bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of a modified polytetrafluoroethylene powder in diaphragms for alkali chloride electrolysis
Authors: Lunkwitz Klaus , Ferse Armin , Handte Dietmar , Klatt Bruno , Horx Manfred 
Published: April 2003

AbstractA shape retaining asbestos diaphragm which is well suited for alkali chloride solution electrolysis can be obtained from sintering of a mixture of asbestos and a modified polytetrafluoroethylene powder. The usual different polymers of tetrafluoroethylene are not suitable as additives to asbestos diaphragms, whereas an irradiation process permits the production of a modified polytetrafluoroethylene powder which has proved its worth as a component in the diaphragm composition. With reactants present during the irradiation process, functional groups which reduce the water repellency of the polytetrafluoroethylene are incorporated into the polymer. The parallel process of partial polymer chain degradation simultaneously provides an intense reduction of the melt viscosity of the polytetrafluoroethylene so that a composite structure with asbestos can be formed by sintering.
Photo‐oxydation d'elastomères EPDM et EPM en présence de systèmes photosensibles, 2. Rôle de la benzophénone et de ses dérivés
Authors: Bousquet Jean‐Alain , Fouassier Jean‐Pierre 
Published: April 2003

AbstractUne étude de la photo‐oxydation d'élastomères de type poly[éthyléne‐co‐propéne‐co‐(1,4‐hexadiéne)] (EPDM) et poly(éthyléne‐co‐propéne) (EPM) amorçée dans le proche UV‐visible par la benzophénone (BP) et quelquns de ses dérivés parasubstitués (4‐méthoxy‐BP, 4‐chloro‐BP) a permis l'élaboration d'un schéma réactionnel détaillé. Le comportement photochimique des photo‐amorçeurs dans les milieux élastomère est décrit avec précision (nature et quantité des photoproduits formés) grâce à l'emploi d'une méthode originale de dosage spectrométrique IR. Les processus réactionnels prépondérants sont mis en valeur ainsi que leur dépendance vis à vis d'une part, des propriétés spécifiques du photo‐amorçeur et d'autre part, de la structure et de la composition chimique de l'élastomère.
Photo‐oxydation d'elastomères EPDM et EPM en présence de systèmes photosensibles, 3. Rôle de la benzophénone à l'etat greffé
Authors: Bousquet Jean‐Alain , Fouassier Jean‐Pierre 
Published: April 2003

AbstractLa photo‐oxydation à λ = 313 nm d'un poly[éthyléne‐co‐propéne‐co‐(1,4‐hexadiéne)] (EPDM) greffé contenant en faible quantité des motifs benzophénone, a été étudiée en calculant les rendements quantiques des réactions observées. Il ressort de la comparaison avec les systèmes mélangés que le greffage du photosensibilisateur favorise plus nettement la formation des produits d'oxydation et des coupures de chaînes que la réticulation. Une deuxième comparaison avec un autre système greffé — un EPDM phénylé — permet de montrer que la propagation des hydroperoxydes inactifs dépend fortement de la nature des groupements photosensibles impliqués.
Morphology of glassy polymers grafted onto polybutadiene in relation to monomer diffusivity and initiator solubility
Authors: Beati Enrico , Pegoraro Mario , Pedemonte Enrico 
Published: April 2003

AbstractThe morphology of polybutadiene grafted in emulsion with vinylchloride, methylmethacrylate, styrene, was examined by transmission electron microscopy. The morphology depends on synthesis conditions. Solubility of initiators in the monomers or in water, diffusivity of monomers in the rubber and transfer mechanism during the polymerization were found to be important factors in determining the morphology. New experimental data of diffusion coefficients of the monomers in polybutadiene are given. A special technique was used for liquid VC diffusivity measurements.
Radiation grafting of hydrophilic monomers onto poly(4‐methylpentene‐1), I. Grafting of acrylic acid
Authors: Soebianto Yanti S. , Yoshii F. , Makuuchi K. , Ishigaki I. 
Published: April 2003

AbstractRadiation grafting of acrylic acid (AAc) onto poly(4‐methylpentene‐1) (TPX) with different crystallinity has been investigated under various conditions. Free radicals formed by pre‐irradiation of TPX in vacuum were more stable than those in the presence of air and might initiate the grafting reaction if come in contact with the AAc. Grafting yields increased with increasing preirradiation dose, grafting temperature, and concentration of AAc. Lower crystalline TPX (24%) showed a higher initial grafting rate compared with higher crystalline one. The distribution of grafting was observed by X‐ray microanalyzer. The grafting reaction proceeded gradually with time from the surface of the film to the inner part. In high crystalline TPX (34%) the grafting distribution in the final stage depended on the film thickness, while in lower crystalline TPX it was homogeneous regardless the film thickness.
Interpenetrating polymer networks from castor oil based polyurethane and poly(methyl methacrylate), III
Authors: Patel Mayur , Suthar Bhikhu 
Published: April 2003

AbstractLiquid prepolyurethanes (PPU) were obtained from castor oil and toluene‐2,4‐diisocyanate under different experimental conditions varying NCO/OH ratio. All these prepolyurethanes were subsequently interpenetrating with poly(methyl methacrylate) made by radical polymerization initiated with benzoyl peroxide. The novel PPU/PMMA interpenetrating polymer networks were obtained as though films by transfer moulding. They were characterized by thermal studies (DSC and TGA) and mechanical properties viz., tensile strength, modulus of elasticity, and percent elongation at break. The morphological behaviour was analyzed by scanning electron microscopy.
Synthesis and characterization of poly(keto‐amines). 3. poly(keto‐amines) containing phenolic groups
Authors: Patel Surekha V. , Patel Hasmukh S. , Patel Shanti R. 
Published: April 2003

AbstractSelf polycondensations of 5‐amino‐2‐hydroxyphenacyl chloride (5A2HP), 3‐amino‐4‐hydroxyphenacyl chloride (3A4HP), and 4‐amino‐2‐hydroxyphenacyl chloride (4A2HP) are carried out in nitrobenzene using pyridine as an acid acceptor. The poly(keto‐amines) thus formed are characterized by elemental analysis, IR spectral studies, estimation of M̄n by non‐aqueous conductometric titration and/or by VPO method, by measurement of solution viscosity in formic acid, and by TGA in air. All three poly(keto‐amines) are reduced to poly(amines) by Wolf‐Kishner reduction. The poly(amines) thus formed are characterized and compared.Polymeric metal chelates of poly(keto‐amines) derived from 5A2HP and 3A4HP with various metal ions are prepared and characterized.
Enantioface differentiation by chiral polymers having (+)‐5,6‐exo‐bornanediol moieties, I. Synthesis and polymerization of (+)‐5,6‐exo‐dihydroxybornyl methacrylate
Authors: Liu Jui‐Hsiang , Lin Shyuh‐Rurng 
Published: April 2003

AbstractA series of bornane derivatives was synthesized. Both new Chiral monomers (+)‐5,6‐dioxobornyl methacrylate and (+)‐5,6‐exo‐dihydroxybornyl methacrylate were prepared from (+)‐borneol. The free‐radical polymerization of both new monomers was carried out at 60°C for 6 h in various organic solvents. The conversion of the polymerization was found to be affected by the kind of solvent, and the lowest conversion was attained in (‐)‐menthol.
Characterization of acrylonitrile‐butadiene‐styrene terpolymers by computer aided FT‐IR spectroscopy
Authors: Fischer G. , Lüderwald I. , Ottenbreit P. 
Published: April 2003

AbstractThe fast identification and accurate characterization of acrylonitrile‐butadienestyrene (ABS) terpolymers by computer aided Fourier transform infrared spectroscopy is described. Samples are prepared as films from chloroform suspensions and identified by a library search routine after FTIR measurement. Calibration curves of monomer specific absorptions obtained from physical mixtures of a known terpolymer with different amounts of the corresponding homopolymers are used to quantify the incorporation ratios of unknown ABS systems.
p‐Chlorostyrene oligomers. Preparation, structure, and stereochemistry
Authors: Kiji Jitsuo , Konishi Hisatoshi , Okano Tamon , Ajiki Eijiro 
Published: April 2003

AbstractThe dimer and trimer obtained by the pyrolysis of poly(p‐chlorostyrene) were 2,4‐di(p‐chlorophenyl)‐1‐butene and 2,4,6‐tri(p‐chlorophenyl)‐1‐hexene, respectively, while those obtained by the cationic oligomerization of p‐chlorostyrene were trans‐1,3‐di(p‐chlorophenyl)‐1‐butene and a diastereomeric pair of trans‐1,3,5‐tri‐(p‐chlorophenyl)‐1‐hexene.
Effect of hydrostatic pressure on the electrical conductivity of FEF carbon black‐loaded sbr vulcanizates
Authors: Nasr G. M. , Amin M. , Osman H. M. , Badawy M. M. 
Published: April 2003

AbstractThe electrical conduction was investigated in styrene butadiene rubber (SBR‐1502) loaded with different concentrations of fast extrusion furnace (FEF) black (70, 80, 90, and 100 phr). On the bases of Holm's model, a qualitative description for the electrical conduction through these composites was sought. The pressure coefficient K was calculated and found to be strongly dependent on the carbon black concentrations.
Humidity dependence of the electric characteristics of quaternized 4‐vinylpyridine‐styrene copolymer/perchlorate complexes
Authors: An Heishoku , Hirata Mitsutoshi , Yosomiya Ryutoku , Yaoquan Xin 
Published: April 2003

AbstractThe dependence of electrical characteristics of copolymer complexes on ambient humidity was studied for complexes of quaternized 4‐vinylpyridine‐styrene copolymer/perchlorate complexes. When the 4‐vinylpyridine content in the copolymer increased, a linear decrease in resistivity was found. From this behaviour, it is concluded that the resistivity can be freely set by variation of the 4‐vinylpyridine content in the design of a sensor material. Furthermore, the resistivity was the smallest in the HClO4 complex and successively became large in the order of the KClO4 complex and the LiClO4 complex. From the electrochemical aspect, it was cleared that the degree of dissociation of the counterion exerted influence upon the resistivity of these complexes.
Thermal behaviour of starches and their graft copolymers with polyacrylonitrile
Authors: Patel A. R. , Patel M. R. , Patel K. C. , Patel R. D. 
Published: April 2003

AbstractThermal behaviour of twelve different starches and their graft copolymers with polyacrylonitrile (PAN) from granular and gelatinized state, has been examined by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). All the starches exhibit two endotherms around 65 and 260°C and an exotherm around 335°C. The graft copolymer from granular starch shows a weak endotherm around 65°C and an exotherm around 300°C, while gelatinized starch exhibits the characteristic exotherm of PAN at about 250°C along with the exotherm of graft product at 300°C. Scanning electron microscopic studies were carried out to explain the endotherms of starch at 65°C and 265°C. The former one may be due to heat of dehydration while the latter one is attributed to the fusion of crystallites in the starch. Legumine starches seem to have a specific property of retaining moisture even if they are grafted in gelatinized state.
Oxidation of polyethylene in closed mixing chamber
Authors: Fodor Zsolt , Iring Margit , Pukánszky Béla , Kelen Tibor , Tüdős Ferenc 
Published: April 2003

AbstractThe degradation of commercial LDPE was studied under dynamic conditions which simulate the processing. Dynamic oxidation above 140°C is similar to static oxidation under low oxygen pressure both having strong diffusion control. Fragmentation and crosslinking (mainly CC bonds) compete in the process. The hydroperoxides predominate at the beginning of the mixing. Their quantity rapidly decreases while that of oxo groups increases and becomes predominant.Below 140°C, the conditions are resembling to static oxidation performed under higher oxygen pressure but the process is still somewhat diffusion controlled. The change in the molecular mass is not considerable in the process. The hydroperoxides predominate among the functional groups formed. Their ratio is constant during mixing. The effect of mechanical stress is not considerable.An increase in the mixing speed resulted in an increase in the rate of the processes studied above.The higher the total amount of oxygen incorporated in the PE, the smaller is the remaining oxidative stability.
Radiation initiated grafting on fluoro polymers, IV. Influence of morphology and structure of homogeneous and porous PVF2 films on the preirradiation grafting with N‐vinyl‐pyrrolidone in aqueous solution
Authors: Niemöller Axel , Ellinghorst Guido 
Published: April 2003

AbstractThe radiation induced grafting of N‐vinylpyrrolidone in aqueous solution on poly(vinylidene fluoride) (PVF2) films by preirradiation technique using 160 keV electrons has been investigated. Two kinds of homogeneous films have been grafted under the same experimental conditions: unoriented PVF2 films show an isotropic volume increase by grafting and a low saturation grafting yield (SGY): biaxially oriented PVF2 films only increase in their thickness by grafting and reveal a relatively high SGY. This behaviour has been correlated to the morphology of the films. Likewise, porous PVF2 films as obtained by phase inversion process for membrane preparation were grafted under similar conditions as homogeneous films. Porous films prepared from different solvents exhibit different SGYs under given grafting conditions; this phenomenon has been attributed to the structure of the films. Obviously, polymerization is heterogeneous and termination reactions easily take place in the solution containing micropores. The hydrophilicity of the graft membranes increases with SGY. Low grafting yields (up to 7%) lead to an increase in product flux in ultrafiltration experiments and a slightly improved separation of poly(ethylene glycol) solutions especially in the low molecular weight range.
Untersuchungen zur thermodynamischen verträglichkeit von polyethylen hoher dichte (HD PE) und polyethylen niederer dichte (LD PE) in schmelzezustand, II. Die spezifische freie mischungsenthalpie
Authors: Freytag Ulrich , Radusch Hans‐Joachim 
Published: April 2003

AbstractAus den Löslichkeitsparametern von HD PE und LD PE wurde ihr temperaturabhängiger Flory‐Huggins‐Wechselwirkungsparameter χ12 und daraus wiederum nach Flory‐Huggins die spezifische freie Mischungsenthalpie ΔGm/V eines HD PE/LD PE‐Systems berechnet. Unter Zuhilfenahme des „reptation”︁‐Modells und der Einstein‐Relation wurde die Diffusionsgeschwindigkeit der PE‐Moleküle abgeschätzt. Die Triebkraft dieser Diffusion ist proportional der spezifischen freien Mischungsenthalphie. Die Ergebnisse zeigen, daß diffusionskontrollierte Entmischungserscheinungen in einer HD PE/LD PE‐Mischung im Schmelzezustand nicht ablaufen. Das bedeutet, daß die Morphologie der Mischungen im Schmelzezustand nur durch die Mischbedingungen im Zusammenspiel mit den Fließeigenschaften der Komponenten festgelegt wird.
Effect of the structure of slightly crosslinked polyurethanes on their thermal stability
Authors: Kościelecka Alicja , Dzierz̊ra Wiesław 
Published: April 2003

AbstractPolyurethanes slightly crosslinked with allophanate and CC linkages have been prepared by reaction of 4,4′‐diphenylmethane diisocyanate with poly(ethylene adipate) and poly(ethylene maleate) as well as with terephthalic‐adipic copolyesterdiol and some low molecular diols.Data obtained from isothermal and dynamic thermogravimetric analysis carried out in an inert atmosphere indicate that the thermal stability of polyurethanes is independent on the crosslinking density and the structural characteristics of crosslinks and hard segments.
Oxirane ring opening with imide‐acids
Authors: Soler Héctor , Cádiz Virginia , Serra Angels 
Published: April 2003

AbstractA study with model compounds was made by 13C‐NMR in order to confirm the two possible sites of attack on an oxirane ring by a carboxylic acid serie. In all cases the presence of signals corresponding to normal and abnormal opening of the ring was detected. Thus, two different methods to quantify the obtained primary and secondary alcohol amounts were used. It was found that the less primary alcohol was obtained the more nucleophilic the carboxylic acid is.
Solute permeation through perfluorocarboxylate membranes
Authors: Kawagoe Jun , Satoh Mitsuru , Iijima Toshiro 
Published: April 2003

AbstractThe sorption and permeability of tetraalkylammonium chlorides and alkali chlorides in perfluorocarboxylate membranes were determined. The water content and density of the membranes were found to change with treatment in boiling water and with different tetraalkylammonium cations as counterions for the carboxylate fixed charge. This is attributed to a change in the structure of the membrane matrices. DSC measurements suggested the existence of three distinct phases in the membranes, i.e. a free water phase, a bound water phase, and nonfreezable water. The nonfreezable water was assumed to be in the fluorocarbon phase. The permeability sequence of the tetraalkylammonium chlorides was found to be TEACl > TMACl > TBACl. To interpret the results, a parallel permeation model was proposed.
Reaction of cellulose‐poly(glycidyl methacrylate) with methylamine
Authors: Abo‐Shosha Mohamed Husein Hassan , Ibrahim Nabiel Abd El‐Basset 
Published: April 2003

AbstractCellulose‐poly(glycidyl methacrylate) copolymer was reacted with methylamine. Factors affecting the reaction, such as methylamine concentration, liquor‐to‐material ratio, pH, temperature, and time were studied. The general kinetics of the process was reported, and a mechanism of the reaction was suggested. Potentiometric titration of the product showed that it was a weak base anion exchanger having a pKb of 7.4.
Solution properties of ultrahigh molecular weight polymers, 15. A viscometric study of poly(isobutyl methacrylate) in different solvents
Authors: Simionescu Bogdan C. , Ioan Silvia , Flondor Aurelia , Simionescu Cristofor I. 
Published: April 2003

AbstractThe paper extends previous studies on ultrahigh molecular weight synthetic polymers. The intrinsic viscosities and the viscosity constants of poly(isobutyl methacrylate) fractions were obtained by the methods of Huggins, Kraemer, Martin, Schulz‐Blaschke, and Fedors in CCl4 and C6H6 at 25°C. It was observed that the method of Fedors is not very sensitive to the possible errors appearing in estimating the relative viscosities in higher concentration domains. This method yields intrinsic viscosity values close to the mean values obtained from the other five methods and to the values calculated according to the averaging procedure suggested by Sakai. The transition concentrations separating the concentration domains (diluted‐semidiluted) and the Mark‐Houwink constants were obtained.
Radiation grafting of hydrophilic monomers onto poly(4‐methylpentene‐1), II. Grafting of long chain monomers and physical properties of the grafted films
Authors: Soebianto Yanti S. , Yoshii Fumio , Makuuchi Keizo , Ishigaki Isao 
Published: April 2003

AbstractRadiation grafting of 2‐hydroxyethyl methacrylate (HEMA) and methoxytetraethyleneglycol methacrylate (M4G) on low crystallinity poly(4‐methylpentene‐1) (TPX) has been investigated. Grafting yield increased with increasing pre‐irradiation dose, grafting temperature, and monomer concentration. Grafting rate depends on length of molecular chain in the monomers and decreases with increasing chain length. The grafting yields of electron beam irradiated samples were higher than those of γ‐irradiated ones because of higher radical concentration. Tensile strength of the grafted film in the dried state increased and the elongation at break decreased with increasing degree of grafting. On the other hand, in the wet state, the tensile strength and elongation at break decreased with increasing the degree of grafting due to the lack of hydrogen bonds between the grafted chains caused by increased water absorption.
Properties of the polyacrylic acid resin duolite es 346 containing amidoxime anchor groups with respect to the separation of uranium from sea water
Authors: Lieser K. H. , Erboy M. , Thybusch B. 
Published: April 2003

AbstractLoading curves, rate of exchange and distribution coefficients of Duolite ES 346 are determined for UO22+, Cu2+ and Fe3+, using simulated sea water. The crude resin gives off ammonia into solution which leads to precipitation of uranyl ions and high apparent distribution coefficients. With the purified resin the following distribution coefficients are measured at pH 8.1: Kd(UO22+) ≈ Kd(Cu2+) ≈ Kd(Fe3+) ≈ 0.6 · 104 ml/g. This leads to a loading of the resin in sea water of pH 8.1 with uranium only to about 20 μg per g of resin.
Sorbents prepared from a composite reactive carrier based on bead cellulose and poly(ethylenemethacrylate‐toluenesulfonate)
Authors: Lenfeld Jiří , Štamberg Jiří 
Published: April 2003

AbstractA composite reactive carrier consisting of bead cellulose and poly(ethylenemethacrylate‐toluenesulfonate) was modified by reactions with sodium sulfite, dimethylaminoethanol, polyethyleneimine, thiourea (followed by hydrolysis with KOH), phenol, and pyrogallol (followed by mercuration with mercury(II) acetate (CH3COO)2Hg) to functional sorbents containing sulfonic, quaternary ammonium, imine, thiol, and Hg+ ion exchange groups. The modification is accompanied by a hydrolytic splitting‐off of the reactive tosyl group. The hydrolysis is supported by the presence of water in the reaction medium and its degree increases with the reaction temperature. The highest conversion was reached in the formation of the thiol sorbent. Its sorption properties were investigated by the sorption of Ag+ ions. The observed high rate of sorption is a consequence of the hydrophilizing effect of the cellulose component of the composite sorbent.
Synthesis and properties of 4‐vinyl pyridine grafted SBS used as charged mosaic membrane
Authors: Hsiue G. H. , Yeh Z. K. 
Published: April 2003

AbstractThe grafting of 4‐vinyl pyridine onto styrene‐butadiene‐styrene triblock copolymer by irradiation was studied. Cationic and anionic groups were introduced by sulfonation and methylation to obtain a charged mosaic membrane.The experiments showed an increased rate of grafting with the increase of irradation dose. The best concentration of monomer was at 20%.After grafting, the contact angle and the water content were tested and morphology studies were performed.Furthermore, the tensile strength of this membrane increased with increased percentage of grafting. After testing, the charged mosaic membrane had a reduced potential. Its anionic and cationic exchange capacitites were between 0.12 to 0.13 meq/g, and 0.24 to 0.343 meq/g, respectively. The ratio of exchanged capacity was up to 0.509. KCI and urea can be separated by dialysis. In the determination of a piezodialysis, the salt enrichment reached a percentage of 10.3.
Synthesis and properties of polyamine‐imides containing phenoxaphosphine units
Authors: Subramaniam Prema , Srinivasan Mahalingam 
Published: April 2003

AbstractPolyamine‐imides were synthesized by polycondensation reaction of bis‐N‐methyl‐olimides and diamines. The reactions were carried out in the aprotic polar solvent dimethylacetamide (DMAc) and polymers with inherent viscosities ranging between 0.36–0.75 dl/g were obtained. The polymers were degraded by conc. H2SO4. All the polymers were characterized by elemental analysis, IR‐ and 1H‐NMR spectroscopy, density, solubility, crystallinity, and thermal analysis.