【作者】 舒巧珍；

【导师】 江金强； 刘晓亚；

【作者基本信息】 江南大学 ， 材料学， 2011， 硕士

【摘要】 本论文总共分为两大部分,第一部分内容为：香豆素类光敏聚合物的合成与性能研究,1)：设计、合成了含二硫键的香豆素衍生物(C-S-S-C),并以其与三丁基膦/水的复合体系为链转移剂,偶氮二异丁腈(AIBN)为引发剂,自由基聚合法制备了链端含香豆素光敏感基元的双亲性遥爪聚N-异丙基丙烯酰胺(C-PNIPAAm); 2):设计、合成了含三个溴原子ATRP引发点的引发剂(C-Br3),以甲基丙烯酸-N,N-二甲氨基乙酯(DMAEMA)、苯乙烯(St)为单体合成了两种双亲性光敏星形聚合物——聚(甲基丙烯酸-N,N-二甲氨基乙酯)C-(PDMAEMA)3和聚苯乙烯-b-聚(甲基丙烯酸-N,N-二甲氨基乙酯)C-(PSt-b-PDMAEMA)3。用傅里叶变换红外光谱仪(FT-IR)、紫外-可见光分光光度计(UV-vis)、凝胶渗透色谱仪(GPC)、液相质谱联用仪(LC-MS)和核磁共振仪(’H-NMR)对C-S-S-C、C-Br3及其中间产物以及三种聚合物进行结构表征,并对三种聚合物胶束的光敏性能、形态大小及光控释放行为进行研究。结果表明,C-PNIPAAm在水中可以自组装成胶束,且可通过光开关来控制水溶液中胶束的形态,因香豆素基元的可逆光二聚作用,经波长为365nm紫外光照射后形成中空球状结构,再经波长为254nm紫外光照射后由于二聚体中四元环的断裂而又重新形成最初的胶束结构,用动态激光光散射仪(DLS)和透射电镜(TME)可对这种纳米聚集体形态变化的现象进行跟踪监测。结果表明,在第一个光照循环中30-50 nm直径的胶束,经光照后可形成直径在200-350 nm之间的大囊泡结构,而经光解交联后又重新形成直径为30-50 nm的胶束结构；以荧光素为疏水性分子,当对包覆有荧光素的聚合物胶束溶液进行波长大于310 nm的紫外光照时,端基的香豆素基元发生光二聚,胶束结构发生改变,使得胶束中疏水荧光素有效地释放到水中,且DLS表明胶束的平均半径从56.6 nm增大到101.0nm。另外,经初步研究,C-(PDMAEMA)3和C-(PSt-b-PDMAEMA)3两种聚合物的胶束也表现出较优良的光响应性能。第二部分内容为：支化聚合物合成新方法的探索,设计、合成了含二硫键的苯乙烯单体(St-S-S-St),并以其为支化单体、苯乙烯(St)为聚合主单体,二氧六环为溶剂,AIBN为引发剂,在三丁基膦/水存在下,自由基聚合法合成了系列支化聚苯乙烯BPSt.用FT-IR,1H-NMR, GPC,三检测器、差示扫描量热仪(DSC)等对聚合物进行一系列结构和性能的表征。结果表明,随着聚合时支化单体加入量的增加,聚合物的重均分子量Mw逐渐增加,而其Tg呈下降趋势,说明通过该方法可成功引入支化结构。另外,通过该方法合成了支化的聚N-异丙基丙烯酰胺BPNIPAAm。更多还原

【Abstract】 There are two parts in this paper, first:synthesis and properties of photo-sensitive telechelic polymer and star polymers. For the telechelic polymer:a coumarin derivative containing disulfide bond (C-S-S-C) was designed and synthesized, which can be used as chain transfer agent in the prescence of tributylphosphine (Bu3P) and water (H2O), to prepare the amphiphilic photo-sensitive telechelic polymer coumarin-poly(N-Isopropyl acrylamide) (C-PNIPAAm). And for star polymers:a three armed ATRP initiator (C-Br3) containing coumarin group was designed and synthesized, which was used to prepare amphiphilic photo-sensitive star polymers, poly(dimethylaminoethyl methacrylate) C-(PDMAEMA)3 and polystyrene-b-poly(dimethylaminoethyl methacrylate) C-(PSt-b-PDMAEMA)3. The structures of C-S-S-C, C-Br3 and polymers were characterized by Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis), gel permeation chromatography (GPC), liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance spectroscopy (1H-NMR), then photo-sensitive properties, size and photo-controlled release of three polymer micelles were studied. It was found that C-PNIPAAm can form micelles in aqueous solution, and the micellar morphology in aqueous solution can be photo-switched into hollow spheres according to the photo-dimerization of coumarin end groups upon 365 nm irradiation and reform the micellar morphology after the subsequent photo-scission of dimers upon 254 nm. This instantly morphology changing phenomenon was successfully monitored by dynamic laser light scattering (DLS) and transmission electron microscopy (TEM) measurements. It was shown that the small spherical shape of micelles with diameter at 30-50 nm before photo-crosslinking, the big vesicles with diameter at 200-350 nm after photo-crosslinking and the small micelles with diameter at 30-50 nm after the subsequent photo-de-crosslinking in the first irradiation cycle. And using fluorescein as a hydrophobic encapsulation, when irradiated by UV light (λ＞310 nm), the hydrophobic fluorescein was effectively released to the water. DLS showed that the average radius of the micelles increased from 56.6 nm to 101.0 nm after irradiation. In addition, it was found that the micelles prepared by two star polymers, C-(PDMAEMA)3 and C-(PSt-b-PDMAEMA)3, have good photo-sensitive property, respectively.Second:the new approach to branched polymers. A styrene monomer containing disulfide bond (St-S-S-St) was designed and synthesized, which can be used as branched monomer in the presence of Bu3P and H2O, and using St as main monomer, dioxane as solvent, AIBN as initiator, to prepare branched polystyrene (BPSt). The polymers were characterized by FT-IR,1H-NMR, GPC, and DSC analysis. It was found that the molecular weight (Mw) of BPSt increased exponentially with the increasing molar dosage of St-S-S-St, while the glass transient temperature (Tg) decreased, which meaned that the BPSt can be obtained through the copolymerization of St-S-S-St and St. In addition, branched poly(N-Isopropyl acrylamide) (BPNIPAAm) was synthesized.更多还原