胶束共聚合法合成丙烯酰胺/4-乙烯基吡啶共聚物

以十二烷基苯磺酸钠为表面活性剂 ,过硫酸钾 /亚硫酸氢钠为引发剂 ,进行丙烯酰胺 - 4-乙烯基吡啶胶束共聚合 ,合成了双亲共聚物 ,用1H NMR分析法、差示扫描量热量 ( DSC)对其进行表征 ,并分析了共聚物形成机理。     

用化学交联法制备聚(4-乙烯基吡啶)纳米凝胶微球

在1,1,2-三氯乙烷/甲醇混合溶剂中用碘代甲烷使聚(4-乙烯基吡啶)(P4VP)线性高分子部分季铵化后，在水中制成微乳液，并用1,4-二碘丁烷交联剂对P4VP微乳液内部进行化学交联，得到固化凝胶微球. 考察了部分季铵化比率、交联温度以及聚合物浓度对微球直径和直径分布的影响，发现微球直径随季铵化比率的增加、交联温度的增加及聚合物浓度的减少而减小. 当季铵化比率为75%(摩尔比)、交联温度为60℃、聚合物浓度为1.0%(w)时，得到了直径为20 nm、粒径分布为±15%的凝胶微球. 本研究的重要特征是不加入任何乳化剂也能得到很小的纳米凝胶微球.     

Synthesis,Characterization of Poly (4-vinyl Pyridine/Vinyl Acetate) Organo Montmorillonite Clay Composites Prepared by Chemical Initiation and their Metallated Products

The nanocomposite of different ratios of (4-vinyl pyridine (VP) vinyl acetate (VAc) copolymers), with montmorillonite (Bent), was prepared by direct interaction of sodium montmorillonite (Bent). It was found that the interaction occurred, through ion exchange between sodium cations in Bent and pyridinium ions, in the copolymers. The structure of the prepared composite was confirmed via X-ray diffraction, thermal stability via thermogravimetric analysis and scanning electron microscope. Also, the formation of metallo composites with Cu⁺², Hg⁺², and Co⁺² cations, and their antimicrobial activities were investigated. The results indicated that the prepared composite exhibited antibacterial activities.     

以b-环糊精、2-羟丙基-b-环糊精和4-乙烯吡啶为功能单体制备氟比洛芬分子印迹聚合物及其吸附特征

以b-环糊精(β-CD)、2-羟丙基-β-环糊精(HP-β-CD)和4-乙烯吡啶(4-VP)为功能单体,以氟比洛芬为模板分子,以环氧氯丙烷和乙二醇二甲基丙烯酸酯为交联剂,采用本体聚合法制备分子印迹聚合物(MIPs),对氟比洛芬与功能单体的相互作用和MIPs的结构进行了表征,比较了3种MIPs对氟比洛芬的吸附性能. 结果表明,β-CD, HP-β-CD和4-VP与氟比洛芬之间以较强的相互作用形成复合物,通过交联、聚合形成聚合物,以HP-β-CD作功能单体所得聚合物印迹效果最佳,具有较强的特异性吸附能力,印迹因子和特异性吸附率分别为1.79和38.92%,分子印迹机制是β-CD的锥筒包结作用和羟丙基的亲和作用形成印迹空穴.     

Selective Solid Phase Extraction of Chromium(VI) using Silica Gel Immobilized 4-vinyl Pyridine/Cupric Ion Complex

Immobilization of 4-vinyl pyridine (4-VP) onto silica gel (SG) and its coordination with cupric ion (SG-4-VP→Cu²⁺) leading to a new solid phase extractor has been carried out by a simple chemical technique. Immobilization and coordination reactions are characterized by chemical, FTIR, UV, and thermo-gravimetric analysis. The role of cupric ion on Cr(VI) binding capacity of the synthesized organic-inorganic hybrid material has been elucidated. The silica gel immobilized 4-VP/Cu²⁺ complex (hybrid material) is tested for selective extraction and pre-concentration of Cr(VI) from aqueous solution. The Cr(VI) binding behavior of the synthesized material is studied at different pH, time, and temperature of the medium in both competitive and non-competitive conditions.     

N-脱氢枞基丙烯酰胺的合成、表征及其聚合性能分析

以歧化松香为原料,先制得脱氢枞胺,再与丙烯酰氯经酰胺化反应合成了N-脱氢枞基丙烯酰胺单体,经提纯为液相色谱纯度97.95%的白色固体。通过 FT-IR、MS、¹H NMR、¹³C NMR、TG、GPC及DSC表征了其结构和性能。结构表征结果显示成功合成了N-脱氢枞基丙烯酰胺。DSC分析显示,单一单体在151~196℃时发生热聚合,且自由基引发剂偶氮二异丁腈(AIBN)的存在可以降低其聚合温度,聚合物的玻璃化转变温度在100.34℃。TG分析显示,聚合物在209~483℃发生热分解。对N-脱氢枞基丙烯酰胺聚合物进行GPC分析,结果为M_n=4 301,M_w/M_n=1.56。     

Hydrogels for water filters: Characterization and regeneration

Acrylic acid was crosslinked with N,N′‐methylenebisacrylamide followed by a reaction with hexamethylenetetramine (HMTA) to form a new hydrogel, Gel ( 2 ). Water absorbance rate and retention of Gel ( 2 ) were characterized. At the same time, factors affecting absorbance rate such as pH, temperature, and ions concentration were studied. The rate decreased with decreasing pH and increasing ions concentration, whereas increased with raising temperature. The effect of the hydrogel on bacterial (Staphylococcus aureus and Escherichia coli) viability and growth rate was determined. Gel ( 2 ) has achieved a 5 log reduction on both E. coli and S. aureus in 2 h while no cells were detected after 3 h in case of S. aureus and 4 h in case of E. coli. Lifetime and regeneration of Gel ( 2 ) using both stirred flask and column (a model for a water filter) methods were determined. Identifying the lifetime using columns showed that the gel stays active up to 5 and 7 runs for both E. coli and S. aureus respectively. In addition, it was recycled successfully up to 10 times, using column and stirred flask methods, against both types of bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of Potassium Methacrylate Content on Synthesis,Swelling, and Diffusion Characteristics of Acrylamide/Potassium Methacrylate Hydrogels

ABSTRACT

Hydrogels based on acrylamide (AAM) and potassium methacrylate (KMA) were synthesized by simultaneous free radical polymerization in aqueous solution using the redox initiator ammonium persulfate (APS) and N,N,N′N′-tetramethylethylenediamine (TMEDA) at room temperature. Eight different compositions of KMA hydrogels were prepared at a fixed concentration of N,N′,-methylenebisacrylamide (MBA) or diallyl phthalate (DP) as crosslinking agents. For all the AAM-KMA hydrogels, the percentage of swelling, swelling kinetics, and diffusion characteristics were investigated. It was found that higher swelling percentage values were obtained for hydrogels crosslinked with DP than for the conventional crosslinker MBA. The de-swelling characteristics of hydrogels were also studied in detail. The power law relationship of hydrogels was evaluated in saline solutions. Hydrogels formation was confirmed by IR spectroscopy. The thermal characteristics of these hydrogels were studied by using differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA) and revealed that MBA crosslinked AAM-KMA hydrogels show higher glass transition temperature (Tg) as well as higher decomposition temperatures (Td) than DP crosslinked AAM-KMA hydrogels. It is further confirmed from the studies that the DP crosslinked hydrogels have good swelling as well as de-swelling and salinity characteristics.     

PAAm／PEG／PVP半互穿网络水凝胶的制备、表征及茶碱释放研究．

以N,N-亚甲基双丙烯酰胺（N,N-MBA）为交联剂、过硫酸钾（KPS）为引发剂·通过丙烯酰胺（AAm）、聚乙二醇（PEG）和聚乙烯吡咯烷酮（PVP）发生共聚反应制备具有半互穿网络结构的水凝胶PAAm／PEG／PVP。采用红外光谱（FTIR）、热重分析（TG）对水凝胶的结构和热学性质进行了分析,研究了中性条件下水凝胶的溶胀性能,并进一步研究了其负栽茶碱在不同缓冲溶液中的释放行为。     

温度和pH双重敏感性P(DEA-co-DMAEMA)/Na2WO4水凝胶的合成与表征

以N,N-二乙基丙烯酰胺(DEA)和甲基丙烯酸二甲氨基乙酯(DMAEMA)为单体,N,N-亚甲基双丙烯酰胺(BIS)为交联剂,采用一锅法制备了温度和p H双重响应性P(DEA-co-DMAEMA)/Na_2WO_4水凝胶。考察了Na_2WO_4的引入对水凝胶的结构、温度和p H响应性能的影响。结果表明:复合水凝胶中除了化学交联外,还存在Na_2WO_4与聚合物间由于氢键和配位作用产生的物理交联;复合水凝胶的低临界相转变温度(LCST)随着Na_2WO_4质量分数的增加呈线性降低,当Na_2WO_4质量分数从0增至3%时,LCST由41.6℃降至34.4℃;复合水凝胶表现出双重p H响应性,即在酸性条件下溶胀,中性条件下溶胀率减小,碱性条件下溶胀率又升高。     

Synthesis and Antimicrobial Activity of p-tetranitrocalix[4]arene Derivative

The present study demonstrates the synthesis and antimicrobial activity of the p-tetranitrocalix[4]arene (3). The microbial activity was determined against a variety of microorganisms, i.e., Gram-positive and Gram-negative bacterial strains such as Staphylococcus aureus ATCC 10231, Streptococcus viridans ATCC 12392, Escherichia coli ATCC 8739, as well as some fungal species including Aspergillus niger ATCC 16404, Aspergillus flavus ATCC 90906, and Candida albicans ATCC 32333. Kirby-Bauer well agar diffusion method was employed for the determination of antimicrobial activity. All the microorganisms were applied to a selective agar medium (Mueller Hinton Agar) for growth. It was observed that compound 3 is considerably effective against selected microorganisms. The MIC values were also evaluated. Thus, from the results it could be deduced that compound 3 may be a valuable addition to the therapeutic index.     

ASPAA/MMA/AN三元共聚物的合成与表征

在合成N-[4-(磺酰胺)苯基]丙烯酰胺(ASPAA)单体,并进行结构表征的基础上,以N,N-二甲基甲酰胺为溶剂,过氧化苯甲酰为引发剂,采用自由基溶液聚合合成了ASPAA／甲基丙烯酸甲酯／丙烯腈三元共聚物,用IR和^1H—NMR图谱确认了结构。共聚结果表明85℃和95℃,引发剂浓度1．0％～1．5％时,聚合初期速率较高;共聚物分子量随聚合温度和引发剂浓度增加而降低。随ASPAA含量的增加,共聚物的玻璃化温度和酸值均升高,并通过ASPAA含量来调节。     

Synthesis and Characterization Superabsorbent Polymers Made of Starch,Acrylic Acid,Acrylamide, Poly(Vinyl Alcohol), 2-Hydroxyethyl Methacrylate, 2-Acrylamido-2-methylpropane Sulfonic Acid

Three polymers with excellent absorption properties were synthesized by graft polymerization: soluble starch-g-poly(acrylic acid-co-2-hydroxyethyl methacrylate), poly(vinyl alcohol)/potato starch-g-poly(acrylic acid-co-acrylamide), poly(vinyl alcohol)/potato starch-g-poly(acrylic acid-co-acrylamide-co-2-acrylamido-2-methylpropane sulfonic acid). Ammonium persulfate and potassium persulfate were used as initiators, while N,N′-methylenebisacrylamide was used as the crosslinking agent. The molecular structure of potato and soluble starch grafted by synthetic polymers was characterized by means of Fourier Transform Infrared Spectroscopy (FTIR). The morphology of the resulting materials was studied using a scanning electron microscope (SEM). Thermal stability was tested by thermogravimetric measurements. The absorption properties of the obtained biopolymers were tested in deionized water, sodium chroma solutions of various concentrations and in buffer solutions of various pH.     

New Antimicrobial Hexapeptides: Synthesis,Antimicrobial Activities,Cytotoxicity, and Mechanistic Studies

Synthetic antimicrobial peptides have recently emerged as promising candidates against drug‐resistant pathogens. We identified a novel hexapeptide, Orn‐D ‐Trp‐D ‐Phe‐Ile‐D ‐Phe‐His(1‐Bzl)‐NH₂, which exhibits broad‐spectrum antifungal and antibacterial activity. A lead optimization was undertaken by conducting a full amino acid scan with various proteinogenic and non‐proteinogenic amino acids depending on the hydrophobic or positive‐charge character of residues at various positions along the sequence. The hexapeptide was also cyclized to study the correlation between the linear and cyclic structures and their respective antimicrobial activities. The synthesized peptides were found to be active against the fungus Candida albicans and Gram‐positive bacteria such as methicillin‐resistant Staphylococcus aureus and methicillin‐resistant Staphylococcus epidermidis, as well as the Gram‐negative bacterium Escherichia coli; MIC values for the most potent structures were in the range of 1–5 μg mL^?1 (IC₅₀ values in the range of 0.02–2 μg mL^?1). Most of the synthesized peptides showed no cytotoxic effects in an MTT assay up to the highest test concentration of 200 μg mL^?1. A tryptophan fluorescence quenching study was performed in the presence of negatively charged and zwitterionic model membranes, mimicking bacterial and mammalian membranes, respectively. The results of the fluorescence study demonstrate that the tested peptides are selective toward bacterial over mammalian cells; this is associated with a preferential interaction between the peptides and the negatively charged phospholipids of bacterial cells.     

Polyetherketones: Synthesis,Characterization and Antimicrobial Activity

ABSTRACT

Friedel-Crafts polyetherketones were prepared from o-chlorophenol, 1,4-phenylenedioxy diacetylchloride (1,4-PDC), chloroacetyl chloride (CAC), 1,2-dichloroethane (DCE), and dichloromethane (DCM) using anhydrous aluminium chloride (AlCl₃) as catalyst and carbon disulfide (CS₂) as solvent. These resins were characterized by IR spectroscopy and gel permeation chromatography. Carius method was employed to obtain the percentage of chlorine content in the resins. The kinetic parameters for the thermal behavior of the resins were evaluated from thermogravimetry (TG) using Broido method. Differential scanning calorimetry (DSC) thermograms of these resins were also obtained. All the polyetherketones were tested for their antimicrobial properties against bacteria, fungi, and yeast. It was observed that most of the polyetherketones synthesized could be used as antibacterial and antifungal agents.     

Friedel-Crafts Polyetherketones: Synthesis, Characterization and Antimicrobial Properties

Low molecular weight Friedel-Crafts polyetherketones (PEK) were prepared from o-chloro anisole, 1,4-phenylenedioxy diacetychloride (1,4-PDC), chloroacetylchloride (CAC), 1,2-dichloroethane (DEC) and dichloromethane (DCM) using anhydrous AlCl₃ as catalyst and CS₂ as solvent. The polyetherketones were characterized by IR spectra and Gel permeation chromatography (GPC). The kinetic parameters for the thermal behaviour of the resins were obtained from thermo gravimetric analysis (TGA) using the Broido and Doyle method. Differential scanning calorimetry (DSC) traces were employed to obtain heat of fusion. All the polyetherketones were tested for their biological activity against bacteria, fungi and yeast. It was observed that most of the polyetherketones synthesized can be used as antibacterial and antifungal agents. This revised version was published online in July 2006 with corrections to the Cover Date.     

g-C3N4/ZnO复合材料的制备、表征及可见光催化性能

以一步法原位合成了g-C3N4/ZnO异质结复合材料,评价其在可见光下降解亚甲基蓝（MB）的光催化活性,并探讨了g-C3N4/ZnO的光催化机制。运用XRD、FT-IR、SEM和UV-Vis DRS对所合成的复合材料进行表征。结果表明,经复合后g-C3N4和ZnO紧密结合,构建了异质结,提高了光生电子-空穴的分离效率,并且在可见光区表现出较强的光响应性;当g-C3N4的质量分数为19%时,复合材料降解MB的反应速率常数为0.0206min-1,是纯g-C3N4的3.8倍。催化剂重复使用5次,仍保持较高的催化活性。     

Homopolymer of 4-chloro-3-methyl Phenyl Methacrylate and its Copolymers with Butyl Methacrylate: Synthesis, Characterization, Reactivity Ratios and Antimicrobial Activity

The methacrylate monomer 4-chloro-3‐methyl phenyl methacrylate (CMPM) was synthesized by reacting 4-chloro-3‐methyl phenol with methacryloyl chloride. The homopolymer and various copolymers of CMPM with n-butyl methacrylate were synthesized by free-radical polymerization in toluene at 70°C using 2,2′-azobis(isobutyronitrile) as the initiator. The CMPM monomer was characterized by Fourier transform IR and ¹H-NMR studies. The copolymers were characterized by IR spectroscopy. The molecular weights (M _n and M _w) and the polydispersity index were obtained from gel permeation chromatography. The solubility and intrinsic viscosity of the homopolymer and the copolymers are also discussed here. The copolymer composition obtained from UV spectra led to the determination of reactivity ratios employing Fineman-Ross and Kelen-Tudos linearization methods. Thermogravimetric analyses of the homopolymer and the copolymers were carried out under a nitrogen atmosphere. The homopolymer and the copolymers prepared were tested for their antimicrobial activity against bacteria, fungi and yeasts.     

Bioactive Organotin Materials: Synthesis, Characterization and Antimicrobial Investigation

Antimicrobial properties of some newly prepared oil based organotin polymers by the condensation reaction between fatty amide diol (N,N′-bis(2-hydroxyethyl) castoroil fatty amide) obtained from castoroil and organotin dihydroxides (dibutyltin dihydroxide, dimethyltin dihydroxide and diphenyltin dihydroxide) have been studied by employing both Gram-positive (Lactobacillus, Staphylococcus aureus) and Gram-negative (Pseudomonas putida, Pseudomonas fluorescens, E. coli) bacteria. The structural studies of these three polymers were carried out by FTIR, ¹HNMR and ¹³ CNMR spectroscopic techniques. Standard laboratory methods were used to study the physiochemical characteristics like acid value, hydroxyl value, saponification value, iodine value, specific gravity and viscosity. A comparative study of the thermal stability was analysed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). All three polymers have been found fairly active against the tested bacterial species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis of copolymeric acrylamide/potassium acrylate hydrogels blended with poly(vinyl alcohol): Effect of crosslinking and the amount of poly(vinyl alcohol) on swelling behavior

A novel series of copolymeric acrylamide/potassium acrylate superabsorbents, blended with poly(vinyl alcohol), have been synthesized by using N, N′‐methylenebisacrylamide as a crosslinker and potassium persulphate (K₂S₂O₈) as an initiator. Swelling behavior of these hydrogels in water was investigated; and on the basis of swelling properties, the diffusional behavior of water into these hydrogel systems was analyzed. It was observed that with the increase of amount of poly(vinyl alcohol) or crosslinking, the swelling of the hydrogels decreased. The hydrogel synthesized by addition of 5% poly(vinyl alcohol) and 0.25% crosslinking showed maximum swelling of 54445%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1927–1931, 2005