纳滤膜的场发射扫描电镜、能量色散X射线、原子力显微镜珊傅里叶转换红外光谱分析

利用场发射扫描电镜、能量色散X射线分析、原子力显微镜与傅里叶转换红外光谱技术,对NF45纳滤膜的表面形态、孔径分布进行了分析研究,同时考察了大豆乳清液的纳滤膜污染特征。研究表明：NF45膜的孔径范围小于0．5nm,膜孔分布均匀,平均表面粗糙度为9．4nm,波峰高度是纳米级;而污染膜面基本表现为无数小葡萄球状的低聚糖类物质组成的块状,且污染物层分布很不均匀,波动很大,平均表面粗糙度为439．7nm,波峰高度是微米级的。     

纳滤膜难溶盐污染过程的介电监测方法

模拟了难溶盐对纳滤膜的污染过程并对其进行了介电谱解析,探讨了介电谱作为一种监测膜内部或表面污染层信息的方法之可行性.测量了NF90、NF270、NF-3种商用纳滤膜分别被4种难溶盐(CaCO3、CaSO4、BaSO4、SrSO4)污染前后膜/液体系的介电谱,介电谱的差异是来自于因膜孔径的不同而分别在膜孔内和膜表面形成的...     

热固性酚醛树脂基微滤炭膜的制备

实验合成了球形热固性酚醛树脂微粒,并以此为原料制备了微滤炭膜.炭膜的孔径分布结果表明,在原料粒度较小的情况下,所制得的炭膜孔径分布较窄,平均孔径和气体透量较小.对几种常见的粘结剂进行了筛选,当以甲基纤维素为粘结剂时,随着甲基纤维素用量的增加,微滤炭膜的孔径分布变窄,平均孔径及气体透量减小.炭化条件中炭化终温对炭膜性能的影响较大.     

基于界面聚合法在受限空间内诱导合成反渗透/纳滤复合膜的研究

一种新的概念,受限空间内的界面聚合,用于研究反渗透膜(RO)/纳滤膜(NF)复合膜的合成。实验设计使用受保护的多胺单体通过延迟扩散与均苯三甲酰氯反应,获得了过渡态结构的RO/NF膜。在NF膜水相配方中加入大分子模板剂,诱导界面反应在受限空间内定向发生,将聚合物网络的聚集态由无序转变为有序,同时NF膜对盐的截留性能不变,水通量提高一倍。RO膜有机相配方中加入纳米分子筛,提升水通量超过50%,复合膜表面结构呈现NF膜的特性,同时脱盐性能保持不变。     

中性溶质环境下纳滤膜分离性能实验研究

对NF270与GE DK两种纳滤膜在异丙醇、葡萄糖和蔗糖3种溶质环境下进行了不同条件实验,以测试膜的基本参数.并采用Matlab软件对S-K模型进行了实验数据的回归分析,得出了纳滤膜的反射系数与溶质透过系数.利用SHP模型测算了纳滤膜的孔径及孔隙率与厚度的比值,同时研究了3种中性溶质在纳滤膜分离过程中的热力学参数.结果表明,实验数据与S-K模型模拟结果的偏差在0～2.0%之间,模拟值与实验数据吻合;NF 270纳滤膜的平均孔径在0.54～0.61nm,GE DK纳滤膜的平均孔径在0.51～0.58nm;异丙醇、葡萄糖和蔗糖在NF 270纳滤膜分离过程中的活化能分别为14.24、31.86和78.41kJ/mol,异丙醇和葡萄糖在GE DK纳滤膜分离过程中的活化能分别为45.83和46.09kJ/mol.     

纳滤初期邻苯二甲酸二(2-乙基己基)酯在膜上的吸附行为

研究了NF90膜和NF70膜对纯水、模拟水和河水中邻苯二甲酸二(2-乙基己基)酯(DEHP)的截留和吸附.结果表明:NF90膜能实现对微量DEHP(浓度为100 μg/L)的有效去除,截留率高达95％以上;纳滤初始阶段,DEHP在膜面的吸附作用较强,吸附率达40％左右.操作压力,pH,共存有机物、无机物和膜孔径影响DEHP在膜上的吸附,初始浓度的影响不大.     

亲和膜分离技术（I）—原理和材料

本文对亲和膜分离技术，装置和发展作了评述，并对亲和膜用作生物大分子纯化化离程序和的原理作了描述，还对亲和膜所用的材料，介质的活化方法作了介绍。     

液晶投影显示的色纯度和色均匀性

用1913CIE和1976CIE分析了液晶投影显示分色系统对图像色纯度和色均匀性的影响。介绍了分色系统的膜系设计，与典型的分色膜系相比，优化膜系由于通带中的波纹显著减小，色纯度得到明显改善，尤其是绿光，讨论了照明光孔径角对分色系统均匀性的影响，提出了用厚度渐变的楔形膜校正色差的方法，使色均匀性得到显著改进。     

热诱导相分离法制备低密度聚乙烯微孔膜——（1I）动力学因素对微孔膜结构的影响

选择低密度聚乙烯（LDPE）为主体材料，二苯醚（DPE）为稀释剂，研究了淬冷温度、粗化时间等影响液滴生长的动力学因素对热诱导相分离法（TIPS）制备LDPE／DPE微孔膜结构的影响。结果表明，在相同粗化时间的条件下，随着LDPE／DPE体系冷却温度的逐渐升高，孔径逐渐变大。对于质量百分数为20％LDPE／DPE体系，在结晶温度以下（0℃、30℃、60℃）粗化时。温度对微孔膜的孔径影响较小。而在90℃的恒温条件粗化时，体系始终处在液一注相分离区域，最终得到微孔膜的孔径接近5μm。在结晶温度以下（60℃）进行恒温粗化，粗化时间对微孔膜的孔径影响不大；而在结晶温度以上（90℃）进行恒温粗化时，则是随着粗化时间的延长，微孔膜的孔径逐渐变大。     

冷侧真空度对压膜蒸馏过程影响的研究

和ＰＴＦＥ膜实验研究了冷侧真空度地减压膜蒸馏过程的影响，实验结果表明，随冷侧真空度的提高，蒸汽的渗透能量增加，分离率也增加，渗透能量和两侧的蒸汽压差成正比，若真空度很高，且冷侧的绝压比膜冷侧的饱和蒸汽压低时，渗透通量有剧增的趋势；渗透能量和膜的孔径大小有关，孔径越大，通量越大。     

树状聚合物PAMAM制备高脱盐纳滤膜

通过发散法合成了以N-(2-胺乙基)哌嗪为核的端胺基树状聚合物聚酰胺胺(PAMAM),并以此为水相单体与均苯三甲酰氯发生界面聚合反应制备了高脱盐率纳滤膜.采用傅里叶转换红外光谱(FTIR-ATR)、X射线光电子能谱(XPS)等手段研究膜表面化学组成的变化,扫描电镜(SEM),原子力显微镜(AFM)观察膜的结构与形貌,接触角测定仪评价膜的亲水性.结果表明,使用高代数PAMAM、增大PAM-AM浓度、延长反应时间均促使膜的致密度增加,脱盐卒增大.使用浓度为4.46×10-3mol/L第二代PAM-AM溶液为反应物制备的纳滤膜对Na2SO4、MgCl2、MgSO4的脱除率分别达到93.0%,92.3%和91.4%.值得注意的是,PAMAM浓度的增加导致酰氯基由过量到相对不足,最终所制备的纳滤膜对NaCl、Na2SO4、MgCl2和MgSO4等4种盐的脱盐顺序也发生相应变化,主要体现在MgCl2的脱除率由低于Na2SO4和MgSO4变化到高于这两种盐最后三者的脱除率趋于近似相等,均>90%.     

以酯端基PAMAM树形分子为模板在N，M-二甲基甲酰胺溶剂中制备金纳米粒子

用UV-vis、FT-IR光谱研究了HAuCl4和酯端基聚酰胺胺(PAMAM)树形分子在N，N-二甲基甲酰胺(DMF)溶剂中的相互作用，提出HAuCl4与树形分子之间的络合机理：[AuCl4]^-离子与质子化叔胺基团形成离子对，Au^3 离子与PAMAM树形分子上的酯基和酰胺基团形成配位作用。在DMF溶剂中酯端基PAMAM树形分子与HAuCl4配位后用柠檬酸钠还原形成金纳米粒子，UV-vis光谱和TEM图像分析表明了随树形分子代数的增加，金纳米粒子的直径减小，并提出了树形分子-金纳米复合物的结构模型：(1)较低代数的树形分子环绕在金粒子的外围；(2)在较高代数的树形分子空腔内部封装金纳米粒子。     

Controllable synthesis of hydroxyapatite nanocrystals via a dendrimer-assisted hydrothermal process

The morphology and size of hydroxyapatite Ca₁₀(PO₄)₆(OH)₂ (denoted HAP) can be controlled under hydrothermal treatment assisted with different dendrimers, such as carboxylic terminated poly(amidoamine) (PAMAM) and polyhydroxy terminated PAMAM. The structure and morphology were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM). IR spectra were also used to investigate the complexation of Ca²⁺ with PAMAM. The results revealed that the inner cores of the PAMAM dendrimers are hydrophilic and potentially open to calcium ions, since interior nitrogen moieties serve as complexation sites, especially in case of the polyhydroxy terminated PAMAM. And the reasonable mechanism of crystallization was proposed that it can be attributed to the localization of nucleation site: external or interior PAMAM. Additionally, the PAMAM dendrimer with carboxylic and polyhydroxy groups has an effective influence on the size and shape of hydroxyapatite (HAP) nanostructures. Different crystal morphology was accomplished by adsorption of different dendrimers onto specific faces of growing crystals, altering the relative growth rates of the different crystallographic faces and leading to different crystal habits.     

Stealth dendrimers for drug delivery: correlation between PEGylation,cytocompatibility, and drug payload

It is advantageous to utilize low generation polyamidoamine (PAMAM) dendrimers for drug delivery because low generations (generation 4.0 or below) have more biologically favorable properties as compared to high generations. Nevertheless, modification of low generation dendrimers with PEG to create stealth dendrimers is still necessary to avoid potential side effects by long term accumulation. However, low generation dendrimers have much fewer surface sites for drug loading as compared to higher generations. To efficiently utilize low generation dendrimer-based stealth dendrimers for drug loading, PEGylation needs to be optimized. In this study, we synthesized a series of stealth dendrimers based on low generation Starburst™ PAMAM dendrimers (i.e., G2.5, G3.0, G3.5, and G4.0) and quantitatively assessed PEGylation efficacy in modulating cytocompatibility of low generation PAMAM dendrimers. Cytocompatibility of stealth dendrimers was examined using endothelial cells. The results showed that PEGylation degree on low generation dendrimers could be dramatically reduced to leave as many unoccupied surface groups as possible for drug loading, while maintaining the drug carrier cytocompatibility. 3PEGs-G3.0 and 10PEGs-G4.0 were considered initially optimized stealth dendrimers that would be further modified to deliver drugs of interest. Correlation of PEGylation, cytocompatibility, and drug payload allowed us to optimize low generation dendrimer-based stealth dendrimers for drug delivery and advance the understanding of structure-property relationship of stealth dendrimers.     

笼状PAMAM模板纳米钯催化Suzuki反应

针对PAMAM模板纳米钯催化剂在循环使用中容易团聚产生钯黑的问题,文章利用4．5代PAMAM端基的酯基团与乙二胺反应形成鸟笼状大分子,以其为模版合成纳米钯催化剂,研究发现,当端基连接50％,反应条件温和,催化剂易于分离,循环使用4次,仍能保持70％的收率。     

Synthesis and characterization of quaternized carboxymethyl chitosan/poly(amidoamine) dendrimer core–shell nanoparticles

With the aim to develop a novel water-soluble modified chitosan nanoparticle with tuned size and improved antibacterial activity, quaternized carboxymethyl chitosan/poly(amidoamine) dendrimers (CM-HTCC/PAMAM) were synthesized. Firstly low-generation amino-terminated poly(amidoamine) (PAMAM) dendrimers were prepared via repetitive reactions between Michael addition and amidation, which were then employed for modifying quaternized carboxymethyl chitosan (CM-HTCC). Prior to the reaction of CM-HTCC with PAMAM, carboxylic groups in CM-HTCC were activated with EDC/NHS in order to enhance the reaction efficiency. FT-IR, ¹H NMR, elemental analysis and XRD were performed to characterize CM-HTCC/PAMAM dendrimers. Turbidity measurements showed that CM-HTCC/PAMAM dendrimers had good water-solubility. TEM images indicated that CM-HTCC/PAMAM dendrimers existed as smooth and spherical nanoparticles in aqueous solution. The results of antibacterial activity explored that CM-HTCC/PAMAM dendrimer nanoparticles displayed higher antibacterial activity against Gram-negative bacteria Escherichia coli (E. coli), whereas they showed much less efficiency against Gram-positive bacteria Staphylococcus aureus (S. aureus) compared to quaternized chitosan (HTCC).     

HPLC separation of different generations of poly(amidoamine) dendrimers modified with various terminal groups

Polyamidoamine (PAMAM) dendrimers of different generations with various terminal groups were analyzed, for the first time, using a combination of high-performance liquid chromatography (HPLC), size exclusion chromatography (SEC), and matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) techniques. Separation of amine-terminated dendrimers from generation 1 through generation 9 (G1NH(2)-G9NH(2)) was achieved using reversed-phase HPLC with elution time increasing gradually as the density of terminal amine groups increases as a function of generation. Furthermore, separation of dendrimers with terminal amino, acetamide, hydroxyl, and carboxylate groups was obtained. It has also been shown that HPLC can be used to separate dendrimers based on some structural defects inherent during the syntheses of PAMAM dendrimers. MALDI-TOF mass spectra of G1NH(2) identify the major imperfections present during typical synthesis processes. The absolute molar masses (M(n)) and molar mass distributions of the dendrimers were measured using the SEC system equipped with multiangle laser light scattering and refractive-index detectors. Findings from this study suggest HPLC can be a vital tool for characterization and preparative separation of PAMAM dendrimers.     

Modifying the adsorption behavior of polyamidoamine dendrimers at silica surfaces investigated by total internal reflection fluorescence correlation spectroscopy

Polyamidoamine (PAMAM) dendrimers were modified and tested for use as solution-phase diffusion probes in silica nanostructures. In order for the successful application of dendrimers as solution-phase probes, their interactions with silica surfaces must be understood and controlled, so that the motion of the probe is not influenced by adsorption. Adsorption/desorption kinetics of PAMAM dendrimers and their diffusion in solution near silica surfaces were investigated with total internal reflection fluorescence correlation spectroscopy (TIR-FCS). Dendrimers of generations 3, 5, and 7 were dye-labeled with carboxyrhodamine 6G. Because PAMAM dendrimers are positively charged in solution (having primary amines as end groups), significant adsorption of these molecules to the negatively charged silica surface was observed. Adsorption/desorption rates and the equilibrium constant for adsorption were determined by fitting the autocorrelation functions to a kinetic model. The desorption rate decreases and the absorption equilibrium constant increases with higher dendrimer generation. To reduce the adsorption of these probes to silica surfaces, the labeled dendrimers were reacted with succinic anhydride, converting the primary amine end groups to negatively charged carboxylic acid groups. These carboxylated dendrimers did not detectably adsorb to silica from aqueous solution. TIR-FCS was used to determine their free-solution diffusion constants near silica surfaces, and the corresponding hydrodynamic radii compare favorably with values reported from forced Rayleigh scattering measurements.     

Binding and conformation of dendrimer-based drug delivery systems:a molecular dynamics study

All atomistic molecular dynamics simulations were performed on poly(amidoamine)(PAMAM) dendrimers that compound non-covalently with anticancer drug molecules including DOX,MTX,CE6,and SN38.The binding energies as well as their associated interaction energies and deformation energies were combined to evaluate the relative binding strength among drug,PAMAM,and PEG chains.We find that the deformation of dendrimers due to drug loading plays a crucial role in the drug binding.It is energetically favorable for the drug molecules to bind with PAMAM while the drugs bind with PEG metastable chains via kinetic confinement.Surface PEGylation helps dendrimers to accommodate more drug molecules with greater strength without inducing too much expansion.This work indicates that tuning the functionalized terminal groups of dendrimers is critical to design efficient dendrimer-based drug delivery systems.     

CdS／PAMAM纳米复合材料的制备及光学性能

以聚酰胺－胺（PAMAM）树形分子为模板，原位合成CdS，AMAM树形分子纳米复合材料，探索不同负载比对其性能的影响及量子点表面的功能性。通过荧光光谱技术，分析Cu^2＋和Mn^2＋重金属离子对其光致发光性能的影响，利用光学性质变化、材料分析稳定度考察其反应机制。