysis and chiroptical materials. In this study, we fistly synthesized optically active helical N-propargylamide copolymers (OAHPs) containing specially designed C=C groups in pendent groups. Using OAHPs as macromonomer, we successfully prepared hollow/porous microspheres grafted with optically active helical chains by template polymerization and two-step swelling polymerization, respectively. The main works were as follows:Firstlty, a novel class of optically active N-propargylamide copolymers bearing C=C groups in side chains were synthesized with high yield (≥95%) and moderate molecular weights (10000-17000). The C=C side groups were characterized by FTIR and H1 NMR. All the copolymers adopted stable helices under the investigated conditions. The composition of the copolymers exerted large influence on their optical activity.Polymeric particles based on maleic anhydride (MAH) and vinyl acetate were prepared and used as the sacrificial templates for the subsequent preparation of core/shell spheres, which were accomplished by using the system consisting of MAH, divinyl benzene and OAHP macromonomers. After extracting the core in the prepared core/shell particles, hollow microspheres grafted with optically active helical polymer chains were successfully obtained. The hollow particles were characterized with FTIR, field-emission SEM and TEM measurements. The size and the shell thickness of these hollow spheres were readily controllable. Circular dichroism (CD) spectra were recorded on the hollow spheres dispersed in THF. The intense CD effects indicated that the hollow spheres possessed high optical activity, arising from the helical polymer chains. The preferential adsorption of (R)-(+)-1-phenylethylamine to the (S)-form by the obtained hollow spheres clearly attested to the chiral recognition ability of the novel spheres.Disersion polymerization was used to produce polystyrene microparticles. Using polystyrene particles as seed, OAHP as macromonomers, styrene as monomers, DVB as cross-linker, porous cross-linked polymeric microspheres. grated with optically active helical chains were prepared by two step swelling polymerization. The porous microspheres composition and microstructure were characterized with FTIR, CD, SEM and TEM measurements.更多还原