bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and electrical properties of poly(3‐thienylacetylene)
Authors: Tanaka Susumu , Okuhara Kunio , Kaeriyama Kyoji 
Published: April 2003

Abstract3‐Thienylacetylene (1) was prepared by reaction of 3‐(2,2‐dichloro‐1‐fluorovinyl)thiophene with butyllithium in a 1 : 2 mole ratio, and subsequent hydrolysis. Polymerization of 1 with WCl6 and tetraphenyltin gave poly(1), poly[1‐(3‐thienyl)vinylene], which contained a small amount of benzene‐insoluble product. On heating poly(1) no weight loss was observed up to 240°C. At 500°C the weight loss was 18%. In differential scanning calorimetry, an exothermic peak appeared at 245°C. A pressed pellet, doped with iodine, exhibits conductivity of about 10−3 S/cm. The absorption spectrum of poly(1) shows a shoulder at 225 nm, a maximum absorption at 360 nm and tailing up to about 660 nm. In a solution of poly(1) and I2, a new absorption appeared in the near‐infrared region, but failed to develop enough to suggest high conductivity of poly(1) doped with iodine. The electrochemical doping of poly(1) and electrochemical polymerization of 1 gave no conducting products.
Dégradation de polybutadiènes par métathèse avec l'hexène‐3 dioate de diméthyle
Authors: Campistron Irène , Reyx Danièle 
Published: April 2003

AbstractStudies of metathetic degradation of polybutadienes containing 70 to 80% of 2‐butene‐1,4‐diyl units (1) in presence of dimethyl 3‐hexenedioate (2) were carried out applying WCl6/Me4Sn as catalyst and r = [2]/[1] values varying between 0,4 and 0,01. The degradation was followed by steric exclusion chromatography, and the structural composition of degraded products was determined by 1H NMR. For r = 0,2, the degradation by cross metathesis between 1 and 2, leading to α,ω‐bifunctionalized “prepolymers”, is superimposed by degradation via intramolecular metathesis and cationic cyclization of 1 units. Cationic side reactions (cyclization) are minimized by addition of ethyl acetate to the catalytic system.
Synthesis of antitumor‐active conjugates of adriamycin or daunomycin with the copolymer of divinyl ether and maleic anhydride
Authors: Hirano Takashi , Ohashi Shinichi , Morimoto Satoshi , Tsuda Keishiro , Kobayashi Tomowo , Tsukagoshi Shigeru 
Published: April 2003

AbstractPolymeric conjugates of adriamycin (ADR) (2) or daunomycin (DM) (3) were synthesized by reaction of the drugs with the copolymer of divinyl ether and maleic anyhdride (DIVEMA) (1). The content of ADR moieties in the DIVEMA conjugate (4) could be varied depending on the reaction conditions up to 35,8 wt.‐%. Considering the low toxicity and the high possibility of renal excretion, DIVEMA with M̄w of 7000 and M̄w/M̄n = 1,6 was used for the conjugation. The rate of drug release from the conjugate was determined under physiological conditions by reversed phase HPLC. Within 14 days only 15% of the attached ADR was released from conjugate 4. The antitumor activity of the conjugates was tested in vitro and in vivo against mouse P388 leukemia. Conjugate 4 proved to be 28 times less active than ADR in vitro, which could be explained from the slow drug‐release. On the contrary 50% of the leukemic mice treated by 4 survived more than 60 days, whereas no mice given ADR alone or the admixture of ADR and DIVEMA survived 30 days. An antitumor activity of the polymeric conjugate better than that of the free drug was also observed in vivo with DM. Such a polymeric effect can be attributed either to the change in body distribution, the difference in pharmacokinetics, or the slow drugrelease.
Lyotropic mesophase of imogolite, 2. Microscopic observation of imogolite mesophase
Authors: Kajiwara Kanji , Donkai Nobuo , Fujiyoshi Yoshinori , Inagaki Hiroshi 
Published: April 2003

AbstractImogolite, though achiral, forms cholesteric spherulites in the anisotropic phase as shown by the regular striations arranged in a swirl‐like or fingerprint pattern observed through a polarizing microscope. Electron microscopy revealed the raft‐like imogolite sheet floating in the anisotropic phase. The structure of the imogolite sheet was deduced from periodicities observed by an electron microscope using various imaging conditions. The origin of the twisting force to maintain the cholesteric ordering is also discussed.
Emulsifying properties of saturated polyesters
Authors: Baumann Harald , Joos Betina , Funke Werner 
Published: April 2003

AbstractSaturated emulsifying polyesters (EPE's) with terminal carboxyl groups were prepared by melt condensation from 1,6‐hexanediol, 1,4‐butanediol, phthalic acid, and adipic acid. The EPE's were characterized by molar mass, acid number, and hydroxyl number. Micelle formation of the EPE in the neutralized state was studied. The critical micelle concentration of the EPE is influenced by chain structure, chain length, temperature, and presence of electrolyte. A monomer mixture of styrene/unsaturated polyester (1 : 1 by wt.) was solubilized with different EPE's. On addition of NaHCO3 and NaCl the monomer mixture is optimally solubilized at a distinct concentration of electrolyte. At the optimal electrolyte concentration the solubilization of the monomer mixture is influenced by chain structure and chain length of the EPE.
Polymeric phthalocyanines and their precursors, 12. Reversible reduction and reoxidation of thin films of octacyanophthalocyanine in polymer matrices
Authors: Wöhrle Dieter , Kaune Holger , Schumann B. , Jaeger Nils 
Published: April 2003

AbstractThin films containing 1–100 μg 2,3,9,10,16,17,23,24‐phthalocyanineoctacarbonitrile (1) and 10–100 μg poly(N‐vinylcarbazole) (2) resp. the polyimide 3 were prepared on gold substrates through casting from solution. Smooth green coloured films were obtained. According to VIS spectra molecules of 1 are aggregated within the polymer matrices. Cyclic voltammetric measurements were carried out in 0,5 M sulfuric acid. Mixed films of 1 and 2 show remarkably stable electrochromic redox behaviour and the charge exchanged in the cathodic and anodic wave, respectively, was found to be between 2,3 and 2,7 F/mol for scan rates up to 400 mV · s−1. For mixed films of 1 and 3 with lower amount of 1 or increasing layer thickness the reduction and reoxidation appears to be a diffusion controlled process.
Morphology of triblock copolymers in the presence of unbonded segments
Authors: Perego Giovanni , Roggero Arnaldo , Vitali Roberto , Zazzetta Alessandro , Skoulios Antoine 
Published: April 2003

AbstractThe morphology of ABA triblock copolymers [A: polystyrene, poly(α‐methylstyrene); B: polybutadine] containing unbonded A′ segments (free A chains) was studied using small‐angle X‐ray scattering and transmission electron microscopy. Experimental results indicate the formation of ‘mixed’ segregation microdomains containing both A and A′ segments. With the assumption that homopolymer molecules locate themselves in the central region of the microdomains, away from the interfacial regions — which sounds reasonable at least when the homopolymer concentration is not too high — simple equations were derived permitting the calculation of the microdomain size that would correspond to systems deprived of their parasitic homopolymer. Values obtained are in fairly good agreement with those predicted by Helfand's thermodynamic theory.
Lithium alkylamide catalyzed addition reactions of alkylamines to vinyl monomers, 1. Selective formation of N‐α‐methylbenzyl‐4‐vinylphenethylamine
Authors: Narita Tadashi , Hagiwara Tokio , Hamana Hiroshi , Kurashima Tomihiro 
Published: April 2003

AbstractThe lithium alkylamide catalyzed addition reaction of α‐methylbenzylamine (1) with styrene was found to produce selectively N‐phenethyl‐α‐methylbenzylamine (3). Under the same reaction conditions, addition of (S)‐α‐methylbenzylamine (1′) to 1,4‐divinylbenzene (5) takes place selectively leading to the optically active novel styrene derivative, (S)‐N‐α‐methylbenzyl‐4‐vinylphenethylamine (6), in a one‐step reaction. The specific rotation was found to be [α]4D = −70,1° (c = 1,61 g/dl, in methanol). The following Q, e‐values and the monomer reactivity rations of 6(M1) and styrene (M2) were obtained: Q1 = 1,59, e1 = −1,28; r1 = 0,86, r2 = 0,92.
Synthesis and curing of poly(styrylpyridine)s. Structural study on models and on the resins, 1. Thermal behaviour of low‐molecular‐weight styrylpyridines
Authors: Clavreul Régine , Bloch Bertrand , Brigodiot Maryvonne , Maréchal Ernest 
Published: April 2003

AbstractIt could be shown that the structure of poly(styrylpyridine)s (PSP), which are heat resistant thermosetting resins resulting from the polycondensation of 2,4,6‐trimethylpyridine (1) with terephtalaldehyde (2), is much more complicated than that expected from this polycondensation. 2‐Styrylpyridines were synthesized from benezaldehyde (5) and 2‐methylpyridines and the stability of the respective intermediate alcohol was studied. The thermal behaviour of the styrylpyridines alone or in the presence of their precursors was studied by GPC, IR and NMR spectroscopy and by chemical analyses. It could be shown that the methyl group of 2‐methylpyridine (4) adds reversibly to the double bond of 2‐styrylpyridine (7) to form 2‐phenyl‐1,3‐bis‐(2‐pyridyl)propane (8). This side reaction takes place also in the case of the condensation of 1 with 5. The structures and the reactivity of the condensation products of 1 with 1,2 or 3 molecules of 5 (compounds 14, 17 and 18) were studied. The condensation product 19, a component of PSP resins, was synthesized from 1 and 2 and its reactivity was studied at 200 and 250°C and compared with the non‐methylated derivative 1,4‐bis[2‐(2‐pyridyl)vinyl]benzene (25). The results of a preliminary analysis of the reactions taking place during the PSP thermosetting are reported.
Synthesis and curing of poly(styrylpyridine)s. Structural study on models and on the resins, 2.1H and 13C NMR study of the models
Authors: Clavreul Régine , Bloch Bertrand , Brigodiot Maryvonne , Maréchal Ernest 
Published: April 2003

AbstractThe structures of the compounds, resulting from the condensation of 2‐methylpyridine, 2,6‐dimethylpyridine and 2,4,6‐trimethylpyridine with benzaldehyde and terephtalaldehyde, were confirmed by high field 1H and 13C NMR spectroscopy. Structural assignments were made based on the NMR spectra of the intermediate compounds, 4‐[1‐hydroxy‐2‐4,6‐dimethyl‐2‐pyridyl‐ethyl]benzaldehyde (5) and 4‐[1‐hydroxy‐2‐(6‐methyl‐2‐pyridyl)ethyl]benzaldehyde (6), of the main reaction products 2‐styrylpyridine (3) and 1,4‐bis[2‐(4,6‐dimethyl‐2‐pyridyl)vinyl]‐benzene (1), and of the side reaction product 2‐phenyl‐1,3‐bis(2‐pyridyl)propane (4) resulting from the addition of the methyl groups of 2‐methylpyridine to the double bond of 3.
Polymerization of isobutene with VOCl3 in heptane
Authors: Hasenbein Norbert , Bandermann Friedhelm 
Published: April 2003

AbstractThe polymerization of isobutene with VOCl3 in heptane was investigated. In contrast to reports in the literature, the polymerization only starts upon irradiation with light, also when naphthalene is added, and it ceases when the light source is switched off. Thus, it is suggested that the reaction proceeds like a photoinitiated cationic polymerization, and the claim of a living system is not corroborated.
Surface wettability of silicone rubber films
Authors: Koßmehl Gerhard , Neumann Walter , Schäfer Horst 
Published: April 2003

AbstractSilicone films were equilibrated with special organosiloxanes in the presence of hexacholorocyclotriphosphatriene as catalyst in ethers as solvents. Thus, the hydrophobic silicone films developed a hydrophilic surface. This surface treatment does in no way reduce the oxygen permeability of the silicone films. The special organosiloxanes required for the equilibration were produced by addition of allyl compounds containing protected OH‐groups to siloxanes containing SiH‐groups, applying H2PtCl6 as catalyst, and subsequent hydrolysis of the addition products.
Effect of N,N,N′,N′‐tetramethylethylenediamine on the reaction parameters of Ziegler‐Natta macromolecular complexes in the polymerization of ethylene
Authors: Mederven Craig , Brun Bruno , Siove Alain , Fontanille Michel 
Published: April 2003

AbstractSoluble complexes of ω‐lithiumbutenylpoly(styrene‐co‐butadiene) (≈ 100: ≈ 3 DP) with TiCl4 were used in conjunction with N,N,N′,N′‐tetramethylethylenediamine (TMEDA), to initiate the polymerization of ethylene. The activity of such a system was measured as a function of the number of amino groups (N) per active center (A. C.) ([N]/[A. C.]). From measurements of the amount of polystyrene‐block‐polyethylene produced and from kinetic studies of the polymerization of ethylene, the influence of TMEDA on both the efficiency of the system and the reactivity of the active species was studied. The depressor effect of the diamine on the reaction parameters, controlling the polymerization of ethylene, was connected with the proposed structure of the active sites. The role of the Lewis base was discussed by assuming a reversible blockage of a vacant coordination site at the titanium throughout the complexation of the electrophilic “host sites” of the polymer [TiCl2, TiCl3, 3 LiCl] complexes.
Copolymerization via zwitterion, 8. β‐butyrolactone and 2‐ethyl‐2‐oxazoline
Authors: Rivas Bernabé L. , Canessa Guido S. , Pooley Sonia A. 
Published: April 2003

Abstract2‐Ethyl‐2‐oxazoline (ETOX) as nucleophilic monomer and β‐butyrolactone (BUL) as electrophilic monomer were copolymerized in bulk in the absence of initiator at 45°C. Copolymers were characterized by elemental analysis, IR, 1H NMR, and 13C NMR spectroscopy. The copolymer composition was determined by elemental analysis and by 1H NMR spectroscopy. All copolymers contain a BUL:ETOX mole ratio greater than one.
Computer simulation of the steady state in reversible polymer‐analogous reactions, 2. Simulation of the statistics in detailed balance
Authors: Krieger Dorit , Klesper Ernst 
Published: April 2003

AbstractThe steady state of reversible polymer‐analogous reactions is simulated by Monte Carlo methods. Two types of sets of relative rate constants were investigated, first, K1 = K2 = K3, K1 · K3 = (K2)2, and second, K1 ≠ K2, K1 ≠ K3, K2 ≠ K3, K1 · K3 = (K2)2. For both cases a detailed balance was found. The sequence probabilities depend on dimensionless relative rate constants Kn only, while the rates of sequence flow depend on reaction probabilities p and ordinary rate constants k. For the first case, the sequence probabilities obey a Bernoullian statistics, while for the second case a first‐order Markov statistics is found.
Kinetics of the free radical terpolymerization of diethyl maleate with methyl methacrylate and styrene
Authors: Braun Dietrich , Cei Gustavo 
Published: April 2003

AbstractThe kinetics of the free radical terpolymerization of diethyl maleate (DEM) (M1) with methyl methacrylate (MMA) (M2) and styrene (M3) was investigated at 60°C with AIBN as initiator. The analysis of the dependence of the terpolymer composition on the feed composition was difficult due to the similar chemical and physical properties of diethyl maleate and methyl methacrylate and also by the low content of the former monomer in the terpolymers. Finally, the terpolymer composition could be determined by means of microanalyses of carbon and hydrogen content. The results of these determinations were confirmed by 13C NMR spectroscopy. The initiation rate constant of AIBN was studied at different feed compositions by means of the inhibition method. For the study of the over‐all polymerization kinetics of this ternary system it was necessary to take into account the dependence of the termination rate on the feed composition. It was found that not only the viscosity of the solution, but also the properties of the polymer segment next to the radical site have to be considered. Containing only parameters and constants measured independently from terpolymerization, the kinetic equation obtained described satisfactorily the initial over‐all rates.
Polymerization of lactams, 77. On the limit temperature (ceiling temperature) of the anionic polymerization of 2‐pyrrolidone
Authors: Fries Tomáš , Bělohlávková Jana , Nováková Olga , Roda Jan , Králíček Jarosloav 
Published: April 2003

AbstractThe kinetics of the nonactivated anionic polymerization of 2‐pyrrolidone (PD) initiated with the potassium salt of 2‐pyrrolidone (KPD) and anionic polymerizations of PD accelerated with CO2 and 1‐(1‐pyrrolin‐2‐yl)‐2‐pyrrolidone or activated with 1‐benzoyl‐2‐pyrrolidone and 1‐acetyl‐2‐pyrrolidone were followed near the ceiling temperature (limit temp. T1) and discussed. The values of T1 were extrapolated from the data obtained for the given initiation systems. The dependence of T1 on the concentration of the initiation system was also investigated.
Steric effects on excimer formation in 2‐amino‐1,3‐di(2‐naphtyl)propane luminiscent markers covalently bonded to poly [N‐(2‐hydroxypropyl)methacrylamide]
Authors: Burešová Marie , Koñák Čestmír , Labský Jiří 
Published: April 2003

AbstractThe fluorescence spectra of poly[N‐(2‐hydroxypropyl)methacrylamide] (poly[1‐(2‐hydroxypropylaminocarbonyl)‐1‐methylethylene]) with covalently bonded luminiscent markers (2‐amino‐1, 3‐di(2‐naphthyl)propane (ADNP)) dissolved in methanol were measured over the temperature range 190–290 K. The effect of the spacer length on intramolecular excimer formation in ADNP was investigated. The ratio of the fluorescence intensities of the dimer ID and the monomer IM follows an Arrhenius temperature dependence in the temperature range 190–250 K with an activation energy independent of the spacer length. The numerical value of ID/IM at constant temperature increased with increasing spacer length reaching quickly a limiting value. The effect is explained by increasing hindrance to intramolecular excimer formation which is due—particularly for the shortest spacers—to increased steric interactions of the marker with the polymer chain.
Influence of termination and transfer on molecular weight distribution of polymers, 8. Spontaneous transfer
Authors: Yuan Cui‐ming , Yan De‐yue 
Published: April 2003

AbstractThe kinetics of cationic polymerization with instantaneous initiations and spontaneous transfer is treated theoretically. By means of a non‐steady state analysis, rigorous expressions for the molecular weight distribution and other molecular parameters are derived from the set of differential equations without introducing any approximations. The influence of spontaneous transfer on the molecular weight distribution is discussed in detail based on several numerical examples.
Conductivity and spectroscopic characterization of polyacetylene doped with ferric chloride
Authors: Chen Zhongxin , Shen Zhiquan , Chen Changshen , Zhao Yonggang , Yang Mujie 
Published: April 2003

Abstractcis‐ and trans‐PolyacetyleneSystematic name: (Z)‐ and (E)‐poly(viny1ene).
films prepared by a rare‐earth coordination catalyst were doped with ferric chloride in nitromethane solution. The doped polyacetylene films [CH(FeCl4)y]x exhibit high electrical conductivities which change very little when stored in dry air. Infra‐red absorption bands at 900 cm−1, 1300 cm−1 and 1400 cm−1 are typical for cis‐and trans‐polyacetylenes slightly doped with FeCl3. In the samples with dopant mole fractions y < 0,02, two superimposed ESR signals with different g values are observed: one very narrow, the other one extraordinarily broad. 57Fe‐Mössbauer effect measurements reveal that Fe(II) and Fe(III) species coexist in freshly doped cis‐polyacetylene, appearing in the form of FeCl2 · nH2O and FeCl−4, respectively. Fe(II) species do not interact with the polyacetylene chain; they exist at a site separated from Fe(III) species.
Polymerizable tautomers, 4. Solvent effects in radical copolymerization of ethyl 3‐oxo‐4‐pentenoate and styrene
Authors: Masuda Seizo , Tanaka Masami , Ota Tadatoshi 
Published: April 2003

AbstractEthyl 3‐oxo‐4‐pentenoate (1) exhibits the coexistence of two tautomers, the ketonic and enolic form, and its tautomeric equilibrium shifts with the solvent. The monomer reactivity ratios for the radical copolymerization of 1 (M1) and styrene (M2) in various solvents were determined. There is a marked and a minor solvent effect on r1 and r2, respectively. Regression analysis of r1 with the solvatochromic parameters yields a fairly good linear relationship, taking into account three factors: polarity and hydrogen bond donating and accepting powers of the solvents.
A calorimetric investigation of interactions in aqueous solutions of poly(oxyethylene), 1. Heats of mixing of oligomeric models
Authors: Biroš Ján , Pouchlý Julius , Živný Antonín 
Published: April 2003

AbstractHeats of mixing with water as function of the composition of the mixtures for oligomeric models of poly(oxyethylene) at 25°C are reported, i. e. for compounds of the type XO(CH2CH2O)nX (where X = H or CH3 and n = 1, 2, 3, or 4) and CH3O(CH2CH2O)mH (where m = 1 or 2). These dependencies greatly depend on the character of the end groups and on the degree of oligomerization. A procedure has been suggested for the comparison between the heat of mixing of longer chains and that of shorter ones with elimination of the effect of end groups. On the same mass basis, longer chains release more heat than shorter ones in mixing with water for concentrated solutions; hence, one may assume some kind of cooperativity of ether oxygen atoms in the same chain by hydration.
Crystallization kinetics of 1,4‐trans‐polyisoprene, 1. Pure polymer
Authors: Chaturvedi Prakash N. 
Published: April 2003

AbstractThe Crystallization kinetics of an unfractionated sample of 1,4‐trans‐polyisoprene was studied from its melt by means of the dilatometric method. The data are analysed according to the secondary nucleation theory. A critical discussion and comparison of previously published kinetic parameters with those derived in the present study is made. The values of the product of interfacial free energies, σσe, were found to be 590,5 and 915 erg2/cm4 for the low melting and high melting polymorphs, respectively. The observed deviation from the Avrami theory towards completion of the process is interpreted to be due to the low molecular weight species of the low melting polymorph.
Spherulites primary nucleation in binary miscible blends of poly(ethylene oxide) with poly(methyl methacrylate)
Authors: Bartczak Zbigniev , Martuscelli Ezio 
Published: April 2003

AbstractThe influence of composition on the primary nucleation process of poly(ethylene oxide) spherulites in the case of poly(ethylene oxide)/poly(methyl methacrylate) (PEO/PMMA) blends was investigated by optical microscopy and DSC. In the case of isothermally crystallized samples it was found that heterogeneous nucleation is depressed in the blends in comparison with plain PEO. This depression is caused by the dilution effect of PMMA. The self‐seeding nucleation mode is also disturbed by the presence of PMMA in the blends. This is due to both the diluent effect and to the decrease of the PEO melting temperature. In the case of non‐isothermally crystallized samples of PEO/PMMA blends an apparent increase of the nucleation density was observed. This observation is attributed to the fact that the growth rate is depressed in the blends: thus, at an earlier stage of crystallization, the volume in which the nuclei are free to develop (for a given crystallization condition) is larger.