摘要:

AbstractChlorine‐containing polyketones of low molecular weight were synthesized from anisole, chloroacetyl chloride and dichloroalkanes, i. e. dichloromethane and 1,2‐dichloroethane, by the Friedel‐Crafts reaction using carbon disulfide as solvent. The resins were characterized by IR spectra and vapour pressure osmometry. The thermal properties were studied by thermogravimetry and differential scanning calorimetry. The characteristics of the decomposition reactions were evaluated by the Broido and Doyle methods. All the resins were tested for their microbial activity against bacteria, fungi and yeast. The results show that most of the resin can be used as bio

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200101

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe flocculating efficiency of two cationic polyelectrolytes with quaternary ammonium salt groups in the main chain, with different branching degrees, on a bentonitic clay suspension, in comparison with polyacrylamide (PAM) was followed. The cationic polymer with a smaller branching degree operated similar to PAM. In both cases a purification of 100% was achieved. When the cationic polymer with a higher branching degree was used, a stabilization effect on the suspension was observed. The flocculating activity of the mixtures of the cationic polymer and polyacrylamide was also studied.

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200102

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe adsorption of cis‐1,4‐polyisoprene on alumina and silica gel was studied at three temperatures. The solvents used were toluene, chlorobenzene and various mixtures of both. The adsorption from the mixtures of the solvents was much less than from either of the pure solvents. The amount of adsorption was an inverse function of temperature. The thermodynamic quantities of adsorption at infinite dilution were obtained by extrapolation and at isosteric conditions. They were computed and discussed for all the syst

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200103

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractA supported titanium catalyst was prepared by using MgCl2·6H2O as a precursor for generating an active support. The performance of such catalyst was evaluated for propylene polymerization in conjunction with triethylaluminium as cocatalyst and dimethoxydiphenylsilane as an external Lewis base. The efficiency of the catalyst system is dependent on the polymerization parameters such as time, temperature and monomer pressure. The variation in the concentration of hydrogen used as a chain transfer agent alters the performance of the catalyst system and molecular weight characteristics of polypropylene. The morphology of polymer particles is of globular type and is not affected by the variation in the melt flow characteristics of the polymer

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200104

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effect of hydrolysis time at 70°C on molar mass and mechanical properties of commercial poly(ester urethanes), i.e., Estanes 54600, 54610, and 54650, was analyzed. Kinetics of hydrolysis is plausibly described in terms of a first‐order reaction with an average induction period of about 7 days. The resulting reduction of molar mass brought about a significant decrease in ultimate properties, particularly in stress at break and tensile energy to break, while elastic properties were affected much less. A quantitative correlation between relative changes in tensile strength and molar mass was attempted. Hydrolysis resistance of Estanes decreasing in the succession 54650>54600>54610 was related to their chemical compositi

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200105

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe synthesis of a water‐insoluble chelating resin was carried out by radical copolymerization of 4‐vinylpyridine and N‐hydroxymethyl acrylamide with subsequent crosslinking. Both the crosslinked reference homopolymers of 4‐vinylpyridine and N‐hydroxymethyl acrylamide were also synthesized. The resins were characterized by elemental analyses and FT‐IR spectroscopy. The ability of these resins to bind copper(II), iron(II), iron(III) and uranyl ions as well as the elution of the metal ions from the loaded resins were studied. For uranyl ions, pH 1 was the optimum sorption pH value for all the resins. Sorption selectivity from the binary mixture Cu(II) + U(VI) was studied at the optimum sorption pH value. Finally, the uranium(VI) sorption isotherms, binding constants, and ΔG°, ΔH° and ΔS° corresponding to the uranium(VI) sorption proces

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200106

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractDyes for nonlinear optics have been synthesized in two steps from 2‐hydroxyethyl methacrylate (HEMA), 4‐carboxybenzaldehyde and various substituted anilines. The obtained dyes (aromatic imine esters of HEMA) have been copolymerized with styrene, the copolymers characterized by DSC as well as IR,1H NMR and UV‐VIS spectroscopy, and studied for their nonlinear properties. The d31and d33nonlinear coefficients proved to be dependent on the dye content of the copolymers and on the nature of electrondonating g

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200107

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractUltrathin films of poly(dimethylsiloxane)‐polyamide copolymers (PAS) with different silicone contents were prepared by the methods of water casting and spin coating. The surface properties of the films were investigated in detail using contact angle measurements and X‐ray photoelectron spectroscopy (XPS). The water‐cast films were thin enough to be applicable as laminate films for an artificial lung or an air‐separator for oxygen‐enrichted air. Uniform and ultrathin films were obtained by the spin coating method. XPS and contact angle measurements suggested that poly(dimethylsiloxane) segments were condensed at the outermost surface of spin‐coated PAS films. XPS measurements also revealed that the surface properties of PAS were affected by the molding method, especially the solvent evaporation

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200108

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractNetworks were prepared from Bisphenol A diglycidylether and 4,4′‐diaminodiphenylmethane both in the presence of different amounts of imidazole and in the absence of any accelerator. The ratio of epoxy groups to amino hydrogen was varied: the networks were made with amino hydrogen excess, a stoichiometric ratio of epoxy groups to amino hydrogen, and an epoxy excess.The resulting networks were investigated by thermomechanical analysis, by torsion pendulum analysis and by uniaxial compression modulus measurements in the rubbery‐plateau zone. Further characterization was done by sol gel analysis of the cured samples.It was shown that imidazole does not significantly influence the glass transition temperature and the soluble content of the samples of an excess of amino hydrogen was used. In the case of a stoichiometric ratio of epoxy groups to amino hydrogen and in the case of an epoxy excess, imidazole considerably influences the glass transition temperature of the networks. A dependence of the soluble content of the samples on imidazole concentration used for network synthesis was found mainly in epoxy excess sy

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200109

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThis work reports on a study conducted to achieve carbon fibre functionalization by means of a diazide derivative(p‐(azidosulfonyl)benzoyl azide) in two stages. The first stage comprises surface oxidation of the fibres, which causes an increase of the number of superficial COOH groups. During the second stage the oxidated fibres are brought to react with the diazide derivative via the isocyanate group, obtained by means of the Curtius transposition of the carbonyl azide groups. Fibre oxidation depends on reaction time, following a similar patterns as the one described for carbon black particles. Oxidized fibres functionalization is evidenced both in the progressive decreases in SO2N3groups in the reagent solution and through differential scanning calorimetry analysis (DSC), which shows an exothermal peak around 190°C due to the decomposition of the azide grafted onto the carbon fibre.The degree of attainable functionalization is a function of COOH groups concentration, generated during fibre oxidation, and the ratio of the functionalizing agent with regard to the carboxy groups form

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052200110

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY