An alternating copolymer of maleimide and atropic acid with narrow molecular weight distribution prepared by radical mechanism

Three basic conditions for preparation of alternating copolymer with narrow molecular weight distribution were derived from the element kinetic equations of binary radical copolymerization. Using maleimide (MI) and atropie acid (ATA) as model monomer pairs and dioxane as the solvent the alternating copolymer with molecular weight distribution in the range of 1.09--1.20 was prepared successfully by charger transfer complex (CTC) mechanism in the presence of benzoyl peroxide at 85℃. The monomer reactivity ratioes r_1(MI)=0.05±0.01 and r_2(ATA)=0.03±0.02 were measured. The alternating eopolymerization was carried out through formation of a contact-type CTG and then alternating addition of MI and ATA monomers. The molecular weight of the copolymers is nearly independent of the feed ratio in a large range and the polymerization rate dropped with an increase in ATA in feed ratio.     

Electroactivity, electrochemical stability and electrical conductivity of multilayered films containing poly(3,4-ethylendioxythiophene) and poly(N-methylpyrrole)

Multilayered systems of poly(3,4-ethylendioxythiophene) and poly(N-methylpyrrole) have been prepared using a layer-by-layer electrodeposition technique. The electrochemical and electrical properties of films formed by 3, 5, 7 and 9 layers have been characterized and compared with those of pure polymers and copolymers prepared from mixtures of 3,4-ethylendioxythiophene and N-methylpyrrole with various concentration ratios. Results indicate that the electroactivity and electrical stability of the multilayered systems are higher than those of both poly(3,4-ethylendioxythiophene) and copolymers. Furthermore, these electrochemical properties improve when the number of layers increases. On the other hand, the electrical conductivity of the multilayered systems is slightly lower than that of pure poly(3,4-ethylendioxythiophene), and significantly higher than those of poly(N-methylpyrrole) and copolymers.     

具有电活性苯胺四聚体接枝聚谷氨酸的合成与表征

以N-羟基琥珀酰亚胺(NHS)活化聚L-谷氨酸的羧基并与苯胺四聚体的氨基缩合,得到了以可生物降解的聚谷氨酸为主链,具有电活性的苯胺四聚体为侧链的新型接枝聚合物.用1H-NMR、质谱分析、光谱分析的方法确定了化合物的结构.侧链羧基的存在使聚合物可以溶解于碱性的缓冲溶液中.对聚合物的电化学性质进行了紫外及循环伏安的表征,研究结果表明,接枝后的聚合物具有与苯胺低聚体相似的可逆的氧化还原过程并可被质子酸掺杂,表现出良好的电化学活性.同时,以定量紫外吸收及元素分析的方法分别测定了聚合物的接枝率.实验中通过控制反应的投料比可以使苯胺四聚体的接枝率达到40%以上,并对聚合物的自掺杂现象进行了讨论.     

Synthesis of a soluble pyrrole copolymer with phenetidine

A new series of copolymers was synthesized through the oxidative polymerization of pyrrole (PY) and o‐phenetidine (PHT) with inorganic oxidants in acidic media. The polymerization parameters including the mixing method of the oxidant with the comonomer, the comonomer ratio, the time, the temperature, the oxidant, the organic medium, and the acid were systematically optimized for the synthesis of copolymers with high yields, intrinsic viscosities, and solubility. The resultant copolymers were characterized by elemental analysis, infrared, ultraviolet–visible, solution high‐resolution ¹H NMR and solid‐state high‐resolution ¹³C NMR, circular dichroism spectroscopy, and cyclic voltammetry. The results showed that the PY observed content in the copolymers was much higher than the PY feed content. The regular variation of the polymerization yield, intrinsic viscosity, solubility, macromolecular structure, and electroactivity of the resulting polymers with the comonomer ratio, together with the complete solubility of a PY/PHT (10/90) polymer in highly polar solvents, indicated the formation of real random copolymers containing both PY and PHT units rather than a mixture of two homopolymers. However, the polymers containing more than 59 mol % PY were not homogeneous copolymers consisting of soluble and insoluble parts. A semiquantitative relationship between the polymerization yield or solubility of the copolymers and the polarity index of the organic solvents was examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2073–2092, 2004     

Synthèse de copolymères supports de sulfanilamide. Hydrolyses dans un milieu gastrique de pH=1.2

Hydrolyses of two copolymers with amide functions, and of monomer carrier of sulfanilamide have been carried out mostly in heterogeneous acid medium (pH=1.2). A suitable percentage of sulfanilamide has been released after some hours. The drug release depends on the ammonium cation formed during the hydrolyses and the release of the drug being not described by a classical kinetics equation (0, 1, 2 and n). These kinetics are probably partially controlled by diffusion, and they can also be explained by the diffusion of the liquid (pH=1.2) through the copolymers.     

pH‐sensitive hemolysis by random copolymers of alkyl acrylates and acrylic acid

We have been designing and synthesizing synthetic polymers that mimic viral fusogenic peptides, which contain peptide residues having alkyl groups and carboxyl groups. We have synthesized two different types of such polymers, and their abilities to hemolyse red blood cells at pH 7.4 and 5.5 are compared here. The polymers are poly(2‐alkylacrylic acid)s such as poly(2‐propylacrylic acid), and random copolymers of poly(alkyl acrylate‐co‐acrylic acid) where the alkyl group is propyl or butyl. We have found that the poly(2‐alkylacrylic acid)s such as poly(2‐propylacrylic acid) are significantly more hemolytic at acidic pH than the random copolymers of equivalent propyl and carboxyl contents.     

Électrochimie dans l'oxydipropionitrile: Comportement électrochimique du solvant. Stabilité des complexes argent(I) halogénures. Solvatation des anions

Electrochemical possibilities of oxydipropionitrile have been shown. The system Ag(s)/Ag⁺ has been used to make a reference electrode in this medium. The electroactivity range which depends on the electrolyte and the kind of electrode used has been specified. At a platinum electrode, in LiClO₄ medium, the electroactivity range is very large. At a mercury electrode, water does not interfere but at a platinum electrode it is oxidizable; the electroactivity range depends on its concentration. The second part treats the complexes with silver ion and halides. Stability constants of complexes and solubility products have been obtained from potentiometric titration curves. The determination of the transfer parameters for ionic species is based on the Strehlow assumption that the potential of the ferrocene/ferricinium couple is constant in all solvents. The results show that the silver ion is more strongly solvated in oxydipropionitrile than in water; on the other hand halide ions are little solvated in this solvent.     

Copolymer electrosynthesis of ethyl-3-thiophene acetate and 3-methylthiophene and characterization of the resulting copolymers by spectroscopic studies

Copolymers of ethyl-3-thiophene acetate (ETA) and 3-methylthiophene (MT) were synthesized electrochemically. Electrospray ionization mass spectra of the electrolyte containing 2×10^–3 M MT + 3×10^–2 M ETA after copolymerization showed cooligomers with different combination of ETA and MT units. Just one value of the glass transition temperature was observed by differential scanning calorimetry of the formation of homogeneous copolymers. Change of the copolymer composition led to change of thermal stability characterized by thermogravimetric analysis. The morphology of the copolymer film was studied by scanning electron microscopy, indicating a homogeneous and compact film. The electroactivity of the homopolymer/copolymer films was studied. Cyclic voltammograms of the polymer films revealed that poly(ethyl-3-thiophene acetate) possesses high electroactivity in non-aqueous solution, but its electroactivity was lost entirely after 50 cycles in 0.1 M N(Bu)₄PF₆/acetonitrile solution having 5 volume percentage of water; however, the copolymer of ETA and MT maintains its high electroactivity even in the aqueous solution. Similar results were also derived from impedance and photoelectrochemical measurements. Additionally, it was found that a bilayer of poly(3-methylthiophene) and copolymer was formed.     

The decomposition of H2O2 catalyzed by polymer supported transition metal complexes

The synthesis and use of nitrogen-containing copolymers for anchoring Ru(II) and Rh(I) species is described. The supported species are effective as catalysts for the decomposition of H₂O₂ in aqueous medium at neutral pH. The polymers as well as the supported catalysts have been characterised by physical and chemical methods. The effects of [H₂O₂], catalyst loading and pH of the medium on the rate of decomposition have been studied. Suitable mechanisms have been proposed to account for the kinetics. Recycling efficiencies of the catalysts are found to be good.     

Alumina interaction with AMPS-MPEG random copolymers III. Effect of PEG segment length on adsorption, electrokinetic and rheological behavior

The effect of different 2-acrylamido-2-methylpropanesulfonic acid sodium salt (AMPS)-methoxypolyethyleneglycol methacrylate (MPEG) comb-like copolymers on the adsorption behavior, electrokinetic and rheological properties of alumina suspensions has been investigated. The change in adsorption isotherms with the content of the two monomers, the medium pH and the ionic strength indicated that the interaction of these copolymers was found to be controlled by both the fraction of ionic groups on the polymer and by the length of the polyethyleneglycol (PEG) segments. Adsorption of the copolymers on alumina particles is accompanied by a shift in the IEP toward acid pH values and may lead to a charge reversal above a certain level. The presence of the PEG segment equally affects the magnitude of the zeta potential by moving the shear plane forward. Addition of the copolymers greatly affects the rheological behavior of the suspension; the viscosity at a defined shear rate decreases and reaches an optimum, which is all the lower as the fraction of the ionic groups is higher. The dispersing effect of the copolymer was controlled by both the ionization level of the copolymer and by the length of the PEG segments.     

Spectroscopic and quantum chemical investigation of enol-enol tautomerism of 2-acetyltetronic acid

Vibratonal spectra of 2-acetyltetronic acid (ATA) (3-acetyloxolane-2,4-dione) were investigated in different aggregate states.Ab initio quantum chemical calculations (3-21G basis set) of 2-formyltetronic acid as analogue of ATA and semi empirical calculation of ATA were carried out. The tautomeric forms of ATA can be arranged in the following series with respect to thermodynamic stability (in decresing order):1a,1b,2a,2b.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1043–1048, June, 1995.     

电活性大单体的合成

利用氧化偶联反应,由对苯二胺与端胺基被保护的苯胺二聚体,合成了包含苯胺五聚体的电活性大单体,这条合成路线的特点是,保护了苯胺二聚体的胺端基,防止其进一步反应。利用缩聚反应,由已二胺和１,１,２－十二二胺与大单体合成了电活性聚合物。     

一种新型固体酸的制备及其在二（1-萘）甲烷加氢裂解中的催化性能

煤直接液化制取轻质燃料油和重要化学品是实现煤炭资源高效洁净利用的有效途径。煤液化的关键是在适当的温度、氢压、溶剂和催化剂存在的条件下,通过加氢裂解反应使连接煤中有机质大分子结构单元的较弱的桥键断裂生成可作为液体燃料的有机小分子,经后续的精细分离得到高附加值有机化学品和制备高性能炭材料前驱体,进而实现煤炭资源的高效利用。传统的煤液化工艺反应条件苛刻,需要高温和高氢压,导致能耗大和设备成本较高。酸性催化剂可使煤结构中的桥键在远低于煤热解反应的温度下断裂,并可有效除去煤中的杂原子,大幅提高液化油收率,因此酸性催化剂得到许多研究者关注。液体酸,如三氟甲磺酸、氟硼酸以及金属卤化物熔盐等均相酸性催化剂是煤液化工艺中常用的催化剂。虽然这些催化剂具有催化效率高和不易失活等优点,但大多数均相催化剂难以回收和再生,生产成本高,设备腐蚀性大,环境污染严重,因此在实际应用中受到限制。固体酸是具有广泛工业应用前景的环境友好催化剂,因而对固体酸的研究具有重要意义。本研究将液体三氟甲磺酸(TFMSA)通过浸渍吸附法负载到酸化的凹凸棒土(ATA)上制备了一种新型固体酸催化剂 TFMSA/ATA,并在相同条件下制备了 TFMSA/g-Al2O3和 TFMSA/ZSM-5作为对比。对TFMSA/ATA进行了透射电镜、傅里叶变换红外光谱、X射线光电子能谱、X射线衍射、N2吸附以及 NH3程序升温脱附表征。结果表明, TFMSA有效负载于 ATA载体表面及孔隙中,未发现明显的团聚,载体与活性组分之间存在较强的相互作用;另外, TFMSA/ATA上出现超强酸位点,说明 TFMSA/ATA具有超强酸性。以二(1-萘)甲烷加氢裂解作为探针反应考察了 TFMSA/ATA对 Car–Calk桥键断裂的催化活性。结果表明,二(1-萘)甲烷在 N2气氛和甲醇溶剂中选择性地加氢裂解,仅得到萘和1-甲基萘,未检测到加氢产物,且产物萘的收率明显高于1-甲基萘的收率,说明 TFMSA/ATA对二(1-萘)甲烷选择性加氢裂解和由此产生的1-甲基萘脱甲基反应有显著的促进作用。在相同反应条件下, TFMSA/ATA的活性明显高于 TFMSA/g-Al2O3和 TFMSA/ZSM-5,这是由于 TFMSA/ATA较大的比表面积以及载体 ATA与活性组分 TFMSA之间存在较强的相互作用有利于催化剂释放质子。由催化剂释放的质子优先进攻二(1-萘)甲烷中的取代位导致 Car–Calk键断裂是二(1-萘)甲烷加氢裂解的关键步骤。催化剂循环实验表明, TFMSA/ATA在循环使用4次后仍具有较高的催化活性,使用后催化剂酸性没有明显降低,说明 TFMSA/ATA具有良好的稳定性。     

Synthesis and characterization of new optically active copoly(amid-imide)s based on N-phthalimido-L-aspartic acid and aromatic diamines

<正>In this article,six new optically active copoly(amide-imide)s(10a-f) were synthesized through the direct polycondensation reaction of N-phthalimido-L-aspartic acid(4) with 1,5-diamino naphthalene(8),3,4-diamino benzophenone(9) in the presence of therphthahc acid(7),fumaric acid(6) and adipic acid(5) as a second diacid in a medium consisting of N-methyl-2-pyrrolidone,triphenyl phosphite, calcium chloride and pyridine.The resulting copolymers were fully characterized by means of FT-IR spectroscopy,elemental analyses, inherent viscosity,solubility tests and UV-vis spectroscopy.Thermal properties of resulting copolymers(10a-c) containing three different second diacid in the main chain were compared by using TGA and DTG thermograms.     

Determination of percolation threshold electroactivity and phase behavior study on conducting blends of thermotropic polyesters and polyaniline

The new thermotropic polyester/polyaniline (PIn/PAni) blends have been prepared by solution blend of synthesized liquid crystalline poly[4,4′‐bis (ω‐alkoxy) biphenylisophthalate]s having four and six methylene units in spacer (PI4 and PI6) with PAni doped with camphorsolfonic acid (CSA). The percolation threshold electroactivity of prepared blend films has been determined by cyclic voltammetry. The effect of the PAni concentration, solvent nature and polyester structure on the electroactivity of the blends has been investigated. The extremely low percolation threshold of prepared PIn/PAni‐CSA blends from dimethylformamide (DMF) and m‐cresol solution was 3% weight of PAni‐CSA. The amount of conducting polymer necessary to retard the formation of the liquid crystalline (LC) phase is up to 45% by weight. Phase behavior studies by differential scanning calorimetry and polarizing microscopy show that blends with 45% of conducting polymer are both liquid crystal and conductive. The morphology of the blends has been investigated by scanning electron microscopy. Copyright © 2004 John Wiley & Sons, Ltd.     

COPOLYMER OF 1-(ACETYLSALICYLYLOXY)ETHYL METHACRYLATE AND ITS HYDROLYSIS

The copolymers of 1-(acetylsalicylyloxy)ethyl methacrylate (HEMA-ASA) with methacrylicacid (MA) have been prepared and their hydrolysis in dioxane-H_2.O either in acdic or alkaline medium,at 60℃or 37℃have been investigated. It is found that the chief product of hydrolysis is alwaysaspirin with minor amount of salicylic acid. Due to its neighbouring group effect, the hydrolysisrate of (HEMA-ASA)-MA copolymer markedly depends on its composition and the pH value ofhydrolysis medium, i.e. the hydrolysis rate increases with increasing mole fraction of MA in the copoly-mer and pH value of hydrolysis medium.     

Synthesis and Characterization of a Modified Chitosan

Chitosan has been modified by incorporating a cationic moiety N- (3-chloro 2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC) onto its primary amine group in aqueous alkali medium. A series of modified chitosan copolymers (Chito-cat-1 to Chito-cat-5) was synthesized by varying the CHPTAC to chitosan ratio. The modified chitosan copolymers have been characterized by viscometry, elemental analysis, infrared spectroscopy (IR), thermal analysis and X-ray diffractometry. From the above investigations, it has been confirmed that the cationic moiety was successfully incorporated onto chitosan.     

Determination of boron in boron-alloyed steels by inductively coupled plasma atomic emission spectrometry

An inductively coupled plasma atomic emission spectrometry (ICP-AES) procedure has been developed and examined for the determination of boron content (0.01 up to about 2% B) in boron-alloyed steels such as POLDI ATA BOR (65% Fe, 19%Cr, 12% Ni, 1.5% Mn, 1% B), POLDI ATA BOR EXTRA (62% Fe, 18% Cr, 13% Ni, 2.5% Mo, 1.5% Mn, 1% B) and POLDI ATA BOR-R (75% Fe, 18% Cr, 3.5% Ti, 1.8% B). The steel sample is dissolved with a mixture of hydrochloric, nitric, sulfuric and phosphoric acids in a quartz vessel. Borides of alloyed metals, especially of iron and chromium, are quantitatively decomposed. The presence of phosphoric acid in a sample solution reduces the volatility of boric acid with water vapour.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria     

Synthesis of electroactive and biodegradable multiblock copolymers based on poly(ester amide) and aniline pentamer

A new family of multiblock copolymers (PEA‐b‐AP) based on poly(ester amide) (PEA) and aniline pentamer (AP) with the unique properties of being both electroactive and biodegradable was synthesized via a two‐stage active solution polycondensation. The new synthesis approach proceeded smoothly, and avoided the complicated purification steps for separating the intermediate products. The molecular weight of PEA blocks was regulated by varying the nucleophilic/electrophilic monomers feed ratios. The chemical structures of the copolymers were confirmed by both IR and NMR spectra. UV‐Vis spectroscopy indicated that the copolymers possessed of the intrinsic electroactivity of AP blocks, and showed three reversible oxidation states. The copolymers had lower degradation rates than the PEA homopolymers with similar molecular weight, and their degradation rates were greatly affected by the proportion of AP blocks. In vitro cell culture studies of the PEA‐b‐APs revealed that they facilitated the proliferation of RSC96 Schwann cells and displayed a good biocompatibility. These biodegradable copolymers with electroactive function may have great potential for use as nerve repair and regeneration scaffold materials in tissue engineering. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4722–4731     

Crown-tetrathiafulvalenes attached to a pyrrole or an EDOT unit: synthesis, electropolymerization and recognition properties

A crown-tetrathiafulvalene electroactive receptor has been covalently linked to electropolymerizable pyrrole or 3,4-ethylenedioxythiophene monomers. The synthetic route to the monofonctionalized tetrathiafulvalene (TTF) ligand has been optimized. Two derivatives of pyrrole (N- and 3-substituted) were synthesized. The various substituted monomers have been electropolymerized to produce polypyrrole (PP) and poly(ethylenedioxothiophene) (PEDOT) films bearing the electroactive TTF moiety. The electroactivity of the polymer films is efficiently controlled by the well-defined two-step redox behavior of the TTF unit. In the case of PEDOT, an alternative post-polymerization derivatization strategy has been used, involving the grafting of the crown-TTF ligand on the previously grown PEDOT backbone. Though chemical derivatization is realized under heterogeneous conditions, in the bulk of the film, this strategy proved to be particularly efficient. These electrodes constitute the first examples of conducting polymer-based modified electrodes incorporating a TTF electrochemical probe, able to interact with a guest ion, such as Ba2+. The cation recognition properties of these various electrodes have been analyzed by cyclic voltammetry and their electroactivity in water as well as their regeneration capability have been investigated.