bluuebunny/crossref_metadata_2025 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

The 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

The 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

A 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

Simultaneous 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

The 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

The 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

A 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

A 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

The 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

A 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

Radical 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

Novel 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

Kapton 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

Four 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

The 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

The 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

The 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

Electrochemical 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

1,3‐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

Three 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

A 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.
Compartmentalization of chromophores in a molecular composite consisting of amphiphilic polyelectrolyte‐surfactant ion complexes
Authors: Morishima Yotaro , Seki Michiko , Tominaga Yukio , Kamachi Mikiharu
Published: April 2003

A molecular composite of an amphiphilic polyanion and cationic surfactants was prepared by treating a terpolymer [consisting of sodium 2‐acrylamido‐2‐methylpropanesulfonate, N‐(1‐adamantyl)methacrylamide, and a small mole fraction of N‐(1‐pyrenylmethyl)methacrylamide] with didodocyldimethylammonium bromide in aqueous solution. The molecular composite was soluble in organic solvents with a wide range of polarities. Fluorescence spectra indicated that the pyrenyl (Py) residues in the molecular composite experienced polar microenvironments even though the composite was dissolved in nonpolar solvents. Exciplex formation of the Py residue with 4,4′‐dicyanobenzene was strongly suppressed due to the polar microenvironments and steric “protection” of the chromophore. Photoinduced electron transfer (ET) from the Py residue to pyromellitic dianhydride (PMDA) in acetonitrile showed characteristics of long‐range ET between fixed donor and acceptor sites and yielded long‐lived transient Py cation radicals and PMDA anion radicals which persisted for tens of milliseconds. These findings imply that the micellelike structure of the parent amphiphilic polyelectrolyte formed in aqueous solution is retained, to some degree, in the molecular composite dissolved in organic solvents. © 1992 John Wiley & Sons, Inc.
Aspects of the chemical‐ and the radiation‐induced polymerization of biphenylyl acrylate (BPA)
Authors: Guthrie J. T. , Morton A.
Published: April 2003

Two chemical initiation routes have been used in the polymerization of biphenylyl acrylate. Radiation‐induced polymerization was used in a comparable study. In each instance, dimethyl formamide was used as the solvent. The radiation‐induced polymerizations were carried out over a range of dose rates and of monomer concentrations. The use of evacuated conditions provides a marked increase in chain length compared with products arising from polymerizations undertaken in air. Using evacuated systems as an example, for equivalent reaction times and conditions, the value of Mw increases in the order: AIBN initiated < BP initiated < radiation‐induced initiation. High conversion levels were recorded. For the radiation‐induced polymerization study, the initial rates of polymerization were calculated. The copolymerization of BPA with hydroxyethyl acrylate was also studied to give a guide to the relative reactivity status of the monomers. © 1992 John Wiley & Sons, Inc.
Polymerization of propylene catalyzed over highly active and stereospecific catalysts synthesized with Mg(OEt)2/benzoyl chloride/TiCl4
Authors: Kim Il , Choi Hong Ki , Han Taek Kyu , Woo Seong Ihl
Published: April 2003

A series of monoester catalysts has been studied, each catalyst prepared by the reaction of magnesium diethoxide with benzoyl chloride [BzCOCl, to produce ethyl benzoate (EB) in situ] in the presence of excess titanium tetrachloride. Solid product and catalysts obtained by subsequent treatments with titanium tetrachloride were characterized by elemental analysis, IR spectroscopy, x‐ray diffraction, BET measurement, and thermal gravimetric analysis. The catalysts yielded very high activity (above 20 kg polymer/g Ti h atm) for the polymerization of propylene in slurry reactions. From the results of polymerization as well as catalyst characterization, the effects of internal and external Lewis bases on the isospecificity and stability of catalysts are discussed in detail. © 1992 John Wiley & Sons, Inc.
Poly(dimethylsilylene‐co‐diphenylsilylene)
Authors: Sartoratto Patrícia P. C. , Yoshida I. Valéria P.
Published: April 2003

In this work several polyorganosilylenes were synthesized including homo‐and copolymers containing SiMe2 and SiPh2 units. A Wurtz‐type coupling reaction of the respective dichlorodiorganosilanes with sodium metal, varying the Ph2SiCl2/Me2SiCl2 ratio was the chosen synthesis method. Products with different characteristics for solubility, structure (cyclic or linear), composition, and molecular weight distribution could be obtained depending on the comonomer ratios employed. The polysilane derivatives were characterized by infrared spectroscopy (IR), proton nuclear magnetic resonance (1H‐NMR), and gel permeation chromatography (GPC). Valuable information related to the comonomers' reactivities was obtained, such as molecular weight distribution, composition, and relationships between yields of soluble, insoluble, and cyclic materials of each polycondensation reaction. © 1992 John Wiley & Sons, Inc.
Preparation and properties of new random and block copolyamides derived from 1,3‐bis(3‐aminopropyl)tetramethyldisiloxane, aromatic diamines, and isophthaloyl chloride
Authors: Oishi Yoshiyuki , Nakata Shoichi , Kajiyama Mikio , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

Random and block disiloxane‐containing copolyamides were prepared through one‐ and two‐step procedures, respectively, by the low temperature solution polycondensation in chloroform containing triethylamine hydrochloride starting from 1,3‐bis(3‐aminopropyl)tetramethyldisiloxane, an aromatic diamine [3,4'‐diaminodiphenyl ether (ODA) or m‐phenylenediamine], and isophthaloyl chloride. The random copolyamides exhibited composition‐dependent single glass transition temperature (Tg), and gave transparent and tough films by solution casting or hot pressing. The ODA‐based block copolyamides had two Tg's, and the solvent‐cast transparent films exhibited microphase separated morphology. The block copolymers gave better quality films than the single‐phase random copolymers. © 1992 John Wiley & Sons, Inc.
Synthesis and crosslinking of polyethers with nadimide derivative pendant groups
Authors: Galiá M. , Cádiz V. , Mantecón A. , Serra A.
Published: April 2003

Polyethers with nadimide derivatives pendent groups have been prepared by ring‐opening polymerization of nadimide glycidyl derivatives. The structure of the linear polymers has been confirmed by spectroscopic methods. Properties such glass transition temperatures and thermal resistance have been measured and related to their chemical structure. Crosslinking studies have been carried out by DSC and TGA. Kinetic parameters could be obtained by dynamic method. The crosslinking causes an increase in Tg of the system and it has been possible to relate this increase to the chemical structure of the network. © 1992 John Wiley & Sons, Inc.
Aqueous polymerization of acrylamide initiated by cerium (IV)–ethylenediamine tetraacetic acid redox system
Authors: Hsu Wen‐Cheng , Kuo Jen‐Feng , Chen Chuh‐Yung
Published: April 2003

Ethylenediamine tetraacetic acid (EDTA) terminated polyacrylamide was obtained by using the EDTA–cerium(IV) ammonium nitrate [Ce(IV)] redox initiator in the aqueous polymerization of acrylamide. The polymerization behaviors as a function of the concentration of Ce(IV), EDTA, and acrylamide as well as temperature were studied. The consumption rate of cerium(IV) depends a first‐order reaction on the ceric ion concentration ([Ce(IV)]). The complex formation constant (K) and disproportionation constant (kd) of Ce(IV)–EDTA chelated complex are 1.67 × 104 and 3.77 × 10−3, respectively. The rate dependences of polymerization on monomer concentration and EDTA concentration both follow a second‐order reaction in the run of initial monomer concentration ([M]i) equal to 0.2 mol dm−3. The number average molecular weight increases linearly with the ratio of [M]i/[Ce(IV)]i. The mechanism and kinetics for the polymerization was proposed. The kinetic parameters involved were determined. © 1992 John Wiley & Sons, Inc.
Theoretical approach to cationic polymerization of alkenylfurans. II. Ab initio and semiempirical study of relevant steps in the reaction mechanism
Authors: Alvarez‐Idaboy J. Raul , Galano Annia , Montero Luis A. , Martínez Ricardo
Published: April 2003

SCF ab initio and AM1 semiempirical calculations with full geometry optimization have been carried out to model the initial steps of alkenylfuran cationic polymerization. Semiempirical procedures have been used to model propagation steps. Proton affinities of the relevant neutral species as well as the heats of formation of probable dimers were calculated. The results allow the explanation of the experimental behavior. The capabilities of the employed methods to describe these type of processes is discussed. It is confirmed that competition between vinyl and ring site attacks is the most important feature in these systems. © 1992 John Wiley & Sons, Inc.
Synthesis and flammability of copolyisophthalamides. I. With phosphorus groups in the main chain
Authors: Gravalos K. G.
Published: April 2003

The influence of certain phosphorus substituted (OH, OMe, Me) 3,3'‐diphenylphosphine oxides on flammability and thermal stability of 1,3‐phenylene isophthalamide copolymers was investigated. Introduction of the above phosphorus groups along the backbone of poly(1,3‐phenylene isophthalamide) was performed in a random manner to a degree of ca. 5‐15 mol %. From the limiting oxygen index (LOI) measurements on copolymers, it was found that the diphenylphosphinic acid group has the highest flame retardance efficiency with an increase of LOI 44‐56%. From thermogravimetric analysis (TGA), it was found that the action of phosphorus groups is limited in the solid phase, increasing the char yield to 27‐42%. This was attributed to crosslinking reactions at the stage of amide bond decomposition. © 1992 John Wiley & Sons, Inc.
Photocrosslinking of copolymers of vinyloxyethyl methacrylate‐styrene initiated by sulfonium salts. II. Photocrosslinking behaviors
Authors: Lin Mao‐Peng , Ikeda Tomiki , Endo Takeshi
Published: April 2003

Vinylether was used as a cationically polymerizable moiety and incorporated into sidechain of polymers as copolymers of vinyloxyethyl methacrylate (VEM) and styrene (St). Photoirradiation of the copolymers containing a small amount of benzyl(4‐hydroxyphenyl) methylsulfonium salt (BSS) resulted in a high crosslinking density as evidenced by a low degree of swelling, which is ascribed to the high reactivity of the vinyloxy moieties. The sensitivity of this photoreaction is significantly high because of a large kinetic chain length of the cationic polymerization of vinylethers, while copolymers of glycidyl methacrylate and St showed crosslinking to much less extent when irradiated under the same condition. The ability of other sulfonium salts, (4‐hydroxyphenyl) methyl(4‐nitrobenzyl) sulfonium salt and (4‐hydroxyphenyl) methyl(1‐naphthylmethyl)sulfonium salt, to induce photocrosslinking was also examined. © 1992 John Wiley & Sons, Inc.
Graft copolymer of polymethyl methacrylate‐g‐polycarbonate urethane and the fully gelled grafted networks
Authors: Zhou Peiguang , Frisch H. L.
Published: April 2003

We have synthesized and characterized the graft copolymer of polymethyl methacrylate (PMMA)‐graft‐polycarbonate urethane (PCU) (designated PMMA‐g‐PCU) and the fully gelled mutually crosslinked network composed of both PMMA and PCU (designated as PMMA‐PCU‐N). Unlike the previously synthesized one phase PCU/PMMA simultaneous interpenetrating polymer networks (IPN's), both of these new materials exhibited two distinct Tg's (from DSC and DMA studies) at all compositions which we have studied. The two‐phase nature of the graft and network polymer was confirmed by TEM with domain sizes smaller than those found in the blends of the linear PCU and PMMA chains. In comparison with the corresponding IPN's, the PMMA‐g‐PCU and the PMMA‐PCU‐N were thermally less stable and had a lower ultimate strength. © 1992 John Wiley & Sons, Inc.
Melt‐processable oligoamides having internal acetylene groups in the backbone, and thermally stable polyamides therefrom
Authors: Takeichi Tsutomu , Kobayashi Akiko , Takayama Yuzi
Published: April 2003

Aromatic oligoamides of DP = 5 and 11 that have all meta‐phenylene linkages were prepared by controlling the ratio of isophthaloyl chloride and diamines [m‐phenylenediamine and bis(3‐aminophenyl)acetylene], and then end‐capped with aniline or 2‐aminobiphenylene. Aromatic oligoamides having para‐phenylene linkages were also prepared similarly using terephthaloyl chloride as a monomer. The oligoamides that have all m‐phenylene linkages were soluble in organic solvents such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide, though the oligoamides having p‐phenylene linkages were much less soluble. The oligoamides having acetylene units in the backbone showed exotherm due to crosslinking. The onset of the exotherm appeared at 310‐340°C for the oligoamides having all m‐phenylene linkages, and 330‐370°C for the oligoamides having p‐phenylene linkages. They were melt‐processed at 350 or 380°C for 1 h, giving tough and insoluble films from oligoamides having all m‐phenylene linkages and brittle films from oligoamides having p‐phenylene linkages. The films showed excellent thermal properties. For example, viscoelastic analyses showed little decrease of mechanical property up to 370°C, and Tg was not observed below the temperature. Thermogravimetric analyses also showed that thermal stability of the melt‐processed films were excellent. © 1992 John Wiley & Sons, Inc.
Kinetic analysis of the melt acidolytic (Co) polycondensation of fully aromatic polyesters
Authors: Vulić I. , Schulpen T.
Published: April 2003

Experiments to determine the initial reaction rate constants of acidolytic (co)polycondensations of fully aromatic polyesters were conducted in the melt. The initial reaction rate was determined by constant monitoring of the evolution of acetic acid. Both homo‐polycondensation ofp‐acetoxybenzoic acid (pAcBA) and copolycondensation of 2 parts pAcBA, 1 partp,p'‐bisacetoxybiphenyl (BAcBP), and 1 part terephthalic acid (TPA) were studied in a batch reactor under nonisothermal conditions. Next to this, the effect of the presence of the catalystN‐methylimidazole (NMI) on the (co)polycondensations was checked. From the series of experiments it was concluded that the reactivities of acetoxy groups of pAcBA and BAcBP were equal. Furthermore, it was found that the catalyst NMI showed an accelerating effect in the homo‐ and copolycondensations, thereby acting as a “conventional catalyst.” The postulated reaction mechanism for the (co)polycondensations is in accordance with the reaction mechanism for acidolysis of esters by carboxylic acids as suggested by Loncrini. The reactivity of TPA could not be determined by the method used because of the poor solubility of TPA in the reaction mixture. © 1992 John Wiley & Sons, Inc.
Hydroxypropyl cellulose (HPC)‐stabilized dispersion polymerization of styrene in polar solvents: Effect of reaction parameters
Authors: Chen Yun , Yang Hung‐Wen
Published: April 2003

Dispersion polymerization of styrene in polar solvents in the presence of hydroxypropyl cellulose (HPC) produces latex particles from ca. 1 to 26 μm depending on reaction parameters. Increasing the initiator concentration or temperature decreases the molecular weight, but increases the particle size and breadth of the size distribution. The decrease in molecular weight with increasing Ri, caused by larger initiator concentration or higher temperature, is expected based of fundamental kinetic relationships. The inverse correlation between size and rate of initiation is rationalized by polarity (stabilizing ability) of the grafted HPC‐polystyrene formed in situ. High polar HPC‐g‐PS, which contains shorter graft polystyrene chain, stabilizes particles less effectively and this leads to larger particles. The primary influence of initial styrene concentration is a solvent effect: larger particles are obtained at high styrene concentration due to high solubility of polystyrene during the initial part of the reaction. The influence of the molecular weight of HPC is to change the polarity of the HPC‐g‐PS stabilizer. Comparison of particle growth of three critical polymerization systems suggests that the favorable continuous‐phase solubility parameter for dispersion polymerization of styrene is around 11.6 (cal/mL)1/2. Too high or too low polarity generates particles with broad size distribution because large particles are formed during the initial stage and nucleation continues as the polymerization proceeds. © 1992 John Wiley & Sons, Inc.
Novel carbamoyl phosphonate monomers and polymers from unsaturated isocyanates
Authors: Ignatious Francis , Sein Arjen , Cabasso Israel , Smid Johannes
Published: April 2003

Carbamoyl phosphonate derivatives of methacrylic acid and α‐methyl styrene were synthesized in good yield by reacting dimethyl and diethylphosphite with isocyanato ethylmethacrylate (IEM) or with meta‐isopropenyl‐α,α‐dimethylbenzylisocyanate (m‐TMI). The IEM derivatives yield soluble homopolymers with common radical initiators. The m‐TMI carbamoyl phosphonates were copolymerized with styrene and with acrylates yielding soluble materials with better than 50 mol % incorporation of the phosphonate monomer. The side chain carbamoyl phosphonate group drastically lowers the Tg relative to those of the parent polymers. Thermogravimetric studies suggest the NHC(O)P(O)(OR)2 bond to be stable to about 225°C. The radiopacifying salt UO2(NO3)26 H2O yields transparent films with the phosphonate‐containing polymers. The Tg increases with uranyl content. © 1993 John Wiley & Sons, Inc.
Thermotropic copolyesters having ordered comonomer sequences and flexible spacers
Authors: Jin Jung‐Il , Kang Chung‐Seock , Chang Jin‐Hae
Published: April 2003

A series of new copolyesters having ordered comonomer sequences were synthesized via multistep routes and their properties such as glass transition (Tg) and melting temperatures (Tm), crystallization tendency, and mesomorphic properties were compared with those of the corresponding random copolyesters. All of the present copolyesters contain 1,8‐octamethylene or 1,10‐decamethylene spacers and hydroquinone (HQ) and terephthalic acid (TPA) moieties. In general, both melting and clearing temperatures of the ordered sequence copolyesters were much higher than those of the random counterparts. Crystallization tendency, however, was comparable. All of the present copolyesters are thermotropic and form nematic phase in melts. © 1993 John Wiley & Sons, Inc.
Aqueous polymerization of acrylamide initiated by cerium(IV)–amino acid chelating agent redox initiators
Authors: Hsu Wen‐Cheng , Kuo Jen‐Feng , Chen Chuh‐Yung
Published: April 2003

Amino acid‐type chelating agents such as nitrilotriacetic acid (NTA), nitrilotripropionic acid (NPA), iminodiacetic acid (IDA), and ethylenediamine tetraacetic acid (EDTA) were used in combination with cerium(IV) ammonium nitrate [Ce(IV)] as the redox initiators for the aqueous polymerizations of acrylamide (AM). The polymerization behaviors and polymer qualities were studied as functions of the concentrations of Ce(IV), chelating agent, AM, as well as temperature. The performances of the chelating agent redox systems varied with the natures of the chelating agents. The NTA–Ce(IV) initiator showed the most promising polymerization rate and conversion. The blank tests for the reactions of cerium and chelating agents were also conducted for finding mechanism of formation of free radicals and determining their complex formation constants (K) and disproportionation constants (kd). The mechanism for the polymerization was proposed and the kinetic parameters were evaluated. © 1993 John Wiley & Sons, Inc.
Amphiphilic copolymers with increased affinity for substrates
Authors: Takagishi Toru , Kim Young Joo , Hosokawa Toshitsugu , Morimoto Keiji , Kono Kenji
Published: April 2003

The copolymers of methyl quaternized 2‐dimethylaminoethyl acrylate and styrene, 2‐vinyl naphthalene, acrylic acid iso‐octyl ester, or acrylic acid n‐butyl ester have been prepared. Studies were made of the binding of a “binding probe,” methyl orange, by the copolymers in aqueous solution. The first binding constants and the thermodynamic parameters in the course of the binding were evaluated. Furthermore, the intensity of fluorescence of a hydrophobic fluorescent probe, 2‐p‐toluidinylnaphthalene‐6‐sulfonate, in the presence of these polymers was investigated. In addition, the fluorescence spectra of monomer and excimer emissions of the polymers with aromatic residues were measured. The excimer/monomer fluorescence intensity ratio was studied in the presence of various additives such as methyl orange, urea, methanol, and NaCl to gain an insight into the nature of microdomains in the polymer. The nature and phenomena of dye binding and hydrophobic fluorescent probe binding with the polymers are discussed. © 1993 John Wiley & Sons, Inc.
Effect of counterion condensation on the acid‐base equilibrium of a pH‐sensitive merocyanine dye covalently attached to polyelectrolytes
Authors: Morishima Yotaro , Higuchi Yuji , Kamachi Mikiharu
Published: April 2003

Effects of monovalent and divalent counterions on the acid‐base equilibrium of a pH‐sensitive merocyanine dye covalently attached to copolymers of acrylic acid and acrylamide with varying charge densities (0.28 < ξ < 2.8) were investigated. Added chloride salts of Li+, Na+, K+, and NH+4 (< 0.2 mM) had essentially no effect on pK observed (pKobs) for the equilibrium. By contrast, the salts of Mg2+, Ca2+, Sr2+, and Ba2+ caused a significant decrease in pKobs for the copolymers with larger ξ. With smaller ξ, most likely when ξ < 0.5, no decrease in pKobs was observed upon addition of the salts of divalent cations. A competitive effect of Ca2+ and Na2+ ions on pKobs in the presence of an excess of Na+ ions implied that Ca2+ ions at very low concentrations were preferentially, and therefore exhaustively, condensed on the polyanions with sufficiently large ξ probably until effective charge density was lowered to 0.5. The observed difference in the influence of the monovalent and divalent cations on pKobs was discussed in terms of the difference in the microscopic behavior of the condensed monovalent and divalent cations. © 1993 John Wiley & Sons, Inc.
Thermal decomposition of glassy poly(di‐t‐butyl fumarate) as a topochemical reaction
Authors: Ermakov I. V. , Yashin V. V. , Litmanovich A. D. , Platé N. A.
Published: April 2003

Decomposition of t‐butyl carboxylate (TBC) groups in a glassy poly(di‐t‐butyl fumarate) (PDTBF) at 140–170°C proceeds with a sharp acceleration caused by interchain interaction of TBC and carboxylic groups. According to selective dissolution data, at 70% degree of conversion the reaction system contains both unchanged PDTBF and a final product: poly(fumaric acid). For TBC groups decomposition in di‐t‐butyl fumarate (DTBF)–styrene copolymers above their Tg an apparent rate constant of autocatalysis increases with the increase of DTBF content in copolymer. Together with previously obtained x‐ray data these results lead to conclusions about the topochemical character of the PDTBF decomposition. The mechanism suggested includes thermal decomposition of TBC groups (initiation), autocatalytic growth of spheric clusters up to a critical size (an appearance of primary germs of the new phase), and growth and branching of thread‐like germs. A mathematical model based on these assumptions describes quantitatively the kinetic data. © 1993 John Wiley & Sons, Inc.
Polyarylate–polystyrene block copolymer from macro‐azoinitiator: Synthesis and its thermal properties
Authors: Ahn Tae Oan , Kim Jung Ho , Lee Jong Chan , Jeong Han Mo , Park Jong‐Yoon
Published: April 2003

A macro‐azoinitiator containing polyarylate segment and azo group was prepared by the solution polycondensation of azobiscyanopentanoyl chloride and hydroxy‐terminated polyarylates having viscosity‐average molecular weights of 6200, 8100, and 12 400. These macro‐azoinitiators were used in the radical polymerization of styrene to synthesize polyarylate‐polystyrene block copolymers. Thermal properties measured by the differential scanning calorimetry indicated the phase separated morphology of the block copolymers except at low molecular weight of the block constituents. © 1993 John Wiley & Sons, Inc.
Synthesis and properties of poly(thioether amide)s from 2,6‐bis(acrylamido)pyridine and dithiols
Authors: Oikawa Eizo , Motomi Kiyoshi , Aoki Toshiki
Published: April 2003

Poly(thioether amide)s containing pyridine moieties in their backbone were obtained by the polyaddition of 2,6‐bis(acrylamido)pyridine (2,6‐BAAP), derived from 2,6‐diaminopyridine and acryloyl chloride, with an aromatic or aliphatic dithiol. The influence of various reaction conditions on the polyaddition was investigated in comparison with the polyaddition of 1,3‐bis (acrylamido)benzene (1,3‐BAAB). 2,6‐BAAP gave the polymer even in the absence of any initiator at lower temperatures while 1,3‐BAAB did not, which was attributable principally to intramolecular base catalysis of the pyridine moieties. Basic additives effectively promoted the reaction rate and increased the chain length. Those facts and NMR of the resulting polymers indicated Michael‐type polyaddition. The polymers from 2,6‐BAAP were amorphous and gave transparent and tough films having a high refractive index exceeding 1.7. GPC and DSC characterizations were also made. © 1993 John Wiley & Sons, Inc.