Novel aqueous spongy foams made of three-dimensionally dispersed wood-fiber: entrapment and stabilization with NFC/MFC within capillary foams

This article describes the preparation of novel aqueous spongy foams that are composed of three-dimensionally distributed wood-fiber networks stabilized with nanofibrillate cellulose (NFC) and/or microfibrillated cellulose (MFC). The free standing aqueous spongy foams were prepared with the entrapment of NFC and/or MFC—stabilized air-in-water (A/W) capillary foams using “gel trapping technique”. The stability of spongy foams could be controlled by manipulating the volume fraction of NFC and/or MFC and a secondary liquid immiscible with the continuous phase of the NFC and/or MFC suspension. Possible morphology and mechanical distribution of NFC and/or MFC within spongy foams were verified with optical microscope, SEM, and functional load-bearing method. Owing to three-dimensionally dispersed wood-fiber structure, ultra-lightweight (0.01–0.06 g/cm³), high porosity (>90%), and microporous (10–80 μm), the NFC and/or MFC reinforced spongy foams, improved compressional strength-vertical direction obviously, from 0.0 to more than 13.78 kPa.     

Preparation and Evaluation of Theophylline Sustained Release Microcapsules Using Coacervation

Preparation of sustained release dosage forms is one of the main objectives in drug formulation. Theophylline that has a narrow therapeutic index, making it a good choice to prepare a sustained release dosage form. Theophylline sustained release microcapsules were prepared by applying the coacervation method. The effect of the type and ratio of polymers, as well as the type of washing solvents, was studied on particle size, drug loading efficiency, and in vitro drug release profile. Results showed that Eudragit RS and RL could be more suitable polymers for preparation of sustained release microcapsules of theophylline when used in ratio of 1:1 and when the washing solvent was hexane.     

Investigation of the anchoring silane coupling reagent effect in porphyrin sensitized mesoporous V-TiO2 on the photodegradation efficiency of methyl orange under visible light irradiation

In order to efficient utilization of visible light in the photodegradation reaction, mesoporous vanadium doped TiO₂ (V-TiO₂) particles sensitized by tetrakis(4-carboxyphenyl)porphyrin (TCPP) dyes were synthesized, and characterized. For investigation of the anchoring coupling between porphyrin and TiO₂ surface, two photocatalyst containing ester-like linkage (TCPP–V-TiO₂) and amide-like linkage (TCPP–NH₂–V-TiO₂) were compared in the photodegradation of methyl orange (MO) aqueous solution. It was found that the photocatalytic activity of the TCPP–V-TiO₂ was higher than TCPP–NH₂–V-TiO₂ (95 % compared to 62 %). Importantly, TCPP–V-TiO₂ was particularly stable in the visible light photocatalytic activity after six cycles.     

Silver Nanoparticles–Polyaniline Nanocomposite for Microextraction in Packed Syringe

A rapid, convenient and reliable method for microextraction in packed syringe (MEPS) of the loop diuretic furosemide (FUR) in urine along with high-performance liquid chromatography (HPLC) was developed. A nanocomposite based on silver nanoparticles/polyaniline (Ag-NPs/PANI) was synthesized and used as the MEPS packing material. This nanocomposite was prepared conveniently using interfacial polymerization without the need for any templates or functional dopants. The feasibility of the synthesized nanocomposites was examined by isolation of FUR from diluted urine samples. After extraction, the analyte was desorbed by 200 μL of methanol. It was then dried and the residue was dissolved in 30 μL of methanol and an aliquot of 25 μL was, finally, injected into the HPLC system. Important parameters influencing the extraction and desorption processes were optimized and 25 cycles of draw–eject gave maximum peak area, when desorption was performed. The linearity was studied by preconcentration of 5 mL of diluted urine sample spiked with a standard solution of FUR in the concentration range of 15–750 μg L^?1. The coefficient of determination was satisfactory (r ² > 0.99) and the relative standard deviation (RSD %) value under the optimized condition was 8.8 %. The limit of detection and limit of quantification were 7 and 15 μg L^?1, respectively.     

Synthesis and properties of butyl rubber–poly(ethylene oxide) graft copolymers with high PEO content

Butyl rubber‐poly(ethylene oxide) (PEO) graft copolymers with high PEO content (40–83 wt %) were synthesized by the functionalization and activation of the double bond moiety of butyl rubber containing high (7 mol %) isoprene content and subsequent reaction with PEO of different molecular weights from 750 to 5000 g/mol. The properties of these copolymers, along with other butyl rubber‐PEO graft copolymers were studied in films and in aqueous solution. Despite the high PEO content, films of the copolymers were quite stable in water with respect to mass loss and were capable of releasing an encapsulated probe molecule in a manner that was dependent on the PEO content. At high PEO content they were resistant to the adhesion and growth of C2C12 cells. Despite the resistance of films to dissolution, it was possible to prepare nanosized aqueous assemblies via a THF‐water exchange process and the sizes of the assemblies were tuned by their method of preparation. The assemblies were also able to encapsulate a probe molecule and were found to be nontoxic in vitro. Combined, this set of properties makes these new amphiphilic copolymers promising for a wide range of potential applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3383–3394     

Chemoselective Synthesis of Fused Phosphorus Compound with 2-Hydropyrimidine-2-Thione Derivatives in Mixture of Water/Acetone as a Green Solvent

Abstract

3,4-Dihydropyrimidin-2(1H)-thione derivatives undergo a chemoselective reaction with dialkylacetylenedicarboxylate in the presence of triphenylphosphine lead to the corresponding stable heterocyclic phosphorus ylides in good yield. In this method, a mixture of water/acetone as a green solvent was used.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the following free supplemental files: Additional figures]     

Identification of volatile organic compounds in flowers of Astragalus lagopoides

Composition of volatile organic compounds (VOCs) in flowers of Astragalus lagopoides was studied using a hydrodistillation extraction procedure coupled with gas chromatography-mass spectrometry. The analyses allowed the identification of a number of 25 compounds, among which the presence of several bioactive aromatic derivatives such as guaiacol, eugenol, linalool, α- and 4-terpineol as well as nerol was attention-grabbing. Moreover, some other compounds like cyclohexane, 2-bromoethyl with repellent function also appeared to be present in the flower. As a result, the floral VOCs profile of A. lagopoides might reflect an adaptation to attract specialised pollinator insects. These findings provide important information for advances in understanding the ecological and evolutionary perspectives of pollination biology of the giant genus Astragalus.     

Electrochemical synthesis and characterization of a new conducting polymer: Polyrhodanine

An antimicrobial drug, rhodanine (Rh), was electrochemically polymerized on a Pt electrode using cyclic voltammetry (CV). The high quality and homogeneous polyrhodanine (pRh) films with a dark-purple color were obtained. The chemical structure characterization was investigated by Fourier transform infrared spectroscopy (FTIR) and UV-vis spectroscopy techniques. Further, thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques used to investigate thermal properties of the film. It is found that thermal stability of pRh films is relatively high. It is also observed that tetrahydrofurane (THF) and N-methyl-2-pyrrolidone (NMP) are good solvents for the polymer.     

Synthesis and photocatalytic activity of V-doped mesoporous TiO2 photosensitized with porphyrin supported by SBA-15

Research on Chemical Intermediates - A highly efficient photocatalyst was produced by immobilizing V-doped mesoporous TiO2/tetrakis(4-carboxyphenyl)porphyrin (V-TiO2/TCPP) onto SBA-15 walls, and...     

SnTCPP-modified ZnO nanorods prepared via a simple co-precipitation method: application as a new photocatalyst for photodegradation and photoreduction processes

Research on Chemical Intermediates - In this paper, ZnO nanorods were synthesized after optimizing the parameters of pH and the concentration of raw materials, reflux temperature, reflux time and...