bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and free radical polymerization of 2‐methylene‐7‐oxabicyclo[2.2.1]heptane
Authors: Bai Ru‐Ke , Li Shi‐Hua , Wu Cheng‐Pei , Zou Ying‐Fang , Pan Cai‐Yuan , Uryu Toshiyuki 
Published: April 2003

AbstractA new monomer, 2‐methylene‐7‐oxabicyclo[2.2.1]heptane (IV) was synthesized via four steps. Its structure was confirmed by IR, 1H‐NMR, and 13C‐NMR spectra as well as elementary analysis. Free radical polymerization and copolymerization of IV were investigated. No homopolymer was obtained due to the effect of allyl inhibition. When IV copolymerized with electron‐donor monomers, such as vinyl acetate and stvrene, IV acted as inhibitor for the polymerization of vinyl acetate, but could not inhibit the polymerization of styrene. However, the copolymers of IV with electron‐accepting monomers, such as methyl methacrylate, acrylonitrile, or maleic anhydride (MA) were obtained. The contents of IV in the copolymers increased as e values of electron‐accepting monomers increased. Strictly alternating copolymer was obtained only in the case of MA and IV. The thermal properties of copolymers were investigated. © 1995 John Wiley & Sons, Inc.
Copolymerization of ethylene/carbon monoxide by a cationic hydridoaquopalladium complex
Authors: Valli V. L. K. , Alper H. 
Published: April 2003

AbstractThe cationic hydridoaquopalladium (II) complex, trans‐[(PCy3)2Pd(H)(H2O)]+BF−4, is an excellent catalyst for the ethylene/carbon monoxide alternating copolymerization in the presence of a bidentate phosphorus ligand and p‐toluenesulphonic acid. © 1995 John Wiley & Sons, Inc.
Control of hard segment size in polyurethane formation
Authors: Lai Yu‐Chin , Quinn Edmond T. , Valint Paul L. 
Published: April 2003

AbstractIn general, segmented polyurethane elastomers are prepared by reacting an isocyanate‐capped polyol prepolymer with a short‐chain diol chain extender, yielding an elastomer with hard segments of uniform size. However, the hard segment size will not be uniform if the polyurethane polymer is prepared by forming the hard segment first, followed by soft segment formation. Because the mechanical properties of polyurethane elastomers depend on the relative ratio of the hard to soft segments as well as the effectiveness of the hard segment as a physical crosslinker, the control of the size distribution of the hard segment is a key factor in designing polyurethane elastomers. It was found that reaction conditions can affect the size distribution of hard segments derived from an aliphatic diisocyanate with differential reactivity between the two isocyanate groups. Lower reaction temperatures and simultaneous mixing of all reactants gave the preferred size distribution of hard segments. © 1995 John Wiley & Sons, Inc.
Ring‐opening metathesis polymerization of 9‐phenyl‐1,5‐cyclododecadiene
Authors: Cho Iwhan , Moon Gyeong Sik 
Published: April 2003

AbstractSynthesis of butadiene‐based sequence‐controlled copolymers that are composed of commercial monomers such as styrene, butadiene, and ethylene was investigated. New substituted cyclododecadiene derivatives, 9‐phenyl‐1,5‐cyclododecadiene was synthesized by reductive‐phenylation method from 1,5‐cyclododecadiene‐9‐one and was polymerized with tungsten‐based catalyst systems to obtain a microstructure‐controlled terpolymer. A sequence‐controlled 2 : 1 : 1 terpolymer of butadiene, styrene and ethylene was successfully synthesized. The glass transition of the terpolymer occurred at −33.6°C. © 1995 John Wiley & Sons, Inc.
Perfluorocyclobutane aromatic ether polymers. II. Thermal/ oxidative stability and decomposition of a thermoset polymer
Authors: Kennedy Alvin P. , Babb David A. , Bremmer Jeffrey N. , Pasztor Andrew J. 
Published: April 2003

AbstractThe results of thermal and oxidative stability studies are reported for one perfluorocyclo‐butane aromatic ether thermoset polymer. The polymer was prepared from 1,1,1‐tris (4‐trifluorovinyloxyphenyl)ethane by the thermal cyclodimerization of the trifluorovinyl either functionality, resulting in a network polymer comprising alternating perfluorocy‐clobutane and aromatic either groups. The results of isothermal and dynamic thermal gravimetric analysis (TGA) studies are reported with kinetic approximations for de‐composition in nitrogen, along with FTIR studies of the oxidative process in air and TGA/mass spec determination of the gasses evolved from decomposition in air. Based on these results, thermal and oxidative decomposition mechanisms are proposed. © 1995 John Wiley & Sons, Inc.
Polymerization of [o‐n‐(perfluorohexyl)phenyl]acetylene and polymer properties
Authors: Seki Hiroyuki , Masuda Toshio 
Published: April 2003

AbstractSynthesis, properties, and membrane‐separation functions of a novel fluorine‐containing poly(phenylacetylene) were examined. The monomer used was [o‐n‐(perfluorohexyl)phe‐nyl]acetylene, which has a rigid rod‐like ortho‐substituent. Polymers, whose intrinsic vis‐cosities ([η]) were ca. 0.4–2.2 dL/g, were obtained in high yields with various W and Mo catalysts. The MoCl5–Ph3Sb catalyst achieved the highest [η] of 2.25 dL/g corresponding to an Mw over one million. The polymer was a brown solid soluble only in F ‐containing solvents such as m‐(CF3)2C6H4. The oxygen permeability coefficient of the polymer mem‐brane was 90 barrers, which is the second highest among those of ortho‐substituted poly(phenylacetylenes). In the pervaporation of an ethanol–water mixture, the poly‐mer membrane showed ethanol permselectivity [α(EtOH/H2O) = 1.7]. © 1995 John Wiley & Sons, Inc.
Tandem GC/MS: A useful tool for studying end‐capping reactions of oligo(styryl)lithium anions
Authors: Brestensky Donna M. , Hoye Thomas R. , Macosko Christopher W. 
Published: April 2003

AbstractAnionic living polymerization methods, using organometallic initiators such as butyllithium reagents, have proven useful for, inter alia, styrene polymerization and are amenable to subsequent functionalization of poly(styryl)lithium in the termination step. In this study, general methods for the selective preparation of small styrene oligomers and termination of the intermediate oligo(styryl)lithium anions were investigated. The crude reaction mixtures were analyzed directly by tandem gas chromatography/mass spectrometry (GC/MS). Of the carbon‐ and silicon‐based electrophiles tested, chloro(chloroalkyl)silanes, Cl‐SiR2(CH2)nCl in particular, were shown by GC/MS to be regioselective end‐capping reagents, thus allowing subsequent transformation to the primary amine. The combined GC/MS data allow not only an estimate of the degree of functionalization, but also the identification of by‐products, thus providing insight into the end‐capping process that otherwise might be difficult to access. © 1995 John Wiley & Sons, Inc.
Main chain scission reaction of poly(methyl methacrylate) caused by two‐photon ionization of dopant
Authors: Sakai Wataru , Tsuchida Akira , Yamamoto Masahide , Yamauchi Jun 
Published: April 2003

AbstractThe main chain scission reaction of poly(methyl methacrylate) (PMMA) doped with N,N,N,′,N′‐tetramethyl‐p‐phenylenediamine (TMPD) was examined by ESR spectroscopy and GPC measurement, and the scission mechanism was analyzed. The two‐photon ionization of TMPD with excimer laser excitation at 77 K produced an ester radical anion of PMMA (PMMA·m̌), which becomes the main chain tertiary radical CH2C˙(CH3)CH2after the detachment of the ester side group by annealing of the sample at room temperature. The main chain scission radical ˙C(CH3)(COOCH3)(PMMA˙) which was produced by the β‐scission fromCH2˙C(CH3)CH2showed the 13‐line ESR spectrum instead of the ordinary 9‐line, due to the fast quenching of the sample to 77 K. The change of the molecular weight distribution was measured by GPC after several irradiation‐and‐annealing operations. The simulation of the GPC curve confirmed that the scission re‐action occurs at random in the PMMA chain in the solid and the main chain scission yield from the ester radical anion, [PMMA˙]/[PMMA·m̌], is 0.30. © 1995 John Wiley & Sons, Inc.
Synthesis of monodisperse polyamides by living anionic polymerization of β‐lactams in the mixture of N,N‐dimethylacetamide and lithium chloride
Authors: Hashimoto Kazuhiko , Hotta Koji , Okada Masahiko , Nagata Shiro 
Published: April 2003

AbstractLiving anionic polymerization of two kinds of methyl‐substituted β‐lactams, 3,3‐dimethyl‐, and 4,4‐dimethyl‐2‐azetidinones, was attained at 25°C in N,N‐dimethylacetamide containing 5 wt % of lithium chloride and proceeded in a homogeneous phase quantitatively. The resulting polyamides were found to have a narrow molecular weight distribution from the gel permeation chromatography. The number average molecular weights estimated from the peak intensities in the 1H‐NMR spectra were almost equal to those calculated from the mol ratio of the consumed lactam to the corresponding N‐benzoyl derivative used as an activator. In addition, the acyllactam‐type growing chain ends were modified quantitatively by the reaction with benzylamine after the polymerization. © 1995 John Wiley & Sons, Inc.
Surface modification of aromatic polyamide film by oxygen plasma
Authors: Inagaki N. , Tasaka S. , Kawai H. 
Published: April 2003

AbstractThe surface of poly(p‐phenylene terephthalamide) (PPTA) films was modified by oxygen plasma, and the modified film surface was analyzed by an advancing contact meter and X‐ray photoelectron spectroscopy (XPS). The advancing contact measurement showed that the oxygen plasma treatment made the surface of the PPTA film hydrophilic. The XPS analyses also showed the increase in the O/C and N/C atom ratio, especially the O/C atom ratio, at the PPTA film surface by the oxygen plasma treatment. A main oxygen functionality formed by the oxygen plasma treatment is a carboxylic acid group, and a main nitrogen functionality formed is a protonated amino group. The formation of the oxygen and nitrogen functionalities formed by the oxygen plasma treatment is not restricted to the surface of the PPTA film, but penetrates at least 35 Å deep from the film surface. The formation of these carboxylic acid and protonated amino groups is a result of the bond scission of the amide linkages in the PPTA film. Interactions of photons in the oxygen plasma rather than interactions of electrons and activated oxygen atoms contribute greatly to the bond scission. © 1995 John Wiley & Sons, Inc.
Graft polymerization of acrylamide onto LLDPE film by electron beam pre‐irradiation in air and argon. II. Influence of mohr's salt
Authors: Wirsén A. , Albertsson A.‐C. 
Published: April 2003

AbstractLLDPE film pre‐irradiated by electron beam (EB) in air and argon was grafted in an aqueous acrylamide solution containing Mohr's salt in the concentration range 0.0025–2% The grafting rate and yield were strongly dependent on the Mohr's salt concentration, mainly as a result of chain termination. The exponential grafting rate dependence on the pre‐irradiation dose was quite insensitive to a hundred‐fold variation in Mohr's salt concentration. © 1995 John Wiley & Sons, Inc.
Studies on thermotropic liquid crystalline elastomers. II. Synthesis and properties of liquid crystalline polyester elastomers
Authors: Sun Shih‐Jieh , Chang Teh‐Chou 
Published: April 2003

AbstractThree series of novel thermotropic liquid crystalline polyester elastomers (TLCPEEs) were prepared by direct polycondensation from terephthalic acid, polyols (Mn = 1000 or 2000), and various diols. The structures and thermal properties of the synthesized TLCPEEs were examined by FTIR spectroscopy, differential scanning calorimetry, thermal optical polarized microscopy, thermogravimetric analysis, and wide‐angle x‐ray diffraction. The effects of kinds and amount of diols and the molecular weight of polyols on the thermal properties of TLCPEEs were studied. By introducing long flexible spacers (PE‐1000 or PE‐2000) into the polymer main chain, all polymers showed two‐phase morphology under the thermal optical microscopic observation. All of the synthesized polymers, except polymer P1‐BPA60 and P2‐BPA60, which were prepared from BPA, exhibited thermotropic liquid crystalline properties that were in the smectic phase. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of poly(cyclohexane 2,2‐dipropargyl‐1,3‐propylene ketal) containing double spiro structure
Authors: Kwon Soon‐Ki , Kim Yun‐Hi , Choi Sam‐Kwon 
Published: April 2003

AbstractThe Polymerization was carried out by MoCl5 and WCl6 associated with various organo‐metallic cocatalysts. MoCl5‐based catalysts were found to be more effective. Polymerization of monomer containing a spiro structure proceeded rapidly to reach 80% yield within 2 h at 30°C. Polymerization of monomer led to a soluble, purple colored polymer with number average molecular weight (Mn) of 50000. Elemental analysis, 1H‐NMR, 13C‐NMR, IR, and UV‐visible spectra of the resulting polymer indicated that the polymer contains alternating double and single bonds along the polymer backbone and a cyclic recurring unit with a double spiro structure. In addition, the polymer had good oxidative and thermal stability and good solubility in common organic solvents. © 1995 John wiley & Sons, Inc.
Synthesis of aromatic polyesters having pendant carboxyl groups in the side chains and conversion of the carboxyl groups to other reactive groups
Authors: Wang Chonghui , Nakamura Shigeo 
Published: April 2003

AbstractAromatic polyester, copolyester, and poly(ester‐amide‐thioester) having pendant carboxyl groups are directly synthesized by the organic phase/water phase interfacial polyconden‐sation using low‐molecular and polymeric phase transfer catalysts. Spectral analysis of the resulting polymers indicates that the nucleophilicity of salts of phenols to diacid chloride is far higher than that of salts of carboxylic acids and chemoselective esterification occurs in a 100% yield. Even if the polymeric catalyst having amino acid moiety as a nucleophilic group is used in the polycondensation, the polymers do not contain anhydride groups. The polyester can be almost quantitatively converted to polymers with different reactive groups by reacting the pendant carboxyl groups with alkyl halides in a DMAc‐H2O mixture con‐taining K2CO3. A bifunctional catalytic mechanism is proposed for the chemical modification of the polyesters. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of polyyne polymer containing nickel in the main chain
Authors: Yang Mujie , Zhang Lingjun , Cai Zhigang , Yang Peiqing , Xu Zhiling 
Published: April 2003

AbstractThe synthesis of the nickel dialkynyl complex Ni(CCC6H4CCH)2(PPh3)2 and of the corresponding polyyne polymer containing nickel in the main chain [Ni(PPh3)2CCC6H4CC]n are described and discussed. A new mixed solvent system DMSO/HNEt2 and homogeneous step‐wise condensation method used for their synthesis are presented for the first time. The Ni‐polyyne polymer obtained is dark yellow powder and soluble in THF or CH2Cl2. Its M̄w is about 104, and the MWD is less than 2. Both the prepared complex and polymer have been characterized by IR, UV, 1H‐NMR, and DTA. Preliminary results on photoluminesence of nickel polyyne polymers are present. © 1995 John Wiley & Sons, Inc.
LC polyimides. XXI. Thermotropic poly(amide‐imide)s based on trimellitimides
Authors: Kricheldorf Hans R. , Gurau Mihai 
Published: April 2003

AbstractPolycondensation of α, ω‐bis(‐4‐aminophenoxy) alkanes with trimellitic anhydride chloride (TMA‐Cl) in m‐cresol yielded a new class of poly(amideimide)s. Starting from the same diamine spacers poly(amideimides) with a more regular sequence of amide and imide groups were prepared by another synthetic method. All these poly(amide‐imide)s are semi‐crystalline and melt in the range of 250–300°C. They form a smectic‐A phase over a narrow temperature range and suffer thermal degradation at the isotropization temperature (330–350°C). The smectic‐A phase was characterized by optical microscopy (“batonnet texture”) and by synchrotron radiation measurements conducted at a heating rate of 20°C. Furthermore, it is demonstrated that slight variation of the chemical structure, such as methyl substituents or meta positions in the spacer prevent the formation of a LC phase. © 1995 John Wiley & Sons, Inc.
A mass spectrometric investigation of the water‐soluble oligomers remaining after the emulsion polymerization of methyl methacrylate
Authors: Thomson Barry , Wang Zhiyu , Paine Anthony , Lajoie Gilles , Rudin Alfred 
Published: April 2003

AbstractA “surfactant‐free” emulsion polymerization of methyl methacrylate was conducted at 80°C with ammonium persulfate initiator. The water‐soluble MMA‐based oligomers re‐maining were isolated and analyzed both as‐produced and after hydrolysis. NMR analysis revealed that the mole ratio of MMA repeat units to sulfate end groups in the former is 6.5. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and gel permeation chromatography both showed that the mean number of MMA repeat units comprising the extracted material is 8–9. The hydrolysis procedure rids the oligomers of their terminal groups and converts some of the methyl ester groups to acid, greatly sim‐plifying the mass spectrum. This appears to be the first direct measurement of “surfactants” produced in situ from monomer and persulfate initiator. © 1995 John Wiley & Sons, Inc.
Kinetics of competitive polymerization in bidisperse seed systems using oil‐soluble initiators: Calculation of effect of various dimensionless parameters
Authors: Mørk P. C. 
Published: April 2003

AbstractExpressions for calculating the stationary state distribution of radicals in a bidisperse seed system initiated by oil‐soluble initiators were developed. Dimensionless parameters were used throughout, thus making it possible to obtain general trends without introducing specific numerical values. Desorption and reabsorption of radicals, aqueous phase termi‐nation, partition of the initiator into the aqueous phase, and a possible generation of single radicals are taken into account. The radical entry and exit rate coefficients are formulated in terms of power laws with respect to particle diameter. No discrimination of the various radical species and their origin is made. The derivation is based on a probabilistic stationary state analysis leading to third‐order recurrence relations that are solved using confluent, hypergeometric Kummer functions. A selection of curves illustrating the effect of various dimensionless parameters on the calculated average number of radicals per particle, the order of volume growth with respect to the particle diameter, and relative rates are given. © 1995 John Wiley & Sons, Inc.
Aliphatic‐aromatic copolycarbonates derived from 2,2,4,4‐tetramethyl‐1,3‐cyclobutanediol
Authors: Geiger Carey Cecil , Davies Jack D. , Daly William H. 
Published: April 2003

AbstractThe synthesis of copolycarbonates with high aliphatic contents for possible applications as optical plastics is described. Copolymers of 2,2,4,4‐tetramethyl‐1,3‐cyclobutanediol (TMCBD) with a series of 14 bisphenol derivatives were prepared and characterized. The refractive index of these materials varies from 1.49 for the 2,2‐hexafluoropropane substituted copolymer to 1.57 for the 9,9‐fluorene substituted copolymer; thus, all of the copolymers exhibit lower refractive indices than the bisphenol A homopolycarbonate. The glass tran‐sition temperatures of the copolymers vary from 110 to 210°C; the beta transition tem‐peratures vary from ‐70 to 0°C when measured at 10 Hz by dynamic mechanical analysis. The copolymers exhibited good thermal stability (0–3% weight loss) when heated above the glass transition temperature, and only undergo extensive decomposition (80–90%) at 300–360°C. © 1995 John Wiley & Sons, Inc.
Effect of aggregation of p‐phenylphenol on enzymatic polymer synthesis in dioxane/water mixture
Authors: Liu W. , Ma L. , Wang J. D. , Jiang S. M. , Cheng Y. H. , Li T. J. 
Published: April 2003

AbstractThe state of p‐phenylphenol molecules in dioxane/water mixture, a commonly used reaction system for enzymatic polymerization of phenols and aromatic amines, was investigated by difference UV absorption spectroscopy and Fourier transform (FT) Raman spectroscopy. The aggregate of p‐phenylphenols is found on the basis of the exciton peaks observed in difference UV absorption spectra. FT Raman spectroscopy demonstrates further that p‐phenylphenol molecules aggregate together in “face to face” fashion. A simplified model is proposed for aggregation of p‐phenylphenol molecules in dioxane/water mixture, which can elucidate the variation of the molecular weight of poly (p‐phenylphenol) coupled in the reaction system. © 1995 John Wiley & Sons, Inc.
Synthesis and crosslinking of poly (aryl ether)s containing 1,1‐diphenylethylene moieties
Authors: Gao Chunping , Hay Allan S. 
Published: April 2003

AbstractPoly (aryl ether)s containing the diphenylethylene moiety, synthesized from 1,1‐bis(4‐fluo‐rophenyl)ethylene or 1,1‐bis(4‐hydroxyphenyl)ethylene, are thermally crosslinkable. Char‐acterization and crosslinking studies of these polymers were carried out by GPC, DSC, TGA, and NMR. The solvent resistance and Tg's of the resulting crosslinked networks increase after crosslinking. Thermogravimetric analysis shows that no significant mass loss accompanies the crosslinking reaction. © 1995 John Wiley & Sons, Inc.
Synthesis of new ethynylene‐containing aromatic polyamides by palladium‐catalyzed polycondensation of aromatic diiodides with aromatic diethynyl compounds having amide units
Authors: Watanabe Shinji , Tanabe Masaru , Jikei Mitsutoshi , Kakimoto Masa‐Aki , Imai Yoshio 
Published: April 2003

AbstractNew ethynylene‐containing aromatic polymides were synthesized by the carbon–carbon crosscoupling polycondensation of aromatic diiodides with aromatic amide‐bearing diethynyl compounds in the presence of a palladium catalyst, cuprous iodide, and an organic base. The polymers having sulfone linkages were soluble in various organic solvents and their weight average molecular weights were in the range of 12,500 and 26,500. The polymers with the highest inherent viscosity were obtained, when the monomer ratio of a diethynyl compound to a diiodide was 1.01. The polymers showed no detectable glass transition temperature and no weight loss up to around 300° C in nitrogen. The thermal crosslinking of the polymers occurred at 280°C through the existing internal ethynylene group. © 1995 John Wiley & Sons, Inc.
Addition polymerization of 2‐cyano‐1, 4‐benzenedithiol to 1,4‐diethynylbenzene and properties of polymers
Authors: Kobayashi Eiichi , Yoshino Toshizumi , Aoshima Sadahito , Furukawa Junji 
Published: April 2003

AbstractA novel addition polymerization of 2‐cyano‐1,4‐benzenedithiol to 1,4‐diethynylbenzene was carried out by UV irradiation in toluene at 50°C under nitrogen atmosphere. The polymerization proceeded readily, and a pale‐yellowish conjugated polymer contain‐ing sulfur atoms and cyano groups (M̄n = 20,400–80,800) was obtained in a 60–80% yield for 120–250 min. The polymer was found to be 1 : 1 alternating structure of anti‐Markownikoff's type and was insolu‐ble in conventional organic solvents. Since the polymer having molecular weight of the order of 104 had a softening point at 115°C, a thin polymer film was obtained by heat press. TG analysis of the polymer indicated its decomposition point at about 620°C under argon atmosphere. The electrical conductivity of the polymer pellet was 10−10 S/cm at 300 K without doping and on the order of 10−5 S/cm on I2 doping. Fur‐thermore, the electrical conductivity of the undoped polymer pellet reversibly changed from the order of 10−10 S/cm at 300 K to 10−7 S/cm at 435 K with temperature variation, accompanying with increasing carrier density and mobility. The polymer pellet (M̄n = 80,800) aged at 250°C for 5 min under nitrogen atmosphere exhibited the order of 10−7 S/cm at 300 K. Thermal treatment of the polymers was thought to cause spreading of conjugated system through molecular rearrangement supported by x‐ray diagrams. An absorption edge of diffuse reflectance spectra of the polymer (M̄n = 80,800) was 635 nm and shifted to 880 nm by heat treatment of the polymer. © 1995 John Wiley & Sons, Inc.