bluuebunny/crossref_metadata_2025_split huggingface dataset:
Binding of metal ions by polyethylenimine and its derivatives
Authors: Takagishi Toru , Okuda Sadatsugu , Kuroki Nobuhiko , Kozuka Hiroshi 
Published: April 2003

AbstractMeasurements have been made of the binding of divalent metal ions, Cu2+, Ni2+, Co2+, and Zn2+ ions, by polyethylenimine (PEI) and its acetyl or alkyl derivatives by the equilibriumdialysis technique. These metal ions, in particular the Cu2+ ion, exhibited tremendously remarkable binding affinity toward PEI. The extent of complexation of the polymer with the metal ions was decreased markedly by acetylation or alkylation of the polymer. PEI with no primary amine showed an appreciable decrease in its affinity for the metal ion. These results indicate the participation of the primary amine of the polymer in the formation of the complex. A cooperative binding isotherm was observed in PEI–metal ion complex formation, suggesting swelling or conformational change of the polymer induced by this coordination process. Binding of the Cu2+ ion by PEI was found to be essentially independent of temperature over the range 5–35°C.
A regenerable immobilized nadh model IV: Reduction of pyridine‐2‐carbaldehyde by immobilized 1,4‐dihydronicotinamide in the presence of Mg2+ ions
Authors: Eling Berend , Challa Ger , Pandit Upendra K. 
Published: April 2003

AbstractDihydronicotinamide, anchored to a macroreticular polystyrene resin, reduces pyridine‐2‐carbaldehyde (PCA) in the presence of Mg2+ ions in acetonitrile. The reactions are clean at room temperature, the high rate precluding complications arising from slow side reactions. The influence of Mg2+ concentration on the rate of reduction of PCA by polymer‐bound reagent and BNAH (1‐benzyl‐1,4‐dihydronicotinamide; low‐molar‐mass analog) has been studied. Analysis of the kinetic data showed that of the processes contributing to the overall reduction, the reaction between the reductant and the complexed substrate proceeded at the highest rate. In the polymer‐bound reagent, “site isolation” on the rigid matrix was observed to prevent bimolecular disproportionation of the neighboring dihydronicotinamides. Regeneration of the polymeric reagent was achieved with an efficiency of 98% per cycle.
A simplification of the terpolymerization equation
Authors: Chien James C. W. , Finkenaur Amy L. 
Published: April 2003

AbstractThe terpolymerization composition equation has been modified to eliminate the consideration of interactions between monomers 2 and 3 when they are present in low concentration in the feed mixture relative to monomer 1. Terpolymers with a wide variety of comonomers and compositions have been synthesized and used to demonstrate that a simplified terpolymerization equation accurately predicts terpolymer composition.
Analysis of products of the thickening reaction between polyesters and magnesium oxide
Authors: Rao K. Balakoteswara , Gandhi K. S. 
Published: April 2003

AbstractThe products of the reaction between MgO and polypropylene‐glycol adipates of different acid values and water contents were analyzed for the water generated and the magnesium reacted into the resin by means of Karl Fischer titration and atomic absorption spectroscopy, respectively. The results conclusively show that both basic and neutral salts are present in the products. The ratio of the amounts of basic and neutral salts present in the mixture, rB/N, could also be calculated from the results. It was found that as R, the moles of MgO added per mole of acid groups, is increased both the amount of oxide reacted and rB/N increase while these are relatively unaffected by the water content of the resin. The minimum value of R at which basic salt exists in the reaction products was found to increase with decreasing acid value. It is proposed that diffusional effects account for these observations as well as those reported in literature.
Synthesis of isotactic, syndiotactic, and heterotactic poly(tributyltin methacrylate) and poly(tributyltin methacrylate‐co‐styrene)
Authors: Zeldin M. , Lin J. J. 
Published: April 2003

AbstractPure isotactic and enriched syndiotactic poly(tributyltin methacrylate) were synthesized by the reaction of the respective poly(methacrylic acid) with tributyltin oxide. The heterotactic polymer was prepared in a similar manner and from free radical initiated (AIBN or BPO) polymerization of tributyltin methacrylate. In each case, polymer configuration was confirmed by 1H‐NMR of the hydrolyzed/esterfied product. The relatively large 119Sn‐NMR linewidth of the isotactic tributyltin containing polymer suggests an intra‐molecular exchange of the pendant tin groups. Tg, Td, and Mv data are also reported. Poly(tributyltinmethacrylate‐co‐styrene) was prepared by free radical polymerization and reactivity ratios [r(styrene) = 0.51, r(TBTM) = 0.49] and Q‐e values for TBTM (0.78, 0.38) were determined.
Molecular structure and photosensitivity of polyesters with conjugated double bonds
Authors: Iwata Kaoru , Hagiwara Tsuneo , Matsuzawa Hiroshi 
Published: April 2003

AbstractPhotocrosslinkable polyesters of m‐ and p‐phenylenebis(α‐cyanoacrylic acids) (I‐a and I‐b), m‐ and p‐phenylenebis(α‐cyanobutadiene carboxylic acids) (I‐d and I‐e), p‐phenylenebis(acrylic acid) (I‐c), and p‐phenylenebis(butadiene carboxylic acid) (I‐f) were prepared, and their photosensitivities were investigated. The spectral sensitivities of I‐a, I‐c, I‐d, and I‐e ranged up to 365, 385, 510, and 560 nm, respectively. This order corresponds to that of λmax due to the π‐π* transition in their absorption spectra. I‐e was sensitive to the visible part of argon ion laser even in the absence of photosensitizer. The highest sensitivity observed with I‐e was estimated to be 1.5 mJ/cm2. In contrast, the sensitivity of I‐c was low (> 105 mJ/cm2) and that of I′‐d, a modified I‐d, was 1300 mJ/cm2, respectively. Addition of 2,6‐di(4′‐methoxyphenyl)‐4‐(4′‐n‐amyloxyphenyl)thiapyrylium perchlorate to them extended their sensitivity range, improving their sensitivity values to 35 and 110 mJ/cm2, respectively.
Electrochemical polymerization of acetylene on a surface of platinum
Authors: Chen Show‐An , Shy Hsiou‐Jeng 
Published: April 2003

AbstractPolyacetylene (PA) deposited on a platinum surface is synthesized by electrochemical polymerization of acetylene in a cell with platinum strip as cathode, nickel strip as anode, and nickel bromide in acetonitrile as electrolyte. The electrolytic solution is presaturated with acetylene. The PA so produced has a granular morphology and high surface area (79 m2/g), and is insoluble. Polymerization at lower temperature gives higher content in cis units. It has the same chemical structure as that produced using the Shirakawa method as examined by elemental analysis, infrared spectroscopy, x‐ray diffraction, and differential scanning calorimetry.
Low‐ and high‐molecular‐weight polyacetylenes: Synthesis, characterization, and thermal isomerization
Authors: Chien James C. W. , Schen Michael A. 
Published: April 2003

AbstractProcedures for the synthesis of polyacetylene ([CH]x) with Mn (number average molecular weight) from 400 to about 106 have been developed. This probably represents the largest range of molecular weight (MW) obtainable for a given monomer by a single initiator system. The catalyst residue level in [CH]x can be significantly reduced by acidic‐methanol purification. The very low MW polymer L‐[CH]x (polyacetylenes with Mn 400–500), has the same cis crystal structure as the higher MW polymers but is less ordered along the c‐axis. It is isomerized to the trans material with apparently a more compact unit cell than high MW polymers. There is annealing of crystallite which increases the longitudinal order during thermal isomerization. This process occurs more readily and with lower activation energy in L‐[CH]x than for polymers with higher MW. Isomerization of high MW polymers tends to trap cis units which can result in degradation as evidenced by the formation of sp3 carbon vibrations in IR spectra. This is true even for L‐[CH]x after prolonged heating. The results render credence to the proposal based on anamalous resonance Raman scattering profile that there can be very short trans segments in thermally isomerized trans‐[CH]x.
Oxidation of benzyl alcohol with Fe(III) using polymers containing the nitroxyl radical structure as a mediator
Authors: Miyazawa Takeo , Endo Takeshi 
Published: April 2003

AbstractSome polymers containing the nitroxyl radical structure were prepared and applied to the electron transfer agents from Fe(III) to benzyl alcohol. Benzyl alcohol was also oxidized by Fe(III) in two‐phase or tri‐phase systems using hydrophobic or hydrophilic polymers, which contain 2,2,6,6‐tetramethylpiperidine‐1‐oxyl moiety, as an electron transfer catalyst. Especially, the hydrophilic polymers accelerated the oxidation of benzyl alcohol.
Vinyl polymerization by carbon black V. Solvent effect and the kinetics of the polymerization of N‐vinylcarbazole
Authors: Haque Shah A. , Biswas Mukul 
Published: April 2003

AbstractThe polymerization of N‐vinylcarbazole has been carried out at 60°C under nitrogen with different grades of carbon black, N220, N110, N330, and N660 as heterogeneous catalysts. The order of efficiency of the catalysts in regard to the polymerization is: N220 > N110 > N660 > N330. Effect of solvent polarity on the polymerization has been studied with acetonitrile, 1,2‐dichloroethane, and toluene‐nitrobenzene mixtures. Nitrobenzene, with highest polarity, affords the highest rate, which decreases with decreasing nitrobenzene percentage in the solvent mixture. These features suggest the polymerization to be cationic in nature. The relative viscosities of the polymers are low, but tend to increase only slightly with increasing nitrobenzene content. The rate of polymerization can be expressed by the relation

A suitable kinetic model has been presented in conformity with the experimental findings.
Mechanism of N‐vinylcarbazole polymerization on Co(II)–13X molecular sieve
Authors: Biswas Mukul , Banerjee Madhusudan , Maiti Mrinal M. 
Published: April 2003

AbstractKinetics of polymerization of N‐vinylcarbazole over Co(II)‐13X molecular sieves in toluene have been studied. The rate of polymerization (Rp) has been found to be second order with respect to percent exchange level of Co(II) and also to the NVC concentration at all the reaction temperatures of 40, 50 and 60°C. The rate increases with decreasing pH of the original exchanging salt solution up to a pH of about 3.5, beyond which it falls. The overall activation energy of polymerization has been found to decrease with increase in monomer concentration, exchange level of Co(II), and the hydrogen ion concentration of the original exchange solution. Average degree of polymerization also follows a similar trend. A mechanism of polymerization involving simultaneous propagation on both metal ion Co(II) and proton on a zeolite surface has been suggested. The two propagation routes are characterized by an average activation energy of 10.36 kcal/mol and 5.40 kcal/mol on the metal ion and proton centers, respectively.
Direct polycondensation of hydroxybenzoic acids with diphenyl chlorophosphate in the presence of ethers
Authors: Higashi Fukuji , Yamada Yukiharu 
Published: April 2003

AbstractThe effects of a modification of the relative reactivity of carboxyl groups to hydroxy groups in monomers on the direct polycondensation of hydroxybenzoic acids was investigated. Polycondensation with diphenyl chlorophosphate (DPCP) was largely promoted by carrying out the reaction in the presence of ethers which are capable of complexing with carboxyl groups in the monomers. The amount of alkyl ethers, such as, poly(ethylene oxide) (PEO) corresponding to an equivalent unit mole of carboxyl groups was effectively added. The molecular weights of the polymers produced increased with the higher molecular weights of PEO, showing maximum values by use of PEO of 1–2.5 × 105.
Synthesis of polyamides from active 5,5′‐isophthaloyldithiobis‐2‐aryl‐1,3,4‐oxadiazoles and diamines under mild conditions
Authors: Saegusa Yasuo , Akano Norihiro , Nakamura Shigeo , Chau Nguyen , Iwakura Yoshio 
Published: April 2003

AbstractAs model compounds for determining the potential adaptability of novel leaving group to polyamide synthesis, 2‐aryl‐5‐benzoylthio‐1,3,4‐oxadiazoles having various electron accepting and donating groups in the oxadiazole unit were successfully prepared from the benzoylation of the corresponding 2‐aryl‐1,3,4‐oxadiazoline‐5‐thiones under kinetically controlled conditions ( < −50°C). The aminolyses of all the benzoyl thioesters by aniline afforded quantitative yields of benzanilide at room temperature in a short reaction time. Polycondensations of new active dithioesters, 5,5′‐isophthaloyldithiobis‐2‐aryl‐1,3,4‐oxadiazoles, with both aliphatic and aromatic diamines occured quite rapidly even at room temperature to form polyamides with reduced viscosities up to 0.41 dL/g. The reactivities of the dithioesters having electron accepting groups such as p‐chloro and p‐nitro groups, particularly p‐nitro groups, toward diamines were much higher than that of the dithioester having no such groups, but the introduction of electron donating p‐methyl group had an adverse effect. The effects of reaction conditions such as solvent, temperature, and monomer concentration on the reduced viscosity of polyamides were also investigated. It was found that monomer concentration had a remarkable influence on the molecular weight of the resulting polyamides.
On the reaction mechanism of gamma‐ray solid‐state copolymerization
Authors: Hayakawa Kiyoshi , Kawase Kaoru , Yamakita Hiromi 
Published: April 2003

AbstractThe gamma‐ray induced solid‐state polymerization of binary mixtures consisting of a maleimide derivative as the first component and acenaphthylene or trans‐stilbene as the second component was investigated regarding the occurrence of copolymerization. The binary solid mixture of these compounds exhibited a phase‐equilibrium diagram including a simple eutectic mixture, and the irradiation caused the formation of a random copolymer together with that of homopolymers of component comonomers. The reaction rates and the composition of products suggested that the mobility of monomer molecules in the crystals affected the solid‐state polymerization significantly. The solid‐state copolymerization was supposed to take place by the diffusion of comonomer molecules via a vapor phase to the nuclei where the copolymerization proceeded.
pH‐induced reversible permeability control of the 4‐carboxy acrylanilide‐methyl methacrylate copolymer membrane
Authors: Ishihara Kazuhiko , Muramoto Naohiro , Fujii Hideyuki , Shinohara Isao 
Published: April 2003

AbstractTo develop a polymer membrane whose permeability of water‐soluble compounds could be controlled in response to a pH change of the medium, a polyelectrolyte membrane containing an aromatic carboxyl group, i.e., 4‐carboxyacrylanilide (CAAn)‐methyl methacrylate(MMA) copolymer membrane, was prepared. The water content of the CAAn‐MMA copolymer membrane increased with increasing pH owing to ionization change in the CAAn moiety. This increase was particularly remarkable in the pH range from 5 to 7. The change in water content was reversible and could be controlled by the CAAn composition in the copolymer. Permeation of 1,4‐bis(2‐hydroxyethoxy)benzene(DHEB) through the CAAn‐MMA copolymer membrane was investigated in solutions of various pH. Change in the permeability of DHEB in function of the pH was similar to the change in membrane water content. This was explained by an increase in the permeation pathway of DHEB in the membrane, in proportion to that in the water content. Moreover, when a pH‐sensitive membrane was placed in a solution in which an enzymatic reaction occurred, substrate‐induced permeation control of DHEB through the CAAn‐MMA copolymer membrane was possible.
Graft copolymerization of ethyl acrylate onto gelatin using hydrogen peroxide and ascorbic acid in aqueous medium
Authors: George Anne , Radhakrishnan Ganga , Joseph K. Thomas 
Published: April 2003

AbstractGelatin a derived protein from collagen can be modified at 60°C by allowing it to react with ethyl acrylate by use of a novel initiator technique. The polymeric ethyl acrylate side chain is chemically bonded to gelatin. The effects of synthetic variable in the graft copolymerization reactions have been discussed in the light of percent grafting, grafting efficiency, and the rate of polymerization.
Functional polymers and sequential copolymers by phase‐transfer catalysis. 15. Thermotropic copolyethers based on 4,4′‐dihydroxybiphenyl, bisphenol a and 1,9‐dibromononane
Authors: Shaffer Timothy D. , Jamaludin Mustafah , Percec Virgil 
Published: April 2003

AbstractThermotropic liquid crystalline (LC) copolyethers have been synthesized from 1,9‐dibromononane, a nonmesogenic bisphenol (4,4′‐isopropylidenediphenol [BPA]) and a mesogenic bisphenol (4,4′‐dihydroxybiphenyl [HB]) by a two‐phase (organic solvent—aqueous NaOH) phase‐transfer catalyzed polyetherification. LC polyethers were obtained for copolymers containing as much as 70 mol % BPA. Optical polarizing microscopy and DSC have revealed smectic mesomorphism for all the copolyethers. The influence of both copolymer composition and microstructural changes, including the nature of the chain ends, upon the mesomorphic properties of these copolyethers have been discussed.
Permeation through homopolymer latex films
Authors: Chainey M. , Wilkinson M. C. , Hearn J. 
Published: April 2003

AbstractThe helium permeabilities of homopolymer films cast from polymer solutions and latex dispersions have been measured as a function of time. The permeability coefficients of most polymer latex films started off at a value which was considerably higher than that of the corresponding solvent‐cast film, but then dropped at a rate dependent on the polymer concerned. The permeability coefficients levelled off at a value which was closer to, but still higher than that of the equivalent solvent‐cast film. Solvent‐cast film permeabilities remained constant for the period of several months over which time they were examined. The reduction in the permeability of latex films is attributed to ageing processes occurring within the film after casting. The fact that latex film permeability coefficients are always higher than those of solvent‐cast films suggests that latex films never become completely homogeneous. The effect on permeability of the latex type and characteristics, and preparation and storage conditions has been examined. The polymer molecular weight, particle size, and surface‐change density did not appear to exert any influence, within experimental error. However, the time‐dependent permeability behavior was affected by the film preparation and storage temperatures.
Efficiency of polymer sensitizer in photosensitized reaction of tris(bipyridine)ruthenium(II) complex‐containing polymer
Authors: Sumi Katsuhiro , Furue Masaoki , Nozakura Shun‐Ichi 
Published: April 2003

AbstractPhotochemical properties of Ru(bpy)2(poly‐4‐methyl‐4′‐vinyl‐2,2′‐bipyridine)Cl2 (2) were studied and compared with that of Ru(bpy)3Cl2. Continuous irradiation of a solution, which contains polymer 2 as a photosensitizer, methylviologen (MV2+) or 4,4′‐bipyridinium‐1,1′‐bis(trimethylenesulfonate) (SPV) as an electron acceptor and triethanolamine (TEOA) as a sacrificial donor, resulted in the formation of viologen radical ion (MV+ or SPV−). The rate of formation of MV+ or SPV− for the polymer 2 system was smaller than that for the Ru(bpy)3 Cl2 systems. The reason for this fact was kinetically analyzed by quenching experiments of excited Ru(II) complexes by MV2+ or SPV, the photosensitized reactions of the TEOA–Ru(II) complex–MV2+ or ‐SPV systems, and the dye laser photolysis of the Ru(II) complex–MV2+ or ‐SPV systems.
Polymerization of styrene by photoexcited safranine T without additives
Authors: Timpe Hans‐Joachim , Neuenfeld Steffen 
Published: April 2003

AbstractStyrene can be photopolymerized with methanolic solutions of safranine T(STH+) in the absence of any additives. Under these conditions the monomer acts as an electron donor for the excited singlet state of STH+, and after electron transfer an initiating semireduced STH+ radical is produced. The experimentally determined monomer exponent of α = 2 indicates additional deactivation reactions of the primary radicals. The polymerization rate depends on the dye concentration also in those regions, in which all light is already absorbed. Presumably, this dependence is caused by a comproportionation reaction between STH+ and substituted leuco‐safranine T formed in the course of polymerization. © 1993 John Wiley & Sons, Inc.
Control of particle size in dispersion polymerization of methyl methacrylate
Authors: Shen S. , Sudol E. D. , El‐Aasser M. S. 
Published: April 2003

AbstractPoly(methyl methacrylate) (PMMA) particles ranging in diameter from 2 to 10 μm were prepared by dispersion polymerization. The effects of various polymerization parameters on the size and monodispersity were systematically investigated. The particle size was found to increase with increasing polymerization temperature, concentration and decomposition rate of the initiator, and solvency of the dispersion medium. It also increased with increasing concentration and molecular weight of the polymeric stabilizer, poly(vinyl pyrrolidone) (PVP). As the monomer concentration was increased from 5 to 20 wt %, a minimum was found in the particle size at a monomer concentration of 10 wt %. A costabilizer was found to be necessary for preparing monodisperse particles at stabilizer concentrations below 2 wt %. A recycling experiment showed that the consumption of PVP was quite small in each cycle and the residual materials in this system could be reused readily. © 1993 John Wiley & Sons, Inc.
Polymeric phosphonium salts as a novel class of cationic biocides. II. Effects of counter anion and molecular weight on antibacterial activity of polymeric phosphonium salts
Authors: Kanazawa Akihiko , Ikeda Tomiki , Endo Takeshi 
Published: April 2003

AbstractVarious poly[tributyl(4‐vinylbenzyl)phosphonium salt]s with different counter anions were prepared and their antibacterial activities against Staphylococcus aureus were explored by the viable cell counting method in sterile distilled water. Antibacterial activity was found to be affected by the structure of the counter anions. The activity was low for a counter anion which tends to form a tight ion‐pair with phosphonium ion, while it was high for those facilitating ionic dissociation to free ions. Furthermore, the molecular weight dependence of the antibacterial activity was investigated for poly[tributyl(4‐vinylbenzyl) phosphonium chloride] with various molecular weights against S. aureus. Antibacterial activity was found to increase with molecular weight. Various copolymers were prepared in which the compositional ratio of tributyl(4‐vinylbenzyl)phosphonium chloride to acrylamide, N‐vinyl‐2‐pyrrolidone, or styrene was altered, and the effect of the positive charge density on the antibacterial activity was investigated against S. aureus. Antibacterial activity of the copolymers was much higher than that of the low‐molecular‐weight model compound and enhanced with the molar fraction of the phosphonium units in the copolymers. © 1993 John Wiley & Sons, Inc.
Intra–intermolecular gel‐free cyclopolymerization of nonconjugated diene with peroxodiphosphate/different activators redox pairs
Authors: Behari Kunj , Agrawal Uma , Das Rima 
Published: April 2003

AbstractGel‐free cyclopolymerization of N,N′‐methylenebisacrylamide has been carried out using potassium peroxodiphosphate (PDP) as initiator in combination with different activators such as mercaptosuccinic acid (MSA) and thioglycollic acid (TGA) in an inert atmosphere at 45 ± 1°C and 40 ± 1°C, respectively. The rate of polymerization was found proportional to the first power of the monomer and activator concentration and the half‐power of PDP in both redox systems. A mechanism involving cyclopolymerization in the propagation path has been proposed. © 1993 John Wiley & Sons, Inc.