Poly (N-vinylacetatnide) ( PNVA) was synthesized by free radical polymerization in ethanol solution, in which alpha, alpha'-azobisisobutyronitrile was used as an initiator. Tb(III)-PNVA polymer was prepared and ch...Poly (N-vinylacetatnide) ( PNVA) was synthesized by free radical polymerization in ethanol solution, in which alpha, alpha'-azobisisobutyronitrile was used as an initiator. Tb(III)-PNVA polymer was prepared and characterized by ultraviolet-visual (UV), fourier transform infrared (FIF-IR), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy. The experimental results of UV, FT-IR and XPS show that the Tb (III)-PNVA electrovalent complex is formed by electrostatic interaction between terbium (III) cation and complexible atoms of acylamino group in the pendant chain of the polymer. The fluorescence spectrum of the complex exhibits intensive characteristic emission of terbium at 490, 545 and 584 run, which are assigned to D-5(4)->F-7(6), D-5(6)->F-5(6) and D-5(4)->F-7(3) transition, indicating that there exists an efficient intermolecular energy transfer from the polymer ligand to the central rare earth ion. The emission intensity of the complex is increased with the increasing concentration of Tb (III) ion until the weight ratio of Tb (III) on to PNVA is 1.5% (mass fraction), and decreased with the further increasing concentration of Tb (III) ion, which is a typical concentration quenching behavior.展开更多
Thermosensitive poly[N-vinylacetamide-co-vinylacetate][P（NVA-co-VAc）] hydrogels were prepared via free radical copolymerization from hydrophilic NVA and hydrophobic VAc in the presence of butylenes-bis （N-vinylacet...Thermosensitive poly[N-vinylacetamide-co-vinylacetate][P（NVA-co-VAc）] hydrogels were prepared via free radical copolymerization from hydrophilic NVA and hydrophobic VAc in the presence of butylenes-bis （N-vinylacetamide）（Bis-NVA） as crosslinker. Scanning electron microscopy（SEM） images reveal that the as-prepared hydrogels were of three-dimensional network with irregular cave structure. The prepared hydrogels with more NVA in the feed swelled faster and the swelling ratio of the hydrogels gradually decreased with temperature increasing from 10 °C to 60 °C. The dynamic swelling studies indicate that the swelling process of the hydrogels was controlled by diffusion of water molecules considered as Fickian-controlled case. The adsorption amount of model drug, sodium salicylate（SS） was higher in the hydrogels containing more NVA units, whose corresponding release could reach equilibrium in about 6 h.展开更多
Poly (N-vinylacetamide) (PNVA) was synthesized by the free radical polymerization and its samarium (III) binary complex was prepared and characterized by means of IR, UV-vis, X-ray photoelectron spectroscopy (XPS) and...Poly (N-vinylacetamide) (PNVA) was synthesized by the free radical polymerization and its samarium (III) binary complex was prepared and characterized by means of IR, UV-vis, X-ray photoelectron spectroscopy (XPS) and fluorescence spectra. The fluorescent intensity of samarium (III) characteristic emission was increased significantly due to efficient energy transfer from polymeric ligand to Sm (III) ion in the complex.展开更多
采用链转移自由基聚合和端基置换反应的方法,合成了苯乙烯单封端聚N 乙烯基乙酰胺(PNVA)大分子单体,以此大分子单体为反应性分散稳定剂,使之与苯乙烯在乙醇/水的混合介质中进行分散共聚反应,制得表面PNVA接枝聚苯乙烯(PNVA g PSt)聚合...采用链转移自由基聚合和端基置换反应的方法,合成了苯乙烯单封端聚N 乙烯基乙酰胺(PNVA)大分子单体,以此大分子单体为反应性分散稳定剂,使之与苯乙烯在乙醇/水的混合介质中进行分散共聚反应,制得表面PNVA接枝聚苯乙烯(PNVA g PSt)聚合物微球.利用凝胶渗透色谱、激光光散射仪和电子显微镜等对聚合物的相对分子质量、微球动力学直径及其形态进行了表征.结果表明:PNVA大分子单体浓度、苯乙烯浓度、引发剂浓度和聚合温度对微球粒径有较大的影响;溶剂组成对聚合物微球的形态有明显的影响.展开更多
以二硫化二异丙基黄原酸酯(DIP)为链转移剂,AIBN为引发剂,通过可逆加成-断裂链转移(RAFT)自由基聚合的方法制备得到大分子链转移剂聚醋酸乙烯酯(PVAc)。进而引发第二单体N-乙烯基乙酰胺(NVA)进行RAFT反应制备得到不同嵌段比的双亲性嵌...以二硫化二异丙基黄原酸酯(DIP)为链转移剂,AIBN为引发剂,通过可逆加成-断裂链转移(RAFT)自由基聚合的方法制备得到大分子链转移剂聚醋酸乙烯酯(PVAc)。进而引发第二单体N-乙烯基乙酰胺(NVA)进行RAFT反应制备得到不同嵌段比的双亲性嵌段共聚物PVAc-bPNVA。红外光谱(FT-IR)、核磁共振氢谱(1 H NMR)和凝胶渗透色谱(GPC)分析表明,所得聚合物结构明确,且分子量分布较窄,符合活性聚合特征。进而使PVAc-b-PNVA在选择性溶剂(DMF/H2O)中自组装形成胶束,研究了不同初始浓度和链段比对胶束粒径和形态的影响。展开更多
O-Alkylation of oximes with N-vinylpyrrolidin-2-one or N-methyl-N-vinylacetamide was efficiently initiated by a catalytic amount of cerium（Ⅳ） ammonium nitrate（CAN）,giving the corresponding oxime ether derivatives...O-Alkylation of oximes with N-vinylpyrrolidin-2-one or N-methyl-N-vinylacetamide was efficiently initiated by a catalytic amount of cerium（Ⅳ） ammonium nitrate（CAN）,giving the corresponding oxime ether derivatives in good yield.展开更多
文摘Poly (N-vinylacetatnide) ( PNVA) was synthesized by free radical polymerization in ethanol solution, in which alpha, alpha'-azobisisobutyronitrile was used as an initiator. Tb(III)-PNVA polymer was prepared and characterized by ultraviolet-visual (UV), fourier transform infrared (FIF-IR), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy. The experimental results of UV, FT-IR and XPS show that the Tb (III)-PNVA electrovalent complex is formed by electrostatic interaction between terbium (III) cation and complexible atoms of acylamino group in the pendant chain of the polymer. The fluorescence spectrum of the complex exhibits intensive characteristic emission of terbium at 490, 545 and 584 run, which are assigned to D-5(4)->F-7(6), D-5(6)->F-5(6) and D-5(4)->F-7(3) transition, indicating that there exists an efficient intermolecular energy transfer from the polymer ligand to the central rare earth ion. The emission intensity of the complex is increased with the increasing concentration of Tb (III) ion until the weight ratio of Tb (III) on to PNVA is 1.5% (mass fraction), and decreased with the further increasing concentration of Tb (III) ion, which is a typical concentration quenching behavior.
基金Supported by the National Natural Science Foundation of China(No.20876070)
文摘Thermosensitive poly[N-vinylacetamide-co-vinylacetate][P（NVA-co-VAc）] hydrogels were prepared via free radical copolymerization from hydrophilic NVA and hydrophobic VAc in the presence of butylenes-bis （N-vinylacetamide）（Bis-NVA） as crosslinker. Scanning electron microscopy（SEM） images reveal that the as-prepared hydrogels were of three-dimensional network with irregular cave structure. The prepared hydrogels with more NVA in the feed swelled faster and the swelling ratio of the hydrogels gradually decreased with temperature increasing from 10 °C to 60 °C. The dynamic swelling studies indicate that the swelling process of the hydrogels was controlled by diffusion of water molecules considered as Fickian-controlled case. The adsorption amount of model drug, sodium salicylate（SS） was higher in the hydrogels containing more NVA units, whose corresponding release could reach equilibrium in about 6 h.
文摘Poly (N-vinylacetamide) (PNVA) was synthesized by the free radical polymerization and its samarium (III) binary complex was prepared and characterized by means of IR, UV-vis, X-ray photoelectron spectroscopy (XPS) and fluorescence spectra. The fluorescent intensity of samarium (III) characteristic emission was increased significantly due to efficient energy transfer from polymeric ligand to Sm (III) ion in the complex.
文摘采用链转移自由基聚合和端基置换反应的方法,合成了苯乙烯单封端聚N 乙烯基乙酰胺(PNVA)大分子单体,以此大分子单体为反应性分散稳定剂,使之与苯乙烯在乙醇/水的混合介质中进行分散共聚反应,制得表面PNVA接枝聚苯乙烯(PNVA g PSt)聚合物微球.利用凝胶渗透色谱、激光光散射仪和电子显微镜等对聚合物的相对分子质量、微球动力学直径及其形态进行了表征.结果表明:PNVA大分子单体浓度、苯乙烯浓度、引发剂浓度和聚合温度对微球粒径有较大的影响;溶剂组成对聚合物微球的形态有明显的影响.
文摘以二硫化二异丙基黄原酸酯(DIP)为链转移剂,AIBN为引发剂,通过可逆加成-断裂链转移(RAFT)自由基聚合的方法制备得到大分子链转移剂聚醋酸乙烯酯(PVAc)。进而引发第二单体N-乙烯基乙酰胺(NVA)进行RAFT反应制备得到不同嵌段比的双亲性嵌段共聚物PVAc-bPNVA。红外光谱(FT-IR)、核磁共振氢谱(1 H NMR)和凝胶渗透色谱(GPC)分析表明,所得聚合物结构明确,且分子量分布较窄,符合活性聚合特征。进而使PVAc-b-PNVA在选择性溶剂(DMF/H2O)中自组装形成胶束,研究了不同初始浓度和链段比对胶束粒径和形态的影响。
基金Project 20572040 was supported by National Natural Science Foundation of China
文摘O-Alkylation of oximes with N-vinylpyrrolidin-2-one or N-methyl-N-vinylacetamide was efficiently initiated by a catalytic amount of cerium（Ⅳ） ammonium nitrate（CAN）,giving the corresponding oxime ether derivatives in good yield.
