bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phthalocyanine polymers. I. Poly[2,2′‐(4,4′,4″‐,4‴‐metal phthalocyanino)‐5,5′‐bibenzimidazoles] as new high temperature resistant polymers
Authors: Achar B. N. , Fohlen G. M. , Parker J. A. 
Published: April 2003

AbstractA novel class of poly(metal phthalocyanino) benzimidazoles were prepared by the condensation reaction between metal (Cu, Co, and Zn), 4,4′,4″,4‴‐tetracarboxyphthalocyanine, and 3,3′‐diaminobenzidine. The reaction was investigated by melt and solution condensation methods. These polymers showed excellent thermal and thermooxidative stability and are noteworthy for their high char yield (86–90%) at 800°C in an anerobic atmosphere. Elemental analyses, spectra, and TGA studies were used to characterize these materials. Isothermal gravimetric analyses were carried out to determine their long‐term thermal stability.
Aliphatic polyesters. III. Molecular weight and molecular weight distribution in alcohol‐initiated polymerizations of ϵ‐caprolactone
Authors: Schindler A. , Hibionada Y. M. , Pitt C. G. 
Published: April 2003

AbstractThe effect of initiation of ϵ‐caprolactone polymerization with mono‐ and polyfunctional alcohols was investigated. The resulting linear and starshaped polymers were characterized by measurement of the molecular weight and molecular weight distribution. The polymerizations were characterized by (1) rapid initiation, (2) invariance of the number of growing chains corresponding to the amount of initiator, and (3) a dominant role played by ester interchange reactions.
Conformational and neighboring effects in graft polymerization of acrolein onto imidazole‐containing polymer
Authors: Yamashita Natsuki , Morita Satoshi , Maeshima Toshihisa 
Published: April 2003

AbstractThe graft polymerizations of acrolein (AL) onto an imidazole (Im)‐containing polymer, such as a homopolymer of 4(5)‐vinylimidazole (VIm) and several copolymers of VIm‐methyl vinyl ketone, VIm‐butyl acrylate, and VIm‐2‐ethyl hexyl acrylate, have been kinetically carried out in ethanol‐water mixture at 0°C. The graft polymerization rate Rp and the degree of graft polymerization increased with increasing concentration of water in the solvent. Moreover, the Rp of the copolymer system having the hydrophobic group as the side chain decreased in comparison with the homopolymer system. Polymerizations of AL in the presence of propionamide or poly‐acrylamide (AAm) induced by Im were also kinetically carried out in ethanol‐water mixture. The Rp was also affected by the conformational change of poly‐AAm. These results were discussed by assuming the conformation of the parent polymer in ethanol‐water mixture.
Effects of ligands on the “living” radical polymerization initiated by the aged Cr2+ plus benzoyl peroxide system
Authors: Lee Munam , Ishida Yoshikazu , Minoura Yuji 
Published: April 2003

AbstractThe “living” radical polymerization of methyl methacrylate with the aged Cr2+ plus benzoyl peroxide (BPO) system in the presence of various amines as ligand has been studied in N,N′‐dimethylformamide. Aliphatic amines such as ethylenediamine diminished the rate of polymerization, while dipyridyl (dipy) and o‐phenanthroline (phen) accelerated the polymerization rate as follows: phen > dipy > pyridine ≃ none. Specifically, the rate of polymerization in the presence of phen had a maximum value at [phen]/[Cr2+] = 0.5. The retardation of polymerization by aliphatic amines was explained by the interaction of BPO with free and coordinated amines. The latter result may support the mechanism involving the complexed radical proposed for the living radical polymerization with the aged Cr2+ + BPO system. In the presence of phen the effects of aging period and aging temperature as well as polymerization temperature were studied and the nature of complexed radicals is discussed.
Amphiphilic copolymers of some aromatic vinyl compounds and an electrolytic monomer as potential media for photosensitized electron transfer: Fluorescence quenching by an amphiphilic electron acceptor in aqueous media
Authors: Itoh Yoshihiro , Morishima Yotaro , Nozakura Shun‐Ichi 
Published: April 2003

AbstractAmphiphilic polymers were prepared by the copolymerization of 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) and aromatic vinyl compounds such as 9‐vinylphenanthrene (VPh) and 1‐vinylpyrene (VPy) with the expectation that they would serve as potential media for photosensitized electron transfer reactions. AMPS strongly solubilizes the hydrophobic segments into water; i.e., poly(AMPS‐co‐VPh) with VPh mole fraction (fPh) up to about 0.60 and poly(AMPS‐co‐VPy) with VPy mole fraction (fPy) up to about 0.35 were found to be soluble in water. Poly(AMPS‐co‐VPh) in aqueous solution, as compared with that in DMF solution, showed a broad fluorescence spectrum with significant tailing in the longer‐wavelength region along with a decrease in the intensity of the structured, monomer fluorescence band. These phenomena seem to imply the presence of an excimerlike interaction of phenanthryl groups in an aqueous solution through which the fluorescence from excited VPh units may be partly self‐quenched. A considerable enhancement of the fluorescence from sodium 8‐anilino‐1‐naphthalenesulfonate (ANS) caused by hydrophobic interaction of the probe with poly(AMPS‐co‐VPh) in aqueous solution indicated that these copolymers assume micellar structures. The fluorescence of these copolymers in aqueous solutions was quenched by bis(2‐hydroxyethyl)terephthalate (BHET), an amphiphilic quencher, far more effectively than by fumaric acid, a hydrophilic quencher. This tendency is particularly strong for the copolymers with higher content of hydrophobic units. The second‐order rate constants for the quenching of poly(AMPS‐co‐VPh) (fPh = 0.58) by BHET were found to be ca. 3 × 1010 and 1.5 × 109 M−1 s−1 in aqueous and in DMF solution, respectively. The larger value in an aqueous solution is presumably due to an increase of the effective concentration of the amphiphilic quencher around the VPh sequences of the copolymer resulting from hydrophobic interaction.
Synthesis of ion‐exchange membranes by radiation‐induced multiple grafting of methyl α,β,β‐trifluoroacrylate
Authors: Omichi Hideki , Okamoto Jiro 
Published: April 2003

AbstractMethyl α,β,β‐trifluoroacrylate (MTFA) was grafted onto polymer films with the multiple grafting technique initiated by α‐rays: the yields were similar to those of the single‐step grafting procedure with any irradiation dose. Grafted polymer obtained in the single‐step experiments were distributed mainly near the film surface, whereas graft polymer from the multiple grafting experiments were distributed uniformly in the film at graft yields greater than 20%. The electric resistance of the hydrolyzed multiple graft polymer film in a 2N NaOH solution was much lower than that of one‐step graft film at the same graft yield.
Copolymerization of N‐carboxy Nϵ‐carbobenzoxy L‐lysine anhydride with N‐carboxy β‐benzyl L‐aspartate anhydride in acetonitrile
Authors: Ōya Masanao , Takahashi Tomoko 
Published: April 2003

AbstractCopolymerization of N‐carboxy Nϵ‐carbobenzoxy L‐lysine anydride with N‐carboxy β‐benzyl L‐aspartate anhydride was initiated with n‐butylamine in acetonitrile. The copolymerization proceeded almost homogeneously except for the initial stage, when the proportion of N‐carboxy anhydride (NCA) in the polymerization mixture varied from 25 to 75 mol %. This was due to the fact that the copolypeptides formed were soluble or highly swollen in the solvent, in contrast to the homopolymerization of NCAs such as Nϵ‐carbobenzoxy L‐lysine NCA and β‐benzyl L‐aspartate NCA in acetonitrile, which proceeds heterogeneously. The compositions of the copolymers obtained were, within experimental error, the same as their monomer feed compositions. The initial rates of copolymerization were almost the same as the rate of homopolymerization of β‐benzyl L‐aspartate NCA, which propagates with a nonhelical polypeptide, but were slower than the rate of homopolymerization of Nϵ‐carbobenzoxy L‐lysine NCA, which propagates with a helical polypeptide.
Synthesis of polysulfohexyl methacrylate with anticoagulant activity
Authors: Chen W. Y. , Xu B. Z. , Feng X. D. , Voong S. T. 
Published: April 2003

AbstractSulfohexyl methacrylate and its polymer have been prepared. The anticoagulation activity of this polymer and copolymers with hydroxyethyl methacrylate and acrylamide was compared with that of polyhydroxyethyl methacrylate, polysulfoethyl methacrylate, and heparin. The activated‐carbon microcapsule coated with polysulfohexyl methacrylate showed itself a promising adsorbent.
Exactly alternating silarylene‐siloxane polymers. III. Structure‐property relationships for polymers containing p‐phenylene and p,p′‐diphenyl ether silarylene units
Authors: Dvornic Petar R. , Lenz Robert W. 
Published: April 2003

AbstractA series of 12 different exactly alternating silarylene‐siloxane polymers was prepared by low temperature condensation polymerization of arylenedisilanol with bisureidosilane monomers. The structural characterization of the polymers was carried out by 1H NMR spectroscopy, 13C NMR spectroscopy, infrared (IR) spectrometry, gel permeation chromatography (GPC). dilute solution viscometry, and differential scanning calorimetry (DSC). Homopolymers and copolymers that contained either or both p‐phenylene and p,p′‐diphenyl ether units in the silarylene group and dimethyl or methylvinyl units in the siloxane group were prepared in high molecular weights.
The chemistry and kinetic behavior of Cu‐Cr‐As/B wood preservatives. IV. Fixation of CCA to wood
Authors: Pizzi A. 
Published: April 2003

AbstractThe kinetic behavior of copper–chromium–arsenic (CCA) wood preservatives in their reaction with wood, lignin, cellulose, and their respective simple model compounds, guaiacol and D(+)‐glucose, has been elucidated. Copper chromatesVI/lignin guaiacyl units and chromiumIII arsenates/lignin guaiacyl units, which are stable and insoluble complexes formed during the reaction, have been characterized. No copper arsenates were formed during the reactions (which were carried out using a CCA of type C). The sequence, nature, and combined effect of the reactions of CCA with wood, lignin, and cellulose are similar to that already described for the “CrO3 alone,”1 Cu/Cr2, and Cr/As3 systems. Rate constants, energies of activation, and Arrhenius equations have been obtained and reported. The distribution of CrVI, CrIII, Asv, and Cu2+ in CCA‐C‐treated wood has been calculated. The results obtained have allowed meaningful comparisons of several commercial CCA formulations.
Polyiodide composition in poly(vinyl acetate)‐iodine‐iodide complex
Authors: Hayashi Sadao , Hirai Toshihiro , Shimomichi Sonoko , Hojo Nobumasa 
Published: April 2003

AbstractPolyiodide formed by complexation of poly(vinyl acetate) (PVAc) with iodine in the presence of iodide has been investigated by chemical analysis and resonance Raman spectrophotometry. When PVAc films were immersed in iodide‐iodine aqueous solutions which had different ratios of iodide to iodine concentration [I−]/[I2], the complex films exhibited tremendous variations of swelling degree, despite the relatively small change in the amount of bound iodine. From a quantitative chemical analysis, the composition of polyiodide bound to PVAc was found to be 1.01 ± 0.035 in the molar ratio of iodide to iodine irrespective of the composition of the iodide‐iodine aqueous solution ([I−]/[I2] = 2–500). The polyiodide formed in PVAc‐iodine‐iodide complex was therefore inferred to be (I3−)n. Resonance Raman spectra obtained on PVAc‐iodine‐iodide complexes were also identical to those of the benzamide‐iodine complex, in which the polyiodide consists of (I3−)n, consistent with the result from chemical analysis.
Radiation‐initiated emulsion copolymerization of styrene and carboxylic acid monomers
Authors: Egusa Shigenori , Makuuchi Keizo 
Published: April 2003

AbstractThe emulsion Copolymerization of styrene and carboxylic acid monomers such as acrylic, methacrylic, and itaconic acids (AAc, MAAc, IAc) was studied by using 60Co γ‐rays as initiator and sodium do‐decylsulfate as emulsifier. The polymerization behavior of these acid monomers was followed by simultaneous conductometric and potentiometric titrations for a latex sample taken in polymerization. The polymerization rate of these acid monomers increases in the following order of hydrophobicity: IAc < AAc < MAAc; this suggests that their polymerization sites are mainly the surface and/or subsurface regions of latex particles. The copolymerization rate of styrene and acid monomer increases with an increase in the acid monomer content for AAc and MAAc, whereas for IAc the rate decreases. The particle sizes determined by the stopped‐flow method reveal that this variation of copolymerization rate cannot be explained by the number of growing particles and should be attributed to another factor; for instance, the transfer rate of styrene molecules from oil droplets to growing particles.
The complexing of polymetaphosphate anions with calcium cations: A potentiometric (pCa) study
Authors: Packter A. , Doherty W. O. S. 
Published: April 2003

AbstractCalcium cation complexing by polymetaphosphate anions was studied by direct potentiometric measurements with a calcium‐ion‐sensitive electrode. The moderately stable neutral chelate (Ca2P4O)n is formed in (CaP2O6)n solutions according to the equilibria

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logK12 values for complexing with polyanions of Mav ≃ 1200 and 2500 (at C = 0.0003M) were 5.86 and 6.26, respectively; the K12 values then decreased with increasing polyanion concentration and were reduced by addition of equivalent sodium chloride. The very stable chelate anion (CaP4O)n is then formed in (Na2CaP4O12)n solutions according to the equilibrium

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logK14 values for complexing with polyanions of Mav ≃ 1200 and 2500 (at C = 0.0003M) were 7.48 and 8.08, respectively; these K14 values also decreased with polyanion concentration. A less stable complex anion (CaP6O)n is formed in more concentrated solutions at PO3/Ca ratios > 6.
Kinetics of simultaneous decrystallization and crystallization induced in high‐modulus rayon by bromine water
Authors: Lewin Menachem , Guttmann Hilda , Knoll Arie , Derfler David 
Published: April 2003

AbstractStudies of the effect of aqueous Br2 solution on the fine structure of cellulose have shown that the accessibility of the cellulose is a complex function of the duration of treatment. Following immersion of rayon‐cellulose in the Br2 solution, its accessibility is observed to increase until a peak is reached, after which the accessibility decreases with time. For higher temperatures and greater concentrations of Br2, a sharper peak and faster rates of increase and decrease of accessibility are obtained. In order to explain this behavior, a mathematical model of the kinetics is postulated involving two opposing first‐order processes occurring simultaneously. One process describes the decrystallization of crystalline regions within the cellulose by opening intermediate linkages due to Van‐der‐Waals forces involved. The second process relates to the crystallization of the less‐ordered regions. The rate constants for these processes are determined by fitting experimental curves to the postulated analytical expression with the aid of a digital computer program. Experiments carried out on high‐modulus rayon showed that for this type of cellulose, the effect described above was very pronounced. From the calculated rate constants, the activation energies of the crystallization and decrystallization reactions were determined. The plots of the rate constants versus 1/T showed that a break occurs at 25°C, corresponding to a second‐order transition point of cellulose. The energies of activation of the crystallization process are in the range of 7–9 and 10–13 kcal/mol in the temperature ranges 10–25 and 25–40°C, respectively. The activation energies of the decrystallization process are 13 and 18–24 kcal/mol in these temperature ranges.
Synthesis, polymerization, and copolymerization of lactam‐substituted styrenes
Authors: Samyn C. , Smets G. 
Published: April 2003

AbstractFour new substituted styrene derivatives carrying lactam rings (2‐pyrrolidone or 2‐piperidone) in para position have been synthesized, namely 4‐(2‐oxo‐3‐methylene‐pyrrolidinyl)styrene, 4‐(2‐oxo‐3‐methylene‐piperidinyl)styrene, 4‐(p‐styryl)‐2‐pyrrolidone, and 4‐(p‐styryl)‐2‐piperidone. Their homopolymerization and copolymerization with styrene, methyl methacrylate, and acrylic acid have been considered. By ring opening of the side lactam groups, the homopolymers are transformed into the corresponding poly aminocarboxylic acids.
Photoinduced electron transfer from polystyrene pendant tris(2,2′‐bipyridyl)ruthenium (II) complex to methylviologen
Authors: Kaneko Masao , Ochiai Masahisa , Kinosita Kazuhiko , Yamada Akira 
Published: April 2003

AbstractThe characteristics of the photoinduced electron transfer reaction from polystyrene pendant tris(2,2′‐bipyridyl)ruthenium (II) complex [Ru(bpy)] to methylviologen (MV2+) were studied. The rate constant k1 from the excited state of the complex, Ru(bpy), to MV2+ were determined for both the polymeric and monomeric complexes from the lifetime τ of Ru(bpy) and the quenching rate of Ru(bpy) by MV2+. The polymer pendant Ru(bpy) showed three kinds of τ components ranging from 7 to 474 ns, in contrast to the monomeric complex, which showed one component of 350 ns. The k1 values for both complexes were almost the same, on the order of 108 L/mol s. The photoinduced electron transfer from solid‐phase Ru(bpy) to liquid‐phase MV2+ was realized by utilizing the polymer complex, and the solid–liquid interphase reaction system is discussed.
Polymerization of pyrrole by potassium persulfate
Authors: Khulbe K. C. , Mann R. S. , Khulbe C. P. 
Published: April 2003

AbstractPyrrole reacted with potassium persulfate in aqueous media to form polymers or “pyrrole blacks.” The structure and molecular weight depend on the initial pyrrole/K2S2O8 ratio. An ESR line due to trapped electrons or free radical ions appeared at g = 2.0036 (width 3.6 G) in all products and its intensity decreased with an increase in initial concentration of potassium persulfate.
Polymerization of aromatic hydrocarbons with sulfur
Authors: Lewis I. C. , Greinke R. A. 
Published: April 2003

AbstractThe polymerization reactions of elemental sulfur with the polynuclear aromatic hydrocarbons pyrene and chrysene were studied. Heating the hydrocarbons with sulfur produces a series of sulfur‐containing oligomers in which the aromatic ring systems remain intact. Polymerization is effected through the dehydrogenative action of sulfur and leads to thermally stable five‐ or six‐membered heterocyclic ring systems. The major loss of sulfur during subsequent heat treatment occurs only at carbonization temperatures above 1000°C.
Polymerization of vinylpyridinium salts. XII. Occurrence of radical polymerization in spontaneous reactions
Authors: Salamone J. C. , Mahmud M. U. , Watterson A. C. , Olson A. P. , Ellis E. J. 
Published: April 2003

AbstractThere has been considerable disagreement regarding the mechanism of the spontaneous polymerization of vinylpyridinium salts in aqueous or acidic solution above 1.0 mol L−1 in monomer concentration. In this report the position of Ringsdorf and co‐workers is substantiated with regard to the existence of a free‐radical reaction, but the kinetic results obtained differ. In particular, it is shown that a lack of spontaneous polymerization below 1.0 mol L−1 is not due to a nonexistence of‐a critical monomer concentration for aggregation, but is instead a kinetic phenomenon of Rp ∼ [M]2.7.
The reduced equation of state and related properties of molten high polymers
Authors: Cho Han Gook , Yoon Sung Chul , Jhon Mu Shik 
Published: April 2003

AbstractThe significant‐structure theory of liquids has been applied to molten amorphous polymers. Expressions of reduced states for these systems are derived for the equation of state and thermodynamic properties such as expansion coefficient, compressibility, internal pressure, and cohesive energy density, and the surface tension. The calculated values are in good agreement with experimental results in comparison with those from other models. In particular, our model predicts the corresponding dependence of the internal pressure better than other models.
Rare‐earth‐metal‐containing polymers. 5. Synthesis, characterization, and fluorescence properties of Eu3+‐polymer complexes containing carboxylbenzoyl and carboxylnaphthoyl ligands
Authors: Ueba Y. , Zhu K. J. , Banks E. , Okamoto Y. 
Published: April 2003

AbstractPartially 2‐carboxylbenzoyl (1) and 3‐carboxyl‐2‐naphthoyl (2) substituted polystyrene were prepared by the Friedel‐Crafts reaction of polystyrene with corresponding dicarboxylic anhydrides. Europium (III) salts of (1) and (2) and the copolymer of 4‐vinylbenzoyl 2′‐carboxylbenzoate‐di(2‐benzoyl benzoate) and styrene (5) were prepared. Polymer (5) was prepared by the copolymerization of the Eu3+ salt of 4‐vinylbenzoyl 2′‐benzoate and 2‐benzoylbenzoate (ratio 1:2) with styrene. The fluorescence emission intensity was measured on fine powder samples. The intensity of (5) increased linearly as the Eu content increased. However, for the 1 and 2 systems the intensity reached a maximum at a Eu content as small as 0.5 wt% and remained constant when further increases were made. This phenomenon was accounted for by steric hindrance and a decrease in the freedom of bond rotation, which prevent the formation of multiple coordination linkages between Eu3+ and the benzoate groups.
Palladium‐doped polyimides: An X‐ray photoelectron study
Authors: Furstch T. A. , Taylor L. T. , Fritz T. W. , Fortner G. , Khor E. 
Published: April 2003

AbstractFive polyimide films prepared from 3,3′,4,4′‐benzophenone tetracarboxylic acid'dianhydride (BTDA) and diamines, 4,4′‐oxydianiline (ODA), 3,3′‐diaminobenzophenone (DABP), or 3,3′‐diaminodiphenylcarbinol (DADPC) and doped with Li2PdCl4 (LTP) or Pd[(CH3)2S]2Cl2 (PDS) were selected for a detailed x‐ray photoelectron spectroscopic (XPS) study to determine the oxidation state of palladium and the relative distribution of this and other elements in these films, especially as they relate to electrical resistivity. XPS shows that Pd in the films is present as a mixture of zero and +2 valence states. Films that contain lithium as part of the dopant all show that metal is present as Li+ and Li2O, a fact that may have a bearing on film electrical properties. An Auger electron spectroscopic (AES) or XPS profiling was performed on two of the electrically conductive films. A film doped with PDS reveals a majority of palladium at the surface as Pd(0) and much smaller amounts in film bulk as a mixture of Pd(0) and Pd(II). Film behavior is similar to a metal‐vapor deposited film. An LTP doped film, by contrast, exhibits a homogeneous composition with a mixture of Pd(0) and Pd(II). These studies support others that use chemical etching on the film surfaces. Scanning electron microscopy (SEM) has been used to provide surface evaluations.