bluuebunny/crossref_metadata_2025_split huggingface dataset:
Permeation von Gasen in Polymermembranen aus thermoplastischer Stärke
Authors: Sala Robert , Tomka Ivan 
Published: April 2003

AbstractAls Alternative zu den heutigen Massenkunststoffen wurde die Möglichkeit eines Einsatzes von thermoplastischer Stärke (TPS) als Barrierewerkstoff in Filmen und Membranen untersucht. Die Permeations‐ und Diffusionskoeffizienten wurden mitels der Induktionszeit‐Methode an Filmen aus TPS in Abhängigkeit von Temperatur und Weichmachergehalt ermitelt. Die expermentell gefundence gute Gasbarriereeigen schaft der Stärke gegenüber Sauerstoff und Stickstoff wurde durch vergleichende Messungen an Handelsprodukten ergänzt. Die TPS zeigt bei nieedrigen Wassergehalten denhandelsüblichen Barrierepolymeren vergleichbare Gaspermeationsraten. Mit steigen dem Wassergehalt verliert sie‐ wie die meisten hydrophilen Polymere ‐ ihre Gasbarrierewirkung.Gemeinsam mit früheren Arbeiten über die Struktur und die Eigenschaften von thermoplastischer Stärke wurden die molekularen Parameter und ihr Einfluß auf die Gasdurchlässigkeit diskutiert.
Chemische Kopplung von Polystyrol und Polybutadien in Schmelzemischungen durch Verwendung eines organischen Sulfonylazids
Authors: Radusch Hans‐Joachim , Ding Jianmin , Schulz Manfred 
Published: April 2003

AbstractEs wurden Untersuchungen zur chemischen Kopplung heterogener Polystyrol‐Polybutadien‐Blends bei Einsatz eines organischen Sulfonylazids während des Schmelzemischens im Laborinnenmischer angestellt. Die Wirksamkeit des Kopplungsagens wurde anhand infrarotspektroskopischer, mikroskopischer und dynamisch‐mechanischer Analysen sowie anhand des merchanischen Eigenschaftsbildes der Belends beurteilt. Die sich in der Schmelze bildenden Pfropfcopolymeren führen zu einer Erhöhung der Phasenwechselwirkungen un dami zu einer Verbesserung der Festigkeits‐ und Zähigkeits‐eigenschaften der Blends.
Zur Bestimmung des Modifikatorgehaltes von Stearinsäure‐ und Titanat‐modifizierten CaCO3‐Füllstoffen
Authors: Lühr Jens , Janowski Frank 
Published: April 2003

AbstractZur Bestimmung des Modifikatorgehaltes von Stearinsäure(STS)‐bzw. Isopropyltriisostearyltitanat(Titanat)‐modifizierten CaCO3‐Füllstoffen wurde die simultane TG/DTA‐Analyse genutzt. die Methode wurde für Modellproben sowie für verschiedene kommerzielle Füllstoffe mit einem Konzentrationsbereich von 0 – 2,7% STS bzw. 0 – 4% Titanat angewendet. Eine ausreichende Übereinstimmung der Modifikatorkonzentrationen für STS, bestimmt durch simultane TG/DTA‐Analyse sowie eine C‐Analyse, wird erreicht, wenn der Zersetzungsbereich des Modifikators berücksichtigt wird. Dieser liegt für Stearinsäurezwischen180°C und 450°C (bei STS > 1% bei 500°C) und für Isopropyltriisostearyltitanat zwischen 120 und 450°C (Titanat > 1% bei 500°C) und wird aus dem Anstieg der TG‐bzw. DTA‐Kurve erhalten. Der diesem Zersetzungsbereich zuzuordnende Masseverlust entspricht bei STS‐modifizierten Füllstoffen dem Stearinsäuregehalt. Bei Titanat‐modifizierten CaCo3‐Füllstoffen ist ein Betrag von 10% des Masseverlustes hinzuzufügen. Für die Modifikatorgehaltsbestimmung von CaCo3‐Füllstoffen, die einen höheren Feuchtigkeitsgehalt (< 0,2%) aufweisen, ist die Kenntnis dieser Größe notwendig, anderenfalls ist die STS‐Bestimmung über die Oxidationswärme zu realisieren.
Removal of methyl orange by systems of insoluble poly(glycidyl methacrylate)‐g‐tetraethylene‐pentamine and ‐g‐polyethyleneimines
Authors: Tashiro Tatsuo , Thirvenkatam P. 
Published: April 2003

AbstractA study was made of the removal of methyl orange (MO) solutes in water and in a pH 7 buffer solution by the reaction products of insoluble poly(glycidyl methacrylate) (PGMA) with tetraethylenepentamine (TEP) or polyethylenimine (PEI) having molecular weight of about 600 (PEI600). An examination was made of the adaptability of the Freundlich adsorption formula and the Klotz equation to removal behaviour of these polymers, which was noted to conform better to the Klotz equation than to the Freundlich adsorption formula. The removal rate and the amount removed were greater in water than in a pH 7 buffer solution, and decreased due to coexisting salts. The amount removed does not always depend on the amount of PEI600 groups bound to PGMA.
Effect of structure and composition on physico‐mechanical properties of methyl methacrylate/alkyl (meth)acrylate copolymers
Authors: Patnaik M. , Choudhary V. , Varma I. K. , Sinha T. J. M. 
Published: April 2003

AbstractThe paper describes the fabrication of cast acrylic sheets by copolymerizing a prepolymer syrup of methyl methacrylate (MMA) with varying amounts (1‐20 wt.‐%) of 2‐ethylhexyl methacrylate (EHMA), n‐hexyl methacrylate (HMA), 2‐ethylhexyl acrylate (EHA) and n‐hexyl acrylate (HA). The effect of structure of copolymer on light transmittance, density and mechanical properties was evaluated. Tensile strength and storage modulus decreased with increasing comonomer content. Strain increased significantly in the case of MMA/EHA and MMA/HA copolymer sheets having 15 and 20 wt.‐% of comonomer. Softening temperature of copolymer samples was determined using dynamic mechanical thermal analysis. Heat deflection temperature under flexural load and softening temperature decreased with increasing comonomer content in copolymer.
Effect of strain rate and temperature on stress‐strain properties of EVA‐LDPE blends and the mechanism of strain hardening
Authors: Ray I. , Khastgir D. , Mukunda P. G. 
Published: April 2003

AbstractStress‐strain behaviour of different blends of poly(ethylene‐co‐vinyl acetate) (EVA) (28 wt.‐% VA content) and low density polyethylene (LDPE) is studied under various strain rates and temperatures. It is found that stress‐strain plots of such semicrystalline polymer blends consist of three parts, namely, elastic or Hookeian region, region of chain slippage and region of strain hardening. Decrease in strain rate has an increasing effect on the strain hardening region. Increase in measurement temperature adversely affects the whole stress‐strain plot. It is apparent from the study that at an elevated temperature the process of strain hardening is dependent on the crystalline melting point of the major component in the blend. The X‐ray and DSC studies reveal that the process of strain hardening is mainly due to a change in internal order of crystallites in LDPE and LDPE‐rich blends, whereas in EVA and EVA‐rich blends it is due to induced crystallization in the amorphous phase.
Improvement of ageing properties of rubber films prepared from radiation‐vulcanized natural rubber latex
Authors: Yoshii Fumio , Kulatunge Samantha , Makuuchi Keizo 
Published: April 2003

AbstractRadiation‐vulcanization of natural rubber latex (NRL) with n‐butyl acrylate gives a higher tensile strength for films obtained after casting. The ageing properties of radiation‐vulcanized natural rubber in the presence of various antioxidants have been investigated. In order to find out suitable antioxidants for radiation‐vulcanized natural rubber latex (RVNRL) films, extraction of the gel fraction was carried out in xylene with 1 wt.‐% antioxidant and air bubbling. Antioxidants which give less reduction in gel fraction due to oxidative degradation during extraction are effective for ageing tests of RVNRL films. It was found that tris(nonylated phenyl) phosphite (Nonflex TNP) and 2,5‐di‐tert‐amylhydroquinone (Antage DAH), among 12 different antioxidants tested, were the most effective antioxidants for RVNRL films.
Builder performance in detergent formulations and biodegradability of partially dicarboxylated cellulose and amylose containing sugar residues in the backbone
Authors: Matsumura Shuichi , Nishioka Makoto , Shigeno Haruo , Tanaka Toshiyuki , Yoshikawa Sadao 
Published: April 2003

AbstractPoly(sodium carboxylate)s containing varying amounts of unreacted sugar residues as biodegradable segments in the polymer backbone were prepared by the partial oxidation of amylose and cellulose using periodic acid/chlorite. It was found that dicarboxy polysaccharides containing sugar residues showed improved biodegradability comparing to those having no sugar blocks in the polymer chain, and their biodegradability varied according to the glucopyranose content or the degree of dicarboxylation. Dicarboxy polysaccharides containing more than 60% glucopyranose residues tended to biodegrade quickly. When compared on an equal glucopyranose content basis, the biodegradability of dicarboxy amylose (2b) was slightly superior to that of dicarboxy cellulose (2a). The builder performance in detergents was dependent on the degree of dicarboxylation, and a clear relation between the detergency and the content of carboxylate groups was observed. Dicarboxy polysaccharides with more than 40% dicarboxylation showed better builder performance than those of disodium 3‐oxapentanedioate and trisodium citrate, with some of them superior to that of sodium tripolyphosphate (STPP). The detergency of 2b was more effective than that of 2a. It was also found that the detergency was improved much by increasing the amount of polymeric builder.
Porous ion‐exchange membranes, 2. Effect of adhesion promoters
Authors: Bryjak Marek , Poźniak Gryzelda , Trochimczuk Witold 
Published: April 2003

AbstractThe previously described preparation of porous ion‐exchange membranes (PIEM's) from the ternary blends of polyethylene interpolymer with poly(styrene‐co‐divinylbenzene) and polypropylene and calcium carbonate filler has been supplemented with the use of stearic acid and dibutyl phthalate as adhesion promoters. It was noted that both promoters govern the huge increase of pore diameter without any significant disturbances in the other PIEM's properties. The facilitating effect of chlorosulfonic acid diffusion toward calcium carbonate grains and large amounts of carbon dioxide volatilization was concluded. This is the basic point of pore creation to be discussed in this paper.
Macroporous membranes, IV. Synthesis and properties of poly[(2,3‐epoxypropyl methacrylate)‐co‐(N‐vinyl‐2‐pyrrolidone)‐co‐(ethylene dimethacrylate)] membranes
Authors: Hradil J. , Azanova A. A. , Ilavský M. , Švec F. 
Published: April 2003

AbstractMacroporous membranes based on terpolymers of 2,3‐epoxypropylmethacrylate, N‐vinyl‐2‐pyrrolidone, and ethylenedimethacrylate were prepared by radical suspension copolymerization and subsequently modified with ammonia. The membranes were characterized by their porosity, specific surface area, pore size, water permeability and mechanical properties. The low content of N‐vinyl‐2‐pyrrolidone improves the mechanical properties of the membranes. The mechanism of formation of the macroporous structure and heterogeneities is discussed.
Removal of escherichia coli from water by systems based on insoluble poly(glycidyl methacrylate)‐G‐tetraethylenepentamine and ‐G‐polyethylenimine
Authors: Tashiro Tatsuo 
Published: April 2003

AbstractA study was made of the removal of Escherichia coli (E. coli) from water by systems based on insoluble poly(glycidyl methacrylate)‐g‐tetraethylenepentamine and ‐g‐polyethylenimine, i.e., the reaction products of insoluble poly(glycidyl methacrylate) (PGMA) beads with tetraethylenepentamine (TEP) or polyethylenimine having molecular weights of about 600 (PEI600). The polymers (PGMA‐TEP and PGMA‐PEI600) were brought into contact with E. coli in sterilized physiological saline. These polymers made the viable cell numbers decrease in this medium. It was confirmed by observation of polymer surfaces with a scanning electron microscope that this decrease was caused by adsorption of the bacterial cells onto these polymers. The decrease coefficients of viable cell numbers (D) for E. coli by these polymers were 53 ml g−1 h−1 for PGMA‐TEP and 62 ml g−1h−1 for PGMA‐PEI600, being compared with D by other polymers studied previously.
Thermal dehydrochlorination of PVC in the presence of rubber seed oil
Authors: Okieimen Felix E. , Ebhoaye Justus E. 
Published: April 2003

AbstractDehydrochlorination rates of PVC in nitrogen atmosphere were determined in the presence of rubber seed oil (RSO), epoxidized rubber seed oil (ERSO), barium soap of rubber seed oil fatty acids and barium soap of epoxidized fatty acid of rubber seed oil. The initial rates of dehydrochlorination and the time required for the degradation to attain 1% conversion showed that the rubber seed oil derivatives exert a stabilizing effect on the degradation of PVC. The order of the stabilizing effect was found to be metal soaps of ERSO < metal soaps of RSO < ERSO < RSO.
Wirkung von Diisocyanat als reaktiver Koppler in TPU/PA6‐Blends
Authors: Franke C. , Pötschke P. , Rätzsch M. , Pompe G. , Sahre K. , Voigt D. , Janke A. 
Published: April 2003

AbstractZur Verbesserung der Werkstoffeigenschaften von thermoplastischen Polyurethanen (TPU), wie etwa der Wärmeformbeständigkeit, ist es sinnvoll, ein Blending mit Thermoplasten vorzunehmen. Eine gute Phasenverträglichkeit und Phasenhaftung bei thermodynamisch unverträglichen Blendkomponenten kann durch geeignete reaktive Koppler erreicht werden. Bei den Blends aus TPU and PA6 wird Diisocyanat während der Extrusion in der Schmelze eingebracht. Durch die ablaufenden chemischen Reaktionen werden bei extrudierten und verspritzten Blends und bei aus der Lösung erzeugten Systemen aus Polyesterpolyurethan und PA6 verträglichkeitsverbessernde Wirkungen erreicht. Diese wurden als Folge von mit 4,4′‐Diphenylmethandiisocyanat (MDI) initiierten Reaktionen in der Grenzschicht erkannt, wobei die möglichen Reaktionen mit der PA6‐Phase anhand eines Modellsystems aus der Lösung diskutiert werden. Bei Blends aus Polyetherpolyurethan und PA6 wurde keine Verträglichkeitsvermittlung durch MDI nachgewiesen. Die chemische Charakterisierung der Blends erfolgte durch GPC und FTIR, während die morphologischen Eigenschaften mittels DSC, DMA und Elektronenmikroskopie dokumentiert wurden.
Studies on simultaneous curing of nadimides and allyl nadic‐imides and thermal behaviour of cured resins
Authors: Mathur A. , Varma I. K. 
Published: April 2003

AbstractThe effect of composition and chemical structure of addition polyimides on thermal characteristics was investigated using commercially available allyl nadic‐imide resins and phosphorus‐containing nadimide resins. Thermogravimetric analysis, in N2 atmosphere, of resins cured at 300°C for 1 h revealed improvement of thermal stability.
Dextran functionalized by cyclic carbonate groups as supports of bioactive compounds
Authors: Ramírez J. C. , Sánchez‐Chaves M. , Arránz F. 
Published: April 2003

AbstractThis work deals with some features of the reaction of dextran with ethyl chloroformate using triethylamine as catalyst. The presence of cyclic and acyclic carbonate groups in the resulting modified dextrans was demonstrated by IR, 1H and 13C NMR spectroscopy. Preliminary experiments have shown that the reaction of cyclic carbonate groups with several model amines is greatly dependent on the basic character of the amine. Model amino type drugs (Phenethylamine and tyramine) were quantitatively bound to activated dextran with cyclic carbonate groups. The heterogeneous hydrolysis of dextran‐phenethylamine or dextran‐tyramine adducts showed that no hydrolysis takes place under the applied conditions.
Photochromism of polyurethane cationomers with pendent azo groups
Authors: Buruianǎ E. C. , Buruianǎ T. , Airinei A. , Robilǎ G. 
Published: April 2003

AbstractA new polyurethane cationomer with pendent azo groups bounds to quaternary nitrogen atoms has been synthesized by polyaddition reaction between poly(tetramethylene oxide) (PTMO), 4,4′‐bibenzyldiisocyanate and N‐methyldiethanolamine, followed by quaternization of tertiary nitrogen with 4‐(3‐chloropropionyloxy)azobenzene.E–Z photoisomerization of azo chromophores by UV irradiation with a high pressure mercury lamp and Z–E thermal relaxation were studied both in solution and film. An azo urethane model and a synthetic mixture of polyurethane cationomer with azobenzene were used for comparison.
Triazene polymers designed for excimer laser ablation
Authors: Lippert Th. , Wokaun A. , Stebani J. , Nuyken O. , Ihlemann J. 
Published: April 2003

AbstractThe excimer laser‐induced ablation of triazene polymers at a wavelength of 308 nm has been investigated as a function of laser fluence deposited on the surface in one or several pulses. PMMA, which as a homopolymer can not be ablated at 308 nm, has been sensitized for ablation at this wavelength by synthesizing a copolymer in which 0.3 mol‐% of the side chains contain the triazene functional groups. The high ablated depths per pulse achieved in this manner are similar to the ones observed upon physical doping of PMMA with monomeric triazene compounds. In an alternative approach, the triazene functional group is introduced once (polymer TP 1) or twice (TP 2) into each repeating unit of the polymer backbone by a polycondensation reaction. Irradiation of TP 1 gives rise to ill‐defined ablation profiles with sloping wall. In contrast, clean circular ablation profiles are obtained with polymer TP 2, which are characterized by circular contours, steep edges, and flat bottoms of the ablated craters. The origins of these differences are investigated. A comparative study of excimer laser ablation of TP 2 at 248 and 308 nm shows that the latter wavelength is more effective; the plateau value of the ablated depth per pulse corresponds to ≈ 1 μm at 248 nm and ≈ 3 μm at 308 nm. This dependence is attributed to the photolysis behaviour of the triazene compounds: nitrogen released upon photolytic bond cleavage acts as a driving gas which promotes the ablation. As a consequence, no ‘incubation pulses’ are required for triazene polymer ablation in the investigated fluence range.
Nichtadditivität von Brechungsindexinkrementen bei Copolymeren mit N‐Phenylmaleimid
Authors: Francuskiewicz Frieder , Glöckner Gottfried , Kratochvíl Pavel 
Published: April 2003

AbstractBrechungsindexinkremente der Copolymeren von N‐Phenylmaleimid mit Styrol, Methylmethacrylat und Acrylnitril sowie der entsprechenden Homopolymeren wurden in verschiedenen Lösungsmitteln bei 536 nm und 25°C gemessen. Die Brechungsindexinkremente der Copolymeren mit Styrol und Methylmethacrylat zeigten in allen verwendeten Lösungsmitteln positive Abweichungen von der für die meisten Copolymeren üblichen Additivität. Dies wurde durch unabhängige Mesungen der partiellen spezifischen Volumina bestätigt. Mögliche Ursachen der Nichtadditivität werden erörtert.
PET/PHB‐LC polyesters with improved mechanical properties — terminal group coupling with diisocyanate, I
Authors: Leistner Dirk , Stephan Michael , Häßler Liane , Vogel Roland , Rätzsch Manfred 
Published: April 2003

AbstractIn order to increase the molecular weights of poly(ethylene terephthalate‐co‐oxyben‐zoate)s (PET/PHB) these polymers were modified with methylene‐diphenyldiisocyanate (MDI) in the melt to couple the carboxy terminal groups, forming a copolyester amide. Starting from M̄n 12 500, various M̄n values, partly up to 60 400, were obtained in dependence on the MDI quantity. The copolyester amides were characterized by IR spectroscopy, DSC, M̄n and rheological measurements. The MDI modification of PET/PHB causes also an increase in melt viscosity and a decrease in crystallinity in the solid state. Injection molded samples showed a considerable increase in tensile strength, elastic modulus and above all impact strength.
Precipitation polymerization of acrylic acid: Kinetics, viscosity and heat transfer
Authors: Poersch‐Panke Hans‐Günter , Avela Arno , Reichert Karl‐Heinz 
Published: April 2003

AbstractThe free‐radical precipitation polymerization of acrylic acid in toluene was studied in an isothermal reaction calorimeter. The polymerization shows an autocatalytic behaviour of the rate of polymerization typical for precipitation polymerizations. The rate of polymerization with respect to conversion can be modeled by taking the volume fraction of the precipitated polymer into consideration.The viscosity of the reaction mixture increases with increasing volume fraction of precipitated polymer. The viscosity runs through a maximum at high conversion. The final viscosity decrease is probably due to shear stress caused aggregation phenomena of the polymer particles. A model is discussed which can describe the increase and decrease of viscosity of the system.By means of reaction calorimetry it is possible to determine the reaction‐sided heat transfer coefficient during polymerization. The comparison of the experimentally determined temperature course of the reaction mixture and the temperature course calculated with a coupled model of the polymerization and the calorimeter shows that the heat‐transfer characteristic changes instantaneously during a small conversion interval at the very beginning of the polymerization.
Pervaporation and membrane distillation through membranes made of poly(2,6‐dimethyl‐1,4‐phenylene oxide)
Authors: Schauer J. , Schwarz H. H. , Eisold C. 
Published: April 2003

AbstractThe ability of poly(2,6‐dimethyl‐1,4‐phenylene oxide) membranes to separate water‐ethanol mixtures by pervaporation was examined. Asymmetric membranes were prepared from solutions containing chloroform as a solvent and 1‐butanol as a nonsolvent by the phase‐inversion process. Homogeneous, dense membranes were prepared from chloroform solutions by evaporation. Nonporous membranes (membranes precipitated from solutions with a low amount of the nonsolvent or prepared by evaporation) were preferentially permeable to water. Microporous membranes (precipitated from solutions with a high amount of the nonsolvent) were preferentially permeable to ethanol, provided the membrane is not wetted by the feed solution.
Kompensationsspannung als zusätzliches Beurteilungskriterium für PAN‐Precursorfasern
Authors: Mikołajczyk Teresa , Kamecka Katarzyna , Krucińska Izabella , Mikołajczyk Włodzimierz 
Published: April 2003

AbstractFasern aus Poly(acrylnitril‐co‐methylacrylat‐co‐itaconsäure) wurden unter unterschiedlichen Bedingungen verstreckt. Die verstreckten Fasern wurden bezüglich des allgemeinen Orientierungsgrads und des Orientierungsgrads und Anteils der parakristallinen Gebiete charakterisiert; mechanische Kennwerte der Fasern wurden gemessen. Aus der Korrelation der erhaltenen Werte mit der sogenannten Kompensationsspannung der Fasern wird geschlossen, daß letztere ein Maß für die Eigenspannungen in den Fasern darstellt und eine Optimierung der Herstellung und Weiterverarbeitung der Fasern ermöglicht.
Removal of escherichia coli from water by systems based on polystyrene‐g‐ and poly(glycidyl methacrylate)‐g‐amines
Authors: Tashiro Tatsuo 
Published: April 2003

AbstractReaction products of soluble chloromethylated polystyrene with diethylamine, poly(styrene‐co‐chloromethylstyrene) with diethanolamine, and poly(styrene‐co‐glycidyl methacrylate) with diethanolamine were prepared and supported on activated alumina granules. A study was made of removal of Escherichia coli cells from water by these supported alumina granules. When these granules (0.100 g) were stirred in a viable cell suspension (107–8 cells/ml, 20 ml), the viable cell number decreased by the adsorption of the cells to the granules. The adsorption attained approximately to the equilibrium (saturated adsorption) after about 2 h from the start of the adsorption. The decrease coefficient (D, which corresponds to the adsorption rate constant) was determined from the decrease in the viable cell number in the adsorption for about 2 h from the start.
Supported titanium catalyst for propylene polymerization. Convenient synthesis of unsolvated anhydrous magnesium chloride from MgCl2 · 6 H2O
Authors: Gupta Virendra Kumar , Satish Sheo , Bhardwaj Ishwar Singh 
Published: April 2003

AbstractReaction of chlorosilanes (Me3SiCl, R2SiCl2, SiCl4; RMe, Ph) with MgCl2 · 6 H2O were investigated for the efficiency of removal of water. The nature of chlorosilane is found to govern the rate of dehydration. The treatment of hydrated magnesium chloride with dichlorodiphenylsilane gives unsolvated anhydrous magnesium chloride in high yields. Anhydrous MgCl2 is used as support for the preparation of titanium catalyst. The catalyst in conjunction with Et3Al and Ph2Si(OMe)2 as cocatalyst system shows high activity for propylene polymerization.