bluuebunny/crossref_metadata_2025_split huggingface dataset:
Function of vinyl copolymers with pendant porphyrin or metalloporphyrin dimers as photoredox catalyst
Authors: Kamogawa Hiroyoshi , Minoura Shuuji , Miyama Shingo 
Published: April 2003

AbstractPhotoredox catalytic functions of water‐soluble vinyl copolymers with pendant porphyrin or metalloporphyrin dimers were investigated. With FRA‐L‐ascorbic acid in aqueous solution, a vinyl copolymer bearing Mg‐porphyrin dimer linked with the shortest N,N′‐methylenebisamide bridge was found to have a remarkable accelerating effect under illumination of visible light as compared with that bearing Mg‐porphyrin monomer and other copolymers with longer dimer bridges as well as vinyl copolymers bearing porphyrin dimers and monomer. A copolymer bearing Zn‐porphyrin dimer was much inferior to that bearing monomer. Copolymers with other metals such as Co(II), Ni(II), and Cu(II) were almost inert.
4‐N,N‐Dimethylamino‐4'‐Isopropylbenzophenone as polymerization photoinitiator. Effect of solvent and photoinitiator concentration on its photoreactivity and on the polymerization process
Authors: Mateo J. L. , Bosch P. , Catalina F. , Sastre R. 
Published: April 2003

AbstractSeveral kinetics aspects of the methyl methacrylate (MMA) polymerization using 4‐dimethylamino‐4'‐isopropylbenzophenone (PI) as photoinitiator have been studied. The order of the polymerization reaction with respect to monomer and initiator concentrations have been investigated, as well as the polymerization behavior under well‐stirred and unstirred conditions; values of initiation quantum yield (ϕi) and kp/kt1/2 have also been determined. It has been found that the nature of the polymerization‐initiating radicals depends on the type of solvent and the photoinitiator concentration ([PI]). In cyclohexane solution and at low [PI] (< 5 x 10‐5M), the cyclohexyl radical is practically the only polymerization initiating radical, while at higher [PI] both radicals, cyclohexyl and the aminoalkyl derived from PI, participate in the initiation step, increasing the participation of the later as the [PI] increases. When benzene is used as solvent both phenyl and aminoalkyl radicals participate in the initiation step at any [PI] employed. Efficiencies of the radicals derived from solvent and photoinitiator have been determined.
Polyurethane elastomers with hydrolytic and thermooxidative stability. I. Polyurethanes with N‐alkylated polyamide soft blocks
Authors: Chapman Toby M. , Rakiewicz‐Nemeth Donna M. , Swestock John , Benrashid Ramazan 
Published: April 2003

AbstractSegmented polyurethanes with N‐alkylated amides as soft blocks as prepared. Comparisons are made with both a poly(ester urethane) and a poly(ether urethane) with the same hard block; the poly(amide urethane) is more hydrolytically stable than the polyester containing material and demonstrates greater thermooxidative stability than that with the polyether moiety. The aliphatic poly(amide urethane)s remain transparent upon exposure to uv light.
Studies of the photolysis of aromatic esters in solution and in polymer films
Authors: Holdcroft Steven , Yuen Kenneth H. , Guillet James E. 
Published: April 2003

AbstractPhotolysis of 2‐naphthylenemethyl‐1‐naphthylacetate (NMNA) and 9‐anthracenemethyl‐9‐anthrylacetate (AMAA) yields radicals of methylnaphthalene and methylanthracene, respectively. The longevity of these radicals makes them suitable probes for studying primary and secondary cage recombination processes in solution, and in polymeric matrices. 2,2‐Di‐(4‐tert‐octylphenyl‐1‐picrylhydrazyl) (DPPH) is utilized as a radical trap to report on radicals which escape from the solvent cage. Quantum yields for photolysis of NMNA and AMAA were determined in solution and in poly(methyl methacrylate) films. Both unimolecular and bimolecular processes are suppressed as a result of the greater effective viscosity in polymeric media.
Synthesis of poly(alkylene phosphate)s with n‐containing bases in the side chains. III. N1‐Oxoethyleneuracil on the poly(trimethylene phosphate) chain
Authors: Łapienis Grzegorz , Penczek Stanisław 
Published: April 2003

AbstractPoly(2‐hydro‐2‐oxo‐1,3,2‐dioxaphosphorinane) was quantitatively chlorinated, and the resulting polymer was reacted with excess of imidazole, giving the highly reactive polyesteramide. This polymer, treated with N1‐hydroxyethyluracil, gave polyphosphates with N1‐oxoethyleneuracil in the side chains. The final polymers (M̄n ≈ 104) as well as the intermediate products were characterized by 1H‐, 13C‐ and 31P‐NMR spectroscopy.
Inclusion polymerization of 1‐chlorobutadiene in a deoxycholic acid canal
Authors: Tsutsumi Hiromori , Okanishi Ken , Miyata Mikiji , Takemoto Kiichi 
Published: April 2003

AbstractInclusion polymerization of 1‐chlorobutadiene was studied using 3α,12α‐dihydroxy‐5β‐cholan‐24‐oic acid (deoxycholic acid, DCA) as host molecules. It was found that the poly(1‐chlorobutadiene) had almost 100% of head to tail, trans‐1,4‐structure on the basis of 13C‐NMR and IR spectroscopies. This was the first example of preparing the highly regulated poly(1‐chlorobutadiene) by using the inclusion polymerization technique. The polymers obtained were optically active and the maximum value of specific rotation was [α]D‐41.9°. Both the rate constants and the value of activation energy of the elementary reactions of inclusion polymerization of 1‐chlorobutadiene were determined by graphical evaluation. The activation energy of propagation and termination was 11.7 and 11.1 kcal/mol, respectively.
Studies of reactions with polymers. VI. The modification of PAN with primary amines
Authors: Chiang Wen‐Yen , Hu Chun‐Min 
Published: April 2003

AbstractA series of modified polyacrylonitriles have been obtained with several primary amines, such as ethanolamine, ethylenediamine, ethylamine, n‐butylamine, and n‐octylamine, without any catalysts in DMSO. This paper presents the syntheses of these new modified polymers and discusses the resultant structures and reaction mechanism by IR, NMR, and UV spectra. Composition was obtained by elemental analysis. Moreover, some physical properties of polymer were also investigated. It was found that all these primary amines could initiate coloration of polyacrylonitrile, which involves linking up of adjacent nitrile groups, and also reactions of the amines with the nitrile groups. However, the product of polyacrylonitrile with ethanolamine and with ethylenediamine were soluble in water when the mole ratio of amine group to nitrile group was 2. This interesting fact promoted a more detailed study of the modification of polyacrylonitrile with these amines. Crosslinking of the products of PAN with ethanolamine (or with ethylenediamine) was achieved by heat treatment. A mechanism for the formation of crosslinking was proposed.
Synthesis and polymerization of ethyl α‐chloromethylacrylate and related derivatives
Authors: Warren Stephen C. , Mathias Lon J. 
Published: April 2003

AbstractEthyl α‐hydroxymethylacrylate (EHMA) was synthesized from ethyl acrylate and paraformaldehyde, and converted to ethyl α‐chloromethylacrylate (ECMA) by reaction with thionyl chloride. ECMA was bulk polymerized at 65°C with α,α′‐azobis(isobutyronitrile) (AIBN) to give a homopolymer with a viscosity of 0.084 dL/g. Spontaneous polymerization at ambient temperature surprisingly gave material with an intrinsic viscosity of 0.45 dL/g. Combined size exclusion chromatography‐laser light scattering in THF for the former gave Mn = 21,900, Mw = 26,500, and Mz = 34,340 with a dn/dc = 0.079 mL/g. The homopolymer of ECMA was substituted with octadecyl mercaptan in THF using solid NaOH and Aliquat 336 as base and catalyst, respectively. Copolymers of ECMA with styrene were synthesized by free radical polymerization with relatively high conversion. Copolymer compositions were determined using proton NMR and were found to be similar to feed ratios as expected for high conversion products. Both copolymers were reacted with 2‐ethyl‐2‐oxazoline (1:50 mole ratio) in an attempt to graft the oxazoline onto the polymer chain with only limited success. Two potential monomers were synthesized by reacting ECMA with 2‐ethyl‐2‐oxazoline neat and octadecyl mercaptan in CHCl3 using triethylamine as a catalyst. Neither material polymerized under normal radical conditions. Characterization of monomers and polymers involved FTIR and 13C NMR spectroscopy, differential scanning calorimetry, viscosity, and size exclusion chromatography‐laser light scattering.
One‐phase supported titanium‐based catalysts for polymerization of ethylene and its copolymerization with 1‐alkenes. I. Preparation and properties of catalysts
Authors: Salajka Zdeněk , Kratochvíla Jan , Hamřík Oldřich , Kazda Antonín , Gheorghiu Mihnea 
Published: April 2003

AbstractActive one‐phase Ti‐based supported catalysts were prepared by interacting the activated silica gel (0.8 mmol OH groups/g) with RxAlCl3–x (x = 1–3, Al/OH = 0.9–1.0), then with TiCl4 and R2Mg (Mg/Ti = 1–16), and finally with R3Al (Al/Ti = 0–16). The catalyst activity in the fluid bed ethylene polymerization varied between 40 and 540 kg PE/g Ti h, depending on the component used and preparation conditions employed. A mechanism of the polymerization‐active species formation was proposed.
Synthesis and characterization of oxyethylene containing diisocyanates and polyimides therefrom
Authors: Avadhani C. V. , Wadgaonkar P. P. , Vernekar S. P. 
Published: April 2003

AbstractA facile synthesis of a series of oxyethylene containing diisocyanates, the α,ω‐bis(isocyanatophenoxy)alkanes and bis[2‐(isocyanatophenoxy)ethyl] ethers, is described. The key step involves the uneventful decomposition of the corresponding diacylazides to the diisocyanates in the Curtius rearrangement reaction. Further, eight thermally stable oxyethylene containing polyimides were synthesized by the polycondensation reaction of two meta‐ and two para‐oriented diisocyanates, namely, 1,2‐bis(3‐isocyanatophenoxy)ethane and 1,2‐bis(4‐isocyanatophenoxy)ethane, and bis[2‐(3‐isocyanatophenoxy)ethyl] ether and bis[2‐(4‐isocyanatophenoxy)ethyl] ether, with pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylic dianhydride (BTDA) in N,N‐dimethylacetamide (DMAc). These polyimides were characterized by IR spectroscopy, x‐ray diffraction, viscosity measurements, and thermogravimetric analysis.
Preparation and properties of new aromatic polyamides from 4,4′‐diaminotriphenylamine and aromatic dicarboxylic acids
Authors: Oishi Yoshiyuki , Takado Hiroko , Yoneyama Masaru , Kakimoto Masa‐Aki , Imai Yoshio 
Published: April 2003

AbstractNew aromatic polyamides (aramids) having inherent viscosities of 0.5–2.6 dL/g were prepared by the direct polycondensation of 4,4′‐diaminotriphenylamine with various aromatic dicarboxylic acids in N‐methyl‐2‐pyrrolidone using triphenyl phosphite and pyridine as condensing agents. These aramids were amorphous and soluble in a variety of solvents such as N,N‐dimethyl‐acetamide, dimethyl sulfoxide, and pyridine, and afforded transparent and tough films by solvent casting. The glass transition temperatures of these aramids were in the range of 280–310°C, and the 10% weight loss temperatures were above 430°C in air.
Esters of α‐sulfomaleic anhydride as powerful electrophiles for polyolefin functionalization
Authors: Schaedeli Ulrich , Padias Anne Buyle , Brois S. J. , Thaler Warren A. , Hall H. K. 
Published: April 2003

AbstractNew electrophilic derivatives of maleic anhydride were synthesized to test their reactivity in ene reactions with the terminal double bond of hydrocarbon polymers. The methyl ester and new ethyl ester of sulfomaleic anhydride (SMA) were reacted with 2,2,4‐trimethyl‐1‐pentene 3, which is a model compound for the end group of the hydrocarbon polymers. The SMA esters were more oleophilic than SMA itself, but many side reactions occurred. Higher alkyl esters of SMA could not be synthesized. Two silyl esters of SMA, trimethylsilyl and t‐butyldiphenylsilyl, were also synthesized and reacted with 3; ene reactions proceeded well in bulk, but the ene adducts decomposed upon heating. The powerful dienophilic character of these SMA esters was demonstrated by a series of [4 + 2] cycloadditions.
Aggregation of poly(vinyl acetate) or n‐decyl group grafted poly(allylamine) and crosslinking of trunk sequence in selective solvents
Authors: Saito Reiko , Ishizu Koji , Nose Takuhei , Fukutomi Takashi 
Published: April 2003

AbstractPoly(allylamine‐g‐vinyl acetate) [P(AAm‐g‐VAc), VAc content 33 mol%] and poly(allylamine‐g‐n‐decane) [P(AAm‐g‐CH), number of n‐decyl group/allylamine molecule was 4.4] were prepared by redox initiation of vinyl acetate polymerization on poly(allylamine) or a condensation reaction between amino group and 1‐bromo‐n‐decane. These polymers form aggregate in mixed solvents tetrahydrofuran/H2O and acetone/H2O. In acetone/H2O at a volume ratio which is good for poly(vinyl acetate) and not for poly(allylamine) (v/v = 65/35), the distribution of particle diameter shows a bimodal profile. These peaks vary with polymer concentration in the case of P(AAm‐CH). Poly(allylamine) sequences were crosslinked by 1,3‐dibromo‐2‐propanol in this solvent without macrogel formation. The crosslinking of particles with large diameter (several hundred nm) formed in rather concentrated solution was shown by electron micrograph. It was revealed that phase separation occurred in a particle with the proceeding of crosslinking reaction.
A study of the properties and topological trapping of cyclic poly(dimethylsiloxane) in poly(2,6‐dimethyl‐1,4‐phenylene oxide) networks
Authors: Huang W. , Frisch H. L. , Hua Y. , Semlyen J. A. 
Published: April 2003

AbstractPolymeric catenanes have been made from poly(2,6‐dimethyl‐1,4‐phenylene oxide) crosslinked in the presence of several, paucidisperse poly(dimethylsiloxane) cyclics of varying degrees of polymerization. The fraction of cyclic threaded or captured by the polymer network increases as the degree polymerization of the cyclic increases in good agreement with the crude estimates of Frisch and Wasserman. Thermal analysis and electron micrographs reveal microphone separation in all of the polymeric catenanes; with PDMS domain size around 10–50 μ. Most of the catenanes exhibit a lower tensile strength to break than the pure crosslinked PPO.
Electrochemical polymerization of 3‐octylpyrrole
Authors: Masuda Hideyuki , Tanaka Susumu , Kaeriyama Kyoji 
Published: April 2003

AbstractElectrochemical polymerization of 3‐octylpyrrole (OCPY) yielded a film on the anode. Its conductivity was 5 S/cm. Infrared spectra of OCPY and poly(3‐octylpyrrole) (POCPY) were compared with those of related monomers and polymers, and as a result, the pyrrole rings appeared quite likely linked at 2‐ and 5‐positions. Cyclic voltammograms of a PF–6‐doped POCPY film had an anodic peak at 0.16 V vs. Ag and a cathodic peak at 0.12 V. Doped POCPY was stable and soluble in such polar solvents as tetrahydrofuran, N‐methylpyrrolidinone and pyridine. Although the absorption spectrum of the film had three peaks at 1.0, 2.5 and 3.6 eV, as also in the case of poly(3‐methylpyrrole), the spectra in pyridine and THF solutions indicated two peaks at 1.9 and 3.2 eV. Scanning electron microscopy (SEM) showed the POCPY films to have a unique morphology, depending on the electrolytes used for electrochemical polymerization. The introduction of an octyl group made polypyrrole soluble in organic solvents, but effective conjugation length became shorter and the texture of films rougher.
Preparation and polymerization of spiroorthoester bearing the perfluoroalkyl group
Authors: Yokozawa Tsutomu , Sato Makoto , Endo Takeshi 
Published: April 2003

AbstractFor a potential use of spiroorthoesters which polymerize with essentially zero shrinkage during polymerization, the preparation of spiroorthoester (I) bearing the perfluoroalkyl group was carried out. Spiroorthoester I was prepared by the reaction of ε‐caprolactone with 2‐(F‐octyl)ethyl glycidyl ether (II), obtained from 2‐(F‐octyl)ethanol and epichlorohydrin, in the presence of catalytic amount of BF3OEt2. Spiroorthoester I underwent the cationic ring‐opening polymerization by virtue of BF3OEt2 to obtain poly(ether‐ester) with 2.7% expansion on polymerization. The presence of the perfluoroalkyl group had no significant effect on the polymerization of the spiroorthoester.
Photocrosslinking of polyethylene. III. Thermal oxidative stability of photocrosslinked polyethylene
Authors: Chen Yong Lie , Rånby Bengt 
Published: April 2003

AbstractThe thermal oxidative stability of photocrosslinked high density polyethylene was studied. The relative effectiveness of various antioxidants (hindered phenols and amines, aromatic amine, organic sulfides, and phosphites) was examined by comparing the oxidation induction time (OIT) which was measured using differential scanning calorimetry. Hindered phenol antioxidants were found to be most effective. At an antioxidant concentration of 0.20 wt % which gave an OIT value of 20 min at 200°C, the photocrosslinking rate was decreased only to a limited extent as evidenced by a small drop in gel content. However, the efficiency of the antioxidants as stabilizers decreased to a considerable extent after the photocrosslinking process. Serious surface deterioration was found which was ascribed to depletion of antioxidant at the surface mainly due to high rate of oxidation and evaporation.
Synthesis and properties of polyamine resins from epoxy resins
Authors: Yang Chin‐Ping , Lee Lung‐Ta 
Published: April 2003

AbstractPolyamine resins were synthesized by the preparation of ketimine‐terminated resins from epoxy resin and ketimine blocked diethylene triamine (1) and subsequent hydrolysis. 1 was prepared by the condensation reaction of diethylene triamine with methyl isobutyl ketone catalyzed by acid. The hydrolysis of ketimine containing resin was evaluated by the change of the pH value of reaction mixture and the infrared spectroscopy and gel permeation chromatography curve of the resulting product. The hydrolytic rate of ketimine increased with the increase of temperature or the amount of acid added. The crosslinking, emulsion, and electrodeposition properties of these polyamine resins were studied in some detail.
The picryl ether of polyethylene glycol: Preparation, characterization, and reaction with n‐propylamine
Authors: Dust Julian M. , Milton Harris J. 
Published: April 2003

AbstractA new electrophilic polymer, the picryl ehter of methoxypolyethylene glycol (M‐PEG‐OPi), was prepared by reaction of the lithium alkoxide of methoxypolyethylene glycol with picryl chloride. The resultant M‐PEG‐OPi was characterized by 200 MHz 1H and 13C‐NMR, microanalysis, and hydrolytic behavior. The rate constant for hydrolysis in pH 8.0 buffer is consistent with that expected for SNAr hydrolysis of a polyethylene glycol picrate. Reaction of n‐propylamine with M‐PEG‐OPi in (CD3)2SO was followed by 1H‐NMR and UV‐visible spectroscopy. Evidence is presented for formation of a C‐1 Meisenheimer complex; no C‐3 adduct was observed in these experiments despite the steric bulk of the polymeric “group” on the picryl ring. Addition of a large excess of amine results in formation of a 2:1 dianionic complex, as shown by the UV‐visible spectrum. The possibility is discussed of using the reaction of M‐PEG‐OPi with protein amino groups as an analytical tool for measuring the number of available amino groups on protein chains.
Synthesis of novel primary amino‐terminated polymer and application for macromonomer
Authors: Ishizu Koji 
Published: April 2003

AbstractThe carboxyl‐terminated polystyrene (PS) was prepared by free radical polymerization of styrene initiated by functional azo‐initiator under a unimolecular termination mechanism. After replacement of the hydroxyl group of acids by chlorine, the end‐capping reaction of acyl halide‐terminated PS with a large excess of 1,6‐diaminohexane was carried out to obtain primary amino‐terminated PS. Subsequently, various PS macromonomers were derivated from primary amino‐terminated PS.
Syntheses and properties of polyureas from divalent metal salts of p‐aminobenzoic acid, diamine, and diisocyanate
Authors: Matsuda Hideaki , Takechi Shigetoshi 
Published: April 2003

AbstractMetal‐containing polyureas having ionic links in the main chain were synthesized by the polyaddition reactions of 2,4‐toluylene diisocyanate with mixtures of divalent metal salts of p‐aminobenzoic acid and 4,4′‐diaminodiphenylmethane (4,4′‐methylenedianiline). Mg and Ca were used as the divalent metal. The polyureas obtained were slightly yellowish powders and those with low metal content were soluble in dimethylacetamide (DMAc) and dimethylsulfoxide (DMSO). The inherent viscosity (at 0.5 g/100 mL) of the polyureas decreased markedly with an increase in metal content. In addition, the reduced viscosities in DMAc and DMSO were very low at very low concentration but became higher as the concentration increased, especially in DMAc having a somewhat lower dielectric constant. This viscosity increase at high concentrations is attributed to ionic association. Introducing the metal into the polyurea lowered the thermal properties as indicated by decreased decomposition temperatures. The polyureas with low metal contents gave films by solvent‐casting although increasing the metal content made the films brittle. Further, dynamic mechanical properties were discussed.
Model filled polymers. I. Synthesis of crosslinked monodisperse polystyrene beads
Authors: Zou D. , Derlich V. , Gandhi K. , Park M. , Sun L. , Kriz D. , Lee Y. D. , Kim G. , Aklonis J. J. , Salovey R. 
Published: April 2003

AbstractMonodisperse crosslinked polystyrene beads of varied size and crosslink density are prepared by emulsion copolymerization of styrene and divinylbenzene in the absence of emulsifier. Tumbling and internally stirred reactors were used for synthesis, with minimal agglomeration at at least 0.22 wt % potassium persulfate and up to 10% by weight of styrene in aqueous emulsion in the absence of oxygen. Particle sizes decreased from 800 to 200 nm on raising the polymerization temperature from 60 to 95°C. The glass transition temperature of the beads increased from 104.4 to 133°C by the inclusion of up to 10% by weight of divinylbenzene. The thermal stability of the beads was higher for peroxide than for persulfate initiation. The crosslink density estimated from the degree of swelling was about one third that expected from stoichiometry. The polystyrene beads are used as filler particles in polymer composites.
A new dual‐parameter for reactivities of vinyl monomers toward free‐radicals
Authors: Ito Osamu , Matsuda Minoru 
Published: April 2003

AbstractA new dual‐parameter of vinyl monomers for the reactivities toward free‐radicals has been evaluated on the basis of kinetic data obtained by the flash photolysis method. As a model reaction system, the reversible addition reactions of the substituted phenylthiyl radicals to vinyl monomers are selected. The absolute rate constants and the relative equilibrium constants for these reactions have been determined. The Hammett reaction constants (ρ) for the addition reaction rates were evaluated by the variation of the substituents at the para‐position of the arylthiyl radicals. From the values, the polar parameters (P‐ values) have been evaluated. The P values of various vinyl monomers correlate with the e values of the Q‐e scheme proposed by Alfrey and Price. The resonance stabilization terms of the propagating radicals were evaluated from the equilibrium constants (K) which correlate with the Q values. The K‐P dual‐parameter can be used in order to predict the reactivities of vinyl monomers for the primary radicals (initiation step). The monomer reactivities from the copolymerization data are also correlated with the dual parameter. There are some advantages in the new dual‐parameter compared with the Q‐e scheme; the separation of the resonance term from the polar term is complete and the steric factor is not included in the polar term.