NVP-HEMA-AM三元共聚物水凝胶对氯霉素的缓释作用

采用本体共聚法制备了丙烯酰胺(AM)与甲基丙烯酸-2羟-基乙酯(HEMA)以及N-乙烯基吡咯烷酮(NVP)共聚物水凝胶,研究了AM-HEMA-NVP共聚物水凝胶对广谱抗菌药物氯霉素的缓释作用。结果表明,随氯霉素溶液浓度增大、NaC l浓度降低、温度升高以及NVP或者AM组分的含量增大,AM-HE-MA-NVP三元共聚物水凝胶对氯霉素的吸收量增大;随AM-HEMA-NVP三元共聚物水凝胶中NVP或者AM组分含量的增大,氯霉素的释放速度明显增大;氯霉素从水凝胶中缓释的动力学可采用Fick扩散动力学描述,其释放过程受水凝胶溶胀过程以及氯霉素扩散过程控制。     

共聚物阻垢剂中官能团对CaCO3的阻垢协同作用

以水为溶剂,过硫酸铵为引发剂,丙烯酸、异丙烯膦酸、丙烯酰胺为单体,分别合成了低相对分子质量的丙烯酸/丙烯酰胺(AA/AM)、异丙烯膦酸/丙烯酰胺(IPPA/AM)二元共聚物以及不同配比的丙烯酸/异丙烯膦酸/丙烯酰胺(AA/IPPA/AM)三元共聚物.用红外光谱对产物进行了表征.研究了在相同条件下,含有相同基团的共聚物阻垢剂与复配型阻垢剂以及不同组成的共聚物阻垢剂对CaCO3的阻垢性能.结果表明,同一分子链上的基团间具有较好的阻垢协同效应,且基团组成不同,其阻垢协同效应也不同.     

一种新型两亲性聚合物的合成研究

合成了一种新型的两亲性共聚物(丙烯酰胺/醋酸乙烯酯/丙烯酸丁酯,AM/VAc/BA),探讨了在该共聚物合成过程中AM用量和VAc与BA的配比对其表面张力、离心稳定性、乳化性及发泡力的影响,并对该三元共聚物P(AM/VAc/BA)的结构进行表征。结果表明,傅立叶红外光谱(FT-IR)分析在1 680 cm-1~1 620 cm-1处无C=C伸缩振动吸收峰出现,说明体系反应较彻底;差示扫描量热(DSC)分析得共聚物的玻璃化转变温度为37.6℃。     

聚丙烯酸钠/丙烯酰胺复合物的制备及其吸附

以反相悬浮聚合法制备一系列聚丙烯酸钠和丙烯酰胺共聚物[P(AANa-co-AM)],运用傅里叶红外光谱(FT-IR)、热重分析(TG)等手段对其表征。研究了溶液pH值、单体配比、吸附时间、Pb~(2+)浓度和温度等因素对吸附性能的影响。结果显示,在最适pH值下,不同单体配比的聚丙烯酸钠/丙烯酰胺(AA/AM)吸附剂对Pb~(2+)的吸附效果不同,其中AA/AM单体配比为5∶5时,对Pb~(2+)的吸附效果最好。动力学研究表明,该复合材料对铅离子的吸附符合准二级模型;热力学实验数据显示,Langmuir模型比Freundlich模型更符合吸附等温线。当温度由298 K升高到318 K时,最大吸附量由591.7 mg/g增加到625.0 mg/g,热力学研究表明,P(AANa-co-AM)凝胶对Pb~(2+)的吸附为一自发吸热过程。     

丙烯酰胺-马来酸酐共聚合物膜及其对CO2、CH4吸附性能研究

通过自由基聚合制备了丙烯酰胺(AM)和马来酸酐(MA)共聚合物.粘度法测定了聚合物的相对分子量,元素分析法和FTIR等分析表征了共聚物的化学结构,此外研究了共聚合物对CO2和CH4的溶胀吸附性能.在本实验条件下,共聚物的相对分子量、共聚物中两种单体的摩尔数之比m/n、对CO2的平衡吸附量等随聚合过程中单体配比AM/MA的增加而增大;共聚合物的相对分子量在7～17万之间,共聚物中两种单体的摩尔数之比在5～30之间,对CO2的平衡吸附量在45～70mg(CO2)· (g(干膜)) -1之间;而共聚物对CH4的平衡吸附量仅为4mg(CH4)·( g(干膜))-1左右,且不随单体配比AM/MA的增加而变化,这表明丙烯酰胺和马来酸酐共聚合物作为CO2/CH4分离用膜材料,具有较好的CO2优先选择吸附性能.     

双丙酮丙烯酰胺在聚丙烯酰胺改性中的应用

以双丙酮丙烯酰胺(DAAM)和丙烯酰胺(AM)为原料,K2S2O8-NaHSO3氧化还原体系为引发剂,采用水溶液聚合法合成了P(AM-DAAM)二元共聚物,用红外光谱、核磁共振氢谱进行了表征。研究了原料中单体配比、反应时间、引发剂用量对共聚物的特性粘数的影响。结果表明,当DAAM在共聚物中的含量为33.64%时,聚合物的特性粘数比相同条件下合成的聚丙烯酰胺(PAM)提高9.9倍;通过对各种组成共聚物在不同盐溶液中的特性粘数的测定表明,该共聚物具有良好的耐盐性能。     

丙烯腈-丙烯酰胺共聚物的合成与热性能研究

采用溶液自由基法制备了丙烯腈(AN)-丙烯酰胺(AM)共聚物,采用傅立叶变换红外光谱(FTIR)、核磁共振光谱(NMR)、差示扫描量热仪(BSC)和热重分析(TG)等方法对聚合产物进行了表征。研究结果表明,随着AM的加入,共聚物的分子质量和转化率都具有先增大后减小的变化趋势。AN的质量分数为2%(w)时,分子质量和转化率最高,且共聚单体AM能在较低温度时以离子机理形式引发聚丙烯腈(PAN)原丝的氧化、环化放热反应并能减缓放热效应。     

丙烯酸-丙烯酰胺共聚物吸水树脂的制备

采用溶液聚合法,以丙烯酸(AA)和丙烯酰胺(AM)为单体,N,N’-亚甲双丙烯酰胺(NMBA)为交联剂,过硫酸铵为引发剂,制备了丙烯酸-丙烯酰胺共聚物吸水树脂,探讨了单体配比(mAA/mAM)、交联剂和引发剂用量对树脂吸水率的影响。结果表明:在65℃时,丙烯酸-丙烯酰胺共聚物吸水树脂的最佳制备条件为:丙烯酸和丙烯酰胺质量比为4:1,交联剂和引发剂用量分别为聚合单体(丙烯酸和丙烯酰胺)总质量的0.02%和0.4%。     

孪尾疏水缔合丙烯酰胺/丙烯酸钠/N,N-二丁基丙烯酰胺共聚物的合成与性能

以十二烷基硫酸钠(SDS)为表面活性剂,丙烯酰胺(AM)的水溶液为连续相,N,N-二丁基丙烯酰胺(DiC4AM)为分散相,采取先加碱共聚-共水解的方法合成了孪尾疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-二丁基丙烯酰胺)[P(AM/NaAA/DiC4AM)]。用FT IR1、H NMR对其结构、组成进行了表征和测定。用稀释外推粘度法测定了共聚物的特性粘数[η]、Huggins常数KH。用芘荧光探针法及表观粘度法研究了大分子链间的疏水缔合作用,考察了疏水单体用量对其水溶液表观粘度的影响。     

超声辐射下水溶性双丙酮丙烯酸胺-丙烯酰胺-丙烯酸共聚物的合成研究

以双丙酮丙烯酰胺(DAAM)、丙烯酸(AA)、丙烯酰胺(AM)为原料,以(NH4)2S2O8-NaHSO3氧化还原体系为引发体系,在超声的作用下采用溶液聚合法合成水溶性三元共聚物。研究了单体配比、反应时间、反应温度、超声功率以及pH等因素对聚合反应的影响。结果表明:当单体配比为n(DAAM):n(AM):n(AA)=1:1.3:1.1;pH值为5;反应温度25℃;超声功率为200W的条件下反应120min所得产物最佳。     

Probe Molecules for Pulsed-Field-Gradient Diffusion Nuclear Magnetic Resonance Experiments on Micelles

Nuclear magnetic resonance (NMR) diffusion measurements of surfactants suffer from fast exchange of the surfactant between the micellar aggregate and bulk solution. Therefore, hydrophobic probe molecules are commonly used to directly measure aggregate diffusion under the assumption that the probe molecules remain solubilized inside the micelles. Aggregate size is then determined or estimated from the aggregate diffusion value. Unfortunately, the probe molecule also experiences rapid exchange between the aggregate and bulk, leading to inaccurate or unreasonable micelle diffusion values, a fact that has often been ignored in the literature. In this article, we present a systematic evaluation of probe molecules in cationic and anionic surfactants, obtained by measuring the diffusion of probe molecules with varying hydrophobicity. We find that an octanol–water partition coefficient of at least ~5 is required for correct measurements of aggregate diffusion in the systems studied. Notably, some commonly used probes have a partition coefficient much lower than five and are therefore not suitable for aggregate diffusion measurements. Consideration of these results will help researchers obtain accurate results for micelle sizing or partitioning studies with pulsed-field-gradient NMR.     

Untersuchungen zu den Sondeneigenschaften von 7-Hydroxy-cumarinen in micellarer Cetyl-triethyl-ammoniumbromid-Lösung – Hilfsmittel zur Beschreibung von micellaren Systemen

Investigation on Probe Properties of 7-Hydroxy-coumarines in Micellar Cetyl-triethyl-ammoniumbromide Solution – Means for Characterization of Micellar Systems Anions of 3-substituted 7-hydroxy-coumarines ( 1a–c ) as fluorescence probes have been studied in this work. Acid-base equilibria in water and micellar solution of cetyl-triethylammoniumbromide (cmc = 0,72 mmol l⁻¹), fluorescence properties and fluorescence quenching by octacyano-molybdate-IV have been investigated. It has been confirmed that probe and quencher are completely micellized. Fluorescence life times and quenching constants per one quencher molecule in the micell of about 10⁸ s⁻¹ have been determined. The kinetics of saponification of the probe 3-acetyl-7-hydroxy-coumarine at pH = 12 in micellar solution has been followed by probe fluorescence.     

阳离子荧光敏感器的器件化问题研究

通过对石英玻片表面修饰，制作了联有多氨基链萘基的超薄膜荧光敏感器件，研究了它在镍、铜等金属离子水溶液及有机溶剂中的荧光猝灭现象。发现其荧光光谱无论在水或其他有机溶剂中都存在着单体和激基缔合物（excimer)的发射峰，当处于镍离子水溶液中时，其单体峰随离子浓度的增大出现了先增强后减弱的现象，而激基缔合物的发光峰则仅略有减弱但变化不大。在铜离子水溶液中其荧光的变化情况和镍离子有所不同，对单体荧光只能观察到强度减弱的趋势，而激基缔合物则变化不大。比较了未联结的敏感器化合物分子在有机溶剂中荧光被铜离子猝灭的行为，发现与其在器件表面时有很大的差别，表明其分子结构和构象也有很大的不同。     

Photonic Methods to Enhance Fluorescence Correlation Spectroscopy and Single Molecule Fluorescence Detection

Recent advances in nanophotonics open the way for promising applications towards efficient single molecule fluorescence analysis. In this review, we discuss how photonic methods bring innovative solutions for two essential questions: how to detect a single molecule in a highly concentrated solution, and how to enhance the faint optical signal emitted per molecule? The focus is set primarily on the widely used technique of fluorescence correlation spectroscopy (FCS), yet the discussion can be extended to other single molecule detection methods.     

Visualizing spatial and temporal heterogeneity of single molecule rotational diffusion in a glassy polymer by defocused wide-field imaging

Defocused wide-field fluorescence microscopy was used to follow the 3D molecular rotational diffusion of a fluorescent probe molecule in a polymer thin film. The technique allows for visualizing the molecular reorientation both in-plane and out-of-plane. The local environmental change driven by heterogeneous dynamics of the polymer can be probed on a scale of 1 μm as demonstrated by parallel imaging of several molecules. A multi-component rotational diffusion decay is observed which might reflect both different relaxation regimes of the polymer as well as rapid changes of the local environment.     

不同基质(虫胶及PMMA)温敏漆的制备及性能研究

以三氯化钌、氯化钆、联吡啶为原料制备发光探针分子,将探针分子分别加入到聚甲基丙烯酸甲酯基质(PMMA)和虫胶基质中,获得不同基质的温敏漆样品。对探针分子及2种基质温敏漆样品进行了红外、紫外吸收及荧光光谱测试。红外光谱表明,探针分子中联吡啶的结构未被破坏;紫外吸收光谱表明,虫胶的紫外吸收较强,影响了探针分子对紫外光的吸收,所以虫胶基质温敏漆在620nm的荧光发射较弱,而PMMA对紫外光吸收较弱,所以以PMMA为基质的温敏漆在620nm荧光发射较强,同时PMMA基温敏漆的温度猝灭性能也明显比虫胶基温敏漆好。     

液相法制备碳—碳复合材料Si—W涂层表面氧化层的结构

研究了一种液相法及其它方法制备的碳－碳复合材料多层防氧化涂层，并用ＸＲＤ，ＳＥＭ，Ｒａｍａｎ光谱和ＥＭＰＡ研究了液相法制备的Ｓｉ－Ｗ涂层表面氧化后的结构。研究结果表明；氧化后涂层表面生成石英玻璃，且由于Ｗ的高价氧化物进入玻璃的分子网络结构，使其能长时间保持稳定而不析晶。     

Swelling activation energy of κ‐carrageenan in its gel state: A fluorescence study

A steady‐state fluorescence technique was employed to study the swelling of κ‐carrageenan gels at various temperatures. Pyranine was used as a fluorescence probe. The fluorescence intensity of pyranine was measured during the insitu swelling process of κ‐carrageenan gels. The fluorescence intensity increased exponentially as the swelling time increased. The increase in the fluorescence intensity was modeled with the Li–Tanaka equation, from which the swelling time constants and cooperative diffusion coefficients were determined. The swelling time constants decreased and the cooperative diffusion coefficients increased as the swelling temperature was increased. The swelling activation energies were measured to be 47.05 kJ/mol. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

去氧胆酸钠水溶液中4－二甲氨基查尔酮荧光的超常增强

去氧胆酸钠水溶液中４－二甲氨基查尔酮荧光的超常增强江云宝，王秀娟，林莉，黄贤智，许金钩（厦门大学化学系，现代分析化学研究所，厦门３６１００５）关键词双自由基激发态，荧光探针，胆酸型甾族表面活性剂，缔合类似于电子给体受体取代的芭类化合物，４－二甲基氨基...