bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of aromatic polyethers by Scholl reaction. VII. Oxidative polymerization of 2,2‐bis[4‐(1‐naphthoxy)phenyl]propane and 2,2‐bis [4‐(1‐naphthyl)phenyl]propane
Authors: Percec Virgil , Wang James H. , Okita Shigeru 
Published: April 2003

AbstractThe synthesis and the mechanism of oxidative polymerization of 2,2‐bis[4‐(1‐naphthoxy)phenyl]propane (4) and 2,2‐bis[4‐(1‐naphthyl)phenyl]propane (9) are presented. Both monomers polymerize by two different propagation steps. The first one represents a cation‐radical dimerization of the naphthyl groups to dinaphthyl structure. H+[FeCl4]− generated from the first propagation step initiates a transalkylation reaction which provides structural units containing isopropylidenic groups inserted between phenyl and naphthyl, and between two naphthyl groups, respectively. Since the phenyl groups resulted from the second propagation reaction are unreactive in both the oxidative coupling and the transalkylation steps this polymerization reaction leads to polymers with low molecular weights containing phenyl chain ends.
The influence of aliphatic sulfides on the photoinduced polymerization of butanediol‐1,4 dimethacrylate
Authors: Andrzejewska Ewa 
Published: April 2003

AbstractThe photoinduced polymerization of butanediol‐1,4 dimethacrylate was investigated in the presence of various linear sulfides and cyclic dithioacetals. Benzophenone was used as a sensitizer. It was found that the addition of small amounts of sulfides to the polymerization mixture causes, depending on the sulfide structure and concentration, reduction or full elimination of an induction period as well as an increase in the reaction rate and yield both in air and argon‐saturated systems. The explanation of the obtained results is based on the propensity of sulfides to act as hydrogen donors, chain‐transfer agents, and highly oxidizable compounds.
Modeling of the styrene microemulsion polymerization
Authors: Guo J. S. , Sudol E. D. , Vanderhoff J. W. , El‐Aasser M. S. 
Published: April 2003

AbstractA mathematical model was developed to simulate the polymerization kinetics of styrene oil‐in‐water microemulsions. Nucleation of particles in microemulsion droplets was assumed to account for the number of particles generated. It was found that the entry rate coefficient of radicals into microemulsion droplets is much smaller than the entry rate coefficient into monomer‐swollen particles. All particles contain at most one growing radical. Various radical entry mechanisms were evaluated using the simulation. The possibility of flocculation between particles during the later stages of the polymerization and the high desorption rate of monomeric radicals was suggested by the simulation results. The likelihood of re‐entry of desorbed radicals was den onstrated.
Interpenetrating polymer networks of poly(carbonate‐urethane) and polystyrene
Authors: Zhou Peiguang , Frisch H. L. 
Published: April 2003

AbstractSimultaneous two‐component interpenetrating polymer networks (IPN's), pseudo IPN's, and linear blends of urethane‐containing aliphatic polycarbonate (PCU) and polystyrene (PS) have been synthesized and characterized. The simultaneous full IPN's of PCU and PS had one Tg only at compositions above 50 wt % PCU, as determined by DSC and DMA. The single phase morphology in the one Tg region was confirmed by transmission electron microscopy (TEM). However, the pseudo IPN's and linear blends of PCU and PS exhibited multiple (melting and glass) transitions by DSC measurements and phase separation was observed by TEM over the whole composition range. The full IPN's exhibited a maximum in ultimate mechanical properties at an intermediate composition. Superior solvent resistance as well as better thermal stability was shown by the IPN's as compared to the pseudo IPN's linear blends, and pure crosslinked components.
Molecular design, synthesis, and magnetic characterization of poly(phenylacetylene) with pi‐toporegulated pendant nitronyl nitroxide radicals as models for organic superpara‐ and ferromagnets
Authors: Miura Yozo , Inui Kunihiko , Yamaguchi Fumihiko , Inoue Makoto , Tek? Yoshio , Takui Takeji , Itoh Koichi 
Published: April 2003

AbstractThe present article describes the synthesis and magnetic properties of poly(phenylacetylene) (3) with pi‐toporegulated pendant stable 4,4,5,5‐tetramethylimidazolin‐3‐oxide‐1‐yloxyl radicals topologically participating in the pi‐conjugated system of poly(phenylacetylene). Polyradical 3 was prepared by the condensation reaction of poly(p‐ethynylbenzaldehyde) with 2,3‐bis(hydroxylamino)‐2,3‐dimethylbutane followed by oxidation with lead dioxide. The spin concentration of 3 determined by the ESR spectroscopic method was 1.1 × 1021 spins/g. This value approximately corresponds to 0.5 unpaired electron spin per the repeating unit. A powder ESR spectrum of 3 gave a 100% Lorentzian single line showing spin‐exchange narrowing. The vibrating sample magnetometer (VSM) measurement of 3 afforded a straight line with a positive slope, suggesting that 3 has predominant paramagnetic properties within an experimental error.
Polymerization kinetics of octene‐1 catalyzed by metallocene methylaluminoxane investigated with attenuated total reflectance fourier transform infrared (ATR‐FT‐IR) spectroscopy
Authors: Kolthammer Brian W. S. , Mangold Debra Jean , Gifford Dennis R. 
Published: April 2003

AbstractThe kinetic parameters have been measured for octene‐1 solution polymerization at 120°C catalyzed by zirconocene with the cocatalyst methylaluminoxane. The polymerizations were performed in an attenuated total reflectance (ATR) reaction cell. The progress of the reactions were followed by observing the disappearance of octene‐1 using the 910 cm−1 band measured by FT‐IR spectroscopy. The dependence of the reaction rate, Rp, on catalyst concentration and cocatalyst/catalyst ratio was examined. The catalyst deactivation mechanism was studied by fitting the experimental data to mathematical models involving second‐order propagation and either first or second order catalyst deactivation. Second‐order catalyst deactivation provided a much better fit. The calculated deactivation rate constant, kd, is 21 (Ms)−1. This model is used to determine the propagation rate constant for Al/Zr = 4 × 103 as kp = 19.9 (M s)−1. A decrease in Al/Zr = 3 × 102 lowered the propagation rate constant, kp, to 9.6 (M s)−1 indicating that less than 50% of the initial Zr is active at this Al/Zr ratio.
Improvements in compressive properties of high modulus fibers by crosslinking
Authors: Sweeny W. 
Published: April 2003

AbstractA facile method was developed for crosslinking stiff chain polymer fibers such as Kevlar® and polybenzobisthiazoles (PBZT). The method is based on thermolysis of active aryl halides contained in the polymer unit and coupling of the free radicals formed. The method worked well for the PBZT polymers and improvements in fiber single filament recoil stress and shear modulus were demonstrated. In the case of the polyamides chain cleavage apparently accompanied the crosslinking, limiting improvement in the recoil stress test. The mode of degradation appeared to be rearrangement of the amide linkage to isocyanate.
Static secondary ion mass spectrometry of organic plasma‐deposited films created from stable isotope‐labeled precursors. II. Mixtures of acetone and oxygen
Authors: Chilkoti Ashutosh , Ratner Buddy D. , Briggs David , Reich Fraser 
Published: April 2003

AbstractA series of plasma‐deposited films (PDFs), created by blending controlled ratios of acetone vapor and oxygen in the feed to the plasma reactor, were analyzed by static secondary ion mass spectrometry (SIMS). Examination of the quadrupole‐based static SIMS fragmentation patterns of acetone–O2 PDFs created from 13C‐labeled acetone generally allowed the hydrocarbon secondary ions to be distinguished from oxygen‐containing secondary ions. These results were compared with those obtained via high‐mass resolution time‐of‐flight (TOF)‐SIMS. The identified secondary ions were then assigned structural attributes, based on comparison of the static SIMS spectra of the acetone–O2 PDFs with those of conventional hydrocarbon and oxygen‐containing polymers. A preliminary investigation to unravel the mechanism of oxygen incorporation in the acetone–O2 PDFs from the two plasma feed components was undertaken through the analysis of PDFs created from 1,2,313C3‐acetone(16O) vapor and 18O2 gas.
Electrochemically initiated chain polymerization of pyrrole in aqueous media
Authors: Qiu Yong‐Jian , Reynolds John R. 
Published: April 2003

AbstractThe electrochemical quartz crystal microbalance has been employed to investigate the electropolymerization of pyrrole in a variety of aqueous electrolytes. In contrast to the generally accepted cation–radical coupling process for the electropolymerization of pyrrole, an electrochemically initiated chain polymerization, featuring a high polymerization rate and involving little charge transport, was found under specific conditions in the presence of ClO−4, BF−4, and PF−6 electrolytes. The more typical cation‐radical coupling mechanism, characterized by a constant polymerization charge to mass deposited ratio, is observed in the presence of Cl−, NO−3, dodecyl sulfate, copper phthalocyanine tetrasulfonate, β‐cyclodextrin tetradecasulfate, and poly(styrene sulfonate). Electrochemical characterizations of polypyrrole films prepared in aqueous ClO−4 electrolytes reveal that the polymer formed via chain polymerization exhibits the ability to transport both cations and anions during electrochemical switching between redox states, while the polymer synthesized through cation‐radical coupling is only capable of transporting a single ionic species.
Polyisophthalamides with phenylthio pendent groups
Authors: Lozano A. E. , De Abajo J. , De La Campa J. G. , Preston J. 
Published: April 2003

AbstractA series of polyisophthalamides containing pendent phenylthio groups was prepared from seven aromatic diamines and 5‐phenylthioisophthalic acid by the phosphorylation polycondensation method. The properties of these polymers were compared with those of the analogous unmodified ones. The modified polymers exhibited better solubility in organic solvents than their unmodified counterparts. They also showed glass transition temperatures that were lower by approximately 30°C. However, the presence of the side groups did not bring about any substantial lowering of the thermal stability as measured by TGA. Other properties investigated were mechanical strength and water sorption.
Radical polymerization of isopropyl tert‐butyl fumarate and maleate, and characterization of the resulting polymers
Authors: Otsu Takayuki , Yoshioka Masahiro , Sunagawa Takamichi 
Published: April 2003

AbstractRadical polymerization of isopropyl tert‐butyl fumarate (iPtBF) and monomer‐isomerization radical polymerization of isopropyl tert‐butyl maleate (iPtBM) were investigated with 2,2′‐azobisisobutyronitrile as initiator in the presence and absence of morpholine (Mor) as isomerization catalyst. It was found that iPtBF gave high molecular weight polymers in high yield as previously observed for diisopropyl fumarate (DiPF) and di‐tert‐butyl fumarate (DtBF). It was confirmed that iPtBF produced by in situ monomer isomerization of iPtBM homopolymerized to give a polymer. Radical copolymerization of iPtBM with styrene in the presence and absence of Mor was also performed and monomer reactivity ratios obtained were compared. From the kinetic study of the isomerization of iPtBM, it was revealed that the isomerization rate showed first‐order dependence on the concentration of iPtBM and Mor, and that the apparent activation energy was 29.4 kJ/mol. On pyrolysis of the poly(iPtBF) at 180°C, isobutene and isopropanol were eliminated rapidly to yield polymer containing carboxyl groups and anhydrides. The pyrolytic behavior was different from that of a copolymer of DiPF with DtBF.
Preparation and characterization of novel polyaryloxydiphenylsilanes with high glass transition temperature by melt polycondensation of dianilinodiphenylsilane with bisphenols
Authors: Saegusa Yasuo , Kato Takahiro , Oshiumi Hirotaka , Nakamura Shigeo 
Published: April 2003

AbstractNovel polyaryloxydiphenylsilanes with reduced viscosities of 0.31–0.65 dL/g were obtained by the melt polycondensation of dianilinodiphenylsilane with three bisphenols, 2,2‐bis (4‐hydroxyphenyl)‐1,1,1,3,3,3‐hexafluoropropane, 3 (4‐hydroxyphenyl)‐1,1,3‐trimethyl‐5‐indanol, and 9,9‐bis (4‐hydroxyphenyl) fluorene, at 200–320°C in vacuo. These polymers are all amorphous and readily soluble in a wide variety of organic solvents such as chlorinated and aromatic hydrocarbons, cyclic ethers, and polar aprotic solvents. Because of their bulky and/or rigid ring structures, polyaryloxydiphenylsilanes containing diphenylhexafluoropropane, phenylindane, and diphenylfluorene units in the main chain have high glass transition temperatures of 106, 112, and 172°C, respectively. They are thermally stable showing almost no weight loss up to 350°C in air. Colorless, transparent, but brittle films are obtained from these polymers by solution casting. Ultraviolet transmission is sharply cut off by these polyaryloxydiphenylsilane films at ca. 300 nm, and the cut‐off wavelength depends on the bisphenols used.
Surface modification of Kapton film by plasma treatments
Authors: Inagaki N. , Tasaka S. , Hibi K. 
Published: April 2003

AbstractKapton films were treated with seven plasmas: Ar‐, N2‐, O2‐, CO‐, CO2‐, NO‐, and NO2‐ plasmas. Surface properties and chemical composition of the plasma‐treated Kapton films were investigated from the contact angle measurement, and the IR and XPS spectra. The plasmas, especially NO‐ and NO2‐plasma, made the Kapton film surface hydrophilic. The XPS and IR spectra showed that the plasma led to the modification of the imide groups in the Kapton film to secondary amide and carboxylate groups.
Synthesis of polyamides by nickel‐catalyzed coupling polymerization of aryl dichloride containing amide structural units
Authors: Ueda Mitsuru , Ito Takashi , Seino Yoshikatu 
Published: April 2003

AbstractFour aryl dichlorides containing secondary amide structural units as monomers were synthesized from substituted piperazines and chlorobenzoyl chlorides. Polyamides were prepared by the nickel‐catalyzed coupling polymerization of these monomers. Polymerizations were carried out in N‐methyl‐2‐pyrrolidinone (NMP) in the presence of nickel chloride, zinc, triphenylphosphine, and bipyridine, and resulted in polyamides with inherent viscosities up to 0.38 dL/g under mild conditions. The structure of polymer was determined by IR and 13C‐NMR spectroscopies. The polyamide, poly[4,4′‐biphenyldicarbonyl (2,5‐dimethylpiperazine)] 6d, was readily soluble in dipolar aprotic solvents and chloroform. Thermogravimetry of polyamides, poly[(4,4′‐biphenyldicarbonyl piperazine)]s 6, showed 10% weight loss at around 425 and 450°C in air and under nitrogen, respectively. © 1992 John Wiley & Sons, Inc.
Chemical and electrochemical characterization of chemically synthesized conducting polypyrrole
Authors: Sak‐Bosnar M. , Budimir M. V. , Kovac S. , Kukulj D. , Duic L. 
Published: April 2003

AbstractThe conducting polypyrrole chemically synthesized in water, using the variable concentrations of FeCl3 and CuCl2 as oxidizing agents, was chemically and electrochemically characterized and compared with electrochemically generated polypyrrole. According to the results of elemental analysis and counter ion determinations, it can be concluded that a mixture of dimer and trimer was obtained using CuCl2, i.e., a dimer composition using FeCl3 as an oxidant. Cyclic voltammetric studies of polypyrrole obtained by using FeCl3 as an oxidant showed no evidence of polypyrrole decomposition after repetitive cycling. The voltammograms showed also that after the oxidation reaction a high capacitive current remained, confirming the assumption that the capacitive current is intrinsically associated with polypyrrole, irrespective of the way of its preparation. Cyclic voltammogram of the polypyrrole synthesized by oxidation with CuCl2 showed different shape, probably influenced by the presence of copper ions incorporated in polymers. © 1992 John Wiley & Sons, Inc.
Cocondensation of urea with methylolphenols in acidic conditions
Authors: Tomita Bunichiro , Hse Chung‐Yun 
Published: April 2003

AbstractThe reactions of urea with methylolphenols under acidic conditions were investigated using 2‐ and 4‐hydroxybenzyl alcohol and crude 2,4,6‐trimethylophenol as model compounds. The reaction products were analyzed with 13C‐NMR spectroscopy and GPC. From the reaction of urea with 4‐hydroxybenzyl alcohol, the formations of 4‐hydroxybenzylurea, N,N′‐bis (4‐hydroxybenzyl) urea, and tris(4‐hydroxybenzyl) urea were confirmed and the formations of N,N‐bis(4‐hydroxybenzyl) urea and tetrakis (4‐hydroxybenzyl) urea were suggested. From the reaction of urea and 2‐hydroxybenzyl alcohol, 2‐hydroxybenzylurea and N,N′‐bis(2‐hydroxybenzyl) urea were identified. Further, the alternative copolymer of urea and phenol could be synthesized by the reaction of urea with 2,4,6‐trimethylophenol. It was also found that the cocondensation between p‐methylol group and urea prevails against the self‐condensation of the methylolphenol even at the low pH below 3.0, and that p‐methylol group has the stronger reactivity to urea than o‐methylol group. © 1992 John Wiley & Sons, Inc.
NMR analysis of the microstructure of poly(methyl acrylate‐co‐N‐vinylcarbazole)
Authors: Crone G. , Natansohn A. 
Published: April 2003

AbstractThe microstructure of a series of high conversion copolymers of methyl acrylate (MA) and N‐vinylcarbazole (NVC) was characterized by NMR. 1H‐ and 13C‐NMR spectra were assigned by comparison to the homopolymers and by using heteronuclear shift correlation spectroscopy. MA‐centered triad distributions were obtained from the carbonyl carbon. Distributions of NVC sequences were determined from aromatic carbons 1 and 8a, and aromatic proton 1

These experimentally determined sequence distributions were compared to those calculated from reactivity ratios approximated from the copolymer compositions. Agreement was very good for low NVC content copolymers. Three signals were particularly useful in providing rapid assessment of the distribution of NVC units within low NVC content copolymers: proton 1 and carbon 1 of NVC and the carbonyl carbon of MA. © 1992 John Wiley & Sons, Inc.
Electrochemical preparation of polythiophene via 2,5‐bis(trimethylsilyl)thiophene
Authors: Masuda Hideyuki , Taniki Yasushi , Kaeriyama Kyoji 
Published: April 2003

AbstractElectrochemical polymerization of 2,5‐bis(trimethylsilyl) thiophene produced highly conducting films which showed infrared spectra, visible‐near infrared absorption spectra, and cyclic voltammograms identical to films prepared from thiophene. Elemental analysis indicated that almost all silicon atoms were eliminated during the electrochemical polymerization. However, scanning electron microscopy showed a morphological difference between the films from 2,5‐bis(trimethylsilyl)thiophene and from thiophene. The electrochemical polymerization of bis(2‐thienyl)dimethylsilane, 1,2‐bis(2‐thienyl)tetramethyldisilane, and bis(2‐thienyl)diphenylsilane also produced polythiophene films having unique morphologies quite different from the conventional ones. These findings indicate that these electrochemical procedures must be useful for preparation of new conjugated polymers. © 1992 John Wiley & Sons, Inc.
Thermally stable polymers based on acetylene‐terminated adamantanes
Authors: Malik A. A. , Archibald T. G. , Baum K. , Unroe M. R. 
Published: April 2003

Abstract1,3‐Diethynyl‐5,7‐dimethyladamantane, 1,3‐diethynyl‐5‐phenyladamantane, 1,3,5‐triethynyladamantane, and 3,3′‐diethynyl‐1,1′‐biadamantane, were synthesized and polymerized thermally at 210°C. The thermoset resins obtained were post‐cured at 300°C for 16 h to give materials that exhibited onsets of degradation (TGA) in air at 460–477°C and in helium at 460–485°C. The fully cured materials did not exhibit any detectable DSC transitions between 25 and 400°C. An attempt to thermally polymerize 1‐ethynyl‐3‐phenyladamantane was unsuccessful. © 1992 John Wiley & Sons, Inc.
Thermotropic aromatic copolyesters of catechol
Authors: Navarro Fernando , Serrano José Luis 
Published: April 2003

AbstractThree new series of thermotropic aromatic main‐chain polymers were synthesized and studied by differential scanning calorimetry and hot‐stage polarized microscopy. The polymers were random copolyesters of p‐hydroxybenzoic acid (from 60 to 10 mol %), catechol (from 20 to 45 mol %), and one of the following dicarboxylic diacids: terephthalic acid (series 1), 2,6‐naphtalenedicarboxylic acid (series 2), and 1,2‐bis‐p‐carboxyphenoxy ethane (series 3). Copolyesters with more than 25 mol % catechol in their structures were soluble in common organic solvents such as chloroform. All the synthesized copolyesters showed hysteresis of the heat capacity at the mesophase glass transition region and nematic mesophases above their Tg's which were stable over very broad ranges of temperature. Copolyesters containing the 2,6‐naphtylenedioyl group showed the most stable nematic phases due to the increased anisometry of the 2,6‐naphtylenedioyl unit compared to that of the therephthaloyl or the 4‐oxybenzoyl units. © 1992 John Wiley & Sons, Inc.
Spiro(benzoxasilole) catalyzed polymerization of oxetane derivatives
Authors: Xu Baopei , Lillya C. Peter , Chien James C. W. 
Published: April 2003

AbstractA spiro(benzoxasilole) catalyst, 3,3,3′,3′‐tetrakis(trifluoromethyl)‐1,1′‐(3H,3H′)‐spirobis(1,2‐benzoxasilole) was used to polymerize 3,3‐R,R′‐oxetanes: BEMO (R, R′ = ethoxymethyl), AMMO (R = azidomethyl, R′ = methyl), NMMO (R = nitratomethyl, R′ = methyl), BAMO (R, R′ = azidomethyl), and BCMO (R, R′ = chloromethyl) with descending rates in this order. 31P‐NMR of polymerization mixtures quenched using Bu3P are consistent with an oxonium ion propagating species. Water is not a cocatalyst because it increases the induction period which is not eliminated by the proton trap 2,6‐di‐t‐bu‐tylpyridine. The propagating chains were terminated by transfer with the ether oxygen of the polymer either intermolecularly or intramolecularly. The index of propagation to chain transfer, Kkikp/ktr, varies over more than three orders of magnitude for BEMO > AMMO > NMMO > BAMO. However, kp/ktr for the four monomers differ by less than a factor of five indicating the same factors are affecting propagation and chain transfer. Addition of benzyl alcohol and propandiol produced poly(BEMO) having one and two hydroxyl termini, respectively. These telechelic polymers can be used to synthesize linear triblock or multiblock copolymers of oxetane derivatives. © 1992 John Wiley & Sons, Inc.