Mechanical properties of anion exchange membranes by combination of tensile stress–strain tests and dynamic mechanical analysis

The thermomechanical properties of anion exchange polymers based on polysulfone (PSU) quaternized with trimethylamine (TMA) or 1,4‐diazabicyclo[2.2.2]octane (DABCO) and containing hydroxide or chloride anions by tensile stress–strain tests and dynamic mechanical analysis (DMA) have been determined. The reported mechanical properties included the Young's modulus, tensile strength, and elongation at break from tensile tests and the storage and loss modulus and glass transition temperature from DMA. The anion exchange membranes behaved as stiff polymers with Young's modulus in the order of 1 GPa, relatively with high strength (about 30 MPa) and low elongation at break (around 10%) was observed. Tensile tests were also made with membranes exchanged with hydrogen‐carbonate and carbonate anions to control the absence of important carbonation of the OH form. The glass transition temperatures were of the order of 150 °C (PSU‐TMA) or 200 °C (PSU‐DABCO) for the hydroxide form, confirmed by differential scanning calorimetry; they increase further by about 50 K, when hydroxide ions are replaced by chloride. This result and the increase of the storage modulus could be interpreted by the higher hydration of hydroxide ions and the plasticizing effect of water, which reduced the Van der Waals interactions between the macromolecular chains. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1180–1187     

Terahertz optical asymmetric demultiplexer based tree-net architecture for all-optical conversion scheme from binary to its other 2n radix based form

To exploit the parallelism of optics in data processing,a suitable number system and an efficient encoding/decoding scheme for handling the data are very essential.In the field of optical computing and parallel information processing,several number systems like binary,quaternary,octal,hexadecimal,etc.have been used for different arithmetic and algebraic operations.Here,we have proposed an all-optical conversion scheme from its binary to its other 2n radix based form with the help of terahertz optical asymmetric demultiplexer (TOAD) based tree-net architecture.     

Alkylbenzonaphthyridinones and benzonaphthyridinium quaternary salts

Four methyl and ethylbenzonaphthyridinones, along with two ethylbenzonaphthyridinium iodides, 2.5-dimethyl-1,5-benzo[c]naphthyridinium iodide, as well as three isomeric N-3-bromopropylbenzonaphthyridinium bromides have been synthesized and their structures confirmed by¹H NMR spectroscopy. Biological data (minimal inhibitory concentrations) for two of the obtained compounds are presented.Institute of Chemistry, Pedagogical University, 42-201 Czestochowa, Poland Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 944–950, July, 2000.     

Separation of alkylbenzyl quaternary ammonium compounds by capillary zone electrophoresis with sample stacking injection

Summary A systematic investigation of operational buffer systems, sample preparation and instrument parameters for achieving the best possible performance for determinating an homologous series of N-benzyl-N-alkyl-N,N-dimethylammonium chloride compounds by capillary zone electrophoresis with direct UV detection. The most effective separation was achieved within 3.5 min with the addition of acetonitrile (40%) in a phosphate buffer (20 mM pH 5.2) using a 40 cm fused-silica capillary operating at 25 KV and 20°C. Degassing of all electrolyte solutions and samples was very important. The linearity and repeatability for each compounds were satisfactory. To improve detection limits, on-column sample preconcentration, sample stacking, was investigated achieving a tenfold enrichment factor and quantitation limits about 10⁻⁷M.     

Synthesis of Polymer-Bonded Quaternary Ammonium Type Metal Porphyrins

Synthetic metalloporphyrin are efficient models of the cytochrome P-450 family ofmono-oxygen enzymes and have been largely used as catalysts in oxidation of alkanesand epoxidation of alkenesl. Polymer-bonded metalloporphyrin reveal many advantageson the catalytic reaction, where the catalysts can be easily separated from the products,recovered, and reused2. Quaternary ammonium salts as phase transfer catalysts werewide used in aqueous-organic two-phase conditions. Unfortunately, most porphyrin…     

Lipophilic counterion effect on aggregation and adsorption behavior of quaternary ammonium surfactants

The obvious different aggregation and adsorption behavior of six newly quaternary ammonium surfactants with different lipophilic counterions has been discoverd by measurements of equilibrium and dynamic surface tension, fluorescence and conductivity. Interestingly, the critical micelle concentration (CMC) and its surface tension γ_CMC decrease with the increasing counterion chain length. However, three methods have confirmed that an exception of CMC increases slightly from C₁₆NC₁ to C₁₆NC₂. According to experimental results, a balanced mechanism between hydrophobicity and electrostatic of counterion is proposed. Besides, the dynamic surface tension results show the diffusion coefficient increases with the increasing counterion length both at a short time (D_t?→?0) and long time (D_t?→?∞), which indicates a faster adsorption process. Unlike the inorganic counterion, the diffusion coefficient decreases with the increase of hydrophobic chain length. This is attributed to the strong electrostatic interactions between counterions and cationic headgroups.     

溴化苄基取代吡啶类季铵盐的制备和抗菌性能

抗菌材料和抗菌制品的研究与应用一直是世界各国研究的重要课题~([1-3]),其中有机抗菌剂占据主要地位.季铵盐是研究比较多的一类有机抗菌剂,它们表现出良好的物理性质,如胶束浓度低,黏弹性好和溶解性强~([4]),同时此类抗菌剂具有强效的抗菌作用~([5]),引起了人们的极大兴趣.季铵盐广泛应用于医药、卫生、食品、饲料工业、农业、纺织、塑料、橡胶、造纸、水处理、油田开采、涂料、日常生活等多种领域~([6-10]).