bluuebunny/crossref_metadata_2025_split huggingface dataset:
Beurteilung von lichtschutzsystemen bei polyolefinen in der natürlichen und künstlichen bewitterung
Authors: Schaaf R. 
Published: April 2003

AbstractVestolen A 6016 and Vestolen P 5200 were acceleratedly weathered in a Xenotext 1200 and a Xenotest 450. By variation of operating conditions of Xenotest 1200 different spectral distributions in the UV region (with and without UV filter) were obtained. In Xenotest 450 polyethylene and polypropylene showed approximately the same process of damage, wheras polyethylene and polypropylene showed clear different “spectral sensitivities” in Xenotest 1200. The maximum of UV capacity which is possible in Xenotest 1200 enables a maximum of time accelerating effect ‐ also when light protecting systems are used ‐ but it does not admit a more exact evaluation of the quality of a light protecting formulation. The test of light protecting formulations based on UV absorber, HALS and combinations thereof showed, that evaluation can be very different and does not always conform with the results of out door weathering.
Ein beitrag zur beurteilung der alterung von kunststoffen mit hilfe der raster‐elektronenmikroskopie
Authors: Reuß S. 
Published: April 2003

AbstractAfter open‐air weathering water and moisture proof sheetings made of polyvinyl chloride show cracks in some cases. Changes in the characteristics, determined by mechanical testing procedures, doe not explain the reason and the mechanism of crack formation. Therefore scanning electron microscope‐studies have been carried out and evaluated in connection with the results of infrared spectroscopy investigations. Resulting from microcracks and notch impact defects knowledge of age‐depending crack formation has been achieved.
Grundsätzliche gedanken über bewitterung und stabilisierung von polyethylen niederer dichte
Authors: Nikolowa Zi. , Georgiewa M. , Kostow G. , Mladenow Iw. 
Published: April 2003

AbstractAgeing test was done on low density‐polyethylene (tubular type). The tests under combined influence of atmospheric factors started for one year in May. Changes of chemical structure of the polymer are studied by means of infrared spectroscopy.
Eigenschaften von PE‐erzeugnissen nach der bewitterung
Authors: Komitov P. G. 
Published: April 2003

AbstractIn the last years in a joint action with Institute of Chemical Industry ‐ Sofia wide research work was completed on lightstabilized (atmospheric resistant) types of polyethylene high density creation and its implementation in transport packaging production.Quite interesting and unexpected result in relevant improvement of tested articles operating properties in the initial stages of the natural ageing after which they regularly change for the worse. Dynamic properties optimum of the polyethylene articles is reached in one to three months of the production date and direct open exhibition. It is found out that main influence on the results got is by some additives existance and concentration in the polyethylene composition.Available data and influences found out are mainly of quality nature but allow assumption that processes as recrystallization and disorientation in unbalanced structure created in treatment process are carried out which in the initial stages of operation predominate over ageing processes.An research is made on determination of exact quantity ratio between composition of the polyethylene (type and quantity of the additives) and treatment conditions (articles configuration and process parameters). Results with essential implementation value are expected.
Reactive polymers, 45. Use of macroporous glycidyl methacrylate—ethylene dimethacrylate copolymer modified by diethylamine for the separation of pt(IV), pd(II) and rh(III)
Authors: Kálal Jaroslav , Kálalová Eliška , Jandová Lenka , Švec František 
Published: April 2003

AbstractSorbents based on the macroporous copolymer of glycidyl methacrylate—ethylene dimethacrylate modified with diethylamine sorb in a strongly acid solution Pt(IV), Pd(II) and Rh(III) as chloro complexes. By gradual desorption with variously concentrated nitric and hydrochloric acid, it is possible to desorb selectively platinum or rhodium ions and to separate them virtually quantitatively from palladium ions which later on are desorbed only at a high HCl concentration.
Oxygen‐ascorbic acid‐ferric ion initiating system. Kinetics of polymerization of methyl methacrylate
Authors: Reddy G. Gangi , Nagabhushanam T. , Rao K. Venkata , Santappa M. 
Published: April 2003

AbstractThe kinetics of polymerization of methyl methacrylate (MMA) in dilute nitric acid medium at 40°C initiated by the three component initiating system, oxygen‐ascorbic acid (AA)‐ferric ions was investigated. The rate of polymerization, Rp, was found to be proportional to [MMA]1.5 under different experimental conditions. Rp, was independent of [Fe3+] in the concentration range 2 to 5 − 10−5 M, but decreased slightly at higher values. Rp was also independent of [AA] and a dependence on [O2]0.6 was noticed with [O2] < 6.5 × 10−4M. After an initial increase, Rp became independent above [HNO3] ≈ 0.3M. Ionic strength, μ, of the medium had no effect on Rp. A rate increase up to 42°C followed by constancy and decrease with further increase in temperature (>46°C) was noticed. The chain lengths of the polymers were determined to be in the range 102 — 103 by viscometry. A plausible reaction mechanism with initiation by the primary radical and termination by mutual interaction was proposed.
Reactivity ratios of some substituted aromatic amines by linear graphical methods
Authors: Chatterjee S. K. , Singh B. P. , Pachauri L. S. 
Published: April 2003

AbstractReactivity ratios of some halogen substituted aromatic amines have been determined by using Kelen‐Tüdős and Fineman‐Ross linear graphical methods. On copolymerization with p‐toluidine or p‐nitrophenol as comonomer, the reactivity of halogen substituted aromatic amines was found to be in the order of their basic strength. However, this order of reactivity gets reversed when these halogen substituted amines are copolymerized with p‐nitroaniline. This reversal of reactivity has been interpreted in terms of polarization and resonance stabilization of the monomeric species.
Formaldehyde release and cellulose crosslinking with N‐methylol agents: A delicate balance
Authors: Andrews B. A. Kottes , Simoneaux Jacqueline M. , Harper Robert J. 
Published: April 2003

AbstractIn addition to the etherification of cellulose by N‐methylol and N‐alkoxymethyl agents that results in crosslinking, hydrolysis reactions that liberate formaldehyde can also occur. The hydrolysis of representative reactants was followed under acidic and basic conditions, through deetherification and demethylolation, to formaldehyde release. Functional groups were identified by the use of nuclear magnetic resonance spectroscopy. Results were used to interpret the behavior of finishes from these agents on cotton fabrics, particularly with respect to the special influence of alcohols.
Untersuchungen zum Verschleiß beim Spritzgießen von monomerfreien ungesättigten Polyesterformmassen
Authors: Braun Dietrich , Tretner Hartmut 
Published: April 2003

AbstractDie beim Spritzgießen zweier mineral‐ und glasfasergefüllter, monomerfreier ungesättigter Polyesterformmassen entstehenden flüchtigen Zersetzungsprodukte wurden isoliert und identifiziert. Hauptbestandteil der Flüchte ist in beiden Fällen Wasser mit einem Anteil von über 96 Gew.‐%, daneben geringe Mengen des Polymerisationsinitiators und seiner Abbauprodukte. Substanzen, die auf einen Abbau des ungesättigten Polyesters hinweisen, wurden nicht gefunden.
Neue photoreaktive Polymere mit seitenständigen Dimethylmaleinimid‐Gruppen. I. Radikalische homo‐und copolymerisation von N‐(5‐methyl‐3‐oxa‐4‐oxo‐hexen‐5‐yl)‐dimethylmaleinimid
Authors: Berger Joseph , Zweifel Hans 
Published: April 2003

AbstractDie Homopolymerisation von N‐(5‐Methyl‐3‐oxa‐4‐hexen‐5‐yl)‐dimethylmaleinimid (DMI‐MA) führt zu linearen Polymethylmethacrylaten mit seitenständigen lichtvernetzbaren Dimethylmaleinimid‐Gruppen. Dabei nimmt die CC Doppelbindung des Imidylrestes infolge sterischer Hinderung durch die beiden Methylsubstituenten, selbst bei Umsätzen von über 90%, nicht an der Reaktion teil. Für die Homopolymerisation wurde die Polymerisationsgeschwindigkeitskonstante bestimmt zu kp/k = 2,0 – 2,2·10−2(65°C, Toluol, AIBN); die Aktivierungsenergie beträgt Ea = 62,36 ± 2 kJ/mol−1.Aus den Copolymerisationen der Monomerpaare DMI‐MA/Methacrylsäure (MAS), DMI‐MA/Methylmethacrylat (MMA) und DMI‐MA/Ethylacrylat (EA) ergaben sich folgende Copolymerisationsparameter: DMI‐MA (r1) : MAS (r2) = 1,36 ± 0,06 : 0,77 ± 0,06; DMI‐MA (r1) : MMA (r2) = 1,16 ± 0,17 : 0,475 ± 0,17 und DMI‐MA (r1) : EA (r2) = 1,60 ± 0,15 : 0,44 ± 0,15.
Gas chromatography/mass spectroscopy analysis of resols and etherified resols
Authors: Anthony Geoffrey M. , Kemp Graham 
Published: April 2003

AbstractThe characterisation of two resols which had been etherified with methanol under acidic conditions is described for the first time. The resins were converted into trimethylsilyl derivatives and the individual components were separated by means of capillary gas chromatography. Structural assignments were made using mass spectrometry measurements and with the aid of model compounds. The precursor resols have also been analysed by the same technique.
Viskosität hochkonzentrierter Lösungen eines ungesättigten Polyesters in p‐Xylol
Authors: Lešek František , Eichler Josef , Šimek Ludvík , Gajda Josef 
Published: April 2003

AbstractDie Abhängigkeit der Viskosität eines Polyesters auf der Basis von Maleinsäureanhydrid (MA), Phthalsäureanhydrid (FA) und 1,2‐Propylenglykol (1,2 PG) vom Polyveresterungsgrad M̄0 im Säurezahlbereich 30–240 (mg KOH/g) ließ sich in Verdünnung mit 2–10% p‐Xylol durch η = k1M̄ beschreiben. Als Beziehung zwischen Temperatur und Viskosität ergab sich log η = A + B/(T–T0). Für die Korrelation der Viskosität mit dem Polyestergehalt im Temperaturbereich 55–130°C war die Gl. η = C exp(Dx) maßgebend, wobei C und D spezifische Konstanten für den Polyveresterungsgrad und die Temperatur und x der Polyestergehalt der Proben in Gew.−% sind. In der Gl. log η = x1 log η1 + x2 log η2 + Δ, wobei x1 und x2 die Molenbrüche von Polyester und p‐Xylol und η1 bzw. η2 ihre Viskositäten sind, war das Glied Δ eine lineare Funktion von M̄ und dem Polyestergehalt der Proben. Meßwerte der Systeme bei 100°C werden angeführt.
Die Medienabhängigkeit der alkalischen Hydrolyse von Methylmethacrylat‐Polymeren
Authors: Sandner Barbara , Bischof Claus 
Published: April 2003

AbstractDie Geschwindigkeit der alkalischen Hydrolyse von Polymethylmethacrylat (PMMA) und Methylmethacrylat (MMA)‐Ethylacrylat‐Copolymeren erhöht sich mit steigender Dielektrizitätskonstante und abnehmendem OH−‐Ionen‐Solvatationsvermögen der als Lösungsmittel verwendeten aliphatischen einwertigen Alkohole und in aprotischen Lösungsmitteln. Aus dieser Abhängigkeit ergeben sich in der Alkoholreihe maximale Geschwindigkeiten bei den Propanolen. Höhre Wassergehalte führen zur starken Verminderung der Hydrolysegeschwindigkeit. Die Geschwindigkeitskonstanten der Hydrolyse von Ethylacrylat‐ und MMA‐Einheiten im Copolymeren unterscheiden sich bei den untersuchten Reaktionsbedingungen um eine Größenordnung. In Ethanol bilden Hydrolysemischungen von MMA‐Ethylacrylat‐Suspensions‐copolymeren bei 80°C bei niedrigem Alkalihydroxid‐ und Wassergehalt homogene Lösungen, bei mittlerem Alkalihydroxid‐ und Wassergehalt hochgequollene Gele und bei hohem Alkalihydroxid‐ und Wassergehalt unter bestimmten Bedingungen Dispersionen. Für die partielle Hydrolyse ergeben sich technisch interessante Varianten.
Cellulose containing block copolymers. 4. Cellulose triester macroinitiators
Authors: Mezger T. , Cantow H.‐J. 
Published: April 2003

AbstractThe preparation of monofunctional 1‐hydroxy cellulose triesters—propionate‐acetate and tributyrate — and subsequent coupling with bis‐(4‐isocyanatophenyl)‐disulfide is described, thus yielding a macrophotoinitiator for radical threeblock copolymer syntheses. Cellulose triester blocks were obtained by hydrogen halide cleavage of fully substituted cellulose esters under esterification conditions. The terminal halide function introduced in this way yields hydroxyl after hydrolysis at medium pH conditions. Evidence of strict monofunctionality has been demonstrated by analysis of molecular weights as well as of molecular weight distributions before and after coupling with stoechiometric amounts of difunctional coupling agents. Viscosity‐molecular weight relationships were extended towards low degrees of polymerization, applying vapour pressure and membrane osmometry for calibration.
Polymerisation von Vinylchlorid bei Atmosphärendruck. 2. Chemische und spektroskopische Methoden zur Charakterisierung von U‐PVC
Authors: Braun D. , Holzer G. 
Published: April 2003

AbstractBei Atmosphärendruck hergestelltes PVC (sog. U‐PVC) enthält gegenüber normalem PVC relativ hohe Konzentrationen an Strukturanomalien. Die ozonolytisch bestimmten Spaltstellenzahlen x̄ pro 100 Monomereinheiten als Maß für die internen Doppelbindungen der untersuchten U‐Polymeren schwanken zwischen 0,026 und 0,058.Die gemeinsame Bestimmung von allylischem und tertiärem Chlor erfolgte durch die selektive Umsetzung von U‐PVC mit Phenol und 1H‐NMR‐spektroskopische Untersuchung der phenolisierten Polymeren. Mit ca. 0,65 labilen Chloratomen pro 100 VC‐Einheiten wurden vergleichsweise hohe Gehalte dieser Fehlstellen gefunden.Die beim Initiatorzerfall aus K2S2O8 gebildeten OH‐Radikale führen zu alkoholischen Endgruppen im U‐PVC, die durch eine Absorption bei 3580 cm−1 im IR‐Spektrum sichtbar werden. Beim Kettenabbruch mit OH‐Radikalen entsteht eine Chlorhydrinsktruktur, die unter Chlorwasserstoffabspaltung in einen ß‐Chloraldehydrest übergeht, was durch eine Bande bei 1720 cm−1 im IR‐Spektrum angezeigt wird.U‐PVC‐Rohprodukte enthalten im Mittel zwei Verzweigungsstellen pro 100 Monomereinheiten. In den mit CCl4 extrahierten niedermolekularen Anteilen liegt die Zahl der Verzweigungen um den Faktor 10 höher. Die olefinischen Strukturen CHCHCHCl und CHClCHCH2 sind in Konzentrationen von jeweils 0,25 bis 0,3 pro 100 VC‐Einheiten NMR‐spektroskopisch nachweisbar. Die für U‐PVC typische Enddoppelbindung CHCHCH2Cl findet sich vor allem in den niedermolekularen Anteilen der Ausgangsprodukte.
Modification of polyethylene with methacrylic acid, I. Grafting of methacrylic acid onto polyethylene
Authors: Bryjak Marek , Trochimczuk Witold 
Published: April 2003

AbstractThree different methods for grafting methacrylic acid onto polyethylene have been investigated. These were carried out in melt, in the swollen gel, and in solution. It has been found that the membranes obtained by pressing the blends are optically homogeneous when the products obtained in melt or in solution were used, but grafting in gel led to a macroheterogeneous product. For further studies the product containing a relatively high content of grafted methacrylic acid obtained in solution was chosen.
Beitrag zur Problematik der theoretischen und experimentellen Festigkeit von Polyesterfasern
Authors: Kalousková V. , Všianský J. 
Published: April 2003

AbstractIn der vorliegenden Arbeit wird das Problem der Wirkung von Kräften zwischen den Makromolekülen in idealen 100proz. kristallinen und vollständig orientierten Polyesterfasern behandelt und daraus die theoretische Festigkeit berechnet. Bei der Berechnung der theoretischen Festigkeit wurde von der Vorstellung ausgegangen, daß es bei einer Deformation durch Zug sowohl zum Bruch der Makromolekülketten als auch zum gegenseitigen Abgleiten bei Störungen der Kohäsionskräfte kommen kann. Auf Grund der erhaltenen Ergebnisse wird das schwächste Glied der Struktur der idealen Polyesterfasern bestimmt und daraus die Vorstellung über den Mechanismus ihres Bruches abgeleitet.Der experimentelle Teil der Arbeit beschäftigt sich mit der Fraktographie von Polyesterfasern durch mechanischen Abrieb in der Quer‐ und Längsrichtung. Dabei wird die Raster‐Elektronenmikroskopie (REM) eingesetzt. Die Schlußfolgerungen aus dem theoretischen und dem experimentellen Teil der Arbeit ergeben einen eindeutigen Zusammenhang.
Coordination polymers, III. Synthesis and properties of chelate polymers of Cr(III), Fe(II), Co(II), Ni(II), Cu(II) and UO2(II). With schiff base of 4,4′‐(4,4′‐biphenylylene bisazo) disalicylaldehyde with aniline
Authors: Deshpande U. G. , Shah J. R. 
Published: April 2003

AbstractPolychelates of Cr(III), Fe(II), Co(II), Ni(II), Cu(II) and UO2(II) were prepared from Schiff base of 4,4′‐(4,4′‐Biphenylylene bisazo) disalicylaldehyde with aniline. All the chelate polymers are dark coloured and insoluble in common organic solvents. They are characterized on the basis of electronic reflectance spectral and magnetic measurements in conjunction with infrared measurements. Elemental analyses indicate a metal ligand ratio of 1:1 for all the polychelates except polychelate of UO2(II) for which the ratio is 2:3. The various ligand field parameters have been evaluated for Cr(III), Ni(II) and Co(II) polychelates. Except Cu(II) and Co(II), polychelates, the other polychelates show six coordinated structure. Cu(II) and Co(II) polychelates may have a square planar and tetrahydral structure, respectively. The thermal stability of all the polychelates was determined from their thermogravimetric analyses.
Osmotic pressures of concentrated polymer solutions in good solvents
Authors: Kok C. M. , Rudin Alfred 
Published: April 2003

AbstractThe hydrodynamic radii of solvated polymer molecules can be estimated with a theory which has been reported earlier. These radii are employed in a hard sphere model to predict osmotic pressures of polymer solutions. Calculated and experimental osmotic pressures are in quite good agreement even for solutions with concentrations appreciably higher than the critical concentrations for overlap of polymer coils. The theory presented here is limited to good solvents.
Reactive polymers, 46. The effect of diluents on the surface reactivity of polymers obtained from glycidyl methacrylate
Authors: Horák Daniel , Pelzbauer Zdeněk , Švec František , Labský Jiří , Bleha Miroslav 
Published: April 2003

AbstractMacroporous copolymers of glycidyl methacrylate and ethylene dimethacrylate were synthesized under equal conditions in the presence of different solvents as porogenic agents. The products obtained differ in the porosity, specific surface area, content of oxirane groups, and shape. The reactivity was measured using three substrates having low, medium, and high molecular weight (HCl, 4‐amino‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl, human serum albumin). The fraction of the reacted amount of reagent to the amount which would fill in the measured specific surface area in a monomolecular layer was calculated and found to reach a minimum for polymers with the best developed porous structure, although in all cases it is higher than unity. This shows that the reaction proceeds not merely on the available surface and that a new approach to the description of reactions on macroporous polymers is necessary.
Epoxy resins VIII. Thermal properties of 4,4′‐sulfonyldiphenol and bisphenol a epoxy resins
Authors: Bansal R. K. , Agarwal R. , Keshav K. 
Published: April 2003

AbstractEpoxy resins of different molecular weights were prepared from epichlorohydrin and 4,4′‐sulfonyldiphenol (SDP) and from epicholorohydrin and bisphenol A (BA). They were cured at high temperatures with four different crosslinking agents, including aliphatic and aromatic amines. The thermal behaviour of these cured epoxy resins was studied. From the IPDT and IDT data it was observed that sulfone epoxy resins were thermally more stable than bisphenol A epoxy resins. The activation energies of thermal degradation of the resins were calculated and the implications of these results are discussed.
The oxidation of poly(vinyl pyrrolidone) with Ce(IV)
Authors: Staszewska Danuta Urszula 
Published: April 2003

AbstractIt was established that commercial poly(vinyl pyrrolidone) (PVP) may contain hydroperoxides, hydroxyl groups, carbonyl groups and double bonds in the main chain, and substances of low molar mass such as hydrogen peroxide and 2‐pyrrolidone, products of PVP oxidation during processing, handling and/or storage. In a scheme PVP reacting sites with Ce(IV) used as an initiator in the reaction of copolymerization of PVP with vinyl monomers were shown. It was concluded that PVP hydroperoxides were responsible for the formation of a respective homopolymer, whereas PVP hydroxyl groups may form radicals capable of the polymerization of a comonomer. The influence of molar mass of mother PVP on the course of the reaction of copolymerization of PVP was also discussed.
Miscibility of poly(vinyl chloride)/ethylene‐acrylic rubber blends
Authors: Kalfoglou Nikos K. 
Published: April 2003

AbstractThe compatibility behaviour of blends of poly(vinyl chloride) with an ethyleneacrylic rubber was investigated at five compositions. Phase‐contrast microscopy revealed submicron heterogeneities at intermediate compositions, however, on the basis of the dynamic mechanical properties, one concludes that the pair is miscible at the segmental level, throughout the composition range. These properties were studied between 143 and 383 K at 110 Hz. Tensile properties are characteristic of a miscible system and modulus enhancement supports the view that synergistic effects are present. Models proposed for miscible systems accurately predict the compositional variation of Tg. Also, mechanic models suitable for two‐phase systems, fail to predict the modulus dependence on composition. Fire retardancy becomes considerable already at intermediate levels of PVC.
A study of synthesis and characterization of compatibilizers for thermosetting‐thermoplastic polymer blends
Authors: Jayabalan M. , Balakrishnan T. 
Published: April 2003

AbstractModified copolymers or compatibilizers were prepared to blend thermosetting (phenol formaldehyde resin) and thermoplastic (PMMA/PS) polymers. Two compatibilizers, modified phenol formaldehyde‐(s‐triazine)‐polystyrene, P(PF‐g‐S) and poly‐(cinnamaldehyde‐co‐oxypropyleneoxyisophthaloyl‐co‐oxypropyleneoxyfumaroyl), P(C‐g‐E), were synthesized and characterized. The behaviour of the compatibilizers towards UV vacuum irradiation and heat was studied with low molecular weight P(PF‐g‐S) and P(C‐g‐E). Crosslinking was found to occur during the initial 20 h of UV vacuum irradiation, which was confirmed by solubility and swelling data. Thermal degradation of thermoplastic segments in P(PF‐g‐S) was found to occur initially during thermal exposure. Crosslinking of the degraded radical fragments and phenolic segments took place in the continued thermal exposure.A method yielding a simultaneous interpenetrating network (SIN) was adopted to increase the molecular weight of P(PF‐g‐S) and its allied copolymers which is a prerequisite for the present polymer blends. Condensation reaction in phenolic segments and addition reaction in thermoplastic segments were carried out simultaneously, the former reaction was carried out thermally and the latter by photo irradiation.
Trennung von PUR‐Ionomeren mit Sulfonatgruppen und nichtionischen Prepolymeren mittels Gelpermeations‐Chromatographie
Authors: Lorenz O. , Rose G. 
Published: April 2003

AbstractMischungen aus Polyurethanionomeren mit SO3‐ ‐Gruppen und ionenfreien Prepolymeren können mittels Gelpermeations‐Chromatographie unter Verwendung von ß‐Bondagel als stationärer Phase und wasserhaltigen Elutionsmitteln getrennt werden. Derartige Mischungen wurden durch Umsetzung von dünngeschichteten NCO‐Prepolymeren mit N‐(2‐Aminoethyl)‐2‐aminoethansulfonsaurem Natrium bei variiertem Stoffmengenverhältnis erhalten. Die für Ionomere und prepolymere ermittelten Massenbrüche sind mit denen identisch, die sich aus der wahrscheinlichsten Molmassenverteilung ergeben.