bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer reactions, 8. Oxidative pyrolysis of poly(propylene)
Authors: Chien James C. W. , Kiang Joseph K. Y. 
Published: April 2003

AbstractPoly(propylene) has been oxidized at temperatures between 240 and 289°C. The products were GC separated and on‐line identified by an interfaced GC peak identification system. The major products are CO2, H2O, acetaldehyde, acetone, butanal, formaldehyde, methanol and other ketones and aldehydes. Most of the products can be accounted for by well‐known reactions of alkoxyl and peroxyl radicals; the major products are derived from the secondary alkoxy and peroxy species. Oxygen starvation is manifested in diffusion limited products of olefins and dienes, and the increase of CO2 and H2O formation in pure oxygen atmosphere. The first order rate constant at 240°C is 2,4·10−3 S−1 with an overall activation energy of ca. 16 kcal·mol−1 (67 kJ·mol−1). If one assumes the oxidative pyrolysis to share the same reaction pathways as autoxidation at lower temperatures, then the observed rate constants and activation energy may be calculated from kinetic parameters measured earlier for autoxidation of poly(propylene) from 71 to 140°C. Good agreement was obtained implying a similarity of oxidative degradation of the polymers spanning a large temperature range.
Spectroscopic characterization and chiroptical properties of the copolymers of (−)3‐menthyl acrylate and (−)3‐menthyl methacrylate with styrene
Authors: Majumdar Ramendra Nath , Carlini Carlo 
Published: April 2003

AbstractOptically active copolymers of (−)3‐menthyl acrylate (MtA) and (−)3‐menthyl methacrylate (MtMA) with styrene (St) of different compositions were prepared by radical initiation. The reactivity ratios were determined by the least square evaluation of the Kelen‐Tüdös parameters. Substantially alternating copolymers by donor‐acceptor complex polymerization and the corresponding model compounds were also prepared. Spectroscopic and chiroptical properties of these copolymers and models were studied. The possible mechanisms of the generation of the induced dissymmetry of the longest wavelength π → π* electronic transition of the aromatic chromophore of St co‐units are discussed.
Functional metal‐porphyrazine derivatives and their polymers, 3. Catalytic activity of Fe(III)‐3,4,3′,4′,3″,4″,3″′,4″′‐octacarboxyphthalocyanine for decomposition of hydrogen peroxide
Authors: Shirai Hirofusa , Maruyama Akio , Takano Junji , Kobayashi Kesayoshi , Hojo Nobumasa , Urushido Kunio 
Published: April 2003

AbstractThe decomposition reaction of hydrogen peroxide was carried out by using Fe(III)‐3,4,3′,4′,3″,4″,3″′,4″′‐octacarboxyphthalocyanine (Fe(III)‐oaPc) as a catalyst, which has previously been reported by Boston et al. Fe(III)‐oaPc is a remarkably effective catalyst for the reaction, compared with hemin, other metal‐phthalocyanine compounds, or other iron complexes such as [Fe(III)‐(bipy)3]X3. The kinetics of this reaction was also investigated in the pH range 5,5 – 10,5 by measuring the initial velocity, V0, of the increasing concentration of O2 using a Warburg respirometer. The reaction proceeds according the catalase‐like mechanism. On the basis of the results of Sigel et al., the reaction mechanism is discussed.
Functional metal‐porphyrazine derivatives and their polymers, 4. Synthesis of poly(styrene) bonded Fe(III)‐ as well as Co(II)‐4,4′,4″,4″′‐tetracarboxyphthalocyanine and their catalase‐like activity
Authors: Shirai Hirofusa , Maruyama Akio , Kobayashi Kesayoshi , Hojo Nobumasa , Urushido Kunio 
Published: April 2003

AbstractMetal‐4,4′,4″,4″′‐tetracarboxyphthalocyanine [Metal = Fe(III), Co(II), Mt‐taPc] were synthesized by the hydrolysis of metal‐4,4′,4″,4″′‐tetracarboxamidephthalocyanine (Mt‐tamPc). These metal‐taPc are soluble in water and in aprotic polar solvents such as N,N′‐dimethylformamide. Poly(styrene) bonded Mt‐taPc was synthesized by Friedel‐Crafts reaction of poly(styrene) with Mt‐taPc tetraacid chloride. The polymers contain about 4 mole‐% Mt‐Pc rings which are covalently bonded to poly(styrene). The decomposition reaction of hydrogen peroxide by catalysis with polystyrene containing Mt‐Pc rings was carried out in heterogeneous aqueous media at pH 7,0. The polymer catalysts show a catalase‐like activity. The activation energies with the polymer bonded Mt‐Pc were found to be about half of those with Mt‐taPc. From continuous flow experiments in a column, the polymer attached catalyst was found to be very stable, compared with free Mt‐taPc.
Studies of optical activity of poly(l‐menthyl vinyl ether)
Authors: Kurokawa Masahiro , Minoura Yuji 
Published: April 2003

AbstractThe optical activities of poly(l‐menthyl vinyl ether) (PMVE), obtained by cationic polymerization were studied. The polymerizations were carried out at various temperatures (−72 to +30°C), with different solvents and catalysts. The optical rotation of PMVE, which was polymerized with BF3O(C2H5)2 in toluene at −72°C, was found to be independent of the initial monomer concentration; but it depends on the activity of the catalyst. The absolute values of optical rotation of PMVE decreased with increasing temperature and dielectric constant of the solvent. The relationship between the optical activities of PMVE and the polymerization conditions is discussed.
Erweiterte Meßmöglichkeiten in der analytischen Ultrazentrifugation durch die Verwendung eines neuartigen Kollimators
Authors: Floßdorf Josef 
Published: April 2003

AbstractThe experience with a novel collimating system enhancing the intensity of rotor illumination by a factor of 46 as compared with conventional equipment, is reported. This system allows to work at wave lengths down to 220 nm and/or to afford higher optical densities also in the solvent sector.
Poly(ethylene terephthalate): A solid state condensation process, 2. Copolymerization
Authors: Dröscher Michael 
Published: April 2003

AbstractCopolyesters of poly(ethylene terephthalate) containing 0,95 to 14,2 mole‐% di(oxyethylene)oxy units are prepared in a solid state condensation process. A low molecular weight prepolymer with reactive end groups is annealed at temperatures between 235 and 250°C. Samples with molecular weights from 2 000 to 26 000 are obtained. The melting behaviour of the copolyesters is determined by the crystallinity of the precondensate, the counit content, and the degree of polymerization.
Kinetics of nitrogen dioxide initiated polymerization of acrylamide
Authors: Bhadani Suraj N. , Prasad Yugal K. 
Published: April 2003

AbstractThe polymerization of acrylamide initiated by NO2 in DMF was investigated. The initial rate of the polymerization increases with the first power of the monomer concentration and a half power of the initiator concentration. The overall activation energy of the polymerization was determined to be about 20 kcal/mol (84 kJ/mol). The copolymerization of acrylamide was also carried out with MMA in a solution of NO2 in DMF. The copolymer was found to be enriched in MMA content. The polymerization appeared to be initiated by free radicals.
Dynamic mechanical behaviour of chlorinated polyethylene
Authors: Pereña José M. , Fatou José G. , Guzmán Julio 
Published: April 2003

AbstractDynamic mechanical measurements of chlorinated polyethylenes with chlorine contents ranging from 5,4 to 31 wt.‐% were carried out using a dynamic viscoelastometer. The complex modulus and loss factor were determined at four frequencies in the temperature range from −150°C to 100°C. Two relaxation processes (α and γ) were observed. The first one occurs at temperatures ranging from 21°C to 40°C, depending on the chlorine content; there is a minimum in the temperature of the α process at about 20 wt.‐% of chlorine. The activation energies for this α process are higher than 100 kcal/mol, and therefore this α relaxation is considered to be different from the α relaxation in linear polyethylene. On the other hand, the α relaxation of chlorinated polyethylenes is similar to that of the parent polyethylene, taking place at temperatures ranging from −137°C to −116°C (at 3,5 Hz). The activation energies for this α process range from 14 to 26 kcal/mol (1 kcal = 4,184 kJ).
Network disentanglement and time‐dependent flow behaviour of polymer melts
Authors: Wagner M. H. , Meissner J. 
Published: April 2003

AbstractFor small strains Lodge's rubberlike‐liquid theory is a valid description of the rheological behaviour of polymer melts, but at higher strains the theory fails: The phenomenon of shear thinning which is characteristic for the shear flow of nearly all polymer liquids is not explained, and in elongation the deviation of the experimental data from the predictions of Lodge's theory reflect also a flow thinning, and not a strain hardening in spite of the pronounced S‐shape of the stress‐strain diagrams. Comparing the measured stress growth and stress relaxation data with the predictions of the theory, it must be concluded that the temporary physical network structure of the polymer melt is destroyed increasingly with the magnitude of the deformation. Hence, the number of entanglements decreases with increasing strain. For simple shear and uniaxial extension of a well‐defined polyethylene melt the strain dependence of the relative entanglement density is discussed. The irreversibility of the disentanglement process of the network is considered.
Copolymerization of carbon dioxide with propylene oxide catalyzed by O‐methylated or crosslinked poly(p‐hydroxystyrene)/diethylzinc system
Authors: Tsuchida Eishun , Kasai Masanori 
Published: April 2003

AbstractEffective catalysts for the copolymerization of CO2 with 1,2‐epoxypropane were prepared from partially O‐methylated or crosslinked poly[1‐(4‐hydroxyphenyl)ethylene] and Zn(C2H5)2. The highest activity was obtained with catalysts of 30 to 40% methylation or crosslinking. Inactivation of the catalysts during the copolymerization was decreased by crosslinking, increasing the yield of the copolymer. The higher rigidity of the catalyst structure is responsible for its higher activity and stability.
Kinetik der Wachstumsreaktionen der Copolymerisation von Butadien und Styrol mit Lithiumorganylen
Authors: Ohlinger Rainer , Bandermann Friedhelm 
Published: April 2003

AbstractThe rate constants of the propagation reactions of the lithiumalkyl catalyzed copolymerization of butadiene and styrene in toluene were measured and their rate constants and activation energies and the association constants of the initiators were determined. It turned out, that the cross reaction of styryllithium with butadiene is faster by a factor of 100 as hitherto assumed. The problems in determining rate constants from copolymerization reactivity ratios are discussed.
The photosensitized grafting of N‐vinyl‐2‐pyrrolidone on cotton using anthraquinone reactive dyes
Authors: Abdel‐Hay Fouad I. , Barker Paul , Guthrie James T. 
Published: April 2003

AbstractThe photosensitized grafting of N‐vinyl‐2‐pyrrolidone on cotton has been successfully carried out over a range of pH values, monomer concentrations and for various concentrations of dye‐sensitizer. Grafting is shown to be critically dependent on each of these factors. Evidence is presented which suggests that the dye is only physically held by the substrate which in turn indicates that grafting occurs via a hydrogen abstraction process. The physical nature of the graft copolymer (cellulose‐co‐N‐vinyl‐2‐pyrrolidone) is shown through electron micrographs. Reflectance spectroscopy provides an insight into the part played by the dye‐sensitizer in the grafting reaction.
Peroxodiphosphate‐ascorbic acid redox couple as an initiator for vinyl polymerization
Authors: Hariharan S. S. , Maruthamuthu Meenakshi 
Published: April 2003

AbstractPrimary radical termination is found to be significant in the P2O84− ‐ascorbic acid redoxinitiated polymerization of acrylonitrile in aqueous solution at low converstions. Degradative chain transfer involving the P2O84− ‐ascorbic acid complex is invoked to explain the monomer exponent of unity and the initiator exponent of zero at high conversions (>10%) of the monomer.
Copolymerization of 1,6‐anhydro‐sugar derivatives with cyclic monomers, 1. Tri‐O‐benzyl ether and tri‐O‐methyl ether of 1,6‐anhydro‐ß‐D‐glucopyranose as sugar monomers
Authors: Uryu Toshiyuki , Hatanaka Kenichi , Matsuzaki Kei 
Published: April 2003

AbstractThe cationic, ring‐opening copolymerization of 1,6‐anhydro‐2,3,4‐tri‐O‐benzyl‐ß‐D‐glucopyranose with epichlorohydrin, 3,3‐bis(chloromethyl)oxetane and 1,3‐dioxolane was investigated with phosphorus pentafluoride as catalyst at low temperatures. Besides, copolymerization of 1,6‐anhydro‐2,3,4‐tri‐O‐methyl‐ß‐D‐glucopyranose with epichlorohydrin was studied. Structure and composition of the copolymers were determined by 1H and 13C NMR spectroscopy, indicating that copolymerization occurred in each combination of monomers. Number‐average molecular weights of copolymers were in the range of 1 400 to 22 800. From the specific rotation and 13C NMR spectrum of copolymers, it was revealed that the ring‐opening copolymerization of the benzylated 1,6‐anhydro‐glucopyranose with the cyclic monomers occurred in a stereoregular manner to give the C‐1 carbon of glucose unit with α‐configuration. Debenzylation of a copolymer prepared from 1,6‐anhydro‐2,3,4‐tri‐Obenzyl‐ß‐D‐glucopyranose and 1,3‐dioxolane gave a copolymer composed of free sugar units in the polymer main chain. Assignment of 13C NMR spectra of 2,3,4‐tri‐O‐benzyl‐ß‐D‐glucopyranan and of a copolymer of 1,6‐anhydro‐2,3,4‐tri‐O‐benzyl‐ß‐ß‐glucopyranose with 1,3‐dioxolane was attempted.
Synthesis of new monomers having a secondary amino group by lithium alkylamide catalyzed addition reactions of primary amines with 1,4‐divinylbenzene
Authors: Maeda Mizuo , Nitadori Yoshiaki , Tsuruta Teiji 
Published: April 2003

AbstractTo establish appropriate reaction conditions for the synthesis of new monomers having a secondary amino group, a lithium alkylamide catalyzed addition reaction of primary amines with styrene was examined as the model reaction. The selectivity of N‐alkyl‐2‐phenethylamines (2) and the rate constant of the reaction were determined. On the basis of results of the model reaction, new styrene derivatives having a secondary amino group (5) were synthesized by lithium alkylamide catalyzed addition reactions of primary amines with 1,4‐divinylbenzene.
Festphasensynthese von oligonucleotiden, 11. Verwendung eines neuartigen hydrophilen perlpolymerisats als träger
Authors: Heidmann Walter , Köster Hubert 
Published: April 2003

AbstractNew hydrophilic swellable and lowly crosslinked bead copolymers consisting of dimethylaminocarbonylethylene or ‐propylene and alkoxycarbonylethylene or ‐propylene repeating units were prepared starting from activated esters of acrylic acid (8a–10a) or methacrylic esters (8b–10b) and N,N‐dimethylacrylamide (12a). This “hydrophylic Merrifield carriers” were applied for polymer‐supported oligodeoxynucleotide syntheses. They were found to be swellable in a wide range of solvents. The first deoxynucleoside was attached to the carrier via its 5′‐hydroxyl group by an ester bond. The cleavage of the bond between carrier and oligonucleotide was performed with aqueous sodium hydroxide under conditions which do not attack the N‐protecting groups attached to the oligonucleotide chain. The acid labile 1‐ethoxyethyl group was used as 3′‐protecting group for the phosphate component (N‐protected deoxynucleoside‐5′‐phosphate). Some suitable protected deoxynucleosides were synthesized for anchoring and deoxynucleoside‐5′‐phosphates for chain elongation. In a condensation reaction according to the diester method, a dinucleoside monophosphate (7) was prepared and, as a consequence of the flexibility of the polymeric backbone, the synthesis of longer oligonucleotides should be feasible. The alkali labile anchoring of the oligonucleotides to the carrier can allow to avoid wrong sequences by simple acylation of the non‐reacted 3′‐OH groups with acetic anhydride after each condensation step.
Festphasensynthese von oligonucleotiden, 12. Reaktionskinetische untersuchungen an einem quellbaren perlpolymerisat von acrylsäuremethylester
Authors: Heidmann Walter , Köster Hubert 
Published: April 2003

AbstractThe hydrolysis reaction of a swellable and lowly crosslinked bead polymer of methyl acrylate was studied. The linearity of the Arrhenius plot and the activation energy of 79,5 kJ/mol (19 kcal/mol) showed the reaction to be homogeneous. The activation energy of 46 kJ/mol (11 kcal/mol) for the liquid phase ester hydrolysis leads to a difference of 39,5 kJ/mol (8 kcal/mol) which is assumed to be the energy of diffusion. Hence, the swollen polymer behaves like a solvent of high viscosity, and the hydrolysis of the bead polymer of methyl acrylate is influenced in a complex manner by diffusion phenomena. Some of the carboxylate groups in the polymer could be activated with p‐toluenesulfonyl chloride and subsequently linked to the 5′‐OH of a 3′‐O‐protected deoxynucleoside. The minimum space of an ester group needed for being hydrolized by 0,2 M ethanolic sodium hydroxide was estimated to be 12 Å3, whereas the activated complex formed between the carboxylate group in the polymer and p‐toluenesulfonyl chloride needs about 51 Å3.
Analysis of small angle x‐ray scattering intensity of hard elastic polypropylene under extension
Authors: Shimizu Yoshio , Miyasaka Keizo , Ishikawa Kinzo 
Published: April 2003

AbstractThe influence of the changes in density and the extension distribution function on the profiles of the small angle X‐ray scattering of a hard elastic polypropylene film under extension was investigated. So far the scattering behavior of crystalline polymers, consisting of nearly parallel lamellae and intervening layers staked perpendicular to the fiber axis, has been described based on the lattice factor and the structure factor of a constant density difference. In this work it could be shown that the structure factor depends not only on the thickness, decided by the extension distribution function, but also on the density changing with the extension of each layer. Good agreement with the observation that the profile greatly changes in shape and intensity with extension could be obtained by introduction of an extension distribution function and a density function for the intervening layers.
Synthesis of polyamides containing 4,4′‐azodibenzamido units
Authors: Balasubramanian Mannarsamy , Nanjan Moola Joghee , Santappa Muchi 
Published: April 2003

AbstractFour coloured polyamides containing azo‐p‐phenylene units were synthesised from 4,4′‐azodibenzoic acid and four aromatic diamines employing both interfacial and solution polymerization procedures. The polymers were characterized by their UV and IR spectra, by inherent viscosity measurements and by solubility data. The stability in conc. sulfuric acid and the thermal behaviour are discussed.
Structure and properties of segmented poly(ether ester)s and polyurethanes, 5. Synthesis of uniform oligo(oxytetramethylene)s
Authors: Bill Rudolf , Dröscher Michael , Wegner Gerhard 
Published: April 2003

AbstractThe synthesis of a series of homologous α‐hydro‐ω‐hydroxyoligo(oxytetramethylene)s, of the corresponding bis(phenylurethane)s, and of α‐hydro‐ω‐chlorooligo(oxytetramethylene)s is described. The purity of the individual oligomers was characterized by gel permeation chromatography and their melting behaviour was investigated. A value of 45 ± 2°C is derived as the equilibrium melting point of poly(oxytetramethylene) from a suitable extrapolation of the melting point of the oligomers to infinite molecular weight.
Polymerisationsauslösung mit substituierten ethanen, 2. Trennung der Oligomeren aus Methylmethacrylat und 1,1,2,2‐Tetraphenyl‐1,2‐diphenoxyethan
Authors: Błedzki Andrzej , Balard Henri , Braun Dietrich 
Published: April 2003

AbstractThe telechelics 1 from methyl methacrylate and 1,1,2,2‐tetraphenyl‐1,2‐diphenoxyethane, can be separated by adsorption chromatography. The structure of the dimers and trimers was identified by 1H NMR‐spectroscopy. The free radical oligomerization is a process in which the syndiotactic structure is favoured above the isotactic one.
Polymerization of epoxides catalysed by metalloporphine
Authors: Aida Takuzo , Mizuta Ryushin , Yoshida Yasuhiko , Inoue Shohei 
Published: April 2003

AbstractThe catalyst system obtained by the equimolar reaction of diethylaluminium chloride with α,β,γ,δ‐tetraphenylporphine exhibits high catalytic activity in the polymerization of propylene oxide to give a polymer with a narrow molecular weight distribution. Average molecular weight of the polymer can be controlled by the initial mole ratio of propylene oxide to catalyst or by the conversion. Ethylene oxide also produces a polymer having a narrow molecular weight distribution.
15N NMR spectroscopy, 27. Spectroscopic characterization of polyurethanes and related compounds
Authors: Kricheldorf Hans R. , Hull William E. 
Published: April 2003

AbstractNatural abundance 15N and 13C NMR spectra of various polyurethanes were measured in trifluoroacetic acid. The polyurethanes were built up from aliphatic diols, polyesters of diols or oligoethylene glycols on the one hand, and from aliphatic α,ω‐diisocyanates or aromatic diisocyanates, on the other hand. In addition to the polyurethanes various low molecular weight model compounds, such as ureas, biurets, allophanic acid esters, uretdions and 1,3,5‐triazinetriones, were investigated. The substituent effects of phenyl groups in the above mentioned compounds were studied in various solvents. 15N NMR spectra were found to be more useful than 13C NMR spectra for the identification of the various isocyanate derivatives, while 13C NMR spectra have the advantage of a better signal‐to‐noise ratio.
Mass spectrometric characterization and thermal decomposition mechanism of some poly(organophosphazenes)
Authors: Ballistreri Alberto , Foti Salvatore , Montaudo Giorgio , Lora Silvano , Pezzin Giovanni 
Published: April 2003

AbstractThis work is concerned with the mass spectrometric characterization of polyaryloxy‐ and polyaminophosphazenes 1a–e. The mass spectral data show that the pyrolytic breakdown of poly(di‐β‐naphthoxyphosphazene) (1a) leads to the formation of cyclic oligomers. The poly(di‐arylaminophosphazenes) 1b–d decompose at low temperatures by a two‐stage process involving amine evolution. Finally, in the case of poly(dipiperidinophosphazene) (1e) the thermal decomposition leads to the complete destruction of the polymer backbone, with formation of ammonia and elemental phosphorus. The wide range of thermal decomposition pathways observed are peculiar of the phosphazene structure and represent a remarkable difference between this class of inorganic polymers and the organic ones.
Radiation graft polymerization of styrene to cellulose acetate‐butyrate
Authors: Odian George , Tsay Jiunn 
Published: April 2003

AbstractThe kinetics of radiation graft polymerization of styrene onto cellulose acetate‐butyrate is studied over a range of radiation intensities and monomer concentrations. The reaction is diffusion‐free under the experimental conditions as shown by the independence of the grafting rate on film thickness. The dependence of the grafting rate on monomer concentration increases from 3/2‐order to slightly greater than 5/2‐order with increasing radiation intensity. The dependence of the grafting rate on radiation intensity decreases from 1/2‐order to 0‐order with decreasing monomer concentration. Possible mechanisms for these results are discussed.