bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cationic ring‐opening polymerization of 1,4‐anhydro‐2,3‐di‐O‐benzyl‐α‐L‐arabinopyranose and synthesis of L‐arabinofuranan
Authors: Koyama Yoshiyuki , Harima Kazunari , Matsuzaki Kei , Uryu Toshiyuki 
Published: April 2003

Abstract1,4‐Anhydro‐2,3‐di‐O‐benzyl‐α‐L‐arabinopyranose (=1,5‐anhydro‐2,3‐di‐O‐benzyl‐β‐L‐arabinofuranose) (ABAP) was synthesized and underwent cationic ring‐opening polymerization with several kinds of Lewis acids. All the polylmers prepared by Lewis acids as catalyst were found to consist of two different structural units, α‐furanosidic and β‐furanosidic units, and the structure of the polymers greatly depended on the polymerization conditions. Polymerization of ABAP with antimony pentachloride catalyst at 0°C for 42 h gave a polymer with the highest α content of 93%, and that at −20°C for 3 h gave a polymer with the lowest (25%) α content. The other catalysts such as phosphorus pentafluoride, boron trifluoride etherate, niobium pentafluoride, and tantalum pentafluoride also afforded polymers with mixed structure of α‐and β‐furanosides. After debenzylation of poly(ABAP), a new polysaccharide, L‐arabinofuranan was obtained.
Direct polycondensation with tosyl chloride in pyridine by formamide catalyzed alcoholysis
Authors: Higashi Fukuji , Mashimo Toshio 
Published: April 2003

AbstractThe reaction with tosyl chloride was significantly promoted by controlling alcoholysis with bisphenols in the presence of catalytic amounts of formamides to give aromatic polyesters with high molecular weights from aromatic dicarboxylic acids and bisphenols. Mechanistic features of the reaction were studied by use of various formamides and other arylsulfonyl chlorides, as well as by varying the addition mode of bisphenols and changing the relative amount of formamide. The reaction was successfully applied to the preparation of aromatic polyesteramides with high molecular weights from aromatic dicarboxylic acids, bisphenols, and diamines, but with limited success to that of polyamides.
Binding of anthraquinone dyes by polyion complexes consisting of a piperidinium cationic polymer and various polyanions in aqueous solution
Authors: Takagishi Toru , Kuroki Nobuhiko , Kozuka Hiroshi , Mitsuishi Masaru 
Published: April 2003

AbstractThe extent of binding of 1‐amino‐4‐alkylaminoanthraquinone‐2‐sulfonates (alkylmethyl, ethyl, propyl, and butyl), which have different chemical structures from methyl orange derivatives, by polyion complexes consisting of a piperidinium cationic polymer and various polyanions such as sodium poly acrylate, poly methacrylate, poly styrenesulfonate, carboxymethylcellulose, and dextran sulfate, was measured in an aqueous solution. The effect of alkyl group of the anthraquinone dye on the binding behavior was investigated. Also, the resultant binding characteristics were compared with those previously observed with methyl orange and its homologs. These polyion complexes exhibited very strong binding affinity toward the anthraquinone dye. The polyion complex of the polycation and sodium poly styrenesulfonate bound the dye noncooperatively and the binding process was athermal. The first binding constant accompanying the binding is of the order of 105–106. In contrast, the polyion complexes composed of the polycation and the other polyanions exhibited strong cooperative binding and the binding process was exothermic. The possible mode of binding is discussed.
Rate constants in the photopolymerization of H2O2–isoprene systems
Authors: Chang J. F. , Chang T. C. , Ho S. Y. 
Published: April 2003

AbstractThe polymerization reactions of isoprene with the use of H2O2 as the photoinitiator have been studied in acetone solutions. The lifetime of chain radicals, τs, was evaluated to be 0.29 by the rotating sector technique. The rate constants kp and kt were found to be 19.1 and 3.40 × 107 L/mol‐ s, respectively.
Effect of polycondensation methods on molecular weight distribution of nylon 610
Authors: Arai Yumi , Watanabe Masayoshi , Sanui Kohei , Ogata Naoya 
Published: April 2003

AbstractPolycondensation methods greatly influence the molecular weight distribution of poly(hexamethylene sebacamide) (nylon 610) as determined by gel permeation chromatography (GPC). The ratio of weight average molecular weight to number average molecular weight (Mw/Mn) was used as a measure for estimating the molecular weight distribution. The Mw/Mn ratios of nylon 610 obtained from melt, solid phase, and high temperature polycondensation methods were 2 to 3.5, which were expected values for the most probable distribution. However, those for polymers obtained from the direct polycondensation in the presence of triphenylphosphine, interfacial polycondensation and low temperature polycondensation using an acid chloride varied over a wide range from 3.5 to 8.5. The effect of the kind of organic solvents in the interfacial method on the Mw/Mn ratios was especially large, and the molecular weight distribution could be controlled to some extent by selecting an appropriate solvent.
Oxoaminium salts as initiators for cationic polymerization of vinyl monomers
Authors: Yoshida Eri , Nakamura Kazuaki , Takata Toshikazu , Endo Takeshi 
Published: April 2003

AbstractOxoaminium salt (1), derived from 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO, 2) by one‐electron oxidation, could be an initiator for cationic polymerization of vinyl monomers such as isobutyl vinyl ether (IBVE), 2,3‐dihydrofuran, p‐methoxystyrene, N‐vinyl pyrrolidone, etc., to give the corresponding polymers, when 1 had a low nucleophilic counter anion. Formation of the adducts of 1 and IBVE as well as 1H‐NMR and IR data suggested the formation of polymers containing NOC structure as the polymer head group. In the polymerization of IBVE, the effects of solvent and concentration of 1 were little observed, however the polymerization rate was dependent on temperature. Furthermore, the thermal reaction of the polymers obtained, which were regarded as prepolymers for block copolymerization and polymeric initiators for radical polymerization, was studied. For example, poly(2‐benzylidene‐1,3‐dioxane) obtained by the polymerization of 2‐benzylidene‐1,3‐dioxane with oxoaminium hexafluoroantimonate (1, X = SbF6) was employed as an initiator for radical polymerization of MMA to give its block copolymer with PMMA. © 1993 John Wiley & Sons, Inc.
Preparation and properties of new aromatic polyamides from bis(4‐aminophenyl) phenylphosphine and aromatic dicarboxylic acids
Authors: Yamashita Mitsuhiro , Kakimoto Masa‐Aki , Imai Yoshio 
Published: April 2003

AbstractA new triphenylphosphine‐type monomer, bis(4‐aminophenyl) phenylphosphine, was synthesized starting from p‐bromoaniline and dichlorophenylphosphine. The aromatic polyamides (aramids) containing triphenyphosphine unit in the polymer backbone was prepared by the polycondensation of this diamine with various aromatic diacid chlorides using a low‐temperature solution method in N,N‐dimethylacetamide (DMAc). The aramids having inherent viscosities of 0.4–0.7 dL/g were obtained in quantitative yields. The polymers were amorphous and soluble in various organic solvents such as DMAc, N‐methylpyrrolidone, dimethyl sulfoxide, pyridine, and m‐cresol. Transparent, tough, and flexible films were obtained by casting from the DMAc solutions. The glass transition temperatures of the aramids were in the range of 265–310°C, and the 10% weight loss temperatures were above 400°C in air. © 1993 John Wiley & Sons, Inc.
Multifunctional coupling agents for living cationic polymerization. I. Sodiomalonate anions for vinyl ethers
Authors: Fukui Hiroji , Sawamoto Mitsuo , Higashimura Toshinobu 
Published: April 2003

AbstractA series of multifunctional malonate anions, [Na⊕⊖C(COOEt)2CH2]mC6H6−m(I; m = 2–4), were examined as polymer coupling agents for the living cationic polymerization of vinyl ethers initiated with the hydrogen iodide/zinc iodide (HI/ZnI2) initiating system. The bifunctional anion (2;I, m = 2), 1,4‐[Na⊕⊖C(COOEt)2CH2]2C6H4, terminated living polymers of isobutyl vinyl ether (IBVE) (DPn = 10) almost quantitatively in toluene at −15°C to give coupled living polymers with doubled molecular weights in 96% yield; the dianion 2 was dissolved in tetrahydrofuran containing 18‐crown‐6 for maintaining the solution homogeneous. The yield of the coupled polymers was increased with shorter living chains or in less polar solvents. Also by coupling via 2, ABA block copolymers were obtained from living AB block polymers of IBVE and an ester‐functionalized vinyl ether (CH2CHOCH2CH2OCOCH3). Coupling of living poly(IBVE) with the trifunctional anion (3; I, m = 3) led to tri‐armed polymers in 56% yield, whereas with the tetrafunctional version (4; I, m = 4), only three out of the four anions reacted to give another tri‐armed polymer in 85% yield. © 1993 John Wiley & Sons, Inc.
Polymer‐supported Ziegler–Natta catalyst for the polymerization of isoprene
Authors: Ran Ruicheng 
Published: April 2003

AbstractA polymer‐supported Ziegler–Natta catalyst, polystyrene‐TiCl4AlEt2Cl (PS–TiCl4AlEt2Cl), was synthesized by reaction of polystyrene–TiCl4complex (PS–TiCl4) with AlEt2Cl. This catalyst showed the same, or lightly greater catalytic activity to the unsupported Ziegler–Natta catalyst for polymerization of isoprene. It also has much greater storability, and can be reused and regenerated. Its overall catalytic yield for isoprene polymerization is ca. 20 kg polyisoprene/gTi. The polymerization rate depends on catalyst titanium concentration, mole ratio of Al/Ti, monomer concentration, and temperature. The kinetic equation of this polymerization is:Rp=k[M]0.30[Ti]0.41[Al]1.28, and the apparent activation energy ΔEact= 14.5 kJ/Mol, and the frequency factorAp= 33 L/(mol s). The mechanism of the isoprene polymerization catalyzed by the polymer‐supported catalyst is also described. © 1993 John Wiley & Sons, Inc.
Study of bulk chain coupling reactions. II. Reaction between bisoxazolones and amine‐terminated polyether: Synthesis of polyether‐block‐polyamides
Authors: Acevedo Margarita , Fradet Alain 
Published: April 2003

AbstractThe bulk reactions between 2,2′‐bis(4,4‐dimethyl‐5(4H)‐oxazolone) (B3) or 2,2′‐(1,2‐ethylene)‐bis(4,4‐dimethyl‐5(4H)‐oxazolone) (B4) and amine‐terminated polyether (Jeffamine ED‐900) have been studied by SEC, and 1H‐and 13C‐NMR and the resulting polymers were characterized by DSC and TGA. These chain coupling reactions have been applied to the synthesis of polyether‐block‐polyamides, starting from mixtures of amineterminated polyether and polyamide‐12. High molar mass block copolymers were synthesized in the bulk within 1 h at 200°C and under atmospheric pressure, instead of several hours at 240°C under vacuum for the usual reaction between dicarboxy polyamides and dihydroxy polyethers. No other side reactions than the formation of a very small amount of 2‐imidazolin‐5‐ones has been found. The DSC studies of block copolymers show the existence of a phase separation between the soft (polyether) and hard (polyamide) blocks. © 1993 John Wiley & Sons, Inc.
Liquid crystal‐forming aqueous hydroxypropyl cellulose solutions: Effects of surfactants on the turbidity and shear viscosity
Authors: Suto Shinichi , Iwasawa Ichisuke 
Published: April 2003

AbstractThe effects of type and concentration of surfactant on the turbidity and viscometric behavior for dilute and concentrated aqueous hydroxypropyl cellulose (HPC) solutions were examined. Two anionic surfactants, sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS), caused the cloud point of the dilute system to increase, but a nonionic and two cationic surfactants did not do so markedly. The transmittance for the dilute system increased with surfactant. The transmittance and viscometric behavior for the concentrated system were strongly dependent on the phase of the system: In the single‐phase (isotropic and anisotropic), the transmittance and viscosity increased with SDBS, but, in the biphasic region, the behaviors were not as simple. An attempt was made to explain the transmittance and viscometric behavior in the single‐phase on the basis of the change in apparent molecular weight and in order of HPC molecules. The phase transformation appeared to become less sensitive to temperature with SDBS. © 1993 John Wiley & Sons, Inc.
Synthesis and evaluation of polyimides derived from spirobisindane dietheranhydride
Authors: Chao Herbert S.‐I. , Barren Elizabeth 
Published: April 2003

AbstractPolyimides derived from 5,5′‐[(2,2′,3,3′‐tetrahydro‐3,3,3′,3′‐tetramethyl‐1,1′‐spirobi[1H‐indene]‐6,6′‐diyl)bis(oxy)]bis‐1,3‐isobenzofurandione (spirobisindane dietheranhydride, SBIDA) and 20 plus aromatic diamines were prepared. The weight percentage of cyclic contaminants in each polyimide, estimated by gel permeation chromatography, ranges from 4 to 25%. The amount of cyclics formed in each polyimide depends on the distance and spatial orientation of the two amino groups on the aromatic diamines as well as the rigidity of the diamines. The formation of SBIDA‐containing polyimide was found to be catalyzed by alkali metal ions even when the reaction was conducted in m‐cresol. Thermal stability and glass transition temperature of those SBIDA‐derived polyimides were examined with thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Two promising compositions were scaled up and their mechanical properties were obtained. © 1993 John Wiley & Sons, Inc.
One‐step polymerization of polytrithiocarbonate using phase‐transfer catalyst
Authors: Leung Louis M. , Chan W. H. , Leung Sew Koo 
Published: April 2003

AbstractA series of aliphatic and aromatic polytrithiocarbonates was prepared using a novel “one‐pot” synthesis procedure employing a phase‐transfer catalyst. The starting reagents were either an aliphatic or an aromatic dihalide and an excessive amount of carbon disulfide. The effects of the phase‐transfer catalyst and reaction conditions on yield were studied. The structure and composition of the polymers and reaction side‐products were determined from infrared, ultraviolet, 1H‐NMR spectra, and elemental analyses. The polymers were further characterized by viscosity measurement and thermal analysis. © 1993 John Wiley & Sons, Inc.
Synthesis and characterization of novel photopolymerizable multifunctional 2‐propenyl ether analogues
Authors: Crivello James V. , Suh Dong‐Hack 
Published: April 2003

AbstractMonomers bearing two, three, four, and six cationically polymerizable aryl 2‐propenyl groups were synthesized and characterized. These compounds can be readily prepared by the catalytic isomerization of the corresponding allyl compounds. Strong bases and tris(triphenylphosphine)ruthenium(II) dichloride were used as the catalysts for these isomerizations. A study of the cationic photopolymerizations of these novel monomers was carried out using a diaryliodonium salt photoinitiator. The polymerization involves a stepwise condensation of the monomers followed by an intramolecular ring closure to form polyindanes. The resulting photopolymerized polymers underwent thermal oxidative decomposition at temperatures over 430°C. © 1993 John Wiley & Sons, Inc.
Preparation of amphiphilic polyisobutylenes‐b‐polyethylenamines by mannich reaction. I. Synthesis and characterization of α‐phenololigoisobutylenes
Authors: Jamois Didier , Tessier Martine , Maréchal Ernest 
Published: April 2003

AbstractThe cationic polymerization of isobutylene initiated by 4‐(2‐hydroxy‐2‐propyl)phenol/BCl3 system results mainly in α‐phenol‐ω‐chlorooligoisobutylene; however p‐(2‐chloro‐2,4‐dimethyl‐4‐pentyl)phenol is present in all cases. α‐Methyl‐ω‐chlorooligoisobutylene is formed only when the temperature is below−50°C; it results from initiation by the phenol/BCl3 system. Thermal dehydrochlorination of α‐phenol‐ω‐chlorooligoisobutylene is quantitative and leads to a mixture of isomeric ω‐unsaturated oligoisobutylenes. α‐Methyl‐ω‐phenololigoisobutylene is prepared by the Friedel—Crafts reaction between industrial unsaturated oligoisobutylene and phenol in the presence of SnCl4 at −30°C; the reaction is quantitative between −50 and −30°C degradation takes place. © 1993 John Wiley & Sons, Inc.
Phase behavior of pseudo‐IPN's of polycarbonate‐urethane and polystyrene
Authors: Frisch H. L. , Zhou Peiguang 
Published: April 2003

AbstractThe pseudo‐IPN's of PCU/PS with different Mn and narrow MWD of the linear PS have been synthesized and characterized. The effect of Mn and composition on the phase morphology of the pseudo‐IPN's of PCU/PS has been studied by DSC and SEM. The pseudo‐IPN's with ultra‐high Mn of the linear PS appeared to possess a single Tg and no SEM‐resolvable domains at 35 wt % PS and below. This metastable state may reflect the result of a high extent of entanglement of the linear PS chains with the PCU network and the limited molecular mobility of the linear PS chains with high Mn. © 1993 John Wiley & Sons, Inc.
Synthesis and thermooxidative stability of poly[1,4‐phenylene‐4,4′‐(2,2,2‐trifluoro‐1‐phenylethylidene)bisphthalimide] and other fluorinated polyimides
Authors: Scola Daniel A. 
Published: April 2003

AbstractThe synthesis of a novel polyimide (3F‐PDA) derived from 4,4′‐(2,2,2‐trifluoro‐1‐phenylethylidene]bisphthalic acid anhydride or its diethyl ester and p‐phenylene diamine is described. This material shows unique thermooxidative stability compared with commercially available state‐of‐the‐art polyimides. The optimum monomer stoichiometric ratios of diester to diamine to form a stable 3F‐PDA polyimide were investigated. The studies revealed that diester/diamine ratios greater than 1.000 exhibited the greatest resistance to thermooxidative stability at 371°C in 1 atm of circulating air and at 371°C in 4 atm of flowing air. © 1993 John Wiley & Sons, Inc.
Influence of the structure on thermoset cure kinetics
Authors: Stutz H. , Mertes J. 
Published: April 2003

AbstractThe influence of molecular structure on cure kinetics was studied using a new approach for characterizing the cure kinetics of thermosets in the glass transition region. Reactions in or near the glassy state are controlled by chain mobility, where the whole structural unit undergoes small‐angle oscillation motions around the network link. All structural features affecting the mobility such as stiffness, bulky structures, substitution, symmetry effects, and functionality lead to high segment activation energies and slow final curing. The influence of the segment activation energy on the kinetic curves is also discussed. © 1993 John Wiley & Sons, Inc.
Synthesis, characterization, and kinetic study of compatible SIN's based on diallyl phthalate and epoxy resin
Authors: Lin Mu‐Shih , Yeh Ching‐Chou 
Published: April 2003

AbstractDiallyl phthalate (DAP) was blended with diglycidyl ether of bisphenol A (DGEBA) in various weight ratios: 100/0, 75/25, 50/50, 25/75, and 0/100. These blends were then cured simultaneously with dicumyl peroxide (DCP) and hexahydrophthalic anhydride (HHPA) in conjunction with 2‐cyanoethyl‐4‐methyl immidazole (EMI‐CN, 0.5% as catalyst) to obtain simultaneous interpenetrating polymer networks (SIN's). H‐bonding between DAP and DGEBA was detected with FTIR. The SIN's thus obtained were characterized with rheometric dynamic spectroscopy (RDS) and differential scanning calorimeter (DSC) to check the compatibility of components. Gel fractions were measured with a Soxhlet extractor. Viscosity increases of all SIN's were measured with a Brookfield viscometer at curing temperatures. Conversions of C  C and epoxide versus cure time were monitored with FTIR and kinetic parameters were calculated and discussed. Experimental results revealed that H‐bonding in the DAP/DGEBA blends was evidenced from the shift of the IR band (vc=o) to a lower wave number, as well as the shift of epoxide band (vδ) to a higher wave number. Complete compatibility between DAP and DGEBA was supported from the single damping peak in DRS and single glass transition in DSC for each of SIN's. Cure dynamic DSC showed shifts of exothermic peaks to higher temperatures for all SIN's. During SIN formation, the slower viscosity increases of SIN's were found, compared with pure DAP and pure DGEBA, indicating retarded cure rates for all SIN's. In addition, lower gel fractions of SIN's were observed, indicating incomplete cure of SIN's. The retarded cure rate was further confirmed by kinetic study. Lower rate constants with higher activation energies for all SIN's were found. An effect of network interlock was proposed to account for these findings. © 1993 John Wiley & Sons, Inc.
Light‐induced polymerization of new highly reactive acrylic monomers
Authors: Moussa K. , Decker C. 
Published: April 2003

AbstractAcrylic monomers containing an oxetane, dioxolane, oxazolidone or carbonate group in their structural unit have been shown to copolymerize rapidly and extensively with a polyurethane‐diacrylate, upon UV radiation. For the most reactive resin, 50% conversion was reached within 3 ms of exposure to a medium‐pressure mercury lamp. The kinetics of these ultrafast polymerizations was studied quantitatively by infrared spectroscopy. The rate of polymerization, photosensitivity, and amount of residual acrylate in the cured polymer were determined for the various monomers studied, and compared to the values obtained with conventional mono‐, di‐, and triacrylates. The functional group introduced into the monomer unit was shown to have a drastic effect on both the reactivity and the physical characteristics of the photocrosslinked polymer. Soft and highly flexible low‐modulus polymers were produced with the oxetane, dioxolane, and chlorinated monomers, while the carbonate‐acrylate compounds lead to hard and glassy materials. © 1993 John Wiley & Sons, Inc.
Studies on the thermotropic liquid crystalline polycarbonates. II. Synthesis and properties of fully aromatic liquid crystalline polycarbonates
Authors: Sun Shih‐Jieh , Chang Teh‐Chou 
Published: April 2003

AbstractFour series of fully aromatic polycarbonates were prepared by using melt polycondensation from various novel phenylene diphenyl dicarbonates: 1,4‐phenylenc diphenyl dicarbonate, 1,3‐phenylene diphenyl dicarbonate, methyl‐1,4‐phenylene diphenyl dicarbonate, and chloro‐1,4‐phenylene diphenyl dicarbonate with various diols—4,4′‐biphenyl diol, hydroquinone, 2,7‐naphthalene diol and 1,5‐naphthalene diol, respectively. The thermotropic liquid crystalline properties of synthesized polycarbonates were investigated by: (1) examination of the melt birefringence and stir opalescence by a polarizing microscope equipped with a heating stage, (2) characterization by a differential scanning calorimeter (DSC), and (3) analysis of the wide angle x‐ray diffraction. It was found that the 1,3‐phenylene unit is compensated for the nonlinearity of the carbonate group, and polycarbonates which contain this bent shape unit showed excellent wide mesophase transition in this study. © 1993 John Wiley & Sons, Inc.
Synthesis, characterization and thermooxidative stability of addition polymers from 1,4,5,8‐tetrahydro‐1,4;5,8‐diepoxyanthracene and anthracene end‐capped imide oligomers
Authors: Scola Daniel A. 
Published: April 2003

AbstractA series of Diels–Alder addition‐type copolymers prepared from 1,4,5,8‐tetrahydro‐1,4;5,8‐diepoxyanthracence and anthracene end‐capped 6F‐PDA imide oligomers were characterized. The composition of the anthracene end‐capped imide oligomers was found to be sensitive to monomer molar ratios and the mode of monomer addition. The resistance of the copolymer to thermooxidative degradation at 316 and 371°C was compared with a similar commercial polymer called Avimid‐N prepared from 4,4′‐hexafluoroisopropylidene‐2,2′ bis(phthalic acid anhydride) and para‐and meta‐phenylene diamine, abbreviated 6F‐PDA. There are strong indications that the copolymers undergo degradation initially by unzipping the diepoxyanthracene unit from the anthracene end‐capped 6F‐PDA oligomer unit (Avimid‐N like repeat unit), followed by a slower degradation of the more stable residual 6F‐PDA unit. © 1993 John Wiley & Sons, Inc.