bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly (2,6‐dimethyl‐1,4‐phenylene oxide)/poly (butadiene) diol interpenetrating polymer networks: Phase morphological characteristics and glass transition temperature behavior
Authors: Xue Yongpeng , Frisch Harry L. 
Published: April 2003

AbstractThe fracture surface topography of simultaneous interpenetrating polymer networks (SIN'S) of poly (2,6‐dimethyl‐1,4 phenylene oxide) (PPO)/poly (butadiene) diol was examined by scanning electron microscopy (SEM). The phase morphology of the IPNs is highly dependent on PPO/poly (butadiene) diol mass ratio. A single‐phase morphology of the IPNs was achieved when the content of poly (butadiene) diol is below 40 wt % in the initial composition. The SEM observations are also wholly consistent with the glass transition temperature behavior obtained in the differential scanning calorimetric (DSC) measurements. © 1994 John Wiley & Sons, Inc.
Interpolymer complex formation of some nonionogenic polymers with linear and crosslinked polyacrylic acid
Authors: Budtova T. V. , Suleimenov I. E. , Ya. Frenkel S. 
Published: April 2003

AbstractThe formation of interpolymer complexes on the surface of crosslinked poly (acrylic acid) with some nonionogenic polymers is compared with the complex formation in analogous linear polymer systems. The behavior of these systems is compared with that of complexes of two oppositely charged polyelectrolytes. The concentration redistribution of the linear polymer in the system polyelectrolyte network‐polymer solution and the degree of swelling of this network in these solutions were determined. © 1994 John Wiley & Sons, Inc.
Asymmetric polymerization of aromatic isocyanates with optically active anionic initiators
Authors: Okamoto Yoshio , Matsuda Masashi , Nakano Tamaki , Yashima Eiji 
Published: April 2003

AbstractThe asymmetric anionic polymerization of o‐, m‐, and p‐methylphenyl isocyanates, p‐methoxyphenyl isocyanate, p‐chlorophenyl isocyanate, 2,6‐ and 3,4‐dimethylphenyl isocyanates, and 1‐naphthyl isocyanate was carried out using chiral anionic initiators such as the lithium salts of (−) ‐menthol, (−) ‐(2‐methoxymethyl) pyrrolidine, and (+) ‐1‐(2‐pyrrolidinylmethyl) pyrrolidine. Although o‐methylphenyl isocyanate gave an insoluble polymer and 2,6‐dimethylphenyl isocyanate afforded no polymer, the other monomers gave soluble polymers, which showed optical activity due to the prevailing helicity of the polymer chain induced by chiral initiator residues attached to the α‐end of the polymer chain. The molecular mechanics conformational calculation for a tetramer of m‐methylphenyl isocyanate supported the helical conformation of the main chain. The optical rotation of the polymers depended significantly on temperature. © 1994 John Wiley & Sons, Inc.
Fully aromatic thermotropic liquid crystalline homopolyesters of 3,4′‐benzophenone dicarboxylic acid
Authors: Bhowmik Pradip K. , Han Haesook , Garay Raul O. 
Published: April 2003

AbstractA series of fully aromatic, thermotropic homopolyesters, derived from 3,4′‐benzophenone dicarboxylic acid and various aromatic diols, was prepared by the melt polycondensation method and examined for thermotropic behavior by a variety of experimental techniques. The aromatic diols used in the study were hydroquinone, 2,6‐, 1,4‐, 1,5‐, 2,3‐, and 2,7‐naphthalenediol isomers. All of the homopolyesters of 3,4′‐benzophenone dicarboxylic acid with aromatic diols (except that with 2,7‐naphthalenediol) formed a nematic LC phase in the melt. They had the glass transition temperatures (Tg) in the range of 133–164°C, the melting transitions (Tm) in the range 305–360°C and the high thermal stabilities (Td) in the range of 410–483°C. The 2,6‐naphthalenediol based homopolymer had the highest Tm (360°C) and the 2,3‐naphthalenediol based homopolymer had the lowest Tm (305°C) among all of the homopolymers of naphthalenediol isomers. © 1994 John Wiley & Sons, Inc.
Preparation and properties of aromatic polyamides and polyimides derived from 3,3‐bis [4‐(4‐aminophenoxy) phenyl] phthalide
Authors: Yang Chin‐Ping , Lin Jiun‐Hung 
Published: April 2003

Abstract3,3‐Bis[4‐(4‐aminophenoxy)phenyl]phthalide (II) was used as a monomer with various aromatic dicarboxylic acids and dianhydrides to synthesize polyamides and polyimides, respectively. The diamineIIwas derived by a nucleophilic substitution of phenolphthalein withp‐chloronitrobenzene in the presence of K2CO3. PolyamidesIVa‐ghaving inherent viscosities of 0.77–2.46 dL/g were prepared by the direct polycondensation of diamineIIwith diacidsIIIa‐gusing triphenyl phosphite and pyridine as condensing agents. The polyamides were readily soluble in a variety of solvents such asN, N‐dimethylformamide (DMF),N,N‐dimethylacetamide (DMAc), andN‐methyl‐2‐pyrrolidinone (NMP) and afforded transparent and flexible films from the polymer solutions. These polymers had glass transition temperatures (Tgs) in the 227–307°C range and 10% weight loss temperatures occurred up to 450°C. PolyimidesVIa‐ebased on diamineIIand various aromatic dianhydridesVa‐ewere synthesized by the two‐stage procedure that included ring‐opening, followed by thermal or chemical conversion to polyimides. Most of the polyimides obtained by chemical cyclodehydration procedure were found to soluble in DMF, NMP,o‐chlorophenol, andm‐cresol. TheTgs of these polyimides were in the 260–328°C range and showed almost no weight loss up to 500°C under air and nitrogen atmosphere. © 1994 John Wiley & Sons, Inc.
Synthesis of new linear polymers containing phosphorus atom in the main chain by the radical polyaddition: Addition polymers of phenylphosphine with 1,4‐divinylbenzene or 1,4‐diisopropenylbenzene and their properties
Authors: Obata Takatsugu , Kobayashi Eiichi , Aoshima Sadahito , Furukawa Junji 
Published: April 2003

AbstractA polyaddition of phenylphosphine (PH) to 1,4‐divinylbenzene (DVB) or 1,4‐diisopropenylbenzene (DIPB) was carried out by radical initiations or UV irradiation at 60–80°C in toluene under a nitrogen atmosphere. The soluble polymer with higher molecular weight ($\[ \bar M_w = 2 \times 10^4 \]$) was obtained in a high yield with AIBN initiator for 95 h in the presence of 5% excess of PH to DVB (monomer feed ratio [DVB]0/[PH]0 = 1/1.05). On the other hand, a polyaddition of PH to DIPB proceeded much slower than the case of DVB, but the high polymer was obtained in a high yield by choosing polyaddition conditions such as polyaddition temperature and initiator concentration. From 1H‐NMR, IR analyses, and phosphorus content of the polymers, it was characterized that both polymers have the alternating structure consisting of PH and DVB or DIPB units in 1 : 1 ratio. The glass transition and decomposition temperatures of both polymers under a nitrogen atmosphere were almost similar: 15–30°C and 380–385°C, respectively; but, the polymers were oxidized by heating under an atmosphere of air. The polymers had a self‐extinguishing property and the polymer blend of the flammable polymers such as polystyrene and polyethylene with the phosphorus‐containing polymers exhibited an excellent flame resistance. © 1994 John Wiley & Sons, Inc.
Quinone‐amine polymers. XII. Synthesis and characterization of novel polymers from 2‐phenylbenzoquinone and aliphatic diamines
Authors: Reddy T. Ashok , Erhan S. 
Published: April 2003

AbstractIn order to study the effect of the presence of phenyl groups in poly (amino‐quinone) (PAQ) polymers, several novel poly(amino‐2‐phenylbenzoquinone) (PhPAQ) polymers have been prepared from 2‐phenylbenzoquinone and aliphatic diamines, such as 1,6‐diaminohexane, 1,8‐diaminooctane, 1,12‐diaminodod+++++, and 1,4‐diaminocyclohexane. Prior to the polymerization, 2‐phenylbenzoquinone was generated in situ from 2‐phenylhydroquinone in the presence of calcium hypochlorite as the oxidizing agent in dichloromethane. All of the polymers synthesized have been characterized with respect to their corresponding model compounds. It was also found that unlike their analogous PAQ polymers, PhPAQ polymers were highly soluble in many common organic solvents because of the presence of phenyl groups in their polymer backbone. © 1994 John Wiley & Sons, Inc.
Fully aromatic liquid crystalline homopolyesters and copolyesters of 1,1′‐binaphthyl‐4,4′‐diol
Authors: Bhowmik Pradip K. , Lenz Robert W. 
Published: April 2003

AbstractA series of fully aromatic, thermotropic polyesters based on 1,1′‐binaphthyl‐4,4′‐diol, BND, was prepared by the melt polycondensation method and characterized for their thermotropic behavior by a variety of experimental techniques. The homopolymer of BND with terephthalic acid formed a nematic melt at 353°C. In contrast, the polyester from BND and 2,6‐naphthalenedicarboxylic acid had a melting transition, Tm, above 400°C, so it was not possible with the equipment available to determine whether it formed a nematic melt. All of the copolymers of BND formed nematic melts at much lower Tm values than those of its respective homopolymers, as expected, because of the copolymerization effect of the added monomer. Moreover, all of the copolymers had higher glass transition temperatures, Tg, than those of other liquid crystalline polyesters and higher thermal stabilities. © 1994 John Wiley & Sons, Inc.
Synthesis and thermal properties of liquid‐crystalline polyacrylates containing a carbazolyl group in the mesogen
Authors: Kosakasup Yozo , Kato Takashi , Uryu Toshiyuki 
Published: April 2003

AbstractThe new acrylate monomers 4‐(ω‐acryloyloxyalkyloxy)‐N‐(9‐methyl‐2‐carbazolylmethylene) anilines containing from 2 to 11 methylenic units in their alkyl group and a carbazolyl group in the mesogenic unit were synthesized and polymerized by azobisisobutyronitrile (AIBN) as radical initiator and by low‐energy electron beam (EB) initiation. The thermal properties of the resulting polymers were examined using differential scanning calorimetry and thermal optical polarizing microscopy. The polymer prepared by AIBN with a hexamethylene spacer exhibited a nematic phase from 73 to 170°C and with an undecamethylene spacer exhibited a smectic phase from 55 to 202°C. The isotropization temperature of the polyacrylates increased with increasing the number of carbons of the methylenic spacer. The yield of the resulting polymer was changed by EB irradiation temperature from 4.5 to 41%. The highest yield was obtained when the monomer was polymerized in a liquid‐crystalline phase. The same tendency was observed in the molecular weight of the resulting polymers. © 1994 John Wiley & Sons, Inc.
Mechanistic studies of carbonate macrocyclization
Authors: Aquino Eugene C. , Brittain William J. , Brunelle Daniel J. 
Published: April 2003

AbstractThe kinetics of phenylchloroformate (PCF) reactions have been used to model some of the key chemical events in carbonate macrocyclization. Three reactions have been studied using stopped‐flow FT‐IR spectroscopy: formation of acyl ammonium salt from PCF and three different trialkylamines, the conversion of acyl ammonium salt to urethane, and the condensation reaction between acyl ammonium salt and 4‐isopropylphenol. The rate dependence was studied for triethylamine (TEA), diethylmethylamine (DEMA) and tri‐n‐butylamine (TBA) at 0°C in anhydrous CH2Cl2. The reactivity order for acyl ammonium salt formation for TBA: TEA: DEMA is 1 : 2.7 : >444. By contrast, condensation and urethane formation are not sensitive to the structure of the amine. The rate of condensation is comparable to the rate of acyl ammonium salt formation for TEA and TBA, while the rate of urethane formation is the slowest process for all three amines. These results are consistent with the view that the yield of macrocyclic polycarbonates is related to the concentration of the acyl ammonium salt. The optimum amine concentration for obtaining high yields of cyclics varies with the amine structure and parallels the difference in the rates of acyl ammonium salt formation. © 1994 John & Sons, Inc.
Spectroscopic study of solid state photoreaction of di n‐propyl ester of dicyano p‐phenylenediacrylic acid
Authors: Ghosh Manash , Chakrabarti Subhasis , Sarkar Mamata , Misra T. N. 
Published: April 2003

AbstractPhotopolymerization reaction in di n‐propyl ester of dicyano p‐phenylene diacrylic acid crystal is shown to be mediated by exciton–phonon coupling. Raman phonon spectra suggest that at the initial stage of reaction progress, the reactant and the product form a solid solution. In the later stage, the reactant segregates out and forms its own lattice. The polymer lattice is shown to maintain a good degree of order. Infrared and Raman spectra confirm that the polymerization occurs by cyclobutane ring formation. © 1994 John Wiley & Sons, Inc.
Poly‐N,N‐diethylacrylamide prepared by group transfer polymerization: Synthesis, characterization, and solution properties
Authors: Eggert Martin , Freitag Ruth 
Published: April 2003

AbstractThe conditions for preparing poly‐N,N‐diethylacrylamide by group transfer polymerization (GTP) were investigated. While electrophiles did not catalyze the reaction, various nucleophilic substances could be used for that purpose. By using an appropriate initiator, either an ester or a carboxylic acid end group could be formed. The highest yields in the first case were obtained using tetrabutylammonium acetate and dimethylketene methyl trimethylsilyl acetal as catalyst and initiator, respectively, while the use of the corresponding bistrimethylsilyl compound as initiator gave polymers, albeit at lower yields, which carried the acidic end group. The 1H‐NMR, 13C‐NMR, and IR spectra of the polymers were taken and used together with information obtained with soft‐ionization mass spectrometric methods (MALDI‐MS, ESI‐MS, and FD‐MS) to elucidate molecule structure, apparent molecular weight distribution, polydispersity, and possible mechanisms of the termination reaction. The poly‐N,N‐diethylacrylamide prepared, showed an inverse temperature dependency in its water‐solubility, with a lower critical solution temperature between 29.8°C and 30°C. © 1994 John Wiley & Sons, Inc.
Trimethylsilyl‐group containing polyphenylacetylenes for oxygen and ethanol permselective membranes
Authors: Aoki Toshiki , Nakahara Hiroshi , Hayakawa Yoshio , Kokai Masayuki , Oikawa Eizo 
Published: April 2003

AbstractPhenylacetylenes having one or two trimethylsilyl groups at their benzene ring were synthesized, and polymerized by [Rh(cyclooctadiene) (PPh3)2]PF6, [Rh(norbornadiene)Cl]2, or WCl6 to afford high molecular‐weight polymers in high yields. These poly(phenylacetylene)s were soluble in many kinds of solvents and were fabricated to tough membranes by the solvent casting method. The oxygen permselectivities of these membranes were very good. The oxygen permeability coefficients (Po2) and oxygen separation factors (α = Po2/PN2) of poly[2,4‐(o,p)‐bis(trimethylsilyl)phenylacetylene] [poly (o‐1‐p‐1)] and poly[(4(p)‐trimethylsilyl)phenylacetylene] [poly(p‐1)] membranes were 4.73 × 10−8 cc(STP) cm/cm2 s cmHg and 2.65, and 1.52 × 10−8 cc(STP) cm/cm2 s cmHg and 3.39, respectively. In the case of poly(o‐1‐p‐1), Po2 was comparable to that of polydimethylsiloxane (PDMS) and α was higher than that of PDMS. However, the Po2 value reduced to 48% of its initial value in about 1 year. In the case of poly(p‐1), the Po2 value did not change in about 1 year. Ethanol permeated preferentially through these membranes (αEtOH > 1) in pervaporation of aqueous ethanol solution, whereas poly(phenylacetylene) [poly(PhA)] showed water permselectivity (αEtOH < 1). These favorable effects of trimethylsilyl groups on the oxygen and ethanol permselectivities were discussed on the basis of comparison with those of poly(PhA), other poly(substituted phenyl‐acetylene)s, and trimethylsilyl‐group containing polystyrenes. © 1994 John Wiley & Sons, Inc.
Block copolymers by polymer modification: Conversion of polyisoprene segment to hydroxylated polyisoprene
Authors: Kim Young H. 
Published: April 2003

AbstractPolyisoprene (PIP) was found to react with trifluoroacetic acid (TFA) to give an adduct. Saponification of the ester gave a new alternating copolymer of ethylene and α‐methyl vinyl alcohol. TFA did not react with polybutadiene (PBD) under these conditions, thus providing a way to produce amphiphilic block copolymers from PBD‐b‐PIP. TFA addition to the PIP block took place cleanly at an ambient temperature with 2 equiv of the acid in toluene to give block copolymer of PBD and trifluoroacetated PIP. This polymer is very soluble in toluene regardless of molecular weight. Methanolysis with NaOMe cleaved the ester to give PDB‐b‐(ethylene‐alt‐α‐methyl vinyl alcohol) (PIPOH) in a MeOH/toluene mixture. Low molecular weight hydroxylated diblock copolymer is a viscous liquid when the ratio of PIP/PBD is 0.1 ( \documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} = 4100, D = 1.3), but a solid with the ratio 0.5 (\documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} = 7170, D = 1.6). High molecular weight polymer (\documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} = 114,000, D = 1.4) with PIP/PBD ratio 0.1 is a hazy rubbery material. Block copolymers of PIPOH and poly(methacrylic acid) was also obtained from copolymers of PIP and poly(t‐butyl methacrylate). The hydroxylated copolymers showed surface activity by monolayer formation on a Langmuir–Blodgett trough. The transfer of the monolayer on a silicon wafer gave z‐type deposition, with the average ellipsometer thickness of the layer being about 40 Å thick per monolayer for \documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} = 4100 copolymer. © 1994 John Wiley & Sons, Inc.
Carbenoid polycondensation with telechelic polyethers having dichloroacetic acid ester groups
Authors: Tezuka Yasuyuki , Hoshino Chisato 
Published: April 2003

AbstractPoly(ethylene oxide) [poly(EO)], with number‐average molecular weights (Mns) of 1000 and 2000, and poly(tetrahydrofuran) [poly(THF)] with Mns of 1000 and 2000, possessing dichloroacetic acid ester end groups (1, and 2, respectively) were prepared from precursor diols by esterification with dichloroacetyl chloride in the presence of pyridine. 1 and 2 were subjected to the reaction with copper metal in DMSO to produce the corresponding segmented polyethers containing fumarate/maleate groups within the main chain (3 and 4, respectively), through a polycondensation of carbalkoxy carbenoid intermedlates generated via α, α‐dichloro elimination from the end groups of 1 and 2. The radical polymerization of styrene in the presence of 3 and 4 produced network copolymers consisting of poly (EO) or poly(THF) and polystyrene segments. © 1994 John Wiley & Sons, Inc.
A novel acrylate carrying a hindered phenol moiety as monomer and terminator in radical polymerization
Authors: Matsumoto Akikazu , Yamagishi Kenichi , Aoki Shuzo 
Published: April 2003

AbstractRadical polymerizations of methyl methacrylate (MMA), styrene (St), and vinyl acetate (VAc) were carried out in the presence of a novel phenyl acrylate derivative bearing a hindered phenol moiety (HPA). It has been clarified that HPA acts as a retarder and inhibitor for the polymerizations of MMA and VAc, respectively, and that in the polymerization of St it behaves as a monomer to give a copolymer. These additive effects were interpreted in terms of intramolecular transfer of the phenolic hydrogen in competition with propagation of the HPA radical to monomers. © 1994 John Wiley & Sons, Inc.
Azeotropy in terpolymerization of N‐antipyryl acrylamide with different alkyl acrylates or styrene and acrylonitrile
Authors: El‐Hamouly S. H. , Azab M. M. 
Published: April 2003

AbstractTernary copolymerization of N‐antipyryl acrylamide (NAA) with different alkyl acrylates [methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BuA)] or styrene (ST) and acrylonitrile (AN) were carried out in solution at 65°C in the presence of AIBN as a free radical initiator. Experimental terpolymerization daca agree well with calculations based on the Alfrey–Goldfinger equation. The determination of unitary, binary, and ternary azeotropes of various systems studied was easily handled by a computer program. Ternary azeotropic compositions for NAA–MA–AN, NAA–EA–AN, NAA–BuA–AN, and NAA–ST–AN system were 31.0 : 10.0 : 59.0, 37.0 : 09.0 : 54.0, 23.0 : 10.0 : 67.0, and 66.5 : 30.50 : 03.0 mol %, respectively. Selective unitary and binary azeotropic compositions were polymerized and the obtained results show good agreement between the theoretical and experimental terpolymer composition for each case. Also, pseudo‐azeotropic regions were identified where the deviation between feed and polymer composition is very small. The azeotropic points of the four systems were confirmed using Tarasov et al.'s equations and were found to have satisfactory results. © 1994 John Wiley & Sons, Inc.
Chemical preparation of conductive elastomeric blends: Polypyrrole/EPDM. I. Oxidant particle‐size effect
Authors: Zoppi Rita Aparecida , Felisberti Maria Isabel , De Paoli Marco‐Aurelio 
Published: April 2003

AbstractThis work describes the preparation of polypyrrole and EPDM rubber blends, PPy/EPDM, by the sorption of pyrrole (vapor phase) in an EPDM matrix containing CuCl2. We investigated the effect of the oxidant particle‐size on the sorption and polymerization equilibrium, electrical conductivity, and mechanical properties of the blends. Independently of the CuCl2 concentration and polymerization time, the polypyrrole weight fraction in the blend, Xppy, increases when the oxidant particle‐size in changed from 150–250 μm to smaller than 106 μm. For blends containing 50 phr of CuCl2, obtained following 72 h of exposure to pyrrole, an increase in the Young's Modulus (from 2.2 ± 0.2 to 3.9 ± 0.6 MPa) and an increase in the electrical conductivity (from 10−9 to 10−7 S cm−1) was observed when the oxidant particle‐size was decreased. Infrared spectroscopy, thermogravimetric analysis, scanning differential calorimetry, and scanning electron microscopy were used in sample characterization. © 1994 John Wiley & Sons, Inc.
Polymerization of ethylene at high temperature by vanadium‐based heterogeneous Ziegler—Natta catalysts. II. Study of the activation by halocarbons
Authors: Adisson E. , Deffieux A. , Fontanille M. , Bujadoux K. 
Published: April 2003

AbstractThe enhancement of the activity and productivity of heterogeneous V‐based catalysts in the presence of halogenated additives, has been investigated for high‐temperature ethylene homopolymerization (160°C). The influence of both the nature and structure of various organic halides on polymerization kinetics and on the oxidation state of vanadium derivatives has been examined in detail. Results suggest, as previously reported for lower temperature polymerizations, that the main role of the halogenated derivatives may be accounted for by their oxidizing character. It allows re‐oxidation of the reduced VII species formed during the polymerization process, to valence III. The various pathways able to lead to the formation of new active species from (re‐)formed VIII are examined and discussed. © 1994 John Wiley & Sons, Inc.
Preparation and properties of polyborosiloxanes as precursors for borosilicate formation of SiO2–B2O3 gel fibers and oxides by the sol‐gel method using tetraacetoxysilane and boron tri‐n‐butoxide
Authors: Kasgoz A. , Misono T. , Abe Y. 
Published: April 2003

AbstractFormation of SiO2–B2O3 gel fibers and oxides was investigated by the sol‐gel method using tetraacetoxysilane (TAS) and boron tri‐n‐butoxide (BTB). Low molecular weight borosiloxanes (BS) were formed by the reaction of TAS with BTB in THF. Partial alkoxylation and hydrolysis of BS followed by further condensation of the resulting polymer (PBS) solutions led to the formation of highly polymerized polyborosiloxanes (HPBS) with good spinnability. Gel fibers were obtained by dry spinning of HPBS. The compositions of PBS and gels were not consistent with that in feed. Heat treatment of the gels, however, provided SiO2–B2O3 oxides with compositions almost compatible with those of the gels. © 1994 John Wiley & Sons, Inc.