【作者】 张晓君；

【导师】 李莉；

【作者基本信息】 华东理工大学 ， 材料化学工程， 2012， 硕士

【摘要】 环糊精具有独特的外亲水内疏水结构,其疏水性空腔使它能够与某些尺寸大小匹配的疏水性客体分子形成主客体包合结构。基于环糊精和偶氮苯包合作用的光敏性网络体系因为在光控药物释放、光控开关、显示装置等方面具有广阔的应用前景而备受科学工作者青睐。本文分别合成了α-环糊精(α-CD)修饰的聚丙烯酸(α-CD-PAA)和偶氮苯(azo)修饰的聚丙烯酸(azo-PAA),然后将α-CD-PAA和azo-PAA进行复配,成功制备了具有紫外光响应性的聚合物网络结构,并采用流变学手段研究了聚合物网络的光敏性以及影响网络结构的因素,采用核磁共振谱图和紫外-可见分光光度计研究了聚合物网络的光敏机理。具体研究工作分述如下：首先对a-CD进行改性,合成六位单磺酰化α-CD (α-CD-6-OTs),然后与乙二胺反应合成六位单氨化α-CD (α-CD-6-EDA),最后通过酰胺化反应接枝到聚丙烯酸主链上,得到具有一定接枝度的α-CD改性聚丙烯酸(α-CD-PAA);将对氨基偶氮苯通过酰胺化反应同样接枝到具有相同分子量的聚丙烯酸主链上,得到具有一定接枝度的偶氮苯修饰的聚丙烯酸(azo-PAA),中间产品及最终产品均用核磁共振和傅里叶红外进行了表征。其次,将a-CD-PAA和azo-PAA的水溶液按照一定的摩尔配比进行复配,制备得到聚合物网络,用高级旋转流变仪测试了其粘度随紫外光照和避光处理的变化,发现其可随外界光照条件的变化而反复可逆的变化,表现出明显的光敏特性。研究复配体系光照前后粘度变化的影响因素发现,当聚合物浓度为6wt%时,紫外光照射后粘度下降最大,达到96%。另外,α-CD单体加入复配体系后可优先与偶氮苯包合,从而破坏了网络结构,明显降低体系的粘度。最后,本文用紫外可见吸收光谱研究了环糊精和偶氮苯的包合作用机理,比较了α、β、γ-CD与单体azo的包合能力,发现α-CD>β-CD>γ-CD,因此选择α-CD作为主体构筑光敏性网络；研究了α-CD与azo-PAA的包合行为,发现a-CD与azo基团的包合摩尔比为1：1,结合常数为4.7×103M-1；研究了azo-PAA的光响应性,发现azo-PAA且有良好的光响应特性,顺式构型在紫外光照射前后分别占10%和78%；单体α-CD的加入加速了azo-PAA的光异构速率,异构速率常数在加入α-CD前后分别为0.084和0.14s-1。更多还原

【Abstract】 Self-assembly polymer networks based on a-CD have attracted much attention. In this paper, a kind of photoresponsive polymer network based on the photo-regulated interaction of azobenzene and a-CD was prepared, which has potential application in photonic, photo storage, photo switch and so on.Two kinds of polymers,α-CD modified poly(acrylic acid)s (α-CD-PAA) and azobenzene modified poly(acrylic acid)s (azo-PAA) were synthesized first. The photoresponsive polymer network was prepared by mixingα-CD-PAA and azo-PAA in water and then studied by rheology. Viscosity of the system changed repetitively and reversibly under UV irradiation and in dark, indicating the successful preparation of photoresponsive polymer network. Photoresponse mechanism was studied by UV-Vis absorption spectra and 1H NMR.For synthesis ofα-CD-PAA, mono-sulfonatedα-CD(a-CD-6-OTs) was synthesized first. Then mono-aminatedα-CD (α-CD-6-EDA) was obtained withα-CD-6-OTs and ethylenediamine. At lastα-CD-PAA was prepared by graftingα-CD-6-EDA onto PAA chain. Azo-PAA was prepared by reaction of p-amino-azobenzene with PAA.Photoresponsive polymer network was prepared with a-CD-PAA and azo-PAA. Rheological studies show that viscosity ofα-CD-PAA/azo-PAA aqueous solution could respond to UV light and darkness repetitively and reversibly. It decreased under UV irradiation and went back in dark. Effects of polymer concentration and mono-α-CD on viscosity ofα-CD-PAA/azo-PAA system were studied. The results are that the viscosity increased with polymer concentration and decreased with amount of mono-α-CD.Interaction ofα-CD and azo was studied by UV-Vis absorption spectra, which show the photoresponsive mechanism of polymer network. Binding ofα-CD with azo is much stronger thanβ-CD andγ-CD.α-CD and azo-PAA forms 1 to 1 complex and the binding constant was calculated to be 4.7X10 M-1. Azo-PAA can isomerize from trans to cis and cis to trans successfully.10% azo moeties on azo-PAA are in cis form before UV irradiation and 78% after UV irradiation. The trans-cis isomerization was accelerated by addingα-CD and the rate constants in the presence and absence of a-CD were calculated to be 0.084 and 0.14s-1.更多还原