bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zur Beschreibung von Copolymeren aus 3 oder mehr Monomeren
Authors: Wittmer P. , Hungenberg K.‐D. 
Published: April 2003

AbstractDie Beschreibung von Copolymeren aus mehr als 2 Comonomeren auf algebraischem Weg führt zu nur schwer handhabbaren Gleichungen. Dagegen ist die Beschreibung mit Hilfe von Markov‐Ketten sehr einfach. Im einzelnen wird die Berechung der Copolymerenzusammensetzung, Sequenzhäufigkeiten, Sequenzlängenverteilungen, mittleren Sequenzlängen sowie der Häufigkeiten von Diaden diskutiert.
Involvement of the impregnation in the degree of polymerization of cellulose during soda pulping of sugar cane bagasse
Authors: Soubelet Oscar , Maximino Mirta , Marx‐Figini Marianne 
Published: April 2003

AbstractA comparative study had been carried out on the behaviour of the degree of polymerization (DP) of sugar cane bagasse during different times of digestion (soda pulping) with and without previous impregnation. Determination of the average DP (DPη) and its distribution show that the impregnated materials undergo degradation during the digestion, what in contrary is not to observe when digestion is carried out without previous impregnation. It is supposed that the impregnation alters the chemical structure of the cellulose, facilitating thus the degradation during digestion. From the distribution curves arises furthermore, independent from impregnation or not and independent from the digestion time, a very pronounced maximum (about 25 wt.‐% of total mass) at DP < 150 belonging to a non‐cellulosic polysaccharide present in the sugar cane bagasse, which is removed neither by digestion nor by nitration.
Polymer solid electrolytes based on ethylene oxide copolymers
Authors: Florjańczyk Zbigniew , Krawiec Włodzimierz , Wieczorek Władysław , Przyłuski Jan 
Published: April 2003

AbstractEthylene oxide was copolymerized with propylene oxide, epichlorohydrin or styrene oxide at various monomer feed compositions, using partially hydrolyzed organoaluminium compounds as catalysts. The copolymers obtained after doping with NaI form highly conductive polymeric electrolytes. Complex impedance measurements show relaxation semicircles much less depressed than in semicrystalline electrolytes based on Poly(ethylene oxide). The maximum values of the room temperature conductivity for each kind of copolymer containing electrolytes are higher than those for the pristine poly(ethylene oxide)‐Nal system. The highest value, equal to 2.6 · 10−5 S/cm at 25°C, was found for poly(ethylene oxide‐co‐propylene oxide) containing 33 mol‐% of propylene oxide monomeric units.
Azo dyes based on phenolic oligomers
Authors: Patel Hasmukh S. , Lad Babu D. 
Published: April 2003

AbstractA series of new oligomeric disperse and acid azo‐phenolic dyes were prepared by coupling various aromatic diazonium salts to phenol‐formaldehyde (PF), m‐cresol‐formaldehyde (CF) and resorcinol‐formaldehyde (RF) oligomers. They were characterized in terms of their softening points, colour, solubility, IR and UV‐Vis spectra and thermogravimetric properties. Their dyeing on polyester, nylon and wool resulted in yellow, orange, and brown to red shades with good to excellent light‐fastness and wash‐fastness properties.
Synthesis and characterization of some 2,4′‐dibenzyldiisocyanate ionic polymers, 7. Photochromic behaviour of ionenes with viologen units
Authors: Buruianǎ E. C. , Diaconu I. , Buruianǎ T. , Grigoriu G. E. , Caraculacu A. 
Published: April 2003

AbstractThe Photochromic properties by UV and laser irradiation of cationic polyurethanes with viologen groups introducted by Menschutkin reaction were studied and poly(vinylalcohol) was used as matrix.
Impact behaviour and morphology of rubber‐modified epoxy resins
Authors: Pucciariello Rachele , Villani Vincenzo , Bianchi Nadia , Braglia Roberto 
Published: April 2003

AbstractIn the present work the impact behaviour at high speed of rubber‐modified epoxy resins has been investigated. Impact‐tension measurements have been performed to evaluate the toughness of different systems. A detailed post‐failure observation of the fracture surfaces has been made through scanning electron microscopy (SEM). A combination of a solid fluorinated rubber with the generally used carboxy‐terminated butadiene‐acrylonitrile rubber (CTBN) was found to be very effective.A correlation was tempted between the observed fracture behaviour and the bulk morphology, examined by transmission electron microscopy (TEM).
Crystallinity of polyethylene measured by density, DSC, and raman spectroscopy. A comparison
Authors: Földes Enikő , Keresztury Gábor , Iring Margit , Tüdős Ferenc 
Published: April 2003

AbstractIn this work three different techniques were used to determine the crystallinity of polyethylene. After different pretreatment HDPE, LLDPE, and LPDE samples were investigated by density measurements, differential scanning calorimetry, and Raman spectroscopy. The results were compared and relationships were estabilished between the values measured by the different methods.
Untersuchung des einflusses molekularer parameter auf morphologie und eigenschaften von polyethylenen niedriger dichte
Authors: Braun Dieter , Rätzsch Manfred , Fiedler Peter , Weber Günter , Hofmann Heinz , Gutschalk Bernd 
Published: April 2003

AbstractAm Beispiel von PE‐LD‐Sorten und der durch präparative Fraktionierung gewonnenen Modellsubstanzen (Fraktionen im Molmassenbereich M̄w = 1,2 – 390·104 g/mol) wurden umfangreiche Untersuchungen zur Struktur‐Eigenschaftsproblematik durchgeführt.Untersucht wurden die Korrelationen von M̄w mit 15 physikalischen und anwendungstechnischen Parametern unter Berücksichtigung der Reaktionsmechanismen bei der Herstellung von PE‐LD im Rohr‐ und Rührautoklavreaktor, die zur Bildung der sogenannten primären Strukturparameter M̄n,M̄w, Molmassenverteilung, Kurzkettenverzweigung und Langkettenverzweigung führen. Bei der Interpretation der Ergebnisse wurden u. a. auch die morphologischen Gegebenheiten berücksichtigt, die im Zusammenhang mit den molekularen Parametern für bestimmte M̄w‐Bereiche starke Ande‐rungen bzw. Sattigungsbereiche für die physikalischen und anwendungstechnischen Eigenschaften erkennen lassen.
Zum einfluß von oligomeren auf die eigenschaften von styrol‐acrylnitril‐copolymerisaten
Authors: Schellenberg Jürgen , Hamann Bernd 
Published: April 2003

AbstractOligomere des Styrols und Acrylnitrils wurden isoliert und charakterisiert sowie ihr EinfluB auf die Eigenschaften von Styrol‐Acrylnitril‐Copolymerisaten bis zu einem Anteil von ca. 5 Gew.% im Polymerisat untersucht.Hinsichtlich der mechanischen Eigenschaften wurden Biegespannung und Zugfestigkeit mit steigendem Oligomergehalt erniedrigt, während die Schlagbiegefestigkeit verbessert wurde. Die thermischen Eigenschaften wurden besonders hinsichtlich Glasübergangstemperatur und Vicat‐Erweichungstemperatur durch den Oligomergehalt stark beeinflußt. Rheologische Eigenschaften wurden durch Schmelzindex und Schmelzviskosität bei verschiedenen Schergeschwindigkeiten charakterisiert.Der Einfluß der Verarbeitungsbedingungen auf die optischen Eigenschaften, die Lichtdurchlässigkeit und den Gelbindex werden beschrieben.
Alkylation of poly(n‐vinylpyrrolidone‐co‐vinylamine) with esters of phosphorous acids
Authors: Trendafilova‐Gercheva D. , Vassileva V. , Georgieva M. , Troev K. , Panarin E. F. 
Published: April 2003

AbstractAlkylation of amino groups bounded to a polymer chain with esters of phosphorous acids was studied in order to obtain physiologically active polymers. Poly(N‐vinyl‐pyrrolidone‐co‐vinylamine) was chosen as a polymer‐carrier. The phosphorous acid esters used were dimethyl hydrogen phosphonate, dimethyl methanephosphonate, trimethyl phosphate and bis‐(2‐chloroethyl)‐hydrogen phosphonate. The composition and structure of the isolated final products was proved by IR‐ and NMR‐spectroscopy and elemental analysis. It is established that alkylation takes place to various extents.The obtained alkylated phosphorous‐containing polymers exhibit herbicidal activity and could find application as plant growth retardants.
Reactions of iridium on a chelating sorbent involving N‐nucleophilic centres
Authors: Kálalová E. , Thuy P. 
Published: April 2003

AbstractThe chemical behaviour of the [IrCI6]2− choloro complex on a poly(glycidyl methacrylate) sorbent with ethylenediamine functional groups was studied. The [IrCI6]2− ions bonded to the support were found to undergo spontaneous reduction with decreasing acidity of medium, and an extraordinary mobility was observed for the Ir(IV) ⇄ Ir(III) equilibrium in chemical reactions of the chloro complexes on the sorbent. Spectroscopic measurements did not reveal formation of Ir (IV) or Ir(III) aqua compounds ([Ir(H2O)xCI6−x]x−2 or [Ir(H2O)xCl6−x]x−3) as a result of interaction of the bonded [IrCl6]2− ions with water as the solvent; the final product of hydrolysis of the immobilized [IrCl6]2−ions is an Ir(III) complex with the amine functional groups of the sorbent in the coordination sphere.
Bulk grafting of decyl methacrylate onto poly(vinyl chloride) in the presence of a lead carboxylate stabilizer
Authors: Gressier J. C. , Levesque G. , Brault D. 
Published: April 2003

AbstractIn order to improve the permanence of the plasticizer in a poly(vinylchloride) (PVC) compound we have studied the free radical polymerization and grafting of decyl methacrylate (DMA) onto PVC in the presence of a lead stabilizer. The influence of different parameters has been investigated and homogeneous PVC‐g‐PDMA copolymers have been obtained. Their molecular weights and the glass transition temperatures were consistent with the grafted nature of the copolymers.
Studies on hexolic anhydride based polyesters, 1. Characterization and sequence determination in hexolic based copolyesters by 1H‐ and 13C‐NMR
Authors: Sivasamy P. , Palaniandavar M. , Vijayakumar C. T. 
Published: April 2003

AbstractThe copolyesters and terpolyesters containing maleic or phthalic anhydride and 5,6,7,8,10,10‐hexachloro‐3a,4,4a,5,8,8a,9,9a‐octahydro‐5,8‐methanonaphtho‐[2,3‐c]‐furan‐1,3‐dione (‘hexolic anhydride’) with 2‐butene‐1,4‐diol and 2,3‐dichloro‐2‐butene‐1,4‐diol are synthesized by azeotropic condensation technique. The 1H‐ and 13C‐NMR spectra of these polyesters are recorded and the chemical shifts for the corresponding nuclear magnetic atoms are assigned. A good correlation exists between the observed and theoretically calculated chemical shift values. The sequence distribution, the randomness factor, and the number‐average sequence length of each anhydride monomer unit are calculated using 1H‐ and 13C‐NMR spectra. It is found that both methods give identical results for the same copolyesters and terpolyesters. The results indicate that the copolyesters follow Bernoullian statistics and the terpolyesters correspond to alternative copolyesters.
Zur charakterisierung von polymerfilmen und lichtleitfaserummantelungen aus additionsvernetzendem siliconkautschuk
Authors: Häusler Karl‐Georg , Hummel Klaus , Arndt Karl‐Friedrich , Bartz Heidrun 
Published: April 2003

AbstractDas Vernetzungsverhalten des additionsvernetzenden Silicons Wacker SilGel 600 wurde im Bereich von 50 bis 90°C in Abhängigkeit von der Heizzeit untersucht. Quellungsmessungen an dünnen Polymerfilmen auf Spezialpapier (Pecozet Z10) gestatten eine Verfolgung des in wenigen Minuten bis zum Quellungsgleichgewicht ablaufenden Quellprozesses, die Auswahl eines geeigneten Quellmittels und die schnelle Ermittlung der Temperaturabhängigkeit des Quellungsgrades Q. Neben Q sind der „Löslichkeitsparameter”︁ des Polymernetzwerkes, die Geschwindigkeitskonstanten und die Aktivierungsenergie des Vernetzungsprozesses zugänglich. Bei der Kombination der Quellungsmessungen mit einer Bestimmung des Hugginsschen Wechselwirkungsparameters kann auch die Vernetzungsdichte der Polymerfilme ermittelt werden.Auf der Basis dieser Untersuchungen konnte eine schnelle Methode zur Charakterisierung der Ummantelung von Lichtleitfasern entwickelt werden. Die zylindrischen Polymerfilme lösen sich während der Quellung in Toluol(25°C) vom Glaskern. Nach 5 min kann der Quellungsgrad der Ummantelung bestimmt werden.
Halogenation of polymers by dichlorodifluoromethane
Authors: Das Partha S. , Adhikari Basudam , Maiti Sukumar 
Published: April 2003

AbstractFluorination of polyethylene and polyvinyl alcohol was carried out by dichloro‐difluoromethane under cobalt‐60 gamma radiation and under electric spark discharge. The effect of temperature, reaction time, catalyst, inert diluent etc. was studied. Simultaneous chlorination of the polymer samples was observed along with fluorination. The extent of fluorination under electric spark discharge is usually higher than that under gamma radiation. Again, the extent of chlorination is higher than that of fluorination in both the cases. The extent of fluorination as well as chlorination is the highest in case of polyvinyl alcohol.
Studies on cellulose acetate phthalate: Estimation of mark‐houwink‐kuhn‐sakurada constants and viscosity‐temperature relationship
Authors: Patel Chandrakant P. , Trivedi Harikrishna C. , Patel Kanti C. , Patel Raman D. 
Published: April 2003

AbstractCellulose acetate phthalate (CAP) having an acetyl content of 19.5 wt.‐% and a phthalyl content of 21.4 wt.‐% was prepared and fractionated into five fractions of regularly decreasing molecular weight. The values of the number average molecular weight (M̄n) of these fractions were measured in 0.05 N NaHCO3 by the help of high‐speed membrane osmometer. The intrinsic viscosity [η] values for all the fractions of CAP in 0.05 N NaHCO3 were also determined at different temperatures. The Mark‐Houwink‐Kuhn‐Sakurada equation was applied to the obtained results and the [η]‐M̄n relationships for CAP have been established. The results of the values of v suggest that CAP is a stiff polymer. The temperature dependence of the viscosity of dilute CAP solutions has been described by an Arrhenius expression according to Moore's treatment. The activation energy of flow was found to depend on both concentration and molecular weight through an empirical parameter (Ke). The Ke value obtained for CAP also indicates that CAP is a rigid polymer.
The coupling mechanism of benzotriazole pre‐treated copper metal and epoxy resin
Authors: Xue Gi , Wu Peiyi , Dai Qinpin , Cheng Rongshi 
Published: April 2003

AbstractImproved adhesion of epoxy resin to copper metal has been achieved by pre‐treating copper with benzotriazole solution. The coupling mechanism and the interfacial reactions have been investigated by using X‐ray photoelectron and FTIR spectroscopies, and differential scanning calorimetry. It was found that benzotriazole reacted with copper metal in the presence of oxygen to form benzotriazolato Cu(I) and bis(benzotriazolato) Cu(II), which covered the surface of copper metal in a shape of polymeric thin layer. As the pre‐treated copper was heated with epoxy compound, it could induce the crosslinking to form interfacial chemical bonds.
N‐bromo‐poly(styrene‐co‐divinylbenzene) sulphonamide metal salts. Synthesis and basic properties
Authors: Bogoczek Romuald , Kociołek‐Balawejder Elżbieta 
Published: April 2003

AbstractMacromolecular pendant group N‐monobromosulphonamide metal salts SO2NBr−M+ having a macroporous styrene‐divinylbenzene matrix structure have been obtained by two methods:(a) by the action of aqueous metal hypobromites on the appropriate macromolecular pendant group sulphonamide, and(b) by the action of an aqueous metal bromide on the appropriate macromolecular N‐chlorosulphonamide metal salt.In each case the sodium salt product was obtained with a 100% functional yield and it contained 2.1 mmol.g−1 SO2NBr−Na+ groups, i. e., 4.2 meq · g−1 of active bromine. The stability of the resin was investigated in the range 20–100°C in the dry state as well as in aqueous media.A thermoanalysis (TG, DTG, and DTA curves) was carried out up to 1000°C and its course was interpreted. The resin has brominating, oxidative, microbiocidic, and ionexchanging properties. It reacts in a reversible way: after the loss of the active bromine, it can be reactivated again.
Charge transfer copolymerisation and characterization of 2‐vinylpyridine with methylmethacrylate and ethylmethacrylate
Authors: Bixamaiah B. , Rao P. Raghunath , Sundaram E. V. 
Published: April 2003

AbstractCopolymers of 2‐vinylpyridine (2‐VP) with methylmethacrylate (MMA) and ethylmethacrylate (EMA) were synthesized by a charge transfer mechanism using a mixture of n‐butylamine (n‐BA) and carbon tetrachloride (CCl4) as the initiator in dimethyl sulphoxide (DMSO) at 60°C. The copolymers were characterized by IR and 13C NMR spectroscopy. The percentage composition of the copolymers was established by elemental analysis. The monomer reactivity ratios (r1, r2) of 2‐VP‐co‐MMA and 2‐VP‐co‐EMA copolymers were determined by both Fineman‐Ross (F‐R) and Kelen‐Tüdős (K‐T) methods: r1 (2‐VP) = 0.30 ± 0.02, r2 (MMA) = 1.20 ± 0.02 and r1 (2‐VP) = 0.71 ± 0.02, r2 (EMA) = 0.63 ± 0.03 by F‐R method. While r1 (2‐VP) = 0.30 ± 0.04, r2 (MMA) = 1.21 ± 0.04, and r1 (2‐VP) = 0.70 ± 0.03, r2 (EMA) = 0.63 ± 0.03 by K‐T method. These values indicate that the system follows random distribution of the monomeric units.
Chemical synthesis of processible electrically conducting poly(3‐dodecylthiophene)
Authors: Nalwa Hari Singh 
Published: April 2003

AbstractThe chemical synthesis of poly(3‐dodecylthiophene) is reported. The polymer was characterized by 1H‐NMR, IR and UV absorption spectroscopic techniques. The room temperature electron spin resonance spectrum yielded a g value of 2.0091 and a linewidth of 6.60 Gauss. The solution cast polymer films after doping with iodine exhibited an electrical conductivity of 12 S/cm.
Macroporous membranes, I. Reactive macroporous membranes based on glycidyl methacrylate‐ethylene dimethacrylate copolymer for high‐performance membrane chromatography
Authors: Švec F. , Jelínková M. , Votavová E. 
Published: April 2003

AbstractMacroporous membranes were prepared by the radical polymerization of the organic phase, carried out in bulk, opposite to the usually employed suspension radical synthesis of macroporous beads. The properties of the membranes, such as porosity, specific surface area, pore size and distribution and others, approach those of the beads and can be modified by using the same procedures. Water permeability of the membranes is the property important with respect to their application. Dependences of permeability on the polymerization time, concentration of the crosslinking agent in the polymerization mixture, membrane thickness and the polymerization procedure were determined.
Highly active peroxides in the radical polymerization of ethylene under high pressure. Properties of the polymers
Authors: Luft Gerhard , Dorn Max 
Published: April 2003

AbstractUsing highly active peroxide initiators, a number of polyethylene samples were prepared at low temperatures of 70–140°C and a pressure of 1900 bar. The average molecular weight and the melt flow index were adjusted by adding propionaldehyde as modifier. The characteristic properties of the samples as regards the molecular weight distribution, the average molecular weight, the frequency of long chain branching, the crystallinity and the density were determined.As expected, the polymers are characterized by density values of more than 0.955 g/ml and crystallinity values of 65–80% which are characteristic of PE‐HD. The molecular weight distribution, too, remains within narrow limits. On the other hand, rather surprisingly, a relatively high frequency of long chain branching typical of PE‐LD is obtained.The investigation of the phase behaviour has shown that polymerization under high pressure at temperatures above 115–118°C takes place in the homogeneous range. The samples polymerized in the transition zone between the single and the two phase area exhibit maximum crystallinity and melt enthalpy. The frequency of long chain branching passed through a minimum.
The effect of viscosity of polyethylene on the evolution of phase structure during the mixing of polypropylene/EPDM elastomer/polyethylene blends
Authors: Fortelný Ivan , Navrátilová Edita , Kovář Josef 
Published: April 2003

AbstractThe dependences of phase structure and notch impact strength on conditions of mixing have been compared for the binary blend PP/EPDM and for two ternary blends PP/EPDM/PE possessing different viscosities of polyethylene. At low rates and short times of mixing a phase structure with pronounced inhomogeneities (particles of the dispersed phase having diameters of tens μm) is formed in all blends. Conditions of mixing needed for the formation of a homogeneous phase structure (with particles having diameters of several μm) depend on the average viscosity of the components forming the inclusions (EPDM elastomer or EPDM elastomer/polyethylene). Depending on the conditions of mixing and on the rheological properties of components, substitution of one part of the EPDM elastomer with PE may lead to an increase or decrease in the impact strength of the final blend.
Gelpermeationschromatographie von poly(vinylidenfluorid)
Authors: Pastuska Gerhard , Just Ulrich 
Published: April 2003

AbstractEs wird ein Verfahren zur Gelpermeationschromatographie von Poly(vinylidenfluorid) beschrieben. Als Lösemittel wird N,N‐Dimethylformamid bei 50°C an μ‐Styragelbzw. PLgel‐Säulen verwendet.Chemische Reaktionen des PVDF können erfaßt werden.
Encapsulating polymerization of titanium dioxide
Authors: Haga Yutaka , Watanabe Takanobu , Yosomiya Ryutoku 
Published: April 2003

AbstractTitanium dioxide was encapsulated in polymethyl methacrylate and polystyrene by the emulsion polymerization process, and the influence of various polymerization conditions such as the monomer and initiator concentrations and amounts of titanium oxide on the polymerization behavior was investigated. In the polymerization mixture where the end of the polymer chain and the metal oxide surface are oppositely charged, unextractable polymer is formed well. The encapsulating polymers show special structures with high molecular weight and high density.
Thermooxidative degradation of PVC in solution in the presence of metal stearate stabilizers
Authors: Iván Béla , Turcsányi Béla , Kelen Tibor , Tüdős Ferenc 
Published: April 2003

AbstractDetailed research has been carried out to determine the effect of metal stearates (PbSt2, CdSt2, BaSt2, CaSt2, and ZnSt2) on the thermooxidative degradation of PVC in inert dilute solution. The induction periods of free HCl evolution increase in the presence of PbSt2, CdSt2, CdSt2, BaSt2, and CaSt2, while ZnSt2, due to ZnCl2 formation, leads to fast HCl loss without induction period. The induction periods are much shorter than those obtained during thermal degradation, but the relative order of effectiveness of these stabilizers is the same as in inert atmosphere: PbSt2 > CdSt2 > BaSt2 > CaSt2 > ZnSt2. After the induction period, the initial rates of free HCl evolution decrease as metal stearate concentrations increase. Surprisingly, this dependence is independent of the kind of metal. At higher stabilizer concentrations, the initial rates of free HCl loss during the thermooxidative degradation approach the initial dehydrochlorination rate of thermally degraded PVC. As UV and visible spectra indicate, there is a sharp change in the normalized integral absorption versus time plots at the end of the induction periods in the presence of PbSt2, CdSt2, and BaSt2. Based on these experimental results, it has been concluded that effective metal stearates have manifold roles in the course of PVC stabilization under thermooxidative conditions. The main role of these compounds is not the replacement of labile structures and HCl‐scavenging, but the blocking of the rapid zip‐elimination is the most important event of the stabilization process. However, this blocking is reversible, which becomes effective mainly right after the consumption of the metal soaps (reversible blocking mechanism). Another important effect of these stabilizers is that they destroy peroxides and/or peroxy radicals (antioxidant effect).