Electrochemical behavior of a new type of perfluorinated carboxylate membrane/platinum composite

A new type of ionomeric polymer–metal composite (IPMC) based on various compositions of perfluoroalkylacrylate‐acryl acid copolymer with different types of counter cation has been synthesized by a radical copolymerization of fluoroalkylacrylate (FA) and acrylic acid (AA). Swelling behavior of the membranes was studied in deionized water as well as in aqueous single salt solutions (LiCl and NaCl). Swell of membrane increased with the increase in ionic content of the copolymer. Swell in deionized water was much higher than in aqueous single salt solution. To examine its performance as a new electroactive polymer, actuation force and displacement responses to DC and step voltage across the IPMC were measured. Results indicated that membranes prepared from 75/25 (FA/AA) (FA25) gave an adequate flexibility and proper hydrated state, allowing easy deflection toward the applied voltage. Surface morphology measurements (atomic force microscopy and scanning electron microscopy) showed that platinum particles are predominantly located at the surfaces. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Luminescence properties of isomeric and tautomeric lanthanide pyridinedicarboxylates

The luminescence and PMR spectra of europium salts of six isomers of 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-pyridinedicarboxylic acids (PDA) had been studied. The distribution of the effective charge in the nearest surroundings of the Eu³⁺ ion in these salts was evaluated from Stark splittings of electronic transitions. The values of relative integral intensities of electronic transitions ⁵D₀–⁷F_J (J=0–4) in the luminescence spectra were reported. Compounds investigated were divided into three subgroups taking into account the details of the structure of the ligands and details of the luminescence spectra. The ligand coordination manners as well as the strength of interaction between lanthanide ion and ligands were confirmed by data of the PMR and IR spectroscopy.     

Highly conductive poly(ethylene oxide)-poly(methyl methacrylate) blends complexed with alkali metal salts

Solid electrolytes of room temperature ionic conductivity exceeding 10⁻⁵ S cm⁻¹ were obtained by complexing NaI, LiI, LiBF₄ and LiClO₄ with blends prepared by thermal polymerization of methyl methacrylate in the presence of high molecular weight poly(ethylene oxide). All of the studied samples were thermally stable up to at least 60°C. Differential scanning calorimetry studies indicated that these electrolytes contained amorphous phases with very low glass transition temperatures. This is due to the plasticizing effect of the grafted copolymers formed during the polymerization. This is supposed to lead to high mobility of the charge carriers in the systems studied.     

Hydrolytic degradation of polyamidines and its potential application in controlled release of active agents

Hydrolytic degradation of an aliphatic polyacetamidine at different pH values was studied using ¹H NMR spectroscopy. It could be shown that degradation occurred at neutral and basic conditions whereas under acidic conditions the polyamidine was stable. In the course of degradation, aliphatic acetamide, amine and acetic acid are formed. The ability of the polyamidine to release active compounds bonded ionically to the polymer backbone by hydrolytic decomposition was studied by UV spectroscopy. The measurements were performed on a mixture of the polyamidine and salicylic acid as an example. The release behavior of a 1:0.8 mixture at pH 7 was nearly linear within the first 10 h and went to completion after 30 h. This system is discussed with respect to the development of new drug delivery systems based on polyamidines.     

Technetium—aspirin molecule complexes

Technetium-aspirin and technetium-aspirin-like molecule complexes were prepared. The structure of N-acetylanthranilic acid (NAA) has been decided through CNDO calculations. The ionization potential and electron affinity of the NAA molecule as well as the charge densities were calculated. Comparative studies of the electronic absorption spectra of acetylthiosalicylic acid (ATS) and aspirin (Asp) reveal the structure resemblance in which the acetyl carbonyl group is perpendicular to the plane of the corresponding organic acid. The studies of the electronic absorption spectra of NAA and anthranilic acid reveal the planarity of the NAA molecule. The electronic absorption spectra of Tc(V)-Asp and Tc(V)-ATS complexes have two characteristic absorption bands at 450 and 600 nm, but the Tc(V)-NAA spectrum has one characteristic band at 450 nm. As a comparative study, Mo-ATS complex was prepared and its electronic absorption spectrum is comparable with the Tc-ATS complex spectrum.     

高纯硅辐射损伤的正电子湮没和扰动角关联研究

采用正电子湮没和扰动角关联方法研究了１．４５×１０２０、３．１０×１０１７ｎ／ｃｍ２中子辐照和５×１０１１／ｃｍ２１７８Ｗ重离子辐照单晶硅引起的辐射损伤及其退火效应。实验测量的正电子湮没寿命和四极相互作用频率表明在Ｓｉ中存在氧一单空位对．高中子剂量和重离子辐照Ｓｉ后，用两种方法都观察到了双空位复合成四空位。     

Implications of soluble tannin-protein complexes for tannin analysis and plant defense mechanisms

Factors which establish whether tannin and protein interact to form soluble complexes or precipitates were identified. The ratio of tannin to protein in the reaction mixture influenced solubility of the tannin-protein complexes. At protein-to-tannin ratios larger than the optimum ratio, or equivalence point, soluble tannin-protein complexes apparently formed instead of insoluble complexes. Several other factors influenced the amount of protein precipitated by tannin-containing plant extracts, including the length of the reaction time and the conditions of the tannin extraction. The analytical and ecological significances of soluble complexes were considered. A titration method which allows simultaneous determination of the equivalence point and assessment of the protein-precipitating capacity of any plant extract was developed. It was postulated that in vivo, tannin and protein may not only form insoluble complexes with antinutritional effects, but may also form soluble complexes which have unknown metabolic effects.     

Luminescence of Eu(MBA)_2NO_3Phen Complexes

ＬｕｍｉｎｅｓｃｅｎｃｅｏｆＥｕ（ＭＢＡ）_２ＮＯ_３ＰｈｅｎＣｏｍｐｌｅｘｅｓＪｉｎＬｉｎ－ｐｅｉ（金林培）；ＴｏｎｇＪｉｎ－Ｑｉａｎｇ（童金强）；ＷａｎｇＭｉｎｇ－Ｚｈａｏ（王明昭）；（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＢｅｉｊｉｎｇＮｏ...     

Starch radicals Part III: Semiartificial complexes

 Nine starch varieties were blended and kneaded with d-fructose, d-glucose, sucrose, egg albumin and/or ethyl stearate to form semiartificial complexes. They were then thermolyzed and the numbers of unpaired spins in the solid residues were determined. Individual starch varieties began to generate unpaired spin states within 2 h of heating at 285  °C but some starch blends, particularly those of four-component starch (10 : 1 : 1 : 1) mixtures, generated free radicals within 2 h of heating at 160  °C. However, the free radical counts were minimized by the mutual complexation of the blend components and, to a certain extent, by the free radical scavenging in the blends. Received: 21 October 1997 / Revised version: 15 April 1998     

Thermal behavior of poly(acrylic acid)–poly(vinyl pyrrolidone) and poly(acrylic acid)–metal–poly(vinyl pyrrolidone) complexes

Thermal analysis (TGA and DTA) of samples of PAA, PVP, PAA–PVP complexes, containing different weight fractions of PAA and ternary polymer–metal–polymer complexes, were studied. The activation energy parameters for the thermal degradation were also calculated. The study of the effect of FeCl₃, NiCl₂, and Ni(NO₃)₂ on the TGA and DTA curves of the complexes showed that the decompositions are dependent on the concentrations and the nature of the metal ions. The DTA traces of PAA–PVP complex containing FeCl₃, NiCl₂, and Ni(NO₃)₂ showed that the treatment of the complex with these metal ions causes considerable changes in the thermal decomposition of PAA–PVP complex. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4049–4057, 2006