bluuebunny/crossref_metadata_2025_split huggingface dataset:
Model filled polymers. V. Synthesis of crosslinked monodisperse polymethacrylate beads
Authors: Zou D. , Ma S. , Guan R. , Park M. , Sun L. , Aklonis J. J. , Salovey R. 
Published: April 2003

AbstractMonodisperse polymethacrylate beads of varied size and crosslink density are prepared by emulsion copolymerization of methacrylate and divinyl monomers in the absence of emulsifiers. The sizes of polybutyl and polyethyl methacrylate beads decreased with increasing polymerization temperature, while polymethyl methacrylate beads were largely unchanged in size. The molar mass of polymer in polymethyl metnacrylate beads markedly exceeded that in polystyrene beads. The rate of polymerization increased, and bead size decreased, with increasing initiator concentration or decreasing monomer concentration. The polymethacrylate beads are used as filler particles in polymer composites.
Emulsifier‐free emulsion copolymerization of styrene and sodium styrene sulfonate
Authors: Kim J. H. , Chainey M. , El‐Aasser M. S. , Vanderhoff J. W. 
Published: April 2003

AbstractThe kinetics of the emulsifier‐free emulsion copolymerization of styrene and sodium styrene sulfonate have been examined over a range of comonomer compositions. The rate of polymerization was found to increase dramatically in the presence of small amounts of sodium styrene sulfonate. This increase is attributed to the increased number of particles formed when sodium styrene sulfonate was present and to a gel effect enhanced by ion association. At low concentrations of functional comonomer, where a monodisperse product was obtained, a homogeneous nucleation mechanism of particle generation is proposed. At higher concentrations, broader and then bimodal size distributions were obtained, and this is ascribed to significant aqueous phase polymerization of sodium styrene sulfonate. The water‐soluble homopolymer is supposed to act as a locus of polymerization. The occurrence of this aqueous phase side reaction and the generation of secondary particles makes impossible the preparation of highly sulfonated polystyrene latexes by batch or seeded batch emulsion copolymerization.
Synthesis of block copolymer containing dextran and polyamide sequences
Authors: Hashimoto Kazuhiko , Imanishi Shin‐Ichiro , Okada Masahiko , Sumitomo Hiroshi 
Published: April 2003

AbstractA novel AB‐type block copolymer composed of dextran and polyamide sequences was prepared through the following two approaches. One is a coupling reaction of a terminal functional group introduced in the dextran chain with that in the polyamide chain, such as the reaction of an amine group with an acyllactam group or that of a lactone group with an amine group at the corresponding chain ends. The other is an anionic polymerization of a bicyclic lactam activated with a trimethylsilylated dextran derivative having an acyllactam end group. The latter procedure was found to be more effective for the preparation of the block copolymer having a high molecular weight polyamide sequence.
Novel conjugated polymer containing aromatic ring and selenium in backbone: Addition polymerization of 1,4‐benzenediselenol to 1,4‐diethynylbenzene
Authors: Kobayashi Ellchl , Metaka Nobuki , Aoshima Sadahito , Furukawa Junji 
Published: April 2003

AbstractA novel addition polymerization of 1,4‐benzenediselenol (BDSe) to 1,4‐diethynylbenzene (DEB) was carried out by UV‐irradiation in toluene at 60°C under nitrogen atmosphere. The polymerization proceeded at such a fast rate as to give 60–70% yield for 6 min. A paleyellowish polymer (M̄n = 20000–30000) precipitated with the progress of the polymerization. In the presence of BPO, the polymerization also proceeded rapidly to give the polymer (M̄n = 18000) in 50% yield for 4 min. The polymer magnified image was insoluble in conventional organic solvents. In the IR spectrum of the polymer, the characteristic absorption bands of cis‐ and trans‐vinylene groups appeared at 1340 and 940 cm−1, respectively. The microstructures of polymers were evaluated as the cis content was 90% and the trans one was 10%, based on the model adducts of benzeneselenol and ethynylbenzene. The cis ← trans isomerization occurred with UV‐irradiation: the cis vinylene group of the polymer decreased from 90 to 40% for 18 h. The electrical conductivity of the polymer was in the order of 10−13 S/cm without dopant, but increased up to 10−5 S/cm on I2 doping. DSC and TG thermograms of the polymer indicated its decomposition point as 465°C under nitrogen atmosphere.
Synthesis and characterization of monodisperse porous polymer particles
Authors: Cheng C. M. , Micale F. J. , Vanderhoff J. W. , El‐Aasser M. S. 
Published: April 2003

AbstractMonodisperse porous polymer particles in the size range of 10 μm in diameter were prepared via seeded emulsion polymerization. Linear polymer (polystyrene seed) or a mixture of linear polymer and solvent or nonsolvent were used as inert diluents. The pore diameters of these porous polymer particles were on the order of 1000 Å with pore volumes up to 0.9 mL/g and specific surface areas up to 200 m2/g. The physical features of the porous polymer particles depended on the diluent type and the crosslinker content, as well as the molecular weight of polymer seed particles. By varying the molecular weight of the linear polymer, monodisperse porous polymer particles with different pore size distribution could be synthesized. Polymer seed with a low degree of crosslinking instead of linear polymer could also be used to prepare monodisperse porous polymer particles with smaller pore volume and pore size.
Monodisperse porous polymer particles: Formation of the porous structure
Authors: Cheng C. M. , Vanderhoff J. W. , El‐Aasser M. S. 
Published: April 2003

AbstractMonodisperse porous styrene‐divinylbenzene copolymer particles were prepared via seeded emulsion polymerization using a mixture of linear polymer (polystyrene seed) and non‐solvent as inert diluent. Experimental evidence was presented to describe the mechanism of formation of porous polymer particles during the copolymerization and solvent extraction stages, in which porosity was a consequence of phase separation in the presence of diluents. Pore structure formation was investigated by changes in copolymerization kinetics, gel content, crosslinking density, particle morphology, surface area, pore volume, and pore size distribution. The process of copolymerization was presented, based on the concepts of production, agglomeration, and fixation of the interior gel microspheres of polymer particles. A portion of linear polymer used as diluent was found to participate in the network structure while the porous matrix was built‐up. The influence of the removal of the linear polymer from the matrix pores during the solvent extraction process on the porous structure was also discussed.
Photocatalytic production of hydrogen peroxide using polymer bound anthraquinone. I. Photoproducts in 2‐hydroxyethyl methacrylate hydrogels swollen with water and 2‐propanol
Authors: Foyle Victor P. , Takahashi Yoshiyuki , Guillet James E. 
Published: April 2003

AbstractPhotoreductions of polymer‐bound anthraquinone in degassed water‐ and 2‐propanolswollen 2‐hydroxyethyl methacrylate hydrogel films were performed at 313 and 334 nm, and in sunlight for the water‐swollen system. The quantum yield at 334 nm for production of anthrahydroquinone was 0.31 in water and 0.94 in 2‐propanol. Results at 313 nm were very similar. A reversible oxygen insensitive side product, indentified as 10‐hydroxyanthrone, was produced simultaneously to the anthrahydroquinone in water‐swollen films, but not for 2‐propanol. A small amount of irreversible side product, believed to be hydroxylated anthraquinone, was also formed in the water system. A photochemical reaction scheme is suggested to account for these observations. Hydrogen peroxide production from photoreduction‐reoxidation cycling of the hydrogels is reported.
Remote nitrogen plasma treatment of polymers: Polyethylene, nylon 6,6, poly(ethylene vinyl alcohol), and poly(ethylene terephthalate)
Authors: Foerch R. , Hunter D. H. 
Published: April 2003

AbstractA remote nitrogen plasma has been used for the rapid attachment of nitrogen to linear low density polyethylene, nylon 6,6, poly(ethylene vinyl alcohol), and poly(ethylene terephthalate). Analysis was performed using X‐ray photoelectron spectroscopy to investigate the chemistry occurring on the surface. Nitrogen appeared to attach to the polymer chain at specific sites rather than uniformly over the whole chain as seen by the formation of high binding energy components and the continuously high intensity of the hydrocarbon component.
13C‐NMR Study of Anomalous Linkages in Polyurethane
Authors: Kaji Atsushi , Arimatsu Yosikazu , Murano Masao 
Published: April 2003

AbstractSeveral kinds of model compounds for anomalous linkages in polyurethanes (branching or crosslinking; allophanate and biuret) were prepared. The phenylisocyanate (PHI) based models were identified by IR and NMR. The 13C‐NMR chemical shifts effects due to the anomalous linkages were determined. The 4,4′‐diphenylmethane diisocyanate (MDI) based models were purified incompletely but the characteristic signals of the aromatic carbons were nevertheless found in their spectra. Two types of segmented polyurethane (SPU) were prepared and the anomalous linkages were investigated by 13C‐NMR. The signals due to the allophanate (Al) and the triphenylbiuret (TB) linkages were observed in the spectra of the SPU prepared at high temperature (>80°C) or prepolymer gels yielded by abnormal reaction. A small signal due to a phenyl carbon of biuret (Bi) linkage was observed even in a normally prepared SPU (polyetherurethane‐urea). Employing the phenyl carbon signals was advantageous for the determination of anomalous linkages because of their larger intensities.
Processing studies and thermal stability of addition polymers from 1,4,5,8‐tetrahydro‐1,4;5,8‐diepoxyanthracene and Bis‐dienes
Authors: Meador Mary Ann B. , Malarik Diane C. , Olshavsky Michael A. 
Published: April 2003

Abstract1,4,5,8‐Tetrahydro‐1,4;5,8‐diepoxyanthracene reacts with various anthracene end‐capped polymide oligomers to form Diels‐Alder cycloaddition copolymers. The polymers are soluble in common organic solvents, and dehydrate thermally at temperatures of 300–350°C to give thermal oxidatively stable pentiptycene units along the polymer backbone. Because of their high softening points and good thermal oxidative stability, the polymers are candidates for matrix resins for high temperature composite applications. To assess their usefulness for such applications, several parameters have been studied affecting the properties of the final polymer. These parameters include varying the formulated molecular weight of the end‐capped prepolymers, and use of meta‐substituted aromatic diamine in place of some of the para‐substituted diamine. Processability of the resins was studied using rheometric spectrometry, and a processing scheme was devised. Finally, several formulations of neat resins were compression molded into coupons, and evaluated for longterm stability in air at 315 and 371°C. The best combination of good processability and thermal oxidative stability was obtained from polymers synthesized with small amounts of meta‐diamine substitution and higher formulated molecular weight prepolymers.
Poly(methylene sebacate): Synthesis and characterization
Authors: Cimecioglu A. L. , East G. C. 
Published: April 2003

AbstractThe synthesis of poly(methylene sebacate) was carried out via the reaction of cesium sebacate with bromochloromethane in N‐methylpyrrolidone over a range of temperatures (55–130°C). A number of polymers having limiting viscosity numbers in the range of 0.29–0.94 dL g−1 (CHCl3; 25°C) were characterized by elemental analyses, 1H‐ and 13C‐NMR, DSC, and GPC techniques. The polymerization was found to be very rapid at 100°C, being complete in ca. 15 min. and was relatively insensitive to the stoichiometric ratio of the monomers. As high molecular weight polymers were produced without the quantitative conversion of the reactants, the polymerization is considered to be occurring by an interfacial mechanism.
Chromatography of amphiphilic graft copolymers
Authors: Wesslén Bengt , Wesslén K. Bodil 
Published: April 2003

AbstractAmphiphilic comb polymers were prepared through grafting poly(ethylene glycol) methyl ether (MPEG 2000) onto acrylic and methacrylic copolymers. The graft copolymers were purified from unreacted MPEG by partition chromatography on methanol pretreated fibrous cellulose using ethyl acetate and methanol as eluents. The separation was found to depend on the water contents of the cellulose and the eluents. It is proposed that one parameter of importance for the chromatographic separation is the formation of hydrated inverted micelles. The amphiphilic comb polymers were shown by gel chromatography on Sepharose to form high molecular weight aggregates in water. On addition of sodium lauryl sulphate or inorganic salts to the eluent at low ionic strengths these aggregates dissociated and were fractionated by the gel. It was also shown that on GPC in THF solution on Styragel columns the polymers exhibited apparent molecular weights equal or smaller than those of the corresponding backbones. This effect may be a consequence of the graft copolymers having relatively small hydrodynamic volumes, and this idea is supported by the fact that their intrinsic viscosities generally were lower than those of the backbones. However, adsorption on the Styragel columns also may be of importance.
Studies on the syntheses of polymetalloxanes and their properties as a precursor for amorphous oxide. IV. Properties of SiO2–TiO2 oxide fibers from polytitanosiloxane
Authors: Gunji Takahiro , Nagao Yukinori , Misono Takahisa , Abe Yoshimoto 
Published: April 2003

AbstractFrom polytitanosiloxanes (PTS), SiO2–TiO2 oxide fibers with fairly good tensile strength were prepared, and their mechanical and thermal properties were investigated. The precursor fibers PTS‐0.5 and PTS‐1.0 were obtained by dry spinning of a highly viscous PTS solution which were formed as the reaction mixture of silicic acid (SA) with bis(2,4‐pentanedionato)titanium diisopropoxide (PTP) in the molar ratios (SA/PTP) of 0.5 and 1.0. The precursor fibers PTS‐0.5 were too brittle to measure their tensile strength, whereas PTS‐1.0 and the heat‐treated fibers were found to have tensile strength of 130 (precursor), 540 (500°C), and 450 (900°C) MPa, respectively. Heat‐treatment of the fibers PTS‐1.0 at above 1000°C forms anatase and rutile of titanium dioxide. The crystallization is resulted from the unreacted PTP which is not incorporated into the polymer network.
Nature of plasma‐induced radicals on crosslinked methacrylic polymers studied by electron spin resonance
Authors: Kuzuya Masayuki , Ishikawa Masanao , Noguchi Akihiro , Sawada Kazuhiko , Kondo Shin‐Ichi 
Published: April 2003

AbstractPlasma‐induced radicals of several crosslinked methacrylic polymers such as poly(ethyleneglycol dimethacrylate) (PEDMA), poly(2‐hydroxyethylmethacrylate) (PHEMA) and polymethacrylamide (PMAAm) were studied by electron spin resonance (ESR). The observed ESR spectra did not exhibit a drastic difference in the spectral feature caused by the effect of crosslinking. All the spectral features can be represented by “nine‐line spectra” as a major spectral component similar to those of linear methacrylic polymers such as polymethacrylic acid (PMAA). A pronounced effect of crosslinking, however, has emerged on the specific formation in the radical structure and the stability of radicals formed, especially in PEDMA. The formation of fewer kinds of radical in PEDMA is apparently caused by the high degree of crosslinking which leads to a suppression of the occurrence of depolymerization on plasma irradiation.
Synthesis of aromatic polyethers by scholl reaction. VIII. On the polymerizability of 1,5‐bis(phenoxy)pentanes and 1,5‐bis(phenylthio)pentane
Authors: Percec Virgil , Wang James H. , Oishi Yoshi 
Published: April 2003

AbstractThe synthesis and the oxidative polymerization of 1,5‐bis(phenoxy)pentane, 1,5‐bis(phenoxy)pentane substituted with various electron‐donating groups, and 1,5‐bis(phenylthio)pentane is described. The polymers derived from methyl substituted 1,5‐bis(phenoxy)pentane monomers contain diphenyl methane, 1,2‐diphenylethane, and benzyl chloride structural units. The mechanism for the generation of these structural units is presented. It consists of the proton transfer reactions from the cation‐radical propagating species and subsequent reactions of the resulting benzyl radicals. The polymerizability of monomers with 1,5‐pentanedioxy group is lower than that of the monomers with diphenyl sulfone group. This dissimilarity was attributed to the difference between both the reactivity and the concentration of the cation‐radical propagating species resulted from these two classes of monomers.
Synthesis of multifunctional copolyamides with both cyclobutane ring and conjugated double bond in the main chain
Authors: Nishikubo Tadatomi , Iizawa Takashi , Shiozaki Yasunori , Koito Tsutomu 
Published: April 2003

AbstractCopolyamides 1,9, and 10 containing both cyclobutane rings and conjugated double bonds in the main chain were synthesized by polycondensation of 1,3‐di(4‐piperidyl)propane (DPP) with β‐truxinate (β‐BNPT), with di(p‐nitrophenyl) p‐phenylenebis(acrylate) (p‐NPDA), with di(p‐nitrophenyl) p‐phenylenebis (α‐cyanoacrylate) (p‐NPDC), and with di(p‐nitrophenyl) p‐phenylenebis (α‐cyanobutadienecarboxylate) (p‐NPDCB) in aprotic polar solvents at room temperature, respectively. Reduced viscosity of copolyamide 1 was strongly affected by the reaction process, the molar ratio of two ester monomers, and reaction time. The copolyamide 1 with the highest viscosity was prepared by the reaction of DPP with 70–50 mol % of β‐BNPT for 24 h followed by the polycondensation of the resulting precursor with 30–50 mol % of p‐NPDA for 24–96 h. Although copolyamide 9 with high viscosity was not obtained by the polycondensation with β‐BNPT and p‐NPDC, copolyamide 10 with relatively high viscosity was obtained by the reaction with β‐BNPT and p‐NPDCB under the same conditions applied for the synthesis of copolyamide 1. The solubility of copolyamides 1,9, and 10 decreased gradually with increasing p‐NPDA, p‐NPDC, and p‐NPDCB units in the copolymers. Furthermore, it was found that copolyamides 1,9, and 10 crosslinked upon irradiation with 313 or 365 nm light, and these copolyamides also decomposed upon irradiation with 254 nm light. That is, the photochemical property of these copolyamides can be controlled by the selection of wavelength of the photoirradiation.
Silazane oligomers and polymers with phenylene spacing groups
Authors: Kulpinski J. , Lasocki Z. 
Published: April 2003

AbstractHeating N,N′‐diphenyltetramethylcyclodisilazane with phenylenediamines in the melt at temperatures over 200°C was found to yield oligomers composed of linear and cyclic disilazane units interlinked by phenylene groups. Increasing the temperature of the reaction of meta‐ and particularly para‐phenylenediamine over 300°C promotes formation of crosslinked, infusible, and insoluble polymeric material. The succeeding steps of growth of the polymer molecules, which include cyclodisilazane ring cleavage, transaminations, and recyclizations, have been studied by elemental and spectroscopic analyses of the intermediate low molecular and oligomeric species in the distillable and nonvolatile products of the reactions.
Fast atom bombardment mass spectrometric analysis of the partial ozonolysis products of poly(isoprene) and poly(chloroprene)
Authors: Montaudo Giorgio , Scamporrino Emilio , Vitalini Daniele , Rapisardi Roberto 
Published: April 2003

AbstractThe low molecular weight compounds formed by partial ozonolysis of poly(isoprene) and poly(chloroprene) were analyzed by fast atom bombardment mass spectrometry (FABMS). In the poly(chloroprene) case, the ozonized mixtures were treated with piperidine before the MS analysis to transform in amide end groups the reactive acyl chlorides formed by the cleavage of double bonds along the main chain. Only one family of compounds having carboxyl and ketone or carboxyl and amide end groups were obtained from the ozonolysis of poly(isoprene) and poly(chloroprene), respectively. The assigned structures were confirmed by FAB‐MS analysis of the GPC separation fractions [poly(chloroprene)] or by FAB‐MS of the KOH‐doped ozonolysis mixtures [poly(isoprene)]. It has been also ascertained, by GPC experiments, that poly(chloroprene) decomposes more rapidly than poly(isoprene) and poly(butadiene).
Evaluation of furfurylamines as curing agents for epoxy resins
Authors: He Xiaodun , Conner Anthony H. , Koutsky James A. 
Published: April 2003

AbstractEpoxy resin adhesives are widely used because of their strength, versatility, and ability to bond a variety of substrates. Furfurylamines represent a potential, new class of epoxy curing agents. Furfuryl amine (FA), tetrahydrofurfuryl amine (THFA), and 5,5′‐methylenebis‐2‐furanmethanamine (DFA) were studied as possible epoxy curing agents. The utility of FA and THFA are limited by their volatility at the temperatures needed to effect cure of diglycidyl‐ether of bisphenol A (DGEBA) based epoxy resins. DFA is a very effective epoxy curing agent with the ability to cure DGEBA at rates similar to that of standard epoxy curing agents such as liethylenetriamine.
Organoborazines. III. Homo‐ and copolymerization of p‐vinylphenylcyclotriborazines
Authors: Jackson Logan A. , Allen Christopher W. 
Published: April 2003

AbstractThe polymerization and copolymerization with styrene of a series of unsymmetrically B‐p‐vinylphenyl‐N‐methyl and N‐phenyl borazines [R3(R2)2B3N3(R1)3; R1 = methyl, phenyl, R2 = methyl phenyl, R3 = p‐vinylphenyl] has been studied. The polymerization of these monomers yielded both tractable and crosslinked materials. The polymers obtained were characterized by 1H‐ and 13C‐NMR spectroscopy, elemental analysis, gel permeation chromatography, and thermogravimeteric analysis. The reactivity ratios for the copolymerization reaction were calculated by the Mortimer‐Tidwell method.
Laser‐Initiated copolymerization ofN‐vinylpyrrolidone with maleic anhydride and maleimide
Authors: Sadhir R. K. , Smith J. D. B. 
Published: April 2003

AbstractThis article describes the laser‐initiated copolymerization ofN‐vinylpyrrolidone with maleic anhydride and maleimide via charge transfer complexes. The dependence of copolymer yield on the molar ratios of the monomers in the feed and on the irradiation time is described. Based on the ultraviolet and infrared spectroscopy, and chemical analysis results, a tentative mechanism of polymerization is suggested. The rates of polymerization of several monomer systems are compared. TheN‐vinylpyrrolidone and maleimide system shows the highest rate of polymerization.