bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the reaction state on the polymerization of p‐xylenesulfonium salts
Authors: Garay R. O. , Lenz R. W.
Published: April 2003

1,4‐Phenylenebis(methylene) sulfonium salts were polymerized under different conditions to yield p‐xylylene sulfonium salt polyelectrolytes in a broad range of molecular weights. The aqueous reaction mixture formed a reversible gel at initial monomer concentrations higher than 1.0M, but at lower concentrations it remained as an emulsion until reaction completion. The effect of reaction time on intrinsic viscosities and polymer yields for both the emulsion and the gel state is discussed. The higher yields obtained when the reaction was carried out in the presence of a water‐immiscible organic solvent were apparently due to the effect of this solvent on increasing the concentration of the reactive intermediate that led to the polyelectrolyte. Both the addition of an organic solvent and the variation of the initial monomer concentrations allowed some control over the molecular weight of the polyelectrolyte formed.
Polymerization behavior of 2,2,6,6‐tetramethylpiperidinyl methacrylate: A monomer carrying a hindered amine group
Authors: Lee C. S. , Lau Wayne W. Y. , Lee S. Y. , Goh S. H.
Published: April 2003

Copolymers of 2,2,6,6‐tetramethylpiperidinyl methacrylate (TPMA) with styrene (S) and with methyl methacrylate (MMA) were synthesized using AIBN as initiator. S–TPMA copolymers from feed ranging from 0.10–0.80 mole fractions TPMA and MMA‐TPMA copolymers from feed of 0.04–0.85 mole fractions TPMA were used in the determination of monomer reactivity ratios r1, r2. Four different methods were employed in the calculations of r1 and r2 and all calculated results were in good agreement with each other. The structure of S–TPMA copolymers was inferred to be of an alternating nature while that of MMA–TPMA copolymers was random. Both copolymers are potential hindered amine light stabilizers (HALS) and are expected to be less extractable from, and more compatible with, polystyrene and poly(methyl methacrylate) base polymers.
Preparation and properties of novel soluble aromatic polyimides from 4,4′‐diaminotriphenylamine and aromatic tetracarboxylic dianhydrides
Authors: Oishi Yoshiyuki , Ishida Mina , Kakimoto Masa‐Aki , Imai Yoshio , Kurosaki Toshikazu
Published: April 2003

New aromatic polyimides containing triphenylamine unit were prepared by two different methods, i.e., a conventional two‐step method starting from 4,4′‐diaminotriphenylamine and aromatic tetracarboxylic dianhydrides and the one‐step thioanhydride method starting from the aromatic diamine and aromatic tetracarboxylic dithioanhydrides. Both procedures yielded high‐molecular‐weight polyimides with inherent viscosities of 0.47–1.17 dL/g. Some of these polymers were soluble in organic solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, m‐cresol, and pyridine. All the polyimides afforded transparent, flexible, and tough films, and the color varied from pale yellow to dark red, depending markedly on the tetracarboxylic acid components. The glass transition temperatures (Tgs) of these polyimides were in the range of 287–331°C and the 10% weight loss temperatures were above 520°C in air. The polyimides prepared by the one‐step method exhibited better solubility in organic solvents and had somewhat lower Tgs than the polymers prepared by a conventional two‐step method.
Soluble polyarylenes containing alternating binaphthylene and biphenylene structural units
Authors: Percec Virgil , Okita Shigeru
Published: April 2003

This article describes the synthesis of a novel series of soluble polyarylenes containing alternating binapthylene and biphenylene structural units. They were obtained by the cation‐radical polymerization of bis(1‐naphthyl) biphenyls. The following monomers were synthesized and polymerized : 4,4′‐bis(1‐naphthyl) biphenyl (9), 3,3′‐bis(1‐naphthyl) biphenyl (10), 2,2′‐bis(1‐naphthyl)biphenyl (11), and 2,5‐bis(1‐naphthyl)biphenyl (14). All polymerizations were performed in nitrobenzene using FeCl3 as oxidant. Polymers with number average molecular weights of up to 4000 g/mol were obtained.
Amphiphilic segmented polyurethanes as surface modifying additives
Authors: Kober Maria , Wesslén Bengt
Published: April 2003

Amphiphilic segmented polyetherurethanes were prepared from methylene diphenylene diisocyanate (MDI), poly(ethylene glycol) 1500 (PEG), and a fatty acid monoglyceride as a chain extender. The polymers were not soluble in water or methanol, but dissolved readily in organic solvents. The amphiphilic properties were demonstrated as a large hysteresis in the water contact angles, exceeding 110°. The amphiphilic polymers were shown to modify the surface properties of a poly(ether urethane) (PEU) and a poly(ether urethane urea) (PEUU) when added in 1–10 wt %, presumably due to migration of the additive to the surface. The surfaces of particularly the PEU blends became highly amphiphilic, exhibiting contact angles hystereses up to 90–100°. A surface saturation effect was observed at 5% added amphiphilic polymer. A difference in the behavior of PEU and PEUU was ascribed to differences in solubility of the additive in the matrix. On long‐term exposure to water the PEUU blends increased their amphiphilic behavior.
Synthesis and phase‐transfer catalytic activity of crown ethers bound to microporous polystyrene resins by oxyethylene spacers
Authors: Chung Kwang Bo , Tomoi Masao
Published: April 2003

Crown ethers bound to microporous polystyrene resins by oxyethylene spacers were prepared by the reaction of monoazacrown ethers with 2‐tosyloxyethoxymethylated or 2‐(2‐tosyloxyethoxy)ethoxymethylated polystyrene resins crosslinked with 2 mol % of divinylbenzene. The activity of the immobilized lariat crowns for halogen exchange reactions under triphase conditions has been studied as a function of catalyst structure, loading, substrate structure, reagent structure, and solvent. The lariat catalysts with extra oxygen donors in the spacer chain exhibited higher activity than the corresponding immobilized catalysts without the donors in the spacer. The increased activity of the catalyst containing 15‐crown‐5 unit and two extra donors for the reaction of 1‐bromooctane with KI was concluded to result from the enhanced complexation with the K+ ion, induced by the cooperative coordination of the crown unit donors and the donors in the spacer chain. The recovered catalysts could be re‐used without decrease in activity.
Polyimides containing nonaromatic nitrogen linkages
Authors: Feld William A. , Le Tieu‐Binh
Published: April 2003

Two diamines, 2,5‐bis (4‐aminophenyl)‐2,5‐diazahexane and 1,4‐bis (4‐aminophenyl)‐1,4‐diazacyclohexane were chosen as components for polyimidizations because they have melting points that differ by nearly 200°C (66–67 and 229–230°C, respectively) and are relatives of p‐nitro‐N,N‐dimethylaniline. The melting points of the model compounds (phthalic anhydride) do not differ by as much as those of the free amines [303–304 and 386°C (DSC), respectively]. Six polyimides were prepared by a two‐step polycondensation of the diamines with pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, and 5,5'‐[2,2,2‐trifluoro‐1‐(trifluoromethyl) ethylidene] bis‐1,3‐isobenzofurandione. DSC thermograms failed to indicate any distinct transitions up to 450°C, however, the polyimide prepared from 2,5‐bis (4‐aminophenyl)‐2,5‐diazahexane and pyromellitic dianhydride shows a slight break in its DSC curve at 233°C.
Surface modification. I. Polyacrolein microspheres covalently bonded onto polyethylene
Authors: Margel Shlomo , Cohen Ella , Dolitzky Yehudit , Sivan Orit
Published: April 2003

The synthesis and characterization of novel surfaces composed of polyacrolein microspheres covalently bonded onto polyethylene films are described. These surfaces were prepared through a sequence of reactions carried out onto polyethylene films in order to form primary amine groups at the w position. Polyacrolein microspheres in water were then covalently bonded to these modified polyethylene surfaces. The binding between the microspheres and the modified surfaces is due to the interaction between the aldehyde groups of the microspheres and the amine groups of the modified surfaces to form the polyvalent Schiff base bonds. Fourier transform‐infrared/attenuated total reflection, electron spectroscopy for chemical analysis, contact angle measurements, and scanning electron microscopy have been used for the characterization of the modified polyethylene surfaces.
A new synthetic pathway of segmented tri‐block copolyether
Authors: Sangen Osamu , Masuda Singo , Nakano Hidehiko , Yamana Kazusige , Sasaki Kenichi , Ikeda Naoki
Published: April 2003

A new synthetic pathway of A–B–A tri‐block copolyether which is composed of a hydrophilic poly(oxyethylene) unit as an A part and a hydrophobic poly(oxy‐2‐methyl‐trimethylene) unit as a B part is proposed. Telechelic α‐tosyl‐ω‐tosyloxypoly(oxy‐2‐methyl‐trimethylene) derived from tosylation of poly(oxy‐2‐methyl‐trimethylene glycol) (PMTG) was allowed to react with poly(ethylene glycol) (PEG) in the presence of sodium hydroxide. Tg of the resulting A–B–A tri‐block copolyether (PEMG) (M̄n = 1600) was −72°C and its specific gravity [D415] was 1.055.
Thermooxidation of polyarylethersulfone HTA: Oscillations and mechanism
Authors: Brauman S. K.
Published: April 2003

Chemiluminescence in conjunction with x‐ray photoelectron spectroscopic surface analysis has been used to elucidate the thermooxidation of polyarylethersulfone HTA film between 85 and 110°C. Oscillations have been observed in chemiluminescence at different wavelengths and in the concentration of newly identified sulfine intermediates. A reaction mechanism is proposed to account for the chemiluminescence and product behaviors. This mechanism features parallel intramolecular and intermolecular pathways branching from a common sulfinyl sulfonate intermediate; each branch produces different emittering species. Oscillating behavior appears to be general for polyarylsulfone films.
Accessible new acrylic monomers and polymers as highly transparent organic materials
Authors: Boutevin B. , Rousseau A. , Bosc D.
Published: April 2003

Theoretical studies of intrinsic absorption phenomena in organic compounds in a range of wavelengths from visible to near‐infrared (NIR), led us to synthesize acrylic monomers with variable molar number of CH per cubic centimeter, NCH. Thus, halogenoalkyl or aryl α‐chloroacrylates, α‐fluoroacrylates, and methacrylates are prepared. The corresponding homo‐ and copolymers exhibit good thermal (Tg from 120 to 160°C) and optical properties.
Preparation of microspheres by radiation‐induced polymerization. II. Mechanism of microsphere growth
Authors: Naka Yukihiko , Yamamoto Yukio
Published: April 2003

The effects of the monomer concentration were investigated on the preparation of diethylene glycol dimethacrylate (2G) microspheres by radiation‐induced polymerization. The monomer concentration strongly affected the conversion and the shape of the microspheres. The particles were obtained in the range from 2 to 24 vol % of 2G monomer. The effective concentration for the preparation of monodisperse microspheres is around 10 vol %. Higher monomer concentrations up to 24 vol % gave rough surface particles. Considering the effects on the number of microspheres in the solution, the authors introduced the inhibiting region, where one microsphere disturbs the existence of another microsphere, and tried to explain the mechanism of the microsphere growth. The competition between the propagation and the crosslinking reactions is balanced to give the microspheres.
Solid‐state photochemical generation of polymeric polyradicals: Poly(4‐vinylphenoxy) and copolymers with styrene
Authors: Rossitto Frank C. , Lahti Paul M.
Published: April 2003

Synthesis of poly(4′‐vinyl‐2,4,6‐tri‐tert‐butyl‐diphenyloxalate) and its 65 : 35 and 19 : 81 copolymers with styrene are described. Rigid phase broad‐band photolysis of the homopolymer with a quartz filtered xenon arc at 77 K results in production of up to 25% of the theoretical number of spins/mol expected for quantitative production of pendant phenoxyl radicals, and shows no major loss of radical signal in the ESR at temperatures below 100 K. Curie law analysis of the temperature dependence of the ESR radical signal intensity for the neat photolyzed homopolymer 1 shows curvature consistent with antiferromagnetic pairing of radical spins at low temperatures. Since through‐bond conjugation of radical spins is not possible in this system, the antiferromagnetic interaction is interpreted in terms of intrachain and/or interchain through‐space exchange interactions.
Synthesis and properties of aromatic polyureas from N,N′‐bis(trimethylsilyl)‐substituted aromatic diamines and aromatic diisocyanates
Authors: Oishi Yoshiyuki , Padmanaban Munirathina , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

Silylated aromatic polyureas were synthesized by the polyaddition of N,N′‐bis(trimethylsilyl)‐substituted aromatic diamines to aromatic diisocyanates in various organic solvents at a temperature ranging from 30 to 100°C. Colorless and transparent films of the silylated polyureas were obtained by casting directly from these solutions in a dry nitrogen atmosphere. The silylated polyureas thermally decomposed at around 200°C and were easily desilylated with alcohol to convert to almost amorphous aromatic polyureas having inherent viscosities of 0.4–1.0 dL/g. The polyureas exhibited better solubility in organic solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, and dimethyl sulfoxide and had somewhat lower thermal decomposition temperatures (around 300°C) than the polyureas prepared by a conventional method from the parent aromatic diamines and diisocyanates.
Synthesis and characterization of 1,3,4‐oxadiazole‐containing polyazomethines
Authors: Saegusa Yasuo , Koshikawa Toshiya , Nakamura Shigeo
Published: April 2003

Novel 1,3,4‐oxadiazole‐containing polyazomethines were synthesized by the polycondensation of diamines, 2,5‐bis (m‐aminophenyl)‐1,3,4‐oxadiazole (BMAO) and 2,5‐bis (p‐aminophenyl)‐1,3,4‐oxadiazole (BPAO), with aromatic dialdehydes, isophthalaldehyde and terephthalaldehyde, in m‐cresol at 20°C. These polymers were yellow to orange in color and had reduced viscosities up to 1.13 dL/g and electric conductivity as high as 10−11−10−12 S cm−1. All the polyazomethines were insoluble in common organic solvents but dissolved in concentrated sulfuric acid. Thermogravimetry showed that thermal degradation started at around 400°C in air and nitrogen atmospheres. Doping with iodine markedly increased the conductivity and produced the black‐colored semiconductive polyazomethines with a maximum conductivity of the order of 10−6 S cm−1. Electronic spectra of the undoped polymers indicated a large bathochromic shift of the absorption maxima due to CN bonds of the monomer diamines (285 nm for BMAO and 315 nm for BPAO). This suggests that π‐electrons of the polymers are extensively delocalized along the main chain.
Synthesis and characterization of 1,3,4‐thiadiazole‐containing polyazomethines and copolyazomethines
Authors: Saegusa Yasuo , Takashima Toshio , Nakamura Shigeo
Published: April 2003

Novel 1,3,4‐thiadiazole‐containing polyazomethines and copolyazomethines were synthesized by the solution polycondensation, in m‐cresol at 25°C, of aromatic dialdehydes, isophthalaldehyde and terephthalaldehyde, with 2,5‐bis (m‐aminophenyl)‐1,3,4‐thiadiazole (BMAT) and with BMAT and aromatic diamines, bis (4‐aminophenyl) ether and 1,5‐diaminonaphthalene, respectively. These polymers were tan yellow to yellow in color and had reduced viscosities up to 0.32 dL/g in concentrated sulfuric acid and electric conductivity as high as 10−9−10−11 S cm−1 at 25°C. All the polymers were insoluble in common organic solvents but dissolved completely in concentrated sulfuric acid and formic acid. However, they were readily hydrolyzed in concentrated sulfuric acid. X‐ray diffraction diagrams showed that the crystallinity of polyazomethines were low, but copolyazomethines were highly crystalline. These azomethine polymers are highly thermally and thermooxidativelly stable and exhibited no appreciable decomposition up to 400°C in both air and nitrogen atmospheres. Doping with iodine dramatically raised the conductivity and produced the dark brown‐ to completely black‐colored semiconductive polymers with a maximum conductivity of the order of 10−5 S cm−1. Electronic spectra of the undoped polymers indicated a large bathochromic shift of the π−π* absorption band (310 nm) due to CN bonds of BMAT. This result suggests that π‐electrons of the polymers are extensively delocalized along the main chain.
Ion‐exchange rate limitation on a polymer‐supported phase transfer catalytic reaction
Authors: Wang Maw‐Ling , Wu Ho‐Sheng
Published: April 2003

The ion‐exchange rate limitation on the kinetics of the series substitution reactions between hexachlorocyclotriphosphazene (NPCl2)3 and 2,2,2‐trifluoroethanol (HOCH2CF3) by polystyrene‐bound tri‐n‐butylammonium ion in an organic solvent/alkaline solution was studied. It was found that the diffusional limitation involves both ion diffusion and organic reactant diffusion within the catalyst pellet. The displacement reaction rate of (NPCl2)3 in the organic phase was limited by the particle diffusion and the intrinsic reactivity together. The film diffusion in the bulk solution limited the rate of ion exchange. The mass transport of the ion‐exchange step in the aqueous phase was not improved by increasing the concentration of NaOCH2CF3. Drastic kinetic rate improvement was achieved with proper adjustment of the volume of the aqueous solution which was a low concentration of salt in the aqueous phase.
Heteroaromatic polyamides from cyanoimidazoles
Authors: Allan David S. , Rasmussen Paul G.
Published: April 2003

The synthesis of a new class of heteroaromatic polyamides based on cyanoimidazoles are described. The monomer, 2‐amino‐4‐cyanoimidazole‐5‐carboxylic acid (3) is prepared from a two‐step hydrolysis of 2‐amino‐4,5‐dicyanoimidazole (1). A model dimer prepared from condensation of 1 with 4‐cyanoimidazole‐5‐carboxylic acid was structurally characterized by single crystal diffraction. The dimer, C10H8N8O3, crystallizes with Z = 2 and includes two waters of hydration in the P1 space group, a = 7.684 (2), b = 7.864 (3), c = 10.918 (5), α = 100.14 (3), β = 93.15 (3), γ = 103.79 (3). The model dimer is totally planar and shows trans geometry across the amide linkage. The monomer was polymerized by phosphorylation reaction conditions leading to a highly colored oligomeric polyamide. The polymer was characterized by IR spectroscopy, viscometry, GPC chromatography, and luminescence studies. The polymer luminesces strongly under 450 nm laser irradiation at low temperatures.
Fully imidized soluble polyimides based on a novel dianhydride: 2,2′‐dichloro‐4,4′,5,5′‐benzophenone tetracarboxylic dianhydride
Authors: Falcigno Pasquale A. , Jasne Stanley , King Maurice
Published: April 2003

We have synthesized a novel dianhydride, 2,2′‐dichloro‐4,4′,5,5′‐benzophenone tetracarboxylic dianhydride (DCBTDA). Polyimides were synthesized with DCBTDA or 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) and several relatively rigid meta‐ and para‐ substituted mononuclear diamines. The BTDA based systems were insoluble in dipolar, aprotic solvents whereas the DCBTDA based polymers displayed enhanced solubility in these solvents. The thermal stability of these polyimides was excellent as measured by 5% weight loss decomposition. The Tg's of the polymers were all above 290°C.
Synthesis of N‐(arylmethyl)diethanolamines and of other pyrenediols: Addition polymerizations of pyrenyl monomers
Authors: Katritzky Alan R. , Zhu Dong‐Wei , Bernard Marek K.
Published: April 2003

N‐(Arylmethyl)diethanolamines and other spaced dihydroxy compounds bearing pyrenyl groups were prepared using benzotriazole as a synthetic auxiliary. The potential of these diols as precursors for the preparation of condensation polymers containing pendant polycyclic aryl groups was illustrated by reaction of the pyrenyl derivatives with diisocyanates which afforded the corresponding polyurethane polymers.
Model filled polymers. VIII. Synthesis of crosslinked polymeric beads by seed polymerization
Authors: Zou Dezhong , Sun Liquing , Aklonis J. J. , Salovey R.
Published: April 2003

Monodisperse crosslinked polystyrene (PS) and polymethacrylate (PMA) beads of sizes greater than 1 μm in diameter are prepared by particle nucleation onto pre‐existing polymer seeds in a multistage emulsion polymerization, in the absence of emulsifier. An adequate seed number concentration, which decreases with increasing seed size, is necessary to achieve monodisperse beads. Monodisperse multicomposition beads are prepared by polymerizing styrene onto PMA seeds, but not by polymerizing methyl methacrylate onto PS seeds. Phase separation in growing seed particles or surface polymerization following free radical capture may lead to the formation of asymmetric shaped particles.
Anionic polymerization of acrylates. II. Polymerization of 2‐ethylhexyl acrylate initiated by butyllithium/lithium‐tert‐butoxide system in tetrahydrofuran and its mixtures with toluene
Authors: Vlček P. , Kříž J.
Published: April 2003

The anionic polymerization of 2‐ethylhexyl acrylate (EtHA) initiated with the complex butyllithium/lithium‐tert‐butoxide (BuLi/t‐BuOLi) was investigated at −60°C in a medium of various solvating power, i.e., in mixtures of toluene and tetrahydrofuran and in neat tetrahydrofuran. With increasing amount of THF in the mixture the attainable limiting conversion of polymerization decreases; the monomer can be polymerized quantitatively only in a toluene/THF mixture (9/1). Molecular weights of the polymers thus obtained, their distribution, and initiator efficiency are not appreciably affected by the polymerization medium. The molecular weight distribution of the products is medium‐broad (Mw/Mn = 2–2.4), with a hint of bimodality. The 1H‐13C‐NMR, and IR spectra suggest that during the polymerization there is neither any perceptible reesterification of the polymer with the alkoxide nor transmetalation of the monomer with the initiator. In a suitable medium, autotermination of propagation proceeds to a limited extent only, predominantly via intramolecular cyclization of propagating chains; in a medium with a higher content of polar THF, it prevails and terminates propagation before the polymerization of the monomer has been completed. © 1992 John Wiley & Sons, Inc.
Anionic polymerization of acrylates. III. Polymerization of 2‐ethylhexyl acrylate initiated by lithium‐tert‐butoxide
Authors: Vlček P. , Janata M. , Otoupalová J.
Published: April 2003

The polymerization of 2‐ethylhexyl acrylate (EtHA) initiated with lithium‐tert‐butoxide (t‐BuOLi) in tetrahydrofuran (THF) and in the temperature range between −60 and 20°C was investigated. The reaction rate is distinctly temperature‐dependent and at −60°C is already very low, similarly to the polymerization of methacrylates. Molecular weights of the polymers thus formed, particularly at higher temperatures, are inversely proportional to conversion of the monomer due to the slow initiation reaction. This is documented by the low consumption of alkoxide even at long reaction times, which also depends on the reaction temperature. At higher temperatures the polymerization stops spontaneously, due to the greater extent of autotermination reactions. The weak initiating efficiency of the alkoxide decreases still more with decreasing concentration of the monomer during the polymerization, as confirmed by the concentration dependence of the reaction rate in toluene at −20°C. The results suggest a negligible initiating effect of alkoxides in complex bases, particularly at lower polymerization temperatures. © 1992 John Wiley & Sons, Inc.
Photochemistry of bisphenol‐a based polycarbonate: The effect of the matrix and early detection of photo‐fries product formation
Authors: Hoyle Charles E. , Shah Himanshu , Nelson Gordon L.
Published: April 2003

The effect of polymer matrices on a photoinduced rearrangement process has been shown to be dependent upon whether the photoreactive group is attached to a polymer backbone, or free. If diphenylcarbonate is simply embedded in a polymer matrix, the rearrangement process is independent of whether the host film is above or below its glass transition. However, if the diphenylcarbonate group is incorporated as part of a polycarbonate backbone, the Fries rearrangement process is significantly reduced for photolyses conducted at temperatures well below the glass transition of polycarbonate. The utility of fluorescence spectroscopy in identification of the initial salicylate type photo‐Fries type rearrangement product of polycarbonate is also demonstrated. The broad, structureless fluorescence spectrum with peak maximum at 470 nm produced by photolysis of polycarbonate films for short time periods is assigned to emission from phenyl salicylate type photoproducts. © 1992 John Wiley & Sons, Inc.
New water‐soluble polymers and copolymers by interaction of polyelectrolytes with formamide
Authors: Gooda Shaban R. , Huglin Malcolm B.
Published: April 2003

Viscometric measurements on aqueous solutions of the strongly acidic polyelectrolyte, poly(2‐acrylamido, 2‐methyl propane sulphonic acid) (PAS), have shown the necessity to include salt at a very high concentration in order to screen the charges. PAS was found to dissolve in formamide, but the properties of the isolated polymer demonstrated the occurrence of chemical changes during the dissolution process. Several procedures proved the conversion of sulphonic acid moieties to sulphonamide groups to an extent depending on the time and temperature of dissolution. At elevated temperature and extended times dissolution afforded complete conversion, i.e., a solution in formamide of a new neutral polymer, poly(2‐acrylamido, 2‐methyl propane sulphonamide) (PASAM), which does not require the inclusion of salts. By light scattering, the degree of polymerization of this PASAM was shown to be the same as that of the original PAS. The viscometric behavior of the PASAM in salt‐free water was that of a neutral polymer. Similar tests on the dissolution of the weakly acidic polyelectrolyte, poly(acrylic acid) (PAA) in formamide also showed the occurrence of amidation, but even after extended times PAA is not converted completely to polyacrylamide. © 1992 John Wiley & Sons, Inc.
Effect of the substituents on radical copolymerization of dialkyl fumarates with some vinyl monomers
Authors: Otsu Takayuki , Matsumoto Akikazu , Shiraishi Kohei , Amaya Naoyuki , Koinuma Yasumi
Published: April 2003

Radical copolymerization of dialkyl fumarates (DRF) with various vinyl monomers was carried out in benzene at 60°C. The monomer reactivity ratios, r1 and r2, were determined from the comonomer‐copolymer composition curves. The relative reactivity of DRFs with various ester substituents toward a polystyryl radical was revealed to depend on both steric and polar effects of the ester groups. It has also been clarified that α‐substituents of the polymer radical have a significant role in addition of DRF, from the comparison of the monomer reactivity ratios determined in copolymerizations with monosubstituted and 1,1‐disubstituted ethylenes. The absolute cross‐propagation rate constants were also evaluated and discussed. © 1992 John Wiley & Sons, Inc.
Synthesis and characterization of aromatic polymers containing pendant silyl groups. I. Polyarylates
Authors: Choi Kil‐Yeong , Hie Mi Yi , Choi Sam‐Kwon
Published: April 2003

Polyarylates containing pendant silyl group were prepared by the phase‐transfer catalyzed, two‐phase polycondensations of 2,2‐bis (4‐hydroxyphenyl) propane with corresponding dicarbonyl chlorides such as 2‐trimethylsilylterephthaloyl chloride, 5‐trimethylsilylisophthaloyl chloride, 5‐dimethylphenylsilylisophthaloyl chloride, and 5‐triphenylsilylisophthaloyl chloride. The resulting amorphous polyarylates with glass transition temperatures of 163–214°C had inherent viscosities in the range of 0.41–0.95 dL/g. These polyarylates were readily soluble in common chlorinated hydrocarbons and it was possible to obtain transparent, flexible, and tough films from the polymer solutions. The prepared polyarylates showed fairly good thermal stabilities as well as tensile strengths, i.e., the tensile strengths of the cast films from chloroform solution were 6.0–6.7 kg/mm2. And TGA data revealed 10% weight losses and residual weights at 800°C were 437–495°C and 27–40% under nitrogen atmosphere, respectively. © 1992 John Wiley & Sons, Inc.
Synthesis and characterization of aromatic polymers containing pendant silyl groups. II. Aromatic polyamides
Authors: Choi Kil‐Yeong , Yi Mi Hie , Choi Sam‐Kwon
Published: April 2003

In order to improve the solubility of aromatic polyamides without significant loss of thermal stability, synthesis of aromatic polyamides containing pendant silyl groups was carried out by direct polycondensation of silylated aromatic diacids such as 2‐trimethylsilylterephthalic acid (TSTA), 2,5‐bis (trimethylsilyl) terephthalic acid (BTSTA), 5‐trimethylsilylisophthalic acid (TSIA), 5‐dimethylphenylsilylisophthalic acid (DMSIA), and 5‐triphenylsilylisophthalic acid (TPSIA) with various aromatic diamines. The resulting polyamides had inherent viscosities in the range of 0.18–1.10 dL/g and showed improved solubilities toward aprotic polar solvents such as NMP, DMF, DMSO, etc. The prepared aromatic polyamides exhibited fairly good thermal stabilities, which were almost comparable to those of corresponding nonsubstituted aromatic polyamides. That is, thermogravimetric analysis (TGA) data revealed 10% weight losses at 358–500°C and residual weights at 700°C were 46–67% under nitrogen atmosphere. © 1992 John Wiley & Sons, Inc.
Photolysis of poly(o‐acetylstyrene) in solution
Authors: Weir N. A. , Whiting K.
Published: April 2003

Dilute solutions of poly(o‐acetylstyrene) (POAS) were exposed to long‐wave (λ ≥ 300 nm) UV radiation under high vacuum at 25 ± 1°C. Methane and much smaller amounts of ethane were formed, indicating α‐cleavage (Norrish Type I). The quantum yield for CH4 formation (5 × 10−5 mol einstein−1) was an order of magnitude lower than that observed for similar studies of POAS films. Molecular weight (Mn) measurements indicate that chain scission occurs, and this is attributed to β‐scission of the macroradicals formed by H‐abstraction at the α‐C atoms by the carbonyl triplet, and to a lesser extent, by the CH3 radicals. Quenching by both naphthalene and cyclooctadiene conformed to Stern–Volmer kinetics. The effects on chain scission of a number of additives with varying transfer activities were found to be complex and unexpected. Rates of scission not only increased, even when substances with high transfer activity (e.g., cumene) were present, but also varied with the concentration of additive, being higher at lower additive concentrations. It would appear that solvent quality has a dominant influence (these additives are poor solvents). Tighter coiling of the polymer in the solutions containing poorer solvents results in more segment‐segment contacts and with them more photoreduction and chain scission. However, at higher nonsolvent concentrations, diffusive separation of the fragments (and chain scission) becomes more difficult, and the balance is shifted in favor of cyclization (and perhaps also intermolecular crosslinking). The relative high photostability of POAS in solution (cf. thin film) has been interpreted in terms of increased competition from photoisomerization. © 1992 John Wiley & Sons, Inc.
Spectroscopic study of solid‐state photoreaction in organic crystal: Photopolymerization of dimethyl ester of α,α′‐dicyano‐p‐phenylenediacrylic acid and diethyl ester of p‐phenylenediacrylic acid
Authors: Chakrabarti Subhasis , Maity Ashim K. , Misra T. N.
Published: April 2003

Raman spectroscopy has been used to study solid‐state photopolymerization reactions in dimethyl ester of α,α′‐dicyano‐p‐phenylenediacrylic acid (p‐CPAMe) and diethyl ester of p‐phenylenediacrylic acid (p‐PDAEt). The reactants and products were characterized by infrared and Raman spectroscopy. Excitation and emission spectra suggest that in p‐CPAMe exciton–phonon coupling is strong, but in the other monomer it is very weak. Raman phonon spectroscopic study reveal that in both the samples the reaction mechanism is homogeneous in the initial stages. However, in the later stages the reaction becomes heterogeneous in p‐PDAEt. In p‐CPAMe the lattice becomes disordered with the progress of polymerization and finally becomes amorphous whereas in p‐PDAEt the lattice remains highly ordered. © 1992 John Wiley & Sons, Inc.
Investigation of molecular and chiroptical characteristics of optically active functional vinyl copolymers possessing main‐chain chirality
Authors: Dhal Pradeep K.
Published: April 2003

Optically active styrene‐methyl methacrylate and styrene‐methacrylonitrile copolymers were obtained by template assisted asymmetric copolymerization of 3,4‐cyclohexyhdene‐D‐mannitol‐1,2;5,6‐bis‐O[(4‐vinylphenyl)boronate] (1) with the corresponding comonomers followed by removal of the template and deboronation. By polymer analog modification methods, several optically active functional copolymers were obtained starting with these copolymers. The resulting polymers were subjected to different types of spectroscopic analysis. Thus, the results obtained from IR, 13C‐NMR and GPC were of great value for detailed structural analysis of these polymers providing both qualitative and quantitative informations in terms of mode and neatness of substitution and degree of functionalization. The chiroptical measurement results obtained from circular dichroic (CD) studies have been utilized to analyze precisely the substituent dependent local solution stereochemistry of these chiral polymers. © 1992 John Wiley & Sons, Inc.
Accelerated imidization reactions using microwave radiation
Authors: Lewis D. A. , Summers J. D. , Ward T. C. , McGrath J. E.
Published: April 2003

Microwave radiation has been clearly shown to result in enhancement of the rate of reaction for an imidization reaction. Analysis of the kinetic parameters showed that the apparent activation energy for the reaction was reduced from 105 to 55 kJ/mol, under the conditions of this experiment. The mechanism which has been proposed to explain this enhancement is based on the concept of a nonuniform temperature on a molecular scale, rather than a true reduction in the activation energy. © 1992 John Wiley & Sons, Inc.
Polyethers derived from bisphenols and highly fluorinated aromatics
Authors: Irvin Jennifer A. , Neef Charles J. , Kane Kevin M. , Cassidy Patrick E. , Tullos Gordon , St. Clair Anne K.
Published: April 2003

A series of fluorinated aromatic polyethers was synthesized via aromatic nucleophilic substitution of highly fluorinated aromatics (1,2,4,5‐tetrafluorobenzene, hexafluorobenzene, and decafluorobiphenyl) with bisphenol AF or bisphenol A. Polymerization with 1,2,4,5‐tetrafluorobenzene was not observed, and polymerization of hexafluorobenzene with bisphenol proceeded only if the potassium carbonate–bisphenol ratio was carefully controlled. The polymer condensed from decafluorobiphenyl and bisphenol AF was prepared in 77% yield with an inherent viscosity of 1.01 dL/g. The polymer prepared from the condensation of decafluorobiphenyl with bisphenol A was obtained in 48% yield with an inherent viscosity of 0.28 dL/g. These polymers were very soluble in common organic solvents, formed clear, colorless films, and were thermally stable (> 450°C by TGA). The fully fluorinated polymer exhibited low water uptake (0.3%) and dielectric constant (2.17). © 1992 John Wiley & Sons, Inc.
Synthesis and photochemistry of side‐chain liquid crystal polymers based on cinnamate esters
Authors: Whitcombe M. J. , Gilbert A. , Mitchell G. R.
Published: April 2003

The syntheses of three methacrylate monomers with cinnamate ester side‐chains and of a further monomer with a corresponding cinnamide side‐chain are described. Two of the monomers, with isomeric structures, were thermotropic liquid crystals. Although the clearing points were very similar the crystal melting points differed by 8°C. One compound also exhibited a monotropic smectic phase, behavior not shown by its isomer. The other two monomers were not liquid crystalline. The monomers were polymerized by free radical polymerization, both as homopolymers and as copolymers with methyl methacrylate. In the case of one of the mesogenic ester monomers, copolymers with a cyanophenyl benzoate monomer were also prepared. Three of the four monomers formed thermotropic liquid crystalline homopolymers and the copolymers with the benzoate monomer were also liquid crystalline. The monomers were considered as photoactive components of polymeric liquid crystals. As a preliminary investigation of their photochemistry, copolymers with methyl methacrylate were prepared and irradiated in solution with a broad‐band source. Under these conditions two of the materials show a facile photo‐Fries rearrangement of the aryl cinnamate ester group. © 1992 John Wiley & Sons, Inc.
Polymer gel films with simple organic electrochromics for single‐film electrochromic devices
Authors: Tsutsumi Hiromori , Nakagawa Yoko , Miyazaki Koii , Morita Masayuki , Matsuda Yoshiharu
Published: April 2003

Polymer gel films [poly(1‐vinyl‐2‐pyrrolidinone‐co‐N,N′‐methylenebisacrylamide) (PVPD)] which contain simple organic electrochromics [p‐diacetylbenzene (p‐DAB), dimethyl‐ or diethyl terephthalate (p‐DMP or p‐DEP)] are prepared and their optical responses to applied voltage are investigated. p‐DAP/PVPD film is colored in green by the application of 1.2 V vs. Pt wire (quasireference electrode) across the film, and p‐DMP/PVPD and p‐DEP/PVPD films are colored in red by the application of −2.5 and −1.5 V vs. Pt, respectively. Their coloring responses are about a few seconds and the bleaching process also occurs rapidly. The films have no optical memory effect. © 1992 John Wiley & Sons, Inc.
Fundamental aspect and behavior of saturated fluorocarbons in glow discharge in absence of potential source of hydrogen
Authors: Iriyama Yu , Yasuda H.
Published: April 2003

The glow discharge of a series of saturated fluorocarbons, CnF2n+2 (n = 1, 2, 4, 6, and 8), was studied with glass substrates which do not contain any hydrogen. It was found that the deposition rate was a function of the F/C ratio of the starting fluorocarbons. That is, fluorocarbons with higher F/C ratio, such as CF4 and C2F6, hardly polymerized, while fluorocarbons with lower F/C ratio, such as C8F18, polymerized as well as C2F4. After plasma exposure, the surface of glass substrate was characterized by measurements of water contact angle, water droplet rolling‐off angle, and ESCA. Although all saturated fluorocarbon plasmas could alter the surface more hydrophobic than before, the deposited materials from fluorocarbons with higher F/C were not stable. Also, in plasmas with high F/C fluorocarbons, i.e., CF4 and C2F6, sputtering of the electrode material was observed. © 1992 John Wiley & Sons, Inc.
Thermally reversible crosslinking of polystyrene via the furan–maleimide Diels–Alder reaction
Authors: Canary Stephen A. , Stevens Malcolm P.
Published: April 2003

Mixtures of maleimidomethylated polystyrene with difurfuryl adipate or with furfuryl alcohol‐esterified poly[styrene‐co‐(maleic anhydride)] underwent thermally reversible Diels–Alder crosslinking. Reversal of crosslinking occurred rapidly at 150°C. The instability of the furfuryl group, however, limits the practicability of the reaction. © 1992 John Wiley & Sons, Inc.
Condensation and structure of silicic acid in tetrahydrofuran
Authors: Gunji Takahiro , Nagao Yukinori , Misono Takahisa , Abe Yoshimoto
Published: April 2003

Silicic acid (SA) was extracted with THF from aqueous sodium metasilicate (SMS) solutions neutralized with hydrochloric acid, followed by silylation to give silylated SA from which the condensation and structure of SA in tetrahydrofuran (THF) were investigated. The degree of extraction markedly depends on SA and HCl concentrations. The condensation of 0.86 and 3.5 mol/L SA‐THF solutions was followed by measuring the viscosity of the solutions at 0 and 20°C. The silylated SA was isolated as a distillate (LS) and a residue (HS) with low and high M̄ns (ca. 1300 and 3800) by vacuum distillation. The ratio of LS against HS decreased as a SA concentration in THF increased. In an aqueous solution, SA exists as lower molecular weight SAs compared with those in THF. SAs such as monomer, dimer, cyclic tri‐ and tetramer were the main components in a 0.1 mol/L aqueous solution. On the extraction with THF from an aqueous solution, SA was found to undergo condensations to form more polymerized SAs. From the THF solutions of SA concentration above 0.5 mol/L, the HS was obtained as a main component (73%) which was expected to have ladder‐like structures. © 1992 John Wiley & Sons, Inc.
Amphiphilic comb‐shaped polymers from poly(ethylene glycol) macromonomers
Authors: Bo Gao , Wesslén Bengt , Wessléen K. Bodil
Published: April 2003

Comb‐shaped amphiphilic graft copolymers composed of hydrophobic backbones and hydrophilic side chains were prepared by radical copolymerization of poly(ethylene glycol) monomethacrylate macromonomers, and methacrylate and acrylate comonomers in toluene. The copolymerizations were very sensitive to the reaction conditions, and insoluble cross‐linked gels were easily formed. The yields of soluble copolymers were affected by the initiator concentration, the macromonomer concentration, and the choice of chain transfer agents and comonomers. Solubilities of the copolymers in water or methanol were found to depend on the sizes and the numbers of the PEG side chains. The copolymers showed surface activity with CMC:s in the order of 0.1–1.5 g/L and surface tensions of 36–56 dyn/cm. When tested as emulsifiers most of the copolymers gave oil‐in‐water type emulsions at room temperature. Polymers carrying MPEG 2000 side chains were crystalline with melting points of 38–44°C, while those based on PEG 400 and 1000 were mostly amorphous with glass transition temperatures between ‐55 and ‐60°C. © 1992 John Wiley & Sons, Inc.
The synthesis of poly‐L‐amino acids and their characterization by size exclusion chromatography with low‐angle laser light scattering (SEC‐LALLS/UV/DRI)
Authors: Zeng J.‐N. , Magiera D. J. , Krull I. S.
Published: April 2003

The synthesis and characterization of polyamino acids are described in this paper. Detailed polymerization descriptions of newly synthesized polyamino acids are discussed. The final polyamino acids were characterized by elemental analysis, infrared (IR) spectroscopy, mass spectra, and low‐angle laser light scattering (LALLS). LALLS was used to determine the weight average molecular weight (MW) indicating the extent of the polymerization procedure. Isocratic size exclusion chromatography (SEC) coupled to a tri‐detection system consisting of a LALLS, ultraviolet/visible detector (UV/VIS), and a modified differential refractive index detector (DRI) was used to calculate on‐line specific refractive index increment (dn/dc), MW, percent recovery, and polydispersity, all in one injection once one determines the on‐line molar absorptivity value of the synthesized polyamino acid. © 1992 John Wiley & Sons, Inc.
Synthesis and polymerization of N‐[4‐N′‐ (α‐methylbenzyl)aminocarbonylphenyl]maleimide
Authors: Oishi Tsutomu , Fujimoto Minoru
Published: April 2003

A novel type of optically active N‐[4‐N′‐(α‐methylbenzyl)aminocarbonylphenyl]maleimide [(R)‐MBCP] was synthesized from maleic anhydride, p‐aminobenzoic acid, and (R)‐methylbenzylamine. Radical homopolymerization of (R)‐MBCP was performed in tetrahydrofuran (THF) at 50 and 70°C for 24 h to give optically active polymers having [α]25D = ‐141° and ‐129°, respectively. Anionic polymerization of (R)‐MBCP with n‐butyllithium in THF and N,N‐dimethylformamide gave an optically active polymer having −78 to −81° of [α]25D. Radical copolymerizations of (R)‐MBCP (M1) were performed with styrene (ST, M2) and methyl methacrylate (MMA, M2) in THF at 50°C. The monomer reactivity ratios (r1, r2) and the Alfrey‐Price Q‐e values were determined as follows: r1 = 0.009, r2 = 0.091, Q1 = 1.30, e1 = 1.87 in the (R)‐MBCP‐ST; r1 = 0.27, r2 = 1.21, Q1 = 0.93, e1 = 1.46 in the (R)‐MBCP‐MMA system. Chiroptical properties of the polymers were also investigated. © 1992 John Wiley & Sons, Inc.
Liquid crystalline epoxy thermosets based on dihydroxymethylstilbene: Synthesis and characterization
Authors: Barclay G. G. , Ober C. K. , Papathomas K. I. , Wang D. W.
Published: April 2003

This article describes the synthesis and characterization of a new series of liquid crystalline thermosets. Nematic epoxy‐terminated oligoethers based on dihydroxy‐α‐methylstilbene were synthesized for this study. These prepolymers were crosslinked within the nematic mesophase using methylenedianiline. Depending upon the molecular weight and polydispersity of the oligoether, the crosslinking reaction resulted in networks with either a smectic or nematic molecular organization in contrast to the simple nematic phase of the oligoether. The formation of a smectic‐like structure on curing was found to be related to the breadth of the prepolymer molecular weight. In those networks with a low crosslink density a clearing transition could be observed, whereas in the more highly crosslinked networks the molecular organization was frozen in until decomposition. The glass transition temperature of these LC networks rose as the crosslink density was increased, ranging from 35 to 152°C. In agreement with theory, the clearing transition of the networks was found to be dependent on the phase state during curing © 1992 John Wiley & Sons, Inc.
New poly(amide‐imide)s syntheses. II. Soluble poly(amide‐imide)s derived from 2,5‐bis(4‐aminophenyl)‐3,4‐diphenylthiophene and various N‐(ω‐carboxyalkyl)‐trimellitimides, N‐(carboxyphenyl)trimellitimides, or N,N″‐bis(ω‐carboxyalkyl)pyromellitimides
Authors: Yang Chin‐Ping , Hsiao Sheng‐Huei , Lin Jiun‐Hung
Published: April 2003

Various dicarboxylic acids with preformed imide rings were readily obtained by the condensation of ω‐amino acids and aminobenzoic acids with trimellitic anhydride, and omega;‐amino acids with pyromellitic dianhydride. New tetraphenylthiophene‐containing poly(amide‐imide)s having inherent viscosities of 0.58‐1.54 dL/g were prepared by the direct polycondensation reaction of 2,5‐bis(4‐aminophenyl)‐3,4‐diphenylthiophene with the imide‐containing dicarboxylic acids using triphenyl phosphite and pyridine as condensing agents. These polymers were amorphous and readily soluble in a variety of solvents such as dimethylacetamide (DMAc), dimethylformamide (DMF), and N‐methyl–2‐pyrrolidone (NMP), and could be easily solution cast into transparent, flexible, and tough films. Most of the poly(amide‐imide)s showed clear glass transition on the heating traces of differential scanning calorimetry (DSC) in the range of 146–244°C. Almost all the poly(amide‐imide)s exhibited no appreciable decomposition below 400°C, with 10% weight loss being recorded above 420°C in nitrogen. © 1992 John Wiley & Sons, Inc.