共查询到11条相似文献,搜索用时 203 毫秒
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N-甲基丙烯酰-N'-嘧啶哌嗪与过硫酸钾引发体系引发的丙烯酰胺聚合 总被引:4,自引:0,他引:4
queous solution polymerization of acrylamide (AAm) was demonstrated by using initiation system consisting of N-methacryloyl-N '-pyrimidinopiperazine (MPMP ) and persulfate (KPS). The polymerization rate equation was obtained to beRp = Kp[MPMP]1/2 [KPS]1/2 [AAm]1.0The overall activation energy for the polymerization was calculated by Arrhenius quation to be Ea= 5.6 KJ/mol. The redox nature for the polymerization was clarified. A super high molecular weight up to 107 of PAAm was obtained by using this initiation system. From the fluorescent analysis, it was confirmed that MPMP not only acted as a component of the redox system, but also entered into the acrylamide polymer chains. 相似文献
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N-甲基丙烯酰-N′-嘧啶基哌嗪及其聚合物敏化的丙烯腈光聚合 总被引:1,自引:2,他引:1
The photopolymerization of acrylonitrile (AN) sensitized by N-methacrylyl-N'-pyrimidi-nopiperazine (MPMP) and its polymer, P(MPMP) was studied kinetically. It was found that the photopolymerization rate of AN sensitized by monomeric MPMP is proportional to 0.35th power of MPMP concentration and 0.85th power of AN concentration, respectively. In the case sensitized by Polymeric MPMP, P(MPMP) is proportional to 0.30th power of P(MP-MP) concentration and 1.0 power of AN concentration, respectively. The overall activation energies for photopolymerization sensitized with MPMP and P(MPMP) were determined to be 4.71Kcal/mol and 4.58Kcal/mol,respectively.From the fluorescence analysis for P(AN) senstitized by either MPMP or P(MPMP),it was confirmed that MPMP and P(MPMP) not only sensitized the photopolymerization of AN but also entered into the P(AN) chains. 相似文献
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3-甲基丙烯酰胺基-9-乙基咔唑的合成、聚合及其光化学行为研究 总被引:1,自引:0,他引:1
含供电子芳杂环的丙烯酰类功能性单体的合成、聚合及光化学行为一直吸引着人们的兴趣 .原因之一是由于这类单体可用一般的自由基引发剂引发聚合 ,其聚合物表现出包括荧光及光引发行为的光化学性质甚被瞩目[1,2 ] .在以往的工作中发现 ,这类给电子性生色团的丙烯酰类单体在相同生色团浓度下的荧光强度明显低于其聚合物或饱和模型化合物 ,即表现出荧光结构自猝灭效应(SSQE) [3~ 5] .咔唑是一个强给电子性芳香杂环化合物 .虽然文献中已有关于含咔唑生色团的丙烯酰类单体报道 ,但很少涉及其荧光或光敏性质 .近来 ,我们合成了多个含有咔唑生… 相似文献
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Xiaoxuan Liu Xiahong Zhang Xinghong Zhang Guangguo Wu Jianwen Yang Laixing Pang Zhaohua Zeng Yonglie Chen 《Journal of polymer science. Part A, Polymer chemistry》2004,42(11):2659-2665
The photoinduced solution polymerization of 4‐methacryloyl‐1,2,2,6,6‐pentamethyl‐piperidinyl (MPMP), used as a reactive hindered amine piperidinol derivative, was performed. The obtained MPMP homopolymer had a very narrow molecular weight distribution (1.06–1.39) according to gel permeation chromatography. The number‐average and weight‐average molecular weights increased linearly with the monomer conversion, this being characteristic of controlled/living free‐radical polymerizations. Electron spin resonance signals were detected in the MPMP homopolymer and in a polymer mixture solution, and they were assigned to nitroxide radicals, which were bound to the polymer chains and persisted at a level of 10?9 mol/L during the polymerization. Instead of the addition of mediated nitroxide radicals such as 2,2,6,6‐tetramethyl‐piperidinyl‐1‐oxy (TEMPO), those radicals (>N? O ·) were formed in situ during the photopolymerization of MPMP, and so the reaction mechanism was understood as being similar to that of TEMPO‐mediated controlled/living free‐radical polymerization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2659–2665, 2004 相似文献
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We have developed a new intermediate monomer, 2,7‐[bis(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)‐9,9‐bis(3‐(tert‐butyl propanoate))]fluorene, that allows the easy synthesis of water‐soluble carboxylated polyfluorenes. As an example, poly[9,9′‐bis(3′′‐propanoate)fluoren‐2,7‐yl] sodium salt was synthesized by the Suzuki coupling reaction, and the properties of the polymer were studied in aqueous solutions of different pH. Fluorescence quenching of the polymer by different cationic quenchers (MV2+, MV4+, and NO2MV2+; MV=methyl viologen) was studied, and the quenching constants were found to be dependent on the charge and electron affinity of the quencher molecule and the pH of the medium. The largest quenching constant was observed to be 1.39×108 M ?1 for NO2MV2+ at pH 7. The change in polymer fluorescence upon interaction with different proteins was also studied. Strong fluorescence quenching of the polymer was observed in the presence of cytochrome c, whereas weak quenching was observed in the presence of myoglobin and bovine serum albumin. Lysozyme quenched the polymer emission at low protein concentrations, and the quenching became saturated at high protein concentrations. Under similar experimental conditions, the polymer showed improved quenching efficiencies toward cationic quenchers and a more selective response to proteins relative to other carboxylated conjugated polymers. 相似文献