bluuebunny/crossref_metadata_2025_split huggingface dataset:
Free radical copolymerization in the presence of lewis acids. I. Alternating copolymerization of vinyl acetate with acrylic acid in the presence of GeCl4 and BCl3
Authors: Xu Guo Jin , Meng Yue‐Zhong , Song Hong , Lin Qing‐Song 
Published: April 2003

AbstractAlternating copolymers of vinyl acetate (VAC) and acrylic acid (AA) were obtained by free radical polymerization in the presence of GeCl4 and BCl3. For the GeCl4 system, the reaction rate was proportional to [initiator]1/2. Optimum rate was obtained when the molar ratio of the monomers was 1:1. The chain transfer agent CCl4 had no effect on the reaction. By means of ultra‐violet spectra analysis, it was concluded that both VAC and AA formed complexes with GeCl4. ESR analysis gave us the information that salt complexed acrylic acid radical had greater cationic characteristics than uncomplexed radical. Thus the nature of alternation may be due to both complexed AA radical and activated monomer complexes.
Studies in the formation of poly(oxazolidone)s. III. Catalysis and kinetics of the model oxazolidone formation from cyclohexyl isocyanate and phenylglycidyl ether
Authors: Žilić Mirjana , Sendijarević Aiša , Sendijarević Vahid , Frisch Kurt C. 
Published: April 2003

AbstractThe reaction of cyclohexyl isocyanate with phenylglycidyl ether was selected as model reaction for the synthesis of cycloaliphatic isocyanate‐based poly(2‐oxazolidone)s. The selectivity of AlCl3 and AlCl3‐triphenylphosphine oxide (AlCl3–TPPO) and AlCl3‐hexamethylphosphoric triamide (AlCl3–HMPA) complexes was studied for 2‐oxazolidone formation. The reaction products were identified by means of the melting point, 1H‐NMR, and IR spectroscopy. The kinetics of the model reaction was studied using AlCl3‐TPPO in o‐dichlorobenzene at 120 and 140°C.
Heterogeneous dilute acid hydrolysis of cellulose: A kinetic model for the hydrolysis of the difficultly accessible portion of cellulose based on donnan's theory of membrane equilibria
Authors: Zaranyika M. F. , Madimu M. 
Published: April 2003

AbstractThe effect of adding an electrolyte on the rate of the heterogeneous dilute acid hydrolysis of cellulose was studied using 1.3M hydrochloric acid containing varying amounts of sodium chloride up to 0.17M. A general increase in the rate of hydrolysis was observed. In particular, a linear relationship was observed between the rate of hydrolysis of the later portion of the hydrolysis curve and the concentration of added electrolyte, thus confirming that Donnan's theory of membrane equilibria can be applied to the heterogeneous hydrolysis of cellulose in dilute acid. A kinetic model, based on this theory and whose predictions are consistent with the above experimental results is presented.
Crosslinked polystyrene latexes prepared with 12‐(o‐styryloxy)dodecyltrimethylammonium bromide
Authors: Choubal Milind , Ford Warren T. 
Published: April 2003

AbstractCrosslinked polystyrene latexes with high surface charge densities have been prepared with 1, 3, and 5 mol% divinylbenzene and 0.5–5.0 mol% of 12‐(o‐styryloxy)dodecyltrimethylammonium bromide (1). Within experimental error all of surfactant 1 was incorporated into the particles. Analysis of the latex particles by transmission electron microscopy showed nonspherical shapes, aggregates, and number average diameters ranging from 22 to 95 nm. The particle size decreases and the polydispersity increases with increasing amounts of surfactant 1 and of divinylbenzene in the monomer mixture. A mechanism is proposed for particle formation by precipitation of crosslinked polymer from monomer droplets to form primary particles, coagulation of the primary particles to colloidally stable aggregates, and growth by further polymerization.
Binding of methyl orange and the hydrophobic fluorescent probe, 2‐p‐toluidinylnaphthalene‐6‐sulfonate, by 2‐dialkylaminoethyl methacrylate‐N‐vinyl‐2‐pyrrolidone and related copolymers
Authors: Takagishi Toru , Hosokawa Toshitsugu 
Published: April 2003

AbstractThe copolymers of N‐vinyl‐2‐pyrrolidone and 2‐dimethylaminoethyl methacrylate, 2‐diethylaminoethyl methacrylate, 2‐dimethylaminoethyl acrylate, or 2‐dimethylaminopropyl acrylamide have been prepared. Studies were made of the binding of a “binding probe,” methyl orange, by the copolymers in aqueous solution. The first binding constants accompanying the binding were evaluated. Furthermore, the intensity of fluorescence of a hydrophobic fluorescent probe, 2‐p‐toluidinylnaphthalene‐6‐sulfonate, in the presence of these polymers was investigated. The nature and phenomena of dye binding and hydrophobic fluorescent probe binding with the polymers are discussed.
Radiation‐induced graft polymerization of metal‐containing monomers
Authors: Savostyanov V. S. , Pomogailo A. D. , Kritskaya D. A. , Ponomarev A. N. 
Published: April 2003

AbstractGraft polymerization of acrylates and acrylamide complexes of Mn(II), Cr(III), Fe(III), Co(II), Ni(II), and Cu(II) from alcohol solutions onto a polyethylene powder preirradiated in air up to total doses of 10–300 kJ/kg was studied. Graft copolymers with a metal content of as high as 1.7 mass% were obtained. The addition of a σ‐ or a coordinate‐bound metal atom to the monomer molecule (acrylic acid, acrylamide) was shown to decelerate the process of thermal homopolymerization by 4 to 8 times, significantly reduce the reaction order in respect with monomer concentration in solution, and in most cases produce no effect on the polymer chain termination mechanism. The grafting of metal‐containing monomers was found not to alter the structure of the monomer unit, valent state, and coordination of the metal atom, either. The graft polymerization of the monomers from solution is distinguished by a weak effect of the radical reaction inhibitors. The effective activation energies for the grafting of the metal‐containing monomers lie within 42–60 kJ/mol.
Synthesis and polymerizability of 7,8‐dicyano‐7,8‐diphenylquinodimethane
Authors: Brandt M. W. , Mulvaney J. E. , Hall H. K. , Green G. D. 
Published: April 2003

Abstract7,8‐Dicyano‐7,8‐diphenylquinodimethane (DCDPQ) was prepared by oxidation of the dianion of α,α′‐dicyano‐α,α′‐diphenylxylene. 1H‐NMR of a solution of the purified compound showed that the cis and trans isomers were present in a 1:1 ratio. Following further spectroscopic and electronic characterization the polymerizability of the title compound was investigated. DCDPQ did not homopolymerize at 65°C in the presence of AIBN. DCDPQ copolymerized with p‐methoxystyrene and p‐aminostyrene in the presence of AIBN at 65°C. Characterization of the latter two copolymers indicated that they were nearly alternating. The copolymerization between DCDPQ and p‐aminostyrene proceeded in the absence of AIBN.
Models for polyurethane hydrolysis under moderately acidic conditions: A comparative study of hydrolysis rates of urethanes, ureas, and amides
Authors: Chapman Toby M. 
Published: April 2003

AbstractThe hydrolysis of model structures found in the hard blocks of polyurethanes has been studied under moderately acidic and neutral conditions. These include a series of N‐alkyl and N‐phenyl urethanes and ureas; for comparison purposes the corresponding amides and a carbonate ester based on bisphenol A were also studied. Of all functional groups the urethane was the most resistant to hydrolysis and the amide the most labile. Also, the N‐phenyl compounds were hydrolyzed faster than the corresponding alkyl derivatives. The carbonate ester underwent relatively rapid hydrolysis. Polyether containing polyurethanes, known to be relatively stable to hydrolysis, are discussed as to which polymer segments provide the weakest links under hydrolytic conditions.
Functional polymers. XLIX. Copolymerization of ω‐alkenoates with α‐olefins and ethylene
Authors: Purgett Mark D. , Vogl Otto 
Published: April 2003

AbstractThe 2,6‐dimethylphenyl ester of 10‐undecenoic acid was copolymerized with 1‐dodecene, 1‐octene, 1‐hexene, propylene, and ethylene using coordination initiation systems based on “aluminum‐activated” titanium trichloride and dialkylaluminum chlorides. The copolymerizations with higher α‐olefins proceeded smoothly and gave copolymers incorporating from 60 to 90% of the 10‐undecenoate feed. Copolymerization with propylene gave incorporation of 5 mol % of 2,6‐dimethylphenyl 10‐undecenoate; with ethylene only 3 mol % of the ω‐alkenoate was readily incorporated. All copolymers were characterized by elemental analysis, dilute solution viscosity, and by their IR 1H‐ and 13C‐NMR spectra.
A kinetic study of the copolymerization of maleic anhydride with ethyl vinyl ether using the rotating‐sector technique
Authors: Pasquali R. E. , Rodriguez F. 
Published: April 2003

AbstractThe results of polymerization and initiation experiments at 25°C show that the alternating copolymerization of maleic anhydride (monomer 1) and ethyl vinyl ether (monomer 2) is consistent with a theoretical mechanism defined by the usual rate constants (in L/mol s): Propagation: (kp)11 = 0.00; (kp)12 = 1.66 × 105, (kp)22 = 2.0 × 103; and (kp)21 = 2.04 × 105. Termination (kt)11 = 7.40 × 1010; (kt)12 = 52.8 × 1010; (kt)22 = 1.33 × 1010. The relative magnitudes of the two cross‐propagation constants and the three termination constants are consistent with accepted theory with regard to polarity, resonance, and steric factors. The steady‐state and rotating‐sector experiments were carried out in a dilatometer using azobisdiisobutyronitrile as the initiator, acetone as the solvent, and UV light of 365 nm wave length.
Synthesis and polymerization of N‐(ethylene)‐phthalimidyl acrylate
Authors: Pyriadi Thanum M. , Alasli Nabeel J. 
Published: April 2003

AbstractN‐(Ethylene)phthalimidyl acrylate was synthesized starting from phthalimide or phthalic anhydride using two different routes. Free radical or anionic polymerization of the ester resulted in low‐molecular‐weight polymers.
Biocatalytic synthesis of polymers. Synthesis of an optically active, epoxy‐substituted polyester by lipase‐catalyzed polymerization
Authors: Wallace J. Shield , Morrow Cary J. 
Published: April 2003

AbstractThe enantioselective polymerization of bis(2,2,2‐trichloroethyl) trans‐3,4‐epoxyadipate with 1,4‐butanediol using the enzyme porcine pancreatic lipase as a catalyst is described. The polymerization was carried out at ambient temperature in anhydrous ethyl ether. End group analysis provided MN = 5,300 daltons, whereas GPC provided Mw = 7,900 daltons for the polymer. The unchanged (+)‐enantiomer of the diester was shown to have an enantiomeric purity of > 95% by proton NMR in the presence of the chiral shift reagent Eu(hfc)3. The stereochemical purity of the (−)‐polymer was estimated at > 96% by consideration of the amount of the slower reacting enantiomer that could have been incorporated and still attain the observed degree of polymerization (25) when the starting ratio of racemic diester to diol was 2:1. Direct determination of the stereochemical purity of the polymer using Eu(hfc)3 was unsuccessful. Similar studies on polymer having random stereochemical orientations of the epoxide showed that such polymers do not behave as if they are racemic in the presence of the shift reagent. The polymer required for the latter studies was prepared by epoxidation of the product from enzyme catalyzed polymerization of bis(2,2,2‐trichloroethyl) trans‐3‐hexenedioate with 1,4‐butanediol.
Organic monomeric glasses: A novel class of materials
Authors: Molaire Michel F. , Johnson Roger W. 
Published: April 2003

AbstractAn amorphous monomeric glass is defined as a mixture of compatible organic monomeric molecules with an infinitely low crystallization rate under the most favorable conditions. These mixtures can be formed in a one‐part reaction of a multifunctional nucleus with a mixture of substituents. The “noncrystallizability” of the mixture is controlled by the structural dissymmetry of the nucleus and/or the substituents and the number of components making up the mixture. We have developed an equation to calculate the number of components in a given mixture, knowing the structure and functionality of the nucleus and the number of substituents. An HPLC characterization method was developed and used to investigate the effects of various reaction conditions on the component concentration distributions and physical properties of the resulting materials. A dissymmetry number defined as the total weight percent of odd‐substituted components is believed to be a potential measure of the “noncrystallizability” of the mixture. Physical properties such as glass‐transition temperature can be dramatically increased through controlled oligomerization at the price of a moderate increase in melt viscosity. The organic monomeric glasses, like amorphous polymers, have good film‐forming properties. However, unlike polymers, they display extremely low melt‐viscosities and large positive entropy‐of‐mixing values and can be ground easily into extremely small particles. These properties make them ideal for certain applications where compatibility, melt‐flow, and small particle size are important.
Functional monomers and polymers. CLIV. Application of nucleic acid base containing polymers to high performance liquid chromatography
Authors: Nagae Suguru , Suda Yasuo , Inaki Yoshiaki , Takemoto Kiichi 
Published: April 2003

AbstractPoly‐L‐lysine (PLL) derivatives containing pendant nucleic acid base, such as thymine or adenine, were bonded successfully to 3‐aminopropylsilanized silica (APS‐silica) and silica gel. These resins were found to be useful as the column of high performance liquid chromatography (HPLC) for the selective separation of oligoethyleneimine derivatives having pendant thymine or adenine bases.
Chain propagation/step propagation polymerization. III. An XPS investigation of poly(oxyethylene)‐b‐poly(pivalolactone) telechelomer
Authors: Wagener K. , Batich C. , Kirsch B. , Wanigatunga S. 
Published: April 2003

AbstractA combination of chain and step propagations is being used to prepare a series of segmented copolymers containing polyoxyethylene and polypivalolactone segments each with narrow molecular weight distributions. The incompatibility of the two segments coupled with the difference in surface energies of the two segments could result in good phase separation with the polyoxyethylene segment thereby being found on the surface. Poly(oxyethylene)‐co‐(pivalolactone) telechelomer, which is the precursor to the segmented copolymer, is used as a model to develop an XPS method for surface analysis. An angular resolution study shows that negligible amounts of poly(pivalolactone) segments are present near the surface. Core level spectra of the telechelomer and its model compounds are presented to indicate that poly(oxyethylene) segment is richer near the surface.
Preparation and characterization of plasma polymerized (ethylene + oxygen) thin films
Authors: Prohaska G. W. , Nickoson C. G. 
Published: April 2003

AbstractThis report describes the preparation and characterization of plasma polymerized (ethylene + oxygen) (PPEO) thin films. The PPEO films described herein represent a unique class of materials from the standpoint of stoichiometry, chemical functionality, and crosslink density. It will be shown that PPEO deposition rate and structure, evidenced both at the surface and in the bulk, are strongly dependent upon the flow rate of O2 in the ethylene/O2 feed gas mixture. High O2 flow rates produce films with relatively high oxygen concentrations. Furthermore, increasing O2 flow rates lead to film structures which increasingly favor the incorporation of highly oxidized carbon functionalities. These effects (increasing film concentrations of oxygen and highly oxidized carbon functionalities) appear to show no further increase for O2 flow rates greater than or equal to ca. 10% of the ethylene flow rate.
Cinnamates. III. The light sensitive polymers: Cinnamates with internal charge‐transfer spectroscopic properties
Authors: Pa̧czkowski Jerzy , Toczek Maria , S̀cigalski Franciszek , Ćwiklińska Danuta , Sierocka Michalina 
Published: April 2003

AbstractIn this paper, we outline the photochemical and spectroscopic properties of a new light‐sensitive polymer obtained as a result of polystyrene modification by attachment of a pendant 4‐dimethylamino‐cinnamate ester group. This specific cinnamate displays typical charge‐transfer character in the absorption and emission spectra. The photochemical and photophysical properties of photopolymer are compared with the monomeric model photochemistry and photophysics.
Synthesis and ESCA surface studies of octadecyl chain‐extended polyurethanes
Authors: Rahman Ron , Ratner Buddy D. 
Published: April 2003

AbstractPoly(ether urethane)s as biomaterials display certain favorable mechanical and biocompatibility properties. Earlier studies suggest that improved blood compatibility might be attained by introducing hydrocarbon groups at the surface. We synthesized and characterized a series of polyurethanes in which a N‐2,3‐dihydroxypropyl‐N′‐octadecyl urea chain extender (ODCE) was incorporated into the poly(tetramethylene glycol) (PTMO)/4,4′‐methylenebis(phenylene isocyanate) (MDI) system. Molecular weights of the polymers varied between 40,000 and 250,000. An electron spectroscopy for chemical analysis (ESCA) study of the ODCE polyurethane surface revealed a substantially enhanced hydrocarbon concentration compared to a control PTMO/MDI/ethylene diamine (ED) polyurethane surface. Also, bulk composition analyses and ESCA data of the ODCE polymers indicated that the percentage of carbon was higher in the surface region than in the bulk. Thus, the ODCE polymer showed a marked increase in hard‐segment concentration in the surface region compared to the bulk region and to the ED polymer.
Electroinitiated polymerization of acrylamide in nonaqueous media
Authors: Balasubramanian T. R. , Mahadevan V. 
Published: April 2003

AbstractAnodic electroinitiated polymerization of acrylamide has been studied in DMF and DMSO in the presence of Co(NO3)2 or Co(ClO4)2 in the temperature range 25–40°C. The kinetics and mechanism of the process has been investigated as a function of variables and a suitable mechanism proposed. From the experimental observations, the rate of polymerization is seen to be proportional to [AM]1.5, [I]0.5, and [Co2+]1. Current densities exceeding 15 mA/cm2 have no effect on the rates. The average degrees of polymerisation (P̄n) increase with increasing [AM] and decreasing [Co2+] and applied current, I. It has been shown that a monomer‐metal ion complex is oxidized at the anode, generating radical species. The polymerization and termination are confined to the anode compartment. The process is very efficient compared to the NO mediated reaction.
Polymerization of bis(2‐oxazoline) compounds with dicarboxylic acids
Authors: Sano Yasuo 
Published: April 2003

AbstractA side reaction was found in the reaction of a 2‐oxazoline compound with a carboxylic acid. It is an oxazoline ring opening addition to an amide group formed by the main reaction. In addition, certain phosphites were found to act as catalyst for the side reaction. The rate constants of the main and side reactions in the system of 2‐phenyl‐2‐oxazoline andn‐octanoic acid were obtained through simulation of the reactions on an analog computer. The side reaction makes it impossible for a very high molecular weight polymer to form in the reaction of a bis‐2‐oxazoline with a dicarboxylic acid, but makes it possible for a new crosslinked polymer to form when excess bis‐2‐oxazoline and a dicarboxylic acid are heated in the presence of a certain phosphite.
Synthesis of polyphthalocyanines by an oxido‐reduction reaction initiated by the benzhydrol functional group. II. Polymer study
Authors: Pascal Thierry , Malinge Jean , Sillion Bernard 
Published: April 2003

AbstractThree new bis(phthalonitrile) monomers carrying flexible aliphatic polyether sequences were synthesized and thermally polymerized to yield crosslinked poly(metal‐free phthalocyanine) networks. The procedure of thermal conversion of bis(phthalonitrile) monomers involved an oxidoreduction reaction initiated by the alcohol functional group of a benzhydrol phthalonitrile coreactant. The phthalocyanine polymeric networks were characterized by FT‐IR, TGA, TMA, and x‐ray diffraction. Their electrical dc conductive properties were studied in a pure and an iodine‐doped state.
Electron transfer function of kerateine gel and conjugated redox reaction by using the kerateine‐immobilized membrane
Authors: Nakamura Yoshiharu , Yamada Masaru , Miura Jun'ichiro , Hirota Koji , Hori Teruo 
Published: April 2003

AbstractKerateine gel, prepared by reducing wool keratin with alkaline 2‐mercaptoethanol‐urea solution and by partially reoxidizing the dissolved kerateine, reduced iron(III) to iron(II). Reduction of iron(III) was enhanced by addition of copper(II). Reduction of methylene blue (MB) to leuco MB with thioglycollic acid (TGA) as a model compound of wool thiol group was investigated in the presence of copper(II) and intercuticular cementing material (δCu) extracted from wool fiber. It is confirmed that copper(II) is a catalyst for the reduction of MB and the δCu containing copper ion acts as a carrier for electron transfer.Some kerateine/δCu‐immobilized hydrophilic polyurethane membranes were prepared. A conjugated redox reaction combining the reduction of MB and the oxidation of TGA was carried out across these membranes.
Living cationic polymerization of vinyl ethers with a functional group. VII. Polymerization of vinyl ethers with a silyloxyl group and synthesis of polyalcohols and related functional polymers
Authors: Higashimura Toshinobu , Ebara Kenji , Aoshima Sadahito 
Published: April 2003

AbstractLiving cationic polymerizations of two silicon‐containing vinyl ethers, 2‐(t‐butyldimethyl‐silyloxyl)ethyl vinyl ether (tBuSiVE) and 2‐(trimethylsilyloxyl)ethyl vinyl ether (MeSiVE), have been achieved with use of the hydrogen iodide/iodine (HI/I2) initiating system in toluene at −15 or −40°C, despite the existence of the acid‐sensitive silyloxyl pendants. The living nature of the polymerizations was demonstrated by linear increases in the number‐average molecular weights (M̄n) of the polymers in direct proportion to monomer conversion and by their further rise upon addition of a second monomer feed to a completely polymerized reaction mixture. The polymers obtained in these experiments all exhibited very narrow molecular weight distributions (MWD) with M̄w/M̄n around or below 1.1. Desilylation of the polymers under mild conditions (with H+ for MeSiVE and F− for tBuSiVE) gave poly(2‐hydroxyethyl vinyl ether), a water‐soluble polyalcohol with a narrow MWD. The living processes also permitted clean syntheses of amphiphilic AB block copolymers and water‐soluble methacrylate‐type macromonomers, all of which bear narrowly distributed segments of the polyalcohol derived from the silicon‐containing vinyl ethers.
Synthesis and characterization of phenolic hydroxyl terminated phenylquinoxaline oligomers
Authors: Labadie Jeff W. , Hedrick James L. 
Published: April 2003

AbstractThe synthesis of phenylquinoxaline oligomers of predictable molecular weight and with phenolic hydroxyl functional end groups is reported. The synthetic procedure utilizes 4‐hydroxybenzil as a substituted monofunctional monomer in a conventional PPQ synthesis to both control molecular weight and introduce the functional end groups. The molecular weights of the oligomers were determined by derivatization of the hydroxyl end groups with 3‐(trimethylsilyl)propionyl chloride, followed by 1H‐NMR analysis. Comparison of the integration of the trimethylsilyl resonance to the aromatic resonances allowed calculation of the number average molecular weight. A plot of log(η) vs. log(Mn) correlated well with that reported for high molecular weight PPQ. The end groups influenced the solubility behavior of the oligomers in chlorinated solvents, possibly due to hydrogen bonding. The oligomers were chain‐extendable to high molecular weight, confirming their suitability for utilization in copolymerizations to prepare phenylquinoxaline‐based block copolymers.