bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aromatic copolyamides: Effect of phenylene content on optical, spectral, and solubility properties
Authors: Rogers H. G. , Gaudiana R. A. , McGowan C. 
Published: April 2003

AbstractA series of para‐linked phenylene, bis(trifluoromethyl)biphenylene and stilbene copolyamides was synthesized in order to examine the effect of comonomer ratio on absorption spectra, solubility and birefringence. The data clearly showed that decreasing the stilbene content significantly lowered the birefringence and hypsochromically shifted the absorption band. A decrease in the biphenylene content broadened and bathochromically shifted the absorption band and lowered the birefringence and the solubility.
Photostabilizing activity of N‐acylated hindered amine
Authors: Kurumada Tomoyuki , Ohsawa Hisayu , Fujita Takashi , Toda Toshimasa , Yoshioka Takao 
Published: April 2003

AbstractThe influence of the acyl groups of N‐acylated hindered amine on the photostabilization of polymers was discussed. The effects of the N‐acyl derivatives of 4‐benzoyloxy‐2,2,6,6‐tetramethylpiperidine (6) in the photostabilization of polypropylene were compared. Although the stabilizing effects of all the N‐acyl derivatives were lower than that of the N‐oxyl derivative (7), N‐acryloyl (4) and N‐benzoyl (5) derivatives showed higher effects than that of parent NH 6. To discuss the stabilizing mechanism of N‐acylated hindered amine, the reaction of N‐acylated hindered amine with model hydroperoxide (tert‐butyl hydroperoxide) was carried out at an elevated temperature (132°C). N‐Acylated hindered amine decomposed tert‐butyl hydroperoxide more rapidly than corresponding secondary hindered amine, and changed into the parent secondary amine.
Poly[amino‐p‐(hydroquinone or benzoquinone)]amides and poly(p‐benzoquinono)diimidazoles of phenylene dicarboxylic acids. IV
Authors: Kehayoglou A. H. , Sideridou‐Karayannidou I. , Karayannidis G. P. 
Published: April 2003

AbstractPoly(amino‐p‐benzoquinone)amides were indirectly prepared by low‐temperature polycondensation of 2,3,5,6‐tetraamino‐p‐hydroquinone, with terephthaloyl, isophthaloyl, or phthaloyl dichloride and subsequent oxidation of the obtained poly(amino‐p‐hydroquinone)amides. Then the poly(amino‐p‐benzoquinone)amides were converted by cyclodehydration with heating to the corresponding poly(p‐benzoquinono)diimidazoles. The prepared redox thermally stable polymers were characterized by elemental analysis, UV, and IR spectral study, inherent viscosity solubility, and thermal analysis (DSC, TGA). The synthesis and properties of the corresponding model compounds are also reported.
Preparation of aromatic copolyesteramides by the direct polycondensation with a vilsmeier adduct derived from tosyl chloride and N,N‐dimethylformamide
Authors: Higashi Fukuji , Mihara Yuko , Takahashi Ikuo , Chen Wen‐Hsin , Chang Tech‐Chou 
Published: April 2003

AbstractThe reaction promoted by Vilsmeier adduct derived from tosyl chloride (TsCl) with N,N‐dimethylformamide (DMF) was successfully applied to the preparation of copolyesteramides of high molecular weights directly from aromatic dicarboxylic acids, diamines, and bisphenols. The polycondensation was significantly affected by the reaction of activated dicarboxylic acids with bisphenols and diamines. Addition of a mixture of bisphenols and diamines likely caused gelation of the reaction mixtures, resulting in insoluble polymers, especially with high mol % diamines. Stepweise addition of them, however, gave the homogeneous reaction mixtures and copolymers of better solubility. These phenomena were studied in terms of sequence length distribution of polyester units, which was estimated by thermal analyses of the random copolymers prepared under various conditions for the initial reaction with bisphenols.
Origin of the carbon 1s‐core level shifts in polyimide model compounds
Authors: Silverman B. D. , Sanda P. N. , Ho P. S. , Rossi A. R. 
Published: April 2003

AbstractCarbon 1s (C1s) core‐level positions have been calculated for two model compounds which are similar in structure to the PMDA part of the PMDA‐ODA monomer of polyimide. It is found that either one or two N‐phenyl imide groups fused to a benzene ring will lower the C1s energy levels of the benzene ring. The difference in previous interpretation of the origin of the C1s (ESCA) spectra between the two model compounds examined is shown to be consistent with the difference in calculated magnitude of this shift between the two compounds.
A new route to semirigid poly(amide‐ester)s with ordered structure
Authors: Lu C. X. , Li Qiang , Pan Jingqi 
Published: April 2003

AbstractFour novel semirigid poly(amide‐ester)s having the same ordered amide‐amide‐ester‐ester (‐AAEE‐) and the same or the different phenyl structure were synthesized from the various combination of active acylamide of benzotriazole (HBT) such as 1,1′‐(isophthaloyl)bisbenzotriazole (IPBBT) and 1,1′‐(terephthaloyl)bisbenzotriazole (PBBT) with diols such as N,N'‐bis(2‐hydroxyethyl)isophthamide (HEIPA) and N,N'‐bis(2‐hydroxyethyl)terephthamide (HEPTA) which prepared from the selective N‐acylation of IPBBT or PBBT with aminoethanol in excellent yield at room temperature. Before the preparation of diol monomers, a model reaction of selective N‐acylation was also completed from active monoacylamide of benzotriazole, 1‐benzoylbenzotriazole with aminoethanol. The ordered structure of poly(amideester)s were characterized by infrared (IR) and NMR spectra. On the bases of different reactivity between selective N‐acylation and O‐acylation of active acylamide of benzotriazole, poly(amide‐ester)s having the ordered AAEE and the same phenyl structure were also readily synthesized from the IPBBT or PBBT with aminoethanol under mild conditions by one‐bath process.
p‐carboxylation of linear high molecular‐mass polystyrene
Authors: Hird B. , Eisenberg A. 
Published: April 2003

AbstractA simple method is reported for the post‐polymerization partial p‐carboxylation of linear polystyrene without degradation or crosslinking of the polymer. The method is based on Friedel–Crafts acetylation of the polystyrene under mild conditions, followed by oxidation of the acetyl groups by means of a phase‐transfer‐catalyzed haloform reaction. The method is well suited for the synthesis of high molecular mass, monodisperse ionomers with p‐carboxylate groups situated randomly along the polystyrene chain. © 1993 John Wiley & Sons, Inc.
Polyisophthalamides with phenylsulfonyl pendent groups
Authors: Lozano Angel E. , De La Campa Jose G. , Abajo Javier De , Preston Jack 
Published: April 2003

AbstractA series of polyisophthalamides containing phenylsulfonyl groups was prepared from seven aromatic diamines and 5‐phenylsulfonylisophthalic acid by the phosphorylation condensation method, and from 5‐phenylsulfonylisophthaloyl chloride by the solution polycondensation method at low temperature. When compared to the analogous unmodified polyisophthalamides, the modified ones were found to be essentially amorphous, and they showed better solubility in organic solvents, and slightly higher glass transition temperatures. Thermogravimetric analysis showed that the polyisophthalamides containing pendent phenylsulfonyl groups have thermal stabilities similar to the unmodified ones. Mechanical strength of films and water sorption were also investigated. © 1993 John Wiley & Sons, Inc.
Emulsion polymerization of vinyl acetate using a polymerizable surfactant. III. Mathematical model
Authors: Urquiola M. B. , Sudol E. D. , Dimonie V. L. , El‐Aasser M. S. 
Published: April 2003

AbstractA mathematical model was developed to aid in the further understanding of the growth of latex particles in the emulsion polymerization of vinyl acctate using a polymerizable surfactant, sodium dodecyl allyl sulfosuccinate (TREM LF‐40). The model incorporates the main features of the system observed experimentally: copolymerization in the aqueous phase, at the particle surface, and chain transfer to TREM LF‐40. The reactions at the particle/water interface and, more specifically, the chain transfer to TREM LF‐40 leading to a decrease in the average number of radicals per particle, was found to be the most significant mechanism for explaining the difference in kinetic results found for TREM LF‐40 and its nonpolymerizable counterpart. The copolymerization of vinyl acetate with TREM LF‐40 was also shown to slow the overall polymerization rate. However, the copolymerization alone was not sufficient to account for the decreased polymerization rates observed experimentally. A combination of copolymerization and chain transfer to TREM LF‐40 was found to provide a good fit of the experimental results. © 1993 John Wiley & Sons, Inc.
Propenyl ethers. II. Study of the photoinitiated cationic polymerization of propenyl ether monomers
Authors: Crivello J. V. , Jo K. D. 
Published: April 2003

AbstractThe results of studies of the photoinitiated cationic polymerization of mono‐, di‐, and multifunctional propenyl ethers are reported in this article. Real‐time infrared spectroscopy and differential scanning photocalorimetry were used to determine the reactivity of the monomers with respect to each other and in relation to other types of cationically polymerizable monomers. Propenyl ethers were observed to be highly reactive monomers in photoinitiated cationic polymerization undergoing very high conversions to polymer at very short irradiation times. Attempts were also made to correlate the structures of these monomers with their reactivity as well as to examine the effects of various experimental parameters on their photopolymerization. © 1993 John Wiley & Sons, Inc.
Synthesis of poly(styrene‐graft‐ethylene oxide) by ethoxylation of amide group containing styrene copolymers
Authors: Jannasch Patric , Wesslén Bengt 
Published: April 2003

AbstractGraft copolymers containing poly(ethylene oxide) side chains on a polystyrene backbone have been synthesized. Styrene copolymers synthesized by free radical mechanism and containing between 5 and 15 mol % acrylamide or methacrylamide were used as backbones. The amide groups in the copolymers were ionized by using potassium tert‐butoxide or potassium naphthalene, and grafting was achieved by utilizing the amide anions as initiator sites for the polymerization of ethylene oxide in 2‐ethoxyethyl ether at 65°C. The graft copolymers were characterized with respect to molecular weight and composition using elemental analysis, NMR, gel permeation chromatography, IR, and viscosity measurements. The size of the side chains were between 600 and 2000 g/mol. GPC results from a hydrolyzed graft copolymer sample suggest a narrow size distribution for the poly(ethylene oxide) grafts. Solution properties of the graft copolymers were investigated in different toluene/methanol mixtures. The intrinsic viscosities of the graft copolymers were found to depend primarily on the poly(ethylene oxide) content rather than the graft density or the poly(ethylene oxide) chain length. © 1993 John Wiley & Sons, Inc.
Rigid rod polymers with flexible side chains. X. Thermotropic mesophases from aromatic stiff‐chain polyamides bearing n‐alkoxy side chains
Authors: Steuer M. , Hörth M. , Ballauff M. 
Published: April 2003

AbstractThe synthesis of stiff‐chain poly(1,4‐phenylene terephthalamide)s substituted by two as well as by four flexible side chains per repeating unit is described. The solubility of the materials bearing only two side chains is still very low. Appending of four side chains leads to polyamides which dissolve in common organic solvents. All polyamides reported herein form layered structures in the solid state as well as in the mesophase. Polyamides with two side chains have a very weak tendency for crystallization and do not exhibit a transition to the isotropic state even for the longest side chains. Polyamides with four side chains show three reversible thermal transitions: a disordering transition of the side chains, a transition to a layered, smectic‐like mesophase, and finally the transition to an isotropic melt. It is shown that the phase behavior of these materials is mainly governed by the strong segregation of main‐ and side‐chains which can be compared best to the microphase separation in block copolymers. © 1993 John Wiley & Sons, Inc.
Redistribution of cyclosiloxanes to favor formation of decamethylcyclopentasiloxane
Authors: Lambert Joseph B. , Kania Lidia , Schulz William J. 
Published: April 2003

AbstractEfforts to optimize the formation of the cyclic D5 oligomer (D = Me2SiO) of polydimethylsiloxane have led to the development of a new class of redistribution catalyst, the silyl perchlorates. Where as previous Lewis and Bronsted acid catalysts have transformed D3 almost exclusively into D3n oligomers, use of phenyldimethylsilyl perchlorate as the catalyst gives predominantly D4, D5, and other non‐D3n oligomers. This redistribution reaction is particularly useful for obtaining large amounts of the difficulty available D5. Similar studies of D4 with variation of solvent and catalyst led to little redistribution. © 1993 John Wiley & Sons, Inc.
Ultrathin self‐assembled polymeric films on solid surfaces. I. Synthesis and characterization of acrylate copolymers containing alkyl disulfide side chains
Authors: Sun Fang , Grainger David W. 
Published: April 2003

AbstractCopolymers of 2‐hydroxyethyl acrylate and 2‐methoxyethyl acrylate with variable compositions were synthesized, fractionated, and characterized by 1H‐NMR, IR, GPC, and viscometry. These copolymers were further modified via polymer analog esterification of copolymer hydroxy groups by a series of disulfide‐containing carboxylic acids including lipoic acid and (n‐pentyldithio) alkyl carboxylic acids (n‐C5H11SS(CH2)mCOOH, m = 10, 15, 22) in the presence of 1,3‐dicyclohexylcarbodiimide (DCC). Esterification reactions were quantitative for copolymers possessing hydroxy monomer contents ≤ 40% when excess acid and DCC were present for sufficiently long reaction times (2–4 days) at room temperature. Copolymer DSC analysis demonstrates a systematic variation of Tg with copolymer composition in good agreement with ideal mixing theory. These disulfide‐bearing copolymers spontaneously yield two‐dimensional ultrathin polymer films with side chain‐dependent layer thicknesses of 20–45 Å by solution adsorption onto freshly deposited gold surfaces. Such ultrathin polymer films are expected to have diverse applications as bound polymeric surface modification reagents. © 1993 John Wiley & Sons, Inc.
The use of platinum and rhodium catalysts for the preparation and cationic ring‐opening polymerization of silicon‐containing epoxides
Authors: Chung P. H. , Crivello J. V. , Fan M. 
Published: April 2003

AbstractRegioselective platinum and rhodium catalysts were employed for the preparation of novel silicon‐containing polyethers. First, silicon‐containing monomers bearing cycloaliphatic epoxy groups were prepared by a rhodium‐catalyzed regioselective hydrosilation. Then these monomers were polymerized using a platinum‐catalyzed, cationic, ring‐opening polymerization to give the linear polyethers. The obtained polyethers were compared with polymers prepared by photoinitiated cationic ring‐opening polymerization using onium salt photoinitiators and found to be identical. © 1993 John Wiley & Sons, Inc.
Heat‐resistant resins obtained from polymer precursors bearing β,β′‐dicyanovinyl terminal groups
Authors: Mikroyannidis John A. 
Published: April 2003

AbstractCertain polymer precursors of the general formula:
magnified image
where A is an aromatic structure bearing ester, amide, azomethine, or imide linkages were synthesized. Particularly, 4‐hydroxybenzaldehyde was condensed with malonitrile to afford 4‐hydroxy‐β,β′‐dicyanostyrene which reacted with a half molar amount of terephthaloyl dichloride in the presence of an acid acceptor. In addition, 3‐nitrobenzaldehyde was condensed with malonitrile to yield 3‐nitro‐β,β′‐dicyanostyrene that was catalytically hydrogenated to the corresponding amine. The latter reacted with a half molar amount of terephthaloyl dichloride, terephthaldehyde, pyromellitic dianhydride, or benzophenone tetracarboxylic dianhydride. The polymer precursors were characterized by elemental analyses as well as IR and 1H‐NMR spectroscopy. Their curing behavior was investigated by DTA. Crosslinked polymers were obtained by curing the monomers at 300°C for 24 h. They were stable up to 407–437°C in N2 and afforded an anaerobic char yield of 65–50% at 800°C. The thermal stability of resins was correlated with their chemical structures. © 1993 John Wiley & Sons, Inc.
Controlled modification of poly(hydroxybutyrate) surfaces by a perfluorohexane plasma: ESCA and contact angle studies
Authors: Flösch Dietmar , Clarotti Giorgio , Geckeler Kurt E. , Göpel Wolfgang 
Published: April 2003

AbstractPoly(hydroxybutyrate) films and inorganic glass slides were treated by cold plasma. The composition of the gas mixture of perfluorohexane and hydrogen was varied to obtain controlled surface coatings of different hydrophobicities. The analysis by weight variation, scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA), and contact angle measurements were used to evaluate the influence of the flow rate, composition, and the plasma power on the surface structure after the plasma deposition. High‐resolution ESCA spectra were used to determine quantitatively the amount of different fluorine‐containing species present in the plasma‐deposited layers. Molecular structures and surface energies of deposited layers on polymer substrates were compared with those on inorganic substrates. In both cases a strong correlation was found between the surface free energy and the fluorine/carbon ratio as well as the oxygen/carbon ratio. Furthermore, samples with high carbon/fluorine ratios showed a high content of CF2 and CF3 groups. © 1993 John Wiley & Sons, Inc.
Peroxidase‐catalyzed synthesis of lignin–phenol copolymers
Authors: Blinkovsky Alexander M. , Dordick Jonathan S. 
Published: April 2003

AbstractHorseradish peroxidase catalyzes the copolymerization of phenols with kraft lignin in aqueous‐organic solvent mixtures. Nearly all of the lignin and over one‐third of the phenol (either p‐cresol or p‐phenylphenol) is incorporated into the copolymer which is highly insoluble in dimethylformamide (DMF), presumably because of crosslinking of lignin molecules via polyphenol bridges. The copolymer consists of 80% lignin, by weight. In the absence of a phenol, lignin is polymerized into a noncrosslinked, DMF‐soluble material. Thermal analysis shows that the copolymerization of phenols with lignin results in a material with markedly lower glass transition temperatures and higher (and more uniform) curing exotherms. The materials appear to act as thermosets and may have application as replacements of conventional phenolic resins. © 1993 John Wiley & Sons, Inc.
Investigation of a resorcinol–formaldehyde resin by 13C‐NMR spectroscopy and intrinsic viscosity measurement
Authors: Kim Moon G. , Amos Larry W. , Barnes Edwin E. 
Published: April 2003

AbstractVarious molecular weight fractions and oligomers isolated from a novolac type resorcinol–formaldehyde (RF) wood adhesive resin were studied by 13C‐NMR, gel permeation chromatography (GPC), and intrinsic viscosity measurements. The 13C‐NMR results indicate that methylene groups occur mostly between C4–C′4 and C2–C′4 carbons and in minor amounts between C2–C′2 carbons of resorcinol rings. By suppressing the nuclear Overhauser effect (nOe) and using a long delay time for 13C‐NMR measurements, reasonable methylene/aromatic carbon ratios were obtained from the aromatic C1 carbon patterns that have resulted from different numbers of methylene groups bonded on the aromatic ring. This analysis results indicate that the RF resin has an appreciable amount of branch structures and compare favorably with the gel permeation chromatography and intrinsic viscosity measurement results. © 1993 John Wiley & Sons, Inc.
Kinetics of thermoset cure and polymerization in the glass transition region
Authors: Stutz H. , Mertes J. , Neubecker K. 
Published: April 2003

AbstractA theoretical approach to thermoset cure kinetics based on Arrhenius kinetics and mobility was developed by considering the activation of the reacting group and chain mobility as elementary steps for reaction. This extended kinetic equation was successfully applied to the curing of an epoxy by an amine, the trimerization of a cyanate, and to the polymerization of methyl methacrylate. Full agreement between theory and experimental data was obtained in all cases. The activation energies for chain mobility were exceptionally low (0.3–1 kJ/mol for bisphenol‐A‐based epoxy and cyanate) which indicates that the structural units must undergo only small‐angle rotational oscillations to allow a reaction. A theoretical time–temperature–transformation (TTT) diagram is also presented. © 1993 John Wiley & Sons, Inc.
Chain transfer reaction in the polymerization of substituted acetylenes. II. Chain transfer reaction to trimethylvinylsilane in the polymerization of disubstituted acetylenes by MoCl5–n‐Bu4Sn
Authors: Kouzai Hiroaki , Masuda Toshio , Higashimura Toshinobu 
Published: April 2003

AbstractThe effect of various olefins as chain transfer agents was studied in the polymerization of 1‐chloro‐1‐octyne, 1‐chloro‐2‐phenylacetylene, 2‐octyne, etc., catalyzed by MoCl5–n‐Bu4Sn (1 : 1). Si‐containing olefins, especially trimethylvinylsilane, greatly lowered the polymer molecular weight in the polymerization of the Cl‐containing acetylenes, e.g., the Mn of poly(1‐chloro‐1‐octyne) was 4.2 × 105 without an olefin, whereas it decreased to 3.4 × 104, i.e., below 1/10 in the presence of trimethylvinylsilane (1/2 equiv to monomer). In contrast, the molecular weight of poly(2‐octyne) did not decrease that much, even with trimethylvinylsilane. The Cl‐containing polyacetylenes obtained in the presence of trimethylvinylsilane as chain transfer agent possessed the trimethylsilyl group. Thus, the present study enables control of the molecular weight of substituted polyacetylenes by chain transfer, and further verifies the metal carbene mechanism for the polymerization of substituted acetylenes. © 1993 John Wiley & Sons, Inc.
Radical polymerization of 4‐methylene‐4H‐1,3‐benzodioxin‐2‐ones: Cyclic α‐substituted styrenes
Authors: Ueda Mitsuru , Toyota Hidetsugu , Sone Atsushi , Ito Hiroshi 
Published: April 2003

Abstract4‐Methylene‐4H‐1,3‐benzodioxin‐2‐one (MBDOON), an α‐substituted cyclic styrene derivative, was synthesized and polymerized readily with 2,2′‐azobis(isobutyronitrile) (AIBN) as an initiator in solution. The kinetics of the MBDOON homopolymerization with AIBN was investigated in N‐methyl‐2‐pyrrolidone (NMP). The rate of polymerization, Rp, can be expressed by Rp − k[AIBN]0.52[MBDOON]1.1 and the overall activation energy has been calcualted to be 75.7 kJ/mol. Monomer reactivity ratios in copolymerization of MBDOON (M2) with styrene (M1) are r1 = 0.31 and r2 = 3.20, from which Q and e values of MBDOON can be calculated as 3.0 and −0.7, respectively. Ring‐substituted MBDOON monomers such as 6‐chloro, 6‐methyl, and 7‐methoxy derivatives were synthesized and polymerized with AIBN. The 6‐substituted MBDOON's readily underwent radical polymerization while the 7‐methoxy‐MBDOON was slower to polymerize. Poly(MBDOON) is predominantly heterotactic. (rr = 35, mr = 46, and mm = 19%). The polymer releases carbon dioxide at about 200°C and is converted with some depolymerization to poly[(o‐hydroxyphenyl)acetylene]. The thermolysis temperature is very much affected by the ring substituent. The onset of carbon dioxide liberation was observed at 140°C in the case of the 7‐methoxyl derivative while the 6‐substituents had a smaller effect on the decarboxylation temperature. © 1993 John Wiley & Sons, Inc.