Synthesis and luminescent properties of new europium-containing copolymers based on norbornene functional derivatives

New copolymers containing oxadiazole, carbazole, and europium-containing fragments in the side chains were synthesized by ring-opening metathesis polymerization. The polymeric materials obtained were characterized by IR spectroscopy, GPC and DSC methods, and elemental analysis. All the copolymers possess strong metal-centered photoluminescence in solution and in thin film. In the electroluminescence spectra, the emission of the europium cations is exhibited and a broad band with the maximum at 507 nm is observed, which supposedly is attributable to the emission of the electroplexes between the polymeric matrix and the europium-containing fragments.     

Ce-Zr-Ba-O纳米材料的制备及其结构与性能研究

以金属硝酸盐为原料,分别采用高分子前驱体法、柠檬酸盐凝胶法制备了纳米级的Ce-Zr-Ba-O复合氧化物超细粒子,采用X-射线衍射(XRD)、透射电镜(TEM)、BET比表面测定、热重-差热(TG-DTA)技术对催化剂进行了表征,并考察了催化剂的CO氧化活性和热稳定性。实验结果表明,高分子前驱体法和柠檬酸盐凝胶法制备的催化剂粉体都达到了纳米级。两种方法中,高分子前驱体法所制得的催化剂的BET比表面达118.96m²·g^-1,CO氧化反应活性较高,同时该方法制得的催化剂分散性好,无团聚,经1000℃高温焙烧后仍基本无烧结、无团聚现象,具有较高的热稳定性。     

Preparation and characterization of diphasic sol-gel derived unsupported mullite membranes

Diphasic gels prepared by mixing freshly prepared polymeric silica and polymeric boehmite sols through a modified Al-alkoxide route in mullite compositions led to the crystallization of mullite upon heat treatment at 775 °C. Mullite formation was observed at a 100 °C higher temperature when diphasic gels were formed by mixing aged polymeric sols containing about 2 nm in diameter boehmite species. These relatively low mullite formation temperatures were attributed to the nanoscale sizes of the polymeric species of the two amorphous phases present in the diphasic gels.     

布洛芬高分子前体药物及纳米微球的合成和表征

将非甾体消炎药布洛芬以共价键连接到舍双键的甲基丙烯酸-2-羟基乙酯(HEMA)上,制成含布洛芬药物的单体,进而通过自聚或共聚,合成了含布洛芬的高分子药物;采用乳液聚合方法制备了高分子药物蚋米微球。研究了影响聚合反应的有关因素,并对所合成的产物用^1H-NMR,GPC和TEM等检测手段进行了表征。     

聚合物纳米粒子的制备及其新型物理水凝胶结构的AFM和SEM研究

凝胶材料是生物系统的重要组成物质,在生物模拟、仿生等方面具有重大意义.最近凝胶方面的研究日益受到关注^[1,2],高分子凝胶体系的研究也得到深入开展^[3,4].在智能水凝胶、凝胶特性基础研究和医用凝胶材料等领域已取得了较大进展.     

Solvent-free synthesis and properties of carboxymethyl starch fatty acid ester derivatives

Water-soluble, partially hydrophobized polysaccharides have become attractive due to their potential to act as polymeric surfactants. From carboxymethyl starch (CMS), water-soluble polymeric surfactants were prepared by esterification using two unconvential methods based on (A) a reaction with mixed anhydrides and (B) with methyl laureate (MELA) and methyl esters of the fatty acid complex of rape seed oil (MERO) under ‘solvent-free’ conditions. The obtained CMS derivatives were characterized by structural, surface-active and surfactant performance properties. Esterification using method B was successful in contrast to method A which yielded derivatives with a very low extent of esterification. Although the derivatives reduced the surface tension moderately, they exhibited remarkable emulsifying properties. The performance tests indicated good washing power and antiredeposition efficiency. The results suggest that suitable polymeric surfactants can be prepared by the unconventional esterification method B using both acylation agents. The preparations might substitute the expensive and invasive industrially applied conventional methods.     

聚合物复合物层层组装膜的高效负载及大分子和小分子药物的差别性释放

基于聚合物复合物和层层组装技术实现了大分子药物硫酸软骨素和小分子药物头孢曲松钠在聚合物膜中的高效负载以及差别性释放. 壳聚糖(CHI)和大分子药物硫酸软骨素(CSS)通过静电相互作用力复合, 制备了壳聚糖-硫酸软骨素复合物(CHI-CSS). 以CHI-CSS复合物和透明质酸(HA)为构筑基元, 通过层层组装构筑负载有硫酸软骨素的聚合物复合物膜. 利用后扩散的负载方法将小分子药物头孢曲松钠(CTX)负载到聚合物膜中, 从而实现大分子和小分子2种药物在聚合物膜中的负载. 聚合物膜中负载的CTX和CSS在生理条件下具有快慢不同的差别性释放动力学特性, CTX在6 h内快速释放, 而CSS长效缓释长达14 d. 快速释放的抗生素CTX能够有效抑制细菌感染, 而酶降解作用下缓慢释放的CSS可促进伤口愈合, 在包括头颈外科在内的外科术后感染防治领域有良好应用前景.     

Synthesis and fluorescence property of terbium complex with novel schiff-base macromolecular ligand

Novel schiff-base macromolecular ligand was synthesized by copolymerizing schiff-base monomer, methyl methacrylate and ethyl acrylate. New polymeric materials based on terbium complex with this macromolecular ligand were prepared. The fluorescence properties of the terbium-complex polymer were investigated experimentally. The new polymeric materials developed herein exhibit the characteristic fluorescence properties of the terbium(III) ion, making them applicable in a wide range of new technologies.     

Monomer and polymer quinoxaline derivatives for cationic recognition

Monomeric and polymeric 5-nitroquinoxaline derivatives disubstituted in the 2 and 3 positions with 2-pyrrolyl (A), 2-furyl (B) and 2-thienyl (C) groups were prepared and characterized. The substituted 5-nitroquinoxalines were used as active components in poly(vinyl chloride)-membrane and electropolymerized electrodes that were then tested as possible sensors for various cationic species. In contrast to the difurylnitroquinoxaline-based systems, the monomeric and polymeric dipyrrolyl- and dithienylquinoxaline electrodes displayed a good selectivity for Ag(+) ions, providing a near-Nernstian response in the 10(-5) to 10(-2) mol L(-1) concentration range. The similar potentiometric behavior displayed by the monomeric and polymeric forms of systems A and C supports the contention that the main binding modes displayed by the monomeric forms are retained in the corresponding polymeric structures.     

Synthesis of poly(vinylbenzyltriphenylphosphonium)-bound nucleophilic reagents and their applications for anionic activation in nucleophilic substitutions

Insoluble polymer-bound nucleophilic reagents derived from poly(vinylbenzyltriphenylphosphonium chloride) have been prepared by treatment with the sodium salts of carboxylic acids, benzenesulphinic acid and phenols. These reagents were used for the synthesis of carboxylic acid esters, sulphones and C/O-alkylation of phenols by reactions with alkyl halides. In addition to the ease and simplicity of the method and regeneration of the polymeric by-product, the polymeric reagent seems to increase the nucleophilicity of the anions. The products were obtained in higher yields than those for the corresponding polymeric phase transfer catalyst which need long reaction time and gave no satisfactory yields especially in non-polar solvents.     

Synthesis of water-soluble polymeric prodrugs possessing 4-methylcatechol derivatives by mechanochemical solid-state copolymerization and nature of drug release

In this study we synthesized the water-soluble polymeric prodrugs possessing a 4-methylcatechol (4MC) derivative as a side chain by mechanochemical solid-state copolymerization. 1-benzoyl-4-methylcatechol (Bz4MC) was selected as a model compound of 4MC, and its methacryloyl derivative (1) was synthesized. 6-O-methacryloyl-D-galactose (2) was also prepared as a water-soluble monomer. The mechanochemical solid-state copolymerization of 1 and 2 was carried out to obtain the water-soluble polymeric prodrug possessing the Bz4MC as a side chain. The mechanochemical copolymerization of 1 and 2 proceeded to completion, and the polymeric prodrug produced possessed a narrow molecular weight distribution. Three kinds of polymeric prodrugs, whose compositions were different from one another, were hydrolyzed in vitro. The hydrolysis of these polymeric prodrugs proceeded to completion. The rate constants of hydrolysis decreased with increasing the mole fraction of 1 in polymeric prodrug. It was suggested that the rate constant of hydrolysis could be controlled by the composition, the mole fraction of 1 in the polymeric prodrug.     

Preparation and characterisation of membranes with entrapped TiO2 and preliminary photocatalytic tests

The possibility of entrapping polycrystalline TiO2 in a polymeric support, in order to couple the two unit operations, i.e. ultrafiltration and photodegradation of organic pollutants in aqueous solutions, was investigated. To this aim, polymeric membranes for ultrafiltration with entrapped TiO2 were prepared, characterised and tested. The polymeric support chosen was commercial polysulfone (PSf). The membrane preparation was carried out with the technique referred to as phase inversion. A three-component system, with a polymer, a solvent and a non-solvent was used. The best operative conditions were determined in order to obtain the desired membrane morphology. Permeability measurements and photostability tests were also carried out by using a system under pressure. Finally, a preliminary investigation was performed in order to evaluate the photocatalytic activity of the membranes with entrapped TiO2 for the oxidation of 4-nitrophenol as a model molecule in aqueous solutions.     

Polymeric thiols as enzyme activators of serum creatine phosphokinase

Several hydrophilic polymeric thiols were prepared from aminoactivated polymeric supports by reaction with N-acetylhomocysteinethiolactone. Supports include agaroses, cellulose, Glycophase™ controlled-pore glass, and Matrex™ acrylic beads. Thiol content in these polymers was 3–72 μmol SH/g dry polymer. Several were effective solid-phase activators of the sulfhydryl-dependent enzyme creatine phosphokinase at concentrations comparable to that of monomeric thiol required for enzyme activation. The kinetic activation curves for the polymeric and the monomeric (thioglucose) activators were similar, suggesting unhindered interaction of the enzyme with the polymeric activator.     

Polymeric controlled release formulations of niclosamide for control of Biomphalaria alexandrina, the vector snail of schistosomiasis

Schistosomiasis is one of the most important public health problems in many developing countries. The present study was conducted to investigate the effect of the polymeric niclosamide formulations against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni in Egypt. Three new polymeric formulations were prepared for the molluscicide niclosamide. The formulations were prepared either by the chemical modifications of poly(glycidyl methacrylate) or by physical entrapment of the niclosamide in calcium alginate beads. The release of the niclosamide from the polymeric formulations was investigated. The activity of the prepared formulations against Biomphalaria alexandrina was investigated. The results obtained revealed higher potency for polymerized niclosamide B3 than B1; the lowest potency was revealed for B2. After an exposure period of 24 hours, LC(50) values were 0.073, 0.098 and 1.09 ppm for B3, B1 and B2, respectively. In addition, the molluscicidal potency of the test polymeric niclosamide was age-dependent, where old snails were more tolerant to the test solutions than young and newly hatched snails. The results also indicated that the molluscicidal activity of B3 was extended for 21 days and 17 days for B1, compared with 5 days for free niclosamide. However, the molluscicidal potency of the polymerized niclosamide was increased after boiling for one hour, and was increased with increasing the pH of the medium to pH 9. In addition, their potency was increased with decreasing the water hardness concentrations (CaCO(3)).Molluscicidal activity of free niclosamide and its polymeric formulations vs. exposure time.     

Synthesis and properties of polymeric azine and thiazine dyes

Some polymeric azine or thiazine dyes were prepared by radical polymerization of dye monomers or by polymer reactions between dyes and suitable prepolymers, and their photoredox reactivities were studied. The thionine polymers containing labile ? OH groups exhibited photochromism and thermochromism, which were extremely sensitive to the moisture content of the polymer film. The reversibility of the photochromism and thermochromism increased with the water content in the film. The water-soluble polymeric dyes were photobleached under the influence of suitable reducing agents. The degree of photobleaching was smaller than for the monomeric systems except for the dye polymers containing ? OH groups, probably because of the large steric hindrance of the polymers.     

Polymeric Reagents.II. Synthesis and Applications of Crosslinked Poly(vinylpyridinium Hydrobromide Perbromide) Resins

Crosslinked bead polymers containing vinylpyridine units were prepared by pearl copolymerization of monomer mixtures containing various percentagesof 4-vinylpyridine, styrene, and di-vinylbenzene. The polymers were functionalized by reaction with hydrogen bromide and bromine, and the resulting poly-(vinylpyridinium hydrobromide perbromide) resins, which were stable for long periods of time, were used to brominate a number of alkenes and ketones. In most cases, the brominated products were obtained in excellent yields and could be separated from the polymeric by-product by a simple filtration. The polymeric reagent could be fully regenerated after use without loss of activity.     

Tamoxifen-loaded polymeric micelles: preparation, physico-chemical characterization and in vitro evaluation studies

Several samples of polymeric micelles, formed by amphiphilic derivatives of PHEA, obtained by grafting into polymeric backbone of PEGs and/or hexadecylamine groups (PHEA-PEG-C(16) and PHEA-C(16)) and containing different amount of Tamoxifen, were prepared. All Tamoxifen-loaded polymeric micelles showed to increase drug water solubility. TEM studies provided evidence of the formation of supramolecular core/shell architectures containing drug, in the nanoscopic range and with spherical shape. Samples with different amount of encapsulated Tamoxifen were subjected to in vitro cytotoxic studies in order to evaluate the effect of Tamoxifen micellization on cell growth inhibition. All samples of Tamoxifen-loaded polymeric micelles showed a significantly higher antiproliferative activity in comparison with free drug, probably attributable to fluidification of cellular membranes, caused by amphiphilic copolymers, that allows a higher penetration of the drug into tumoral cells. To gain preliminary information about the potential use of prepared micelles as Tamoxifen drug delivery systems, studies evaluating drug release ability of micelle systems in media mimicking biological fluids (buffer solutions at pH 7.4 and 5.5) and in human plasma were carried out. These studies, performed evaluating the amount of Tamoxifen that remains in solution as a function of time, showed that at pH 7.4, as well as in plasma, PHEA-C(16) polymeric micelles were able to release lower drug amounts than PHEA-PEG(5000)-C(16) ones, while at pH 5.5, the behavior difference between two kind of micelles was less pronounced.     

Headspace-solid phase microextraction-gas chromatography as a tool to define an index that establishes the retention capacity of the wine polymeric fraction towards ethyl esters

A headspace-solid phase microextraction followed by gas chromatographic analysis (HS-SPME-GC) was developed to be applied in the study of the interactions between the wine polymeric fraction and the ethyl esters: ethyl hexanoate, ethyl octanoate, and ethyl decanoate. Wine models (WM) were prepared with 10% (v/v) aqueous ethanol at pH 3.5 with distinct wine polymeric concentrations prepared from white wine of Vitis vinifera L. var. Fern?o-Pires: 1.0 g L(-1) (PWM1), with a polymeric concentration approaching the real one in wine; 10.0 g L(-1) (PWM10); and 30.0 g L(-1) (PWM30), saturated with polymeric fraction. A reference wine model (RWM) was prepared without polymeric fraction. Each volatile compound (4.0 mg L(-1)) was added separately to the RWM and to the WM with the three levels of polymeric material (PWM). From the retention index (RI) calculated for each compound using the formula: [RI = 1 - (C(RWM) - C(PWM))/C(RWM)], where C(RWM) is the concentration of the compound in the RWM and C(PWM) is the concentration of the compound in the given PWM, the retention capacity of each wine polymeric fraction towards the three esters was established. The higher retention indexes were observed for ethyl decanoate, the more hydrophobic compound, and for the PWM with higher concentration. Furthermore, this study also suggested that the retained compounds are dosed to the headspace, which may promote the perception of their aroma for a longer period of time.     

Comparison of monomeric and polymeric chiral stationary phases

Two-type polymeric chiral stationary phases (pCSPs) were prepared by surface grafting of chiral acryl-type monomers on a silica gel surface modified with 3-(trimethoxysilyl)propylmethacrylate. The prepared pCSPs were characterized by IR, Fr-Raman, scanning electron microscopy, and elemental analysis. In addition, two-type monomeric chiral stationary phases (mCSPs) were also prepared. The racemic analytes were separated using the prepared mCSPs and pCSPs. The separation factor (alpha) and capacity factor (k1) of the racemic analytes for the pCSP and mCSP were compared. The alpha and k1 values of the mCSP were higher than those of the pCSP.