bluuebunny/crossref_metadata_2025_split huggingface dataset:
New synthetic route to alternating copoly(aromatic ester–aliphatic amide)s
Authors: Lu C. X. , Yang Yang 
Published: April 2003

AbstractThe preparation of three novel alternating copoly(aromatic ester–aliphatic amide)s containing the same ordered amide–amide–ester–ester (AAEE), the same para‐disubstituted phenyl, and the different long methylene chain structure were described. 1,1′‐(Adipoyl)bisbenzotriazole (AdBBT), 1,1′‐(suberoyl)bisbenzotriazole (SuBBT), and 1,1′‐(sebacoyl)bisbenzotriazole (SeBBT) were synthesized. These diacylbenzotriazoles were preferred to aminoethanol at the amino group because of the selective N‐acylation of active acylamide of benzotriazole in excellent yield at room temperature to give diol monomers such as N,N′‐bis(2‐hydroxyethyl)adipic amide (HEAdA), N,N′‐Bis(2‐hydroxyethyl)subaric amide (HESuA), and N,N′‐bis(2‐hydroxyethyl)sebacic amide (HESeA). Polycondensation of 1,1′‐(teraphthaloyl)bisbenzotrizole (tPBT) with HEAdA, HESuA, and HESeA gave the corresponding alternating copoly(aromatic ester–aliphatic amide)s: P(tPE–AdA), P(tPE–SuA), and P(tPE–SeA), respectively. The alternating copoly(aromatic ester–aliphatic amide)s were characterized by 1H‐NMR spectra. The resulting polymers have two different chain units; one is chain unit of poly(ethylene terephthalate) and the other is a chain unit of polyamide‐2,6, polyamide‐2,8, and polyamide‐2,10; both are linked via a CN bond.
Synthesis and characterization of N‐phenylated aromatic polyureas from dianilino compounds and aromatic diisocyanates
Authors: Oishi Yoshiyuki , Kakimoto Masa‐Aki , Imai Yoshio 
Published: April 2003

AbstractN‐phenylated aromatic polyureas were synthesized by the polyaddition of dianilino compounds to aromatic diisocyanates in sym‐tetrachloroethane at around 100°C. Factors that influence the reaction, such as monomer concentration, reaction solvent, catalyst, temperature, and time, were studied to optimize the conditions for the preparation of high molecular weight polymers. Compared with the analogous unsubstituted aromatic polyureas, the N‐phenylated polyureas were almost amorphous and soluble in a variety of solvents and had low glass transition temperatures. Some of the polymers could be cast into transparent flexible films from chloroform solutions.
Preparation and thermal properties of polyquinazolones containing m‐substituted phenyl groups on the quinazolone ring
Authors: Kubota Shigeru , Moriwaki Toshimoto , Ando Torahiko , Fukami Akira 
Published: April 2003

AbstractPolyquinazolones containing m‐substituted phenyl groups (Br, Cl, F, CH3O, NO2, and CH3) on the quinazolone ring were synthesized in m‐cresol, and their thermal properties were studied by using dynamic thermogravimetry and isothermal weight loss. Polyquinazolones with intrinsic viscosities in the range 0.2–1.6 dL/g were synthesized. The introduction of substituted groups into the pendant phenyl group resulted in a decrease in the glass transition temperature and the thermal stability. Oxidative thermal stability of the polyquinazolones was dependent on the position of substituted groups on the pendant phenyl group. The introduction of substituted groups into the meta position reduced thermal stability more than did the introduction into the para position.
Synthesis and characterization of deuterated poly(arylene ether sulfones)
Authors: Hedrick J. L. , Dumais J. J. , Jelinski L. W. , Patsiga R. A. , McGrath J. E. 
Published: April 2003

AbstractSelectively deuterated poly(arylene ether sulfones) were prepared for neutron scattering studies and for deuterium NMR investigations. The availability of these model macromolecules permits molecular‐level identification of the motions responsible for the low temperature relaxations that have been observed in the dynamic mechanical spectra of these engineering polymers. Three labeled sites on the appropriate monomers (bisphenol‐A and 4,4′‐dichlorodiphenylsulfone) were prepared from deuterated intermediates and characterized via chromatographic, spectroscopic, and thermal analysis. The deuterium exhcange between methyl and aromatic sites that occurred during synthesis was quantified. These labeled monomers were mixed with hydrogenous monomers to synthesize high molecular weight, selectively deuterated poly(arylene ether sulfones). A synthetic technique involving N‐methyl‐2‐pyrrolidone/potassium carbonate was employed to afford high molecular weight polymers. The polymers were characterized by FT‐IR, proton, carbon, and deuterium NMR, intrinsic viscosities, and thermal analysis. Molecular weights of the labeled polymers were similar to unlabeled systems.
Conducting polypeptide: Poly(L‐histidinium 7,7,8,8‐tetracyanoquinodimethanide)
Authors: Oshima Ryuichi , Kumanotani Ju 
Published: April 2003

AbstractThe TCNQ anion radical salt of poly(I‐histidinium) with a 1:1 stoichiometry was prepared, which exhibited some degree of crystallinity. In the salt, the helical conformation of the polycation was preserved. It showed high electrical conducivity compared to certain salts with several imidazolium derivatives.
Synthesis and characterization of fluorine‐containing aromatic polyethers from tetrafluoroisophthalonitrile and bisphenols
Authors: Shimizu Masa‐Aki , Kakimoto Masa‐Aki , Imai Yoshio 
Published: April 2003

AbstractNew aromatic polyethers having inherent viscosities of 0.43–0.91 dL/g were synthesized by the phase‐transfer catalyzed polycondensation of tetrafluoroisophthalonitrile with various hisphenols in a nitrobenzene‐water system. All the polyethers were amorphous and soluble in N‐methyl‐2‐pyrrolidone and nitrobenzene. They were cast into transparent and flexible films from the solutions. These polymers had glass transition temperatures around 130°C and dia not lose weight below 400°C in either air or nitrogen.
Poly(enonsulfides) from the addition of aromatic dithiols to aromatic dipropynones
Authors: Bass R. G. , Cooper E. , Hergenrother P. M. , Connell J. W. 
Published: April 2003

AbstractNovel poly(enonsulfides) were prepared with inherent viscosities as high as 1.35 dL/g by nucleophilic addition of various aromatic dithiols to 1,1′‐(1,3‐ or 1,4‐phenylene)bis(3‐phenyl‐2‐propyn‐1‐one) in m‐cresol at 25–40°C. A tough clear yellow film with a tensile strength of 11,300 psi and a tensile modulus of 466,000 psi at 25°C was cast from a chloroform solution of the polymer prepared from 1,3‐dithiobenzene and 1,1′‐(1,4‐phenylene)bis(3‐phenyl‐2‐propyn‐1‐one). The poly(enonsulfides) exhibited Tg's as high as 180°C and weight losses of approximately 10% at 331°C in air. The synthesis and characterization of several poly(enonsulfides) are discussed.
Synthesis and characterization of N‐phenylated aromatic polyamides from N‐silylated dianilino compounds and aromatic diacid chlorides
Authors: Oishi Yoshiyuki , Kakimoto Masa‐Aki , Imai Yoshio 
Published: April 2003

AbstractN‐Phenylated aromatic polyamides of high molecular weights were synthesized by the hightemperature solution polycondensation of N,N′ ‐di(trimethylsilyl)‐substituted dianilino compounds derived from p‐dianilinobenzene, bis(4‐anllinophenyl) ether, and α,α′‐dianilino‐p‐xylene, with isophthaloyl and terephthaloyl chloride. Almost all of the N‐phenylated polyamides were amorphous, and soluble in a variety of organic solvents including dimethylformamide, m‐cresol, and chloroform. Transparent and flexible films of these polymers could be cast from the dimethylformamide solutions. Four wholly aromatic polyamides had glass transition temperatures in the range of 195–255°C, and began to lose weight around 400°C in air.
Polymeric catenanes from crosslinked poly(2,6‐dimethyl‐1,4‐phenylene oxide) and cyclic poly(dimethylsilozane)
Authors: Fyvie T. J. , Frisch H. L. , Semlyen J. A. , Clarson S. J. , Mark J. E. 
Published: April 2003

AbstractPoly(2,6‐dimethyl‐1,4‐phenylene oxide) has been crosslinked in the presence of large poly(dimethylsiloxane) cyclics (92 repeating units). Approximately 26% by weight of the cyclics were threaded and permanently captured by the polymer network forming a topological isomeric structure referred to as a polymeric catenane. Nonentrapped cyclics were extracted with chloroform. Chemical analyses and micrographs showed evidence for crosslinking and cyclic entrapment, while physical testing demonstrated distinct differences in physical properties such as the glass transition temperature, ultimate mechanical properties, and dynamic viscoelastic response between the crosslinked control samples, and those containing cyclic poly(dimethylsiloxane).
Effects of added metal ions on the interaction between polyvinylpyrrolidone and azo dyes carrying hydroxyl groups
Authors: Takagishi Toru , Matsui Naoki 
Published: April 2003

AbstractThe extent of binding of chrome violet, which is a monoazo dye and involves two hydroxyl groups in o and o′ positions to azo group, by polyvinylpyrrolidone is markedly enhanced in the presence of Co2+ ion. The amount of binding in the presence of 1 × 10−4 mol/L of Co2+ ion increases by a factor of about 10 compared to that in the absence of the metal ion. Ni2+ and Zn2+ ions do not perceptively influence the binding affinity of the dye. Cu2+ ion, in contrast, suppresses the binding. To investigate further the action of added metal ions, a cobalt–complex dye was prepared and its binding property for the polymer was compared to that of chrome violet in the presence of metal ions. Some possible mechanisms for the enhancement of chrome violet binding by the addition of Co2+ ion are described.
Kinetics and mechanism of urethane reactions: Phenyl isocyanate–alcohol systems
Authors: Chang Ming‐Chow , Chen Show‐An 
Published: April 2003

AbstractUrethane reactions of phenyl isocyanate alcohol systems with toluene as solvent and various aprotic polar solvents (including tertiary amines) as additives were carried out at constant temperature of 10–40°C. Analysis of the variation of the second order rate constants of these systems and those available in the literature indicates that formation of the hydrogen bonding complexes (alcohol with phenyl isocyanate and with aprotic solvent) and electron donor number (DN) of the aprotic solvent are the two factors allowing satisfactory explanation of the catalysis and inhibition effects of the wide range of aprotic solvents (including amines, amides, etc.). Based on these considerations, an ion‐pair mechanism and the resulting kinetic equation for the urethane reaction are proposed. Verification on the kinetic equation with experimental results for the systems of phenyl isocyanate with alcohol in toluene (for the self catalysis of the alcohol), with dimethyl formamide and dimethyl sulfoxide in toluene (for the catalysis of the aprotic solvents), and with triethylamine in toluene (for the catalysis of the tertiary amines) shows satisfactory. In the mechanism, the aprotic solvent is considered to solvate the complex of phenyl isocyanate/alcohol at the active hydrogen to form an ion‐pair which can undergo the urethane reaction more easily.
Polymerization of cyclic acetals. I. Polymerization of 1,3,6‐trioxacyclooctane and copolymerization with p‐methoxystyrene
Authors: Velichkova R. S. , Gancheva V. B. 
Published: April 2003

AbstractThe polymerization of 1,3,6‐trioxacyclooctane initiated by trityl salts with various counterions in CH2Cl2 was investigated. The reaction mixtures and the isolated polymers were analyzed by GPC (double detection—IR and UV at 254 nm),1H‐, and13C‐NMR spectroscopy. In the early stage of polymerization only oligomers (mainly cyclic) were formed. With longer reaction times, linear polymers (yield 86–94%, M = 70,000–80,000) were obtained. The concentration of each individual oligomer passed through a maximum and decreased, reaching its equilibrium concentration. The time interval necessary to reach the maximum concentration increased with n. The total concentration of the oligomers was 0.2 mol L−1 regardless of the initiator used. Conditions for polymerization with virtually no termination were found. Addition of p‐methoxystyrene to the “living” polyacetals resulted in block copolymers. GPC,1H‐ and 13C‐NMR and acidolytic degradation were used to prove the formation of AB block copolymers. The reactive alkoxycarbenium growing species are responsible for the formation of block polyacetal‐polymethoxystyrene copolymer.
Surface modification by plasma techniques. I. The interactions of a hydrogen plasma with fluoropolymer surfaces
Authors: Clark D. T. , Hutton D. R. 
Published: April 2003

AbstractThe rapid defluorination of fluoropolymer surfaces by their exposure to a hydrogen plasma excited by an inductively coupled RF field has been studied using ESCA. The results are interpreted in terms of a reaction/depth profile; the reaction is not uniform with depth leading to the formation of an approximately 20 Å thick boundary layer of defluorinated material.
Poly(α‐amino acid)‐immobilized polymer adsorbents for optical resolution. I. Synthesis, characterization, and evaluation of poly(L‐glutamic acid) derivatives‐immobilized polymer adsorbents
Authors: Kiniwa Hideaki , Nishikaji Takashi , Ogata Naoya 
Published: April 2003

AbstractAs a novel polymer adsorbent for optical resolution, cross‐linked polystyrene gel incorporating poly(α‐amino acids) was synthesized. The helicity of the incorporated poly(γ‐benzyl L‐glutamate) (PBLG) was demonstrated by Fourier‐transform infrared spectroscopy. The immobilized PBLG (I) was converted to poly(L‐glutamic acid) (II) and poly(N5‐benzyl‐L‐glutamine) (III). The ability of I‐III to resolve DL‐mandelic acid was evaluated by liquid chromatography using toluene/dioxane as an eluent. Of the three resins, III resolves the recemate most effectively. In order to clarify the mechanism of chiral recognition, poly(N5‐benzyl‐D‐glutamine) and poly(N4‐benzyl‐L‐asparagine), with opposite helicity, was incorporated. In Contrast to III, these adsorbents demonstrated affinity for the L isomer. This result strongly indicates that the helical structure of the immobilized poly(α‐amino acids) is essential for chiral recognition.
Polymerization of N‐(p‐aminobenzoyl)caprolactam: Block and alternating copolymers of aromatic and aliphatic polyamides
Authors: Mathias Lon J. , Moore D. Roger , Smith Charles A. 
Published: April 2003

AbstractThe polymerization behavior of N‐(p‐aminobenzoyl)caprolactam was studied. It was found that polymerization could proceed by either elimination of caprolactam or by ring opening. Polymers prepared at temperatures above 200°C showed a greater tendency for ring opening to produce alternating aromatic/aliphatic copolymers than did polymers prepared at lower temperatures. Block copolymers of poly(p‐benzamide) and nylon 6 were prepared by a two‐stage hydrolytic polymerization process or by anionic polymerization at temperatures > 200°C. Polymer microstructures were determined using 13C‐NMR spectroscopy by comparison with homopolymers and model alternating copolymers. The alternating copolymer prepared by condensation of N‐(p‐aminobenzoyl)‐6‐caproic acid showed a melting transition at 300–305°C in the DSC and a Tg in subsequent heating cycles of 116–119°C. Copolymers made with the two‐stage process were rich in p‐benzamide sequences and showed no Tg or Tm below 400°C. Copolymer made with NaH was rich in nylon 6 units, showed a Tm of 175–180°C and a Tg of 80–81°C, and was homogeneous in both the melt and solid.
Polymerization of liposomes composed of diene‐containing lipids by radical initiators. II. Polymerization of monodiene‐type lipids as liposomes
Authors: Ohno Hiroyuki , Takeoka Shinji , Iwai Hidetaka , Tsuchida Eishun 
Published: April 2003

Abstract1‐Palmitoyl‐2(2,4‐octadecadienoyl)‐sn‐glycero‐3‐phosphocholine (POPC), a polymerizable lipid that contains one diene group in only a 2‐acyl chain, was polymerized as liposome in an aqueous medium. Polymerization was initiated by water‐insoluble azobisisobutyronitrile (AIBN), or water‐soluble azobis(2‐amidinopropane) dihydrochloride (AAPD). AIBN was mixed with monomeric lipids, and the mixture was dispersed in an aqueous medium by sonication to prepare AIBN‐containing monomeric lipid liposomes. On the other hand, AAPD was simply added to the liposome suspension. The POPC liposomes were easily polymerized by the addition of AAPD, a water‐soluble radical initiator, but few were polymerized by AIBN. The results suggested that the diene group in the 2‐acyl chain was in an aqueous phase and, therefore, easily polymerized by a water‐soluble radical initiator. The polymerized POPC liposomes were revealed to be more stable than those of monomeric ones because the scattered‐light intensity from the polymerized POPC liposome suspension changed a little by the addition of Triton X‐100. For only the polymerized ones, the liposome structure was confirmed by TEM after addition of an excess amount of Triton X‐100.
Functional polymers and sequential copolymers by phase transfer catalysis. XXVI. Synthesis and characterization of thermotropic liquid crystalline polypodants
Authors: Shaffer Timothy D. , Percec Virgil 
Published: April 2003

AbstractThermotropic liquid crystalline (LC) polyethers and copolyethers have been synthesized from 4,4′‐dihydroxy‐α‐methylstilbene (HMS) and α,ω‐dichlorooligo(oxyethylene)s having between 2 and 5 as well as 8.7 oxyethylene units. Copolyethers were prepared from a 1:1 mol/mol ratio of two dissimilar spacers. These polymers have been prepared by a phase transfer catalyzed (PTC) polyetherification of bisphenols with these electrophiles by utilizing 50 mol% tetrabutylammonium hydrogen sulfate per phenol group. Kinetic experiments with either 5 or 50 mol% catalyst vs phenol groups in the polyetherification of 4,4%‐isopropylidenediphenol with 2‐chloroethyl ether have shown that a change in catalyst primarily affects the rate of reaction, with 50 mol % being faster. The prepared polyethers and copolyethers are soluble in common organic solvents. Both polyethers and copolyethers are crystalline. Polymers prepared to contain tetraoxyethylene spacers exhibit monotropic LC behavior. Copolymers prepared to contain tri‐ and tetraoxyethylene spacers (1 : 1 mol/mol) [PE34] were the only polymers exhibiting enantiotropic LC behavior. Longer spacers tend to destabilize the phase transitions, as suggested by the dependence of thermal transition temperatures upon the differential scanning calorimeter rate. All prepared polymers act as podants in solution, measured by picrate extraction experiments. Solid state complexes have been prepared from the polymer with a pentaoxyethylene spacer [PE5] and PE34 with LiCF3SO3. PE5 can dissolve LiCF3SO3 in the range of 0.21–2.2 mol salt/mol polymer (m.r.u.) [S/P] without the observation of free salt. PE5 complexes of/or below S/P of 0.43, upon annealing at room temperature, exhibited the two melting transitons observed in the polymer alone. PE5 complexes of/or above S/P of 0.77 only exhibited a Tg. The Tg of PE5 complexes were found to change nonlinearly with S/P, while Tm1 changed linearly. Tm2 was independent of S/P. Only one complex with PE34 gave two transitions (Tm2,Ti) in dynamic DSC experiments. Other PE34 complexes followed a behavior similar to PE5 complexes.
Polymerization of N‐methylpyrrole with bis‐triazolinediones via electrophilic aromatic substitution
Authors: Mallakpour Shadpour E. , Butler George B. 
Published: April 2003

AbstractThe reaction of N‐methylpyrrole with 4‐substituted‐1,2,4‐triazoline‐3,5‐diones (4R‐TDs), i.e., MeTD (4‐methylsubstituted) and PhTD (4‐phenyl substituted), at room temperature without use of any catalyst was investigated. The reaction is instantaneous and leads to the formation of a 2:1 adduct in high yield, with substitution occurring at the 2 and 5 positions of the pyrrole moiety via electrophilic aromatic substitution. These compounds were fully characterized by IR,13C‐NMR,1H‐NMR, and elemental analysis, and were used as model compounds for the polymerization reaction. The reaction of bis‐triazolinediones with N‐methylpyrrole was carried out in dimethylformamide at room temperature. The reactions are fast and give novel polymer structures. Some structural characterization and physical properties of these new polymers are reported.
TiO2‐, ZnO‐, and CdS‐photocatalyzed oxidation of ethylene‐propylene thermoplastic elastomers
Authors: Lacoste Jacques , Singh Raj Pal , Boussand Jacques , Arnaud Rene 
Published: April 2003

AbstractThe ZnO‐, TiO2‐, and CdS‐photocatalyzed oxidations of an amorphous ethylene‐propylene copolymer (EP copolymer) containing 75% w/w of ethylene are described. In solid films exposed under polychromatic (λ > 300 nm) or monochromatic (λ = 365 nm) UV light, it is observed that the introduction of pigment (0.5–5% w/w) strongly modified the course of the photooxidation of a transparent sample. Ketonic and lactonic groups accumulate in the polymer matrix without being converted photochemically into acidic, ester, and vinyl groups. In the kinetic study it is pointed out that the variations of the rate of formation of carbonyl groups depend on the nature of the pigment. With highly photoactive pigments (ZnO and untreated TiO2 RL11A), the rate is at first a decreasing function of the pigment percent, then an increasing function. With poorly photoactive pigments (treated TiO2 RL90 and CdS), the rate of formation of carbonyl groups is a decreasing function of the pigment content. It is therefore emphasized that, at a low pigment content, the inner filter effect prevails over the photocatalytic influence with any pigment. It is also observed that the rate of formation of vinyl groups, photoproducts formed from the excited ketones, is a monotonously decreasing function of the pigment content. The complete inhibition of the ketone photochemistries is observed with ZnO in conditions in which the light is not absorbed by the pigment, suggesting that the carbonyl groups formed are adsorbed on the pigment.
Reaction of α,β‐poly(N‐hydroxyethyl)‐DL‐aspartamide with derivatives of carboxylic acids
Authors: Giammona Gaetano , Carlisi Bianca , Palazzo Salvatore 
Published: April 2003

AbstractBenzoic acid, acetylsalicylic acid, and 4‐acetamidobenzoic acid have been covalently linked by ester bonds to α,β‐poly(N‐hydroxyethyl)‐DL‐aspartamide (PHEA), a water soluble and nontoxic polymer, in order to study PHEA as a drug carrier.
Syntheses and some spectroscopic properties of polyanions with pendant merocyanine dyes
Authors: Kobayashi Takaomi , Morishima Yotaro , Nozakura Shun‐Ichi 
Published: April 2003

AbstractPolymers tagged with a local pH reporter were synthesized. A methacrylate‐type monomer containing a merocyanine dye residue as a reporter dye—1‐(2‐methacryloyloxyethyl)‐4‐(2‐(4‐hydroxyphenyl)‐ethenyl)quinolinium bromide—was synthesized. Its homopolymer and copolymers with sodium 2‐acrylamido‐2‐methylpropanesulfonate were prepared by free radical polymerization. These polymers showed a characteristic color change in aqueous solutions from yellow to red with increasing pH from acidic to basic conditions according to the acid‐base equilibria of the merocyanine dye residues. Since the electrostatic potential and polarity of media have a strong effect on the acid–base equilibria, the pendant merocyanine residues are expected to serve as a reporter to provide information on the local environments around the polymer chain at which the dye molecules are incorporated.