bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ammonium salt catalyzed copolymerization of 2‐hydroxy‐4‐(2,3‐epoxypropoxy)benzophenone with phthalic anhydride
Authors: Lustoň Jozef , Maňásek Zdeněk 
Published: April 2003

AbstractAmmonium salt catalyzed copolymerization of 2‐hydroxy‐4‐(2,3‐epoxypropoxy)benzophenone with phthalic anhydride was studied. The conversion curves could be linearized by the first order equation and the experimental rate constants kexp for the initiation by various ammonium salts were determined. The rate of copolymerization was found to depend on the size of the cation but not on the type of anion. kexp is a function of the first power initiator concentration but is independent of epoxide and anhydride concentration. The activation energy for the cetyltrimethylammonium bromide (CAB) initiated copolymerization in nitrobenzene was determined to be 73,5 kJ/mol. The kinetic scheme of copolymerization, which agrees well with the experimental results, was solved. The rate constant of the copolymerization of 2‐hydroxy‐4‐(2,3‐epoxypropoxy)benzophenone with phthalic anhydride catalyzed by CAB in nitrobenzene was found to be 2,76·10−2l.mol−1·s−1. The ratio of rate constants for both propagation steps, i.e. reaction of carboxylate anion with epoxide (k3) and reaction of alkoxide anion with anhydride (k2), was determined to be k3/k2 = 0,2 ± 0,1.
Stabile Polyphenoxyle, 4. Polymere aus sterisch gehinderten, geschützten Vinylphenolen
Authors: Braun Dietrich , Wittig Wolfgang 
Published: April 2003

Abstract2,6‐Di‐tert‐butyl‐4‐vinylphenyl trimethylsilyl ether (1e) and 2,6‐di‐tert‐butyl‐4‐vinylphenyl acetate (1c) were synthesized and polymerized by cationic and free radical initiators. The protecting groups could be splitted off from the polymers by hydrolysis in acidic medium or by reduction with lithium aluminium hydride, resp., yielding high molecular sterically hindered free polyphenols.
Amorceurs radicalaires fonctionnels, 2. Macroinitiateurs à partir de l'α‐hydrogeno‐ω‐hydroxypoly(oxyéthylène) et des acides tert‐butyldioxycarbonylbenzoïques
Authors: Ladousse Alain , Maillard Bernard , Villenave Jean‐Jacques , Filliatre Claude 
Published: April 2003

AbstractModified polystyrenes were obtained by free radical polymerization of styrene using the macroinitiators α‐tert‐butyldioxyterephthaloyl(or phthaloyl)‐ωtert‐butyldioxyterephthaloyl(or phthaloyl)poly(oxyethylene) (3 and 4), which were synthetized. To examine the stability of such compounds, thermolysis kinetics of model compounds, OO‐tert‐butyl O‐methyl monoperoxyphthalate (6) and terephthalate (7) were studied by differential scanning enthalpimetry. Suspension polymerization of styrene applying the industrial method, showed that the macroinitiator is able to initiate the process. A polystyrene containing up to 4% by weight oxyethylene units was obtained.
Approche simple du problème de la distribution des séquences dans les terpolymères
Authors: Rios Léonardo , Guillot Jean 
Published: April 2003

AbstractThis work deals with a very simple determination of the variation limits, and to some extent, to the variation itself of the sequence distribution in a terpolymer without assistance of computer programming. A simple analytical approach is stated and shown that it is sufficient to consider only the corresponding binary copolymerizations involved in the ternary polymerization. Calculations are applied to the function Ac/L̄n(A), i.e. the ratio of the mole fraction of monomer A in the terpolymer Ac to the number average sequence length of this monomer in the terpolymer.
Synthesis of a polydithiocarbonate from carbon disulfide, alkali metal diolate and α,ω‐dihalo compound
Authors: Soga Kazuo , Toshida Yomishi , Hattori Iwakazu , Nagata Koichi , Ikeda Sakuji 
Published: April 2003

AbstractPoly[thio(thiocarbonyl)oxy‐1,4‐cyclohexyleneoxy(thiocarbonyl)thiomethylene‐1,4‐phenylenemethylene] (4) was obtained from 4‐bromomethylbenzyl bromide (1), dipotassium 1,4‐cyclohexanediolate (2) and carbon disulfide at low temperature by using 1,4,7,10,13,16‐hexaoxacyclooctadecane as catalyst. At high temperatures, poly[oxy‐1,4‐ cyclohexyleneoxymethylene‐1,4‐phenylenemethylene] (8) was obtained from the reaction between 1 and 2, however. Mechanisms are proposed for these reactions.
A new route for the synthesis of polyhydroxyethers
Authors: Rokicki Gabriel , Kuran Witold 
Published: April 2003

AbstractPolyhydroxyethers were synthesized from monoalkali metal salts of diphenols and 1‐halo‐2,3‐epoxyalkanes in a one‐step reaction in dipolar, aprotic solvents as reaction media. They were also synthesized from alkali metal salts of diphenols, dihalobenzoid compounds with electron‐withdrawing groups between benzene rings and 1‐halo‐2,3‐epoxyalkanes by a two‐step reaction.
β‐Carotene inhibited photooxidation of polystyrene, 1. Effect of β‐carotene on photochemical reactivity of anthracene in hexane solution
Authors: Nowakowska Maria 
Published: April 2003

AbstractThe effect of β‐carotene on the photochemical reactivity of anthracene in hexane solution was investigated. A kinetic scheme of photochemical and photophysical processes occurring in the system irradiated with light at λ = 365 nm is proposed. The rate constants of physical quenching process and chemical reaction between β‐carotene and singlet oxygen molecule were determined.
β‐Carotene inhibited photooxidation of polystyrene, 2. Effect of β‐carotene on anthracene sensitized photooxidation of polystyrene films
Authors: Nowakowska Maria 
Published: April 2003

AbstractThe inhibiting effect of β‐carotene on anthracene sensitized photooxidation of polystyrene was observed and a kinetic scheme of the photophysical and photochemical processes in the system was proposed. The rate constants of several processes occurring in the system were evaluated. The indexes of reactivity for anthracene and β‐carotene in polystyrene were determined.
Haupt‐ und seitenkettenkristallinität bei isotaktischen poly(alkylethylen)en, 4. Die abhängigkeit des kristallinitätsgrades bei den höheren homologen von der thermischen vorbehandlung
Authors: Blum Klaus , Trafara Gundolf 
Published: April 2003

AbstractCrystallization of the higher homologues of poly(alkylethylene)s containing 12, 13, 14, 16 and 20 C‐atoms in the side chains is investigated varying the temperature and duration of crystallization. On cooling the samples slowly from the melt to about 5 to 10 K below the melting temperature, the modification is formed which was first reported by Turner‐Jones: The main chain conformation is a quaternary helix, the side‐chains crystallize by forming the orthorhombic polyethylene structure. Degrees of crystallinity were determined by X‐rays using the method of Hermans and Weidinger. The degree of crystallinity increases up to a limiting value with increasing duration of crystallization at constant temperature. The limiting value grows by increasing the number of C‐atoms in the side‐chains.
The angular distribution of crystallinity in a stretched rubberlike polymer
Authors: Allegra Giuseppe 
Published: April 2003

AbstractThe distribution of crystallinity around the axis of elongation in a rubberlike polymer stretched above its normal melting temperature is calculated. Although most of the basic assumptions are identical with those adopted by Flory in 1947, the model of rubber elasticity proposed by Ronca and Allegra in 1975 is explicitly adopted, and the assumption of parallelism among the crystallites is avoided. According to some experimental observations, only the extended chain crystallization mechanism is taken into consideration. The incipient crystallization temperature and the equilibrium retractile force are also obtained. The X‐ray intensity distribution for the general reflection on a stretched fiber diagram is formally derived as a function of crystallite orientation. Agreement with several experimental data obtained by Cesari, Perego, Zazzetta and Gargani, from crosslinked cis‐1,4‐polybutadiene may be regarded as satisfactory, considering the simplifying assumptions. According to the theoretical predictions, the crystallites formed at incipient crystallization are quite narrowly aligned around the direction of elongation. Unlike Flory's theory, the present formalism leads to no discontinuity in the derivative of the retractile force vs. the stretch ratio at the incipient crystallization point, in agreement with observation.
Redox polymerization, 4. Kinetics of the polymerization of acrylic acid derivatives initiated by the system cyanoacetic acid/Mn(OCOCH3)3 in dimethylformamide
Authors: Haragopal Mahadevan , Mahadevan Venkatanarayana 
Published: April 2003

AbstractThe kinetics of the polymerization of acrylonitrile, methyl methacrylate, and acrylamide initiated by the redox system cyanoacetic acid/manganese triacetate in dimethylformamide solution were investigated in the temperature range of 25 – 40°C. It was found that an initial complexation between the reactants followed by an electron transfer yields radicals. In contrast to acrylamide, acrylonitrile and methyl methacrylate effectively suppress further oxidation of the primary radicals. Exclusively the mutual termination accounts for the kinetics of these polymerizations. Data on the average degrees of the polymerizations support the suggested mechanisms. Rate and equilibrium constants were evaluated and their significance is discussed.
Chainlength dependence of thermodynamic properties of poly(ethylene glycol)
Authors: Klein Joachim , Jeberien Hans‐Edwin 
Published: April 2003

AbstractInvestigations of ten poly(ethylene glycol) samples with molecular weights of 62 to 20 000 showed that inverse gas chromatography is a sensitive tool to determine molecular weight dependent variations of thermodynamic parameters like specific retention volume, activity coefficient, and Flory‐Huggins interaction parameter. As mobile phase 27 probe molecules with various functional groups could be characterized with respect to their solubility behaviour for the oligomers and polymers due to the ability to form hydrogen bonds. By application of the factor analysis technique two factors could be extracted from the data matrix of retention values. The best fit of the corresponding simple structure was achieved with a combination of group concentrations of the terminal OH‐group and the repeating ether unit of the poly(ethylene glycol)s.
Free radical polymerization in the presence of non‐solvents, 1. Styrene
Authors: Bartoň Jaroslav , Capek Ignác , Juraničová Viera , Mlynárová Mária 
Published: April 2003

AbstractDuring styrene (STY) polymerization, initiated by radicals formed by thermal or photochemical decomposition of 2,2′‐azoisobutyronitrile (AIBN) the overall polymerization rate constant K defined by relation K = Rp/([AIBN]0,5 [STY] η) and the ratio kp/(2kt0) increase with decreasing styrene concentration by hexane or benzene (Rp is the polymerization rate and ηMIX the viscosity of the reaction system). In the thermally initiated polymerization K = kp (2f kd/(2kt0))0,5 and in the photochemically initiated polymerization K = kp (2,303 ϕ I0ϵ d/(2kt0))0,5 where kd, kp, and kt0 are respectively, the rate constants of AIBN decomposition, of propagation, and of termination (for a system of the viscosity 1 mPa·s) reactions, ϕ is the quantum yield of radicals entering into reaction with the monomer, I0 the intensity of the incident light, ϵ the molar absorption coefficient of AIBN, and d the path length of the light. The increase of K and of kp/(2kt0) with decreasing monomer concentration is more marked for the system styrene/hexane than for styrene/benzene and this increase is greater at 30°C than at 60°C. For Θ‐systems formed by binary mixtures like styrene/hexane, styrene/decane and styrene/C1 – C4 alcohols the values of kp and kt0 at 30°C range between 57 and 91 dm3·mol−1·s−1 and (0,9 to 2,2)·107 dm3·mPa·mol−1, i.e. they are in principle identical with the tabulated values of these rate constants for styrene bulk polymerization.
A new method for the estimation of random chain branching from viscosity measurements in two solvents
Authors: Bohdanecký Miloslav 
Published: April 2003

AbstractA method for the evidence of random chain branching (or for the estimation of its degree) is suggested, based on the determination of intrinsic viscosity in two solvents with a very different “solvent power”. Conditions under which the method can be employed are examined (effect of solvent power on the viscosity parameter of branching, effect of polydispersity). The method is verified using reported data for six polymers, mainly with three‐functional random branching. It is less sensitive than the classical method (determination of parameter g′), but does not require the knowledge of molecular weight of the branched polymer, and may therefore be useful in cases where the molecular weight determination of a branched polymer by the light scattering method is not accurate.
Thermotropic liquid crystalline polymers, 3. Comb‐like polymers with side chains simulating the smectic type of liquid crystals
Authors: Shibaev Valery P. , Moiseenko Victor M. , Platé Nikolai A. 
Published: April 2003

AbstractThe syntheses of a number of new comb‐like polymers are described, which contain mesogenic groups as side branches presenting models of low‐molecular liquid crystals of smectic type. The resulting polymers are capable to form an enantiotropic liquid crystalline phase, which may be defined as smectic, according to the terminology used for low‐molecular liquid crystalline substances. The thermodynamic limits of the liquid crystalline state in these polymers were determined, which made it possible to define the liquid crystalline state as a thermodynamically stable phase with spontaneously appearing anisotropy of properties (in particular, the optical anisotropy). The characteristic feature of the structure of these polymers was found to be the layer order of side groups providing — in combination with the packing of the mesogenic groups — the possibility of liquid crystalline properties. Only the mesogenic groups take part in the formation of the crystalline packing in these polymers, whereas the methylene chains are in the amorphous phase together with the backbone chain.
Synthesis and properties of polymers with conjugated double bonds with nitro‐substituted acenaphthenediylidene repeating units
Authors: Schopov Ivan , Kirowa Plumka 
Published: April 2003

AbstractThree new conjugated polymers with nitro‐substituted acenaphthenediylidene repeating units were prepared. The polymers which exhibit semiconductive and paramagnetic properties, differ in number and location of the nitro groups. The comparison of the polymer properties leads to the conclusion that in one of the polymers an intermolecular charge transfer complex could exist, thus improving its semiconductive properties.
Oligomérisation anionique de l'éthylène, 5. Fonctionalisation des oligomères vivants par action directe de l'oxygène
Authors: Aldissi Matt , Schué François , Geckeler Kurt , Abadie Marc 
Published: April 2003

AbstractLiving oligomers of ethylene obtained by sec‐butyllithium complexed with tetramethylethylenediamine (TMEDA) were deactived by oxygen. NMR and mass spectrometry, coupled with gas chromatography of the resulting product allowed us to follow the influence of TMEDA towards functionalization. The two products

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were characterized. Apparently the ratio [TMEDA]/[sec‐BuLi] does not seem to influence the functionalization reaction.
Polymere charge‐transfer‐Komplexe auf der basis von polyvinylalkoholacetalen, 3
Authors: Geißler Ulrich , Schulz Rolf C. 
Published: April 2003

AbstractA new fluorene containing polymer, poly[2‐(2‐fluorenyl)‐1,3‐dioxan‐4,6‐diylmethylene] (3 or 4), and the corresponding model compound, 2‐fluorenecarbaldehydetrimethyleneacetal (6) were synthesized. The fluorescence spectroscopy of the polymer in dilute solution indicates the formation of an intramolecular excimer. Charge‐transfer complex formation with tetracyanoethylene (TCNE), 2,5‐cyclohexadien‐1,4‐diylidenedimalonodinitrile (TCNQ), and 2,4,5,7‐tetranitro‐9‐fluorenone (TENF) was studied by means of absorption spectroscopy.
Copolymerisation von 4‐(1,1‐dicyanoethylazo)benzylmethacrylat mit styrol, methacrylonitril und methylmethacrylat mit anschließender Pfropfung der Azocopolymere
Authors: Nuyken Oskar , Rengel Reinhard , Kerber Robert 
Published: April 2003

Abstract4‐(1,1‐Dicyanoethylazo)benzyl methacrylate (3), a new azo‐monomer, was copolymerized with styrene, methacrylonitrile, and methyl methacrylate (MMA) giving azo‐copolymers. The compositions of the copolymers from 3 and MMA were nearly identical with those of the monomer mixtures. Thus allowing 100% conversion leading to copolymers of almost identical chemical composition. These azo‐copolymers were used as initiators for different monomers in either emulsion or solution, resulting in graft‐copolymers. The graft‐copolymers were characterized by IR and GPC. In one case the raw graft‐copolymer was separated into ungrafted backbone‐polymer, grafted copolymer, and homopolymer of the component to be grafted.
Borverbindungen, 11. Die Metathese der 2‐ethyl‐1,3,2‐dioxaboracycloalkane mittlerer Ringgröuße
Authors: Gerwarth Ulrich W. 
Published: April 2003

Abstract2‐Ethyl‐1,3,2‐dioxaboracycloalkanes polymerize more slowly than the analogous 2‐aryl compounds. This is due to a difference in the bond type of the O—B—O group as shown by IR spectra and mass spectra. For the polymerization of 2‐aryl‐1,3,2‐dioxaboracycloalkanes the metathetic mechanism, postulated and proved in a foregoing paper, was confirmed.
Elektron‐Donor‐Akzeptor‐Komplexe und copolymere mit difluormaleinsäureanhydrid
Authors: Regel Walter , Canessa Guido 
Published: April 2003

AbstractThe formation constants of electron donor acceptor complexes formed by p‐dioxene, α‐methylstyrene, phenanthrene, phenyl vinyl ether and styrene as donor molecules and difluoromaleic anhydride as acceptor are much larger compared to those formed by maleic anhydride and the same donor molecules. However, no relation can be established between the numerical value of the formation constant and the tendency of alternating copolymerization induced by radical initiators. Symmetry considerations lead to the conclusion that electron donor acceptor complexes have no significant involvement in this copolymerization. The result of our kinetic investigations in the system phenyl vinyl ether/difluoromaleic anhydride supports the above statement: The formation of the electron donor acceptor complex is not the rate determining step of copolymerization.
Polymerization of ethylene initiated by homogeneous polybutadienyllithium/TiCl4 complexes
Authors: Siove Alain , Fontanille Michel 
Published: April 2003

AbstractThe chemical structure of polybutadienyllithium/TiCl4 complexes was studied for several values of r = [Li]/[Ti], using spectroscopic methods, gravimetry, and the elemental analysis. Dependent on the molecular weight of the polybutadienyl chain, the complexes are soluble or insoluble in hexane. The soluble systems were used for the initiation of the polymerization of ethylene, leading to a mixture of homopolybutadiene and block copolymers, slightly reticulated. The efficacity of such systems can be estimated to be 0,8.
Study on the complex formation of cobalt chelates with polymer ligands
Authors: Shigehara Kiyotaka , Yamada Akira , Sano Hiroshi , Tsuchida Eishun 
Published: April 2003

AbstractVariously composed copolymers from styrene and 4‐vinylpyridine (4‐VP) were prepared and their complex formation reactions with benzylbis(dimethylglyoximato)Co(III) [BzCo(III)(DMG)2] and N,N′‐ethylenebis(salicylideneiminato)Co(II) (Co(II)salen) were studied kinetically by the stopped‐flow rapid scanning spectroscopy. For the complex formation reaction with BzCo(III)(DMG)2, the relationship between the complex formation constant K and the content of 4‐pyridylethylene units in the copolymers showed an unusual bell‐type curve, and the K values were higher than the K value of complexation with pyridine. From the correlation between K, k (complex formation rate constant), and k′ (complex dissociation rate constant), it resulted that (1) the higher K values of the polymer systems are due to the lower k′ values compared with the pyridine system, and (2) the bell‐type change of the K values is also caused by the k′ values. In the case of Co(II)salen‐copolymer systems, two species of the complex, i.e., mono‐ and diaxial coordinated complexes were clearly identified by spectrometric kinetics, whereas the pyridine system gave only a mono‐axial coordinated complex. The diaxial coordination seems to lead to a much more favorable structure than the monoaxial one, due to the entropic gain or to the polymer chelate effect.
Synthetic polymers containing sugar residues, 7. Synthesis and properties of polyurethanes from D‐cellobiose and diisocyanates
Authors: Kurita Keisuke , Hirakawa Nobuhiko , Iwakura Yoshio 
Published: April 2003

AbstractPolyurethanes containing D‐cellobiose residues in the main chain were synthesized from D‐cellobiose and diisocyanates. The direct addition polymerization without blocking the excess hydroxy groups afforded soluble polyurethanes with inherent viscosities up to 1,08 dl · g−1. The pendant hydroxy groups in these polyurethanes were utilized for polymer reactions such as acetylation and crosslinking. Water absorption values of polyurethane films were confirmed to be very high. Acetylation decreased the values drastically, although the degrees of acetylation were not high. Thermal stability and crystallinity were also studied.
Esterolytic action of poly[p‐vinyl(thiophenol)‐co‐acrylic acid]
Authors: Hayama Shigeru , Takeishi Makoto , Takahashi Kanju , Niino Shogo 
Published: April 2003

AbstractHydrolyses of p‐nitrophenyl acetate (PNPA) and 3‐acetoxy‐N,N,N‐trimethylanilinium iodide (ANTI) catalyzed by poly[p‐vinyl(thiophenol)‐co‐acrylic acid] (PSH) were studied in the pH range of 8 – 9,5. The reaction of PNPA followed pseudo‐first‐order kinetics and was found to be catalyzed by the thiophenolate ions on the polymer backbone. In the case of positively charged ANTI, the rate of catalysis showed substrate saturation phenomena and could be described by a Michaelis‐Menten kinetics. This indicates that this reaction proceeds via a complex formed by electrostatic interaction between the substrate and the negatively charged polymer catalyst. When ionic strength was increased to 0,12 mol/l the reaction did not further follow the Michaelis‐Menten kinetics, suggesting that the complexation constant or the reaction rate of the complex might vary with the amount of the substrate incorporated in the polymer domain. Positively charged N,N,N‐trimethylanilinium iodide competively inhibited the PSH‐catalyzed hydrolysis of ANTI.
Donor acceptor interactions in polymeric systems, 6. Effects of the molecular weight of carbazolyl containing polyesters and the length of spacer between donor groups on the complex formation with 2,4,7‐trinitrofluorenone
Authors: Tazuke Shigeo , Nagahara Hajime 
Published: April 2003

AbstractEDA complex formation between 2,4,7‐trinitrofluorenone (TNF) and polyesters bearing pendant 9‐carbazolyl groups was studied in ethylene dichloride. The formation constant (K) decreases with increasing length of the main chain repeating units separating pendant donor groups and with decreasing degree of polycondensation. In all cases, the values of K in polymeric systems are larger than those for the monomer model system by factors less than three. Thermodynamic parameters for complex formation were also determined. The general trend of the polymer effect is to increase − ΔH, while the entropy term is not much different from the monomer model system. The origin of polymer effects is interpreted as due not only to neighbouring group effects but also to remote group effects, and simultaneous participation of more than one carbazolyl group in complexing an acceptor molecule is considered. The results are compared with the EDA complex formation by ethylenic polymers and polyurethanes with pendant carbazolyl groups.