bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface modification of a polypropylene film by low‐pressure discharge and the adhesion of a vacuum‐deposited layer of aluminium
Authors: Garby L. , Chabert B. , Sage D. , Soulier J. P. , Bosmans R. 
Published: April 2003

AbstractLow‐pressure discharge treatments were applied to the surface of polypropylene. ESCA analyses, wettability measurements and adhesion tests were carried out to characterize surface modifications as a function of treatment time and nature of gas (air or argon). Advancing and receding contact angles were measured with an automatic dynamical tensiometer. The liquids used were water (very polar liquid) and methylene iodide (apolar liquid). The results show an increase in wettability by the surface treatment. This is due to the creation of high‐energy polar sites. ESCA analysis also shows that the modified surface layer is soluble in methanol and is made up of low‐molecular‐weight material.Adhesion of polypropylene/aluminium is also increased by the low pressure discharge treatment from the few first seconds of the treatment. This adhesion increase is a function of the polar component of the polymer surface energy.
Poly‐ε‐caprolactone/poly(Methylmethacrylate) reactive blends: Correlation between synthesis, morphology and physical properties
Authors: di Liello V. , Malinconico M. , Martuscelli E. , Ragosta G. , Rizzo A. , Volpe M. G. 
Published: April 2003

AbstractBlends of poly‐ε‐caprolactone (PCL) and poly(methylmethacrylate) (PMMA) were prepared by a reactive method and characterized by thermal, morphological, dynamic mechanical and mechanical analyses. For comparison, “mechanical” blends, obtained by melt‐mixing of preformed polymers, have been prepared and characterized. The two series of blends are different in phase structure and in mechanical tensile properties, probably due to the formation of grafted species during reactive blending.
Effectiveness of UV‐stabilizers based on oligomeric benzophenone on the stabilization of poly(methyl methacrylate)
Authors: Menon Susha V. , Parmar Jayant S. 
Published: April 2003

AbstractNew oligomeric UV‐stabilizers of the type of 2‐hydroxy‐4‐alkoxy benzophenone‐formaldehyde prepared earlier were incorporated into poly(methyl methacrylate). Accelerated photooxidation as well as oven ageing tests were performed. The stabilizer effectiveness was estimated by IR and UV spectral study, mechanical testing, viscosity measurement, and weight loss measurement. Compared to monomeric stabilizers, the oligomeric compounds show better performance.
Photomodifizierung von Ultrafiltrationsmembranen, 1. Photochemiche Modifizierungen von Polyacrylnitril‐Ultrafiltrationsmembranen mit Arylaziden
Authors: Ulbricht Mathias , Hicke Hans‐Georg 
Published: April 2003

AbstractDurch Photoreaktionen aromatischer Azide sollte die ternwirksame Oberfläche von Ultrafiltrationsmembranen aus Polyarcrylnitril chemisch modifiziert werden, um deren Ultrafiltrations‐Eigenschaften gezielt zu verändern. Neun mit unterschiedlich hydrophilen bzw. hydrophoben Gruppen substituierte Azide wurden eingesetzt. Durch Träanken mit 0,05 molaren Lösungen der Arylazide in Methanol naöhmen die Membranen insgesamt 1,25–1,95 · 10−4 mol/g auf. Davon wurden ca. 1 ·10−4 mol/g an der Oberfläche der Porenmembran (79 m2/g, mit Hilfe der p‐Nitrophenol‐Adsorptions‐isotherme ermittelt) adsorbiert. Die HPLC‐Analyse der Extrakte von Membranproben gestattete für 4‐Azidobenzoesäuremethylester als Modellverbindung die Ermittlung von Umsatz und Produktverteilung bei der UV‐Photolyse. Die Umsatzgeschwindigkeit nimmt mit der Belichtungsdauer ab, nach 32 min waren 59% Azid photolysiert. Als lösliche Photolyseprodukte wurden 4‐Nitroso‐, 4‐Nitro bzw. 4‐Aminodenzoesäuremethylester in 3%, 13% bzw. 5% Ausbeute gefunden, die Azo‐ bzw. Azoxy‐Verbindungen traten nur in Spuren auf. Mit Hilfe von UV‐Reflexions‐ und FT‐IR‐ATR‐Spektroskopie an PAN‐Membranen konnte eine Funktionalisierung der Membranoberfläche durch sekundäre Amin‐Strukturen als Ergebnis der Photomodifizierung nachgewiesen werden. Die entwickelte Photomodifizierungsvariante sollte durch Einsatz von Arylaziden mit Prinzipiell analoger Photogreaktivität, aber unterschiedlichen funktionellen Gruppen die Herstellung spezifisch oberflächenmodifizierter PAN‐UF‐Membranen gestatten.
Photocrosslinking of oriented ultra‐high molecular weight polyethylene
Authors: Zamotaev Pavel V. , Chodak Ivan 
Published: April 2003

AbstractThe crosslinking of drawn tapes and fibers from ultra‐high molecular weight polyethylene (UHMW‐PE) initiated by UV‐irradiation has been investigated. Both xanthone and sulphuryl chloride (SO2Cl2) appeared to be rather effective photoinitiators and high gel content was obtained after UV‐exposition in air. The effect of crosslinking on the properties of UHMW‐PE tapes and fibers was examined by tensile tests, dynamic mechanical spectroscopy, and differential scanning calorimetry. High temperature resistance was shown to increase; photocrosslinked fibers retain the storage modulus being about 100 MPa at 200°C whereas uncrosslinked samples break at 135–137°C. No reducation of mechanical properties was found at ambient temperature and hydrophilization of the surface was observed.
Reactive blending of bioaffine polyesters through free‐radical processes
Authors: Cavallaro Pasquale , Immirzi Barbara , Malinconico Mario , Martuscelli Ezio , Volpe Maria Grazia 
Published: April 2003

AbstractBlends of poly‐ε‐caprolactone (PCL) and poly(β‐hydroxybutyrate‐co‐β‐hydroxy‐valerate) (PHBV) containing 4 mol‐% of hydroxyvalerate were prepared by mixing the two polymers in the presence of either dicumylperoxide (DCPO) at 160°C or dibenzoylperoxide (DBPO) at 100°C. Similarly, blends were obtained by mixing the two polymers without any peroxide added. The blends were prepared in to complementary compositions, namely 70 wt.‐% PCL/30 wt.‐% PH BV and 30 wt.‐% PCL/70 wt.‐% PHBV, respectively. Also pure polymers were reacted with DCPO at 160°C in the same way as the blends.Thermal (DSC), mechanical (tensile tests) and SEM analyses were performed on the blends and on the pure polymers.Significant differences were found in the chemical‐physical characteristics of blends with and with out peroxides as well as in blends prepared at low and high temperatures.
Poly(benzimidazole‐imide‐amide)s containing hexafluoroisopropylidene units
Authors: Hamciuc Elena , Bruma Maria , Mercer Frank W. , Simionescu Cristofor I. 
Published: April 2003

AbstractNew poly(benzimidazole‐imide‐amide)s containing hexafluoroisopropylidene units in the backbone have been synthesized by polycondensation of diaminobenzimidazoles with novel diacid dichlorides which incorporated both imide and hexafluoroisopropylidene groups. These polymers have high thermal stability and low dielectric constant and are soluble in polar aprotic solvents giving transparent, flexible films by casting their solutions. Such properties make them attractive for applications as dielectric coatings in microelectronics.
Polychelates of poly[N‐(4‐carboxy‐3‐hydroxyphenyl)maleimide]
Authors: Patel Dinesh K. , Patel Chetan G. , Parmar Jayant S. 
Published: April 2003

AbstractThe reactions of the bidentate polymeric chelating ligand poly[N‐(4‐carboxy‐3‐hydroxyphenyl)maleimide] with Co(II), Ni(II), Cu(II), Zn(II) and UO2(II) metal ions were investigated. Analytical, magnetic, spectral and thermal studies were used to characterize these polychelates. All these polychelates are stable, intensely coloured solids and insoluble in common organic solvents.
Grafting of polyesters by free‐radical chain transfer
Authors: Braun D. , Hempler P. 
Published: April 2003

AbstractGraft copolymerizations of polyesters with styrene by free‐radical chain transfer reactions were investigated. A model polyester of trans‐l,4‐cyclohexanediol and sebacoy1 dichloride was used as backbone chain. The graft products were characterized. Furthermore, liquid crystalline polyesters with 1,4 : 3,6‐dianhydrosorbitol and 1,4‐anhydroerythritol as diol components were synthesized and used in graft copolymerizations with styrene. Polymer blends of tetramethylbisphenol A polycarbonate and the LC‐polyester with and without polystyrene grafts were prepared by common precipitation of polymer solutions and their behaviour was examined by torsion pendulum, dynamic‐mechanical thermoanalysis and scanning electron microscopy. The grafted polyester turned out to be an efficient phase compatibilizer.
Structural, physical and mechanical properties of carbon fibre‐reinforced composites of diglycidyl ether of bisphenol‐A and bisphenol‐C
Authors: Soni Hitesh K. , Patel Ranjan G. , Patel Vithal S. 
Published: April 2003

AbstractCarbon fibre‐reinforced composites of conventional diglycidyl ether of bisphenol‐A (DGEBA) and liquid diglycidyl ether of bisphenol‐C (DGEBC) were prepared, using 4,4′‐diaminodiphenylmethane (DDM) or 4,4′‐diaminodiphenylsulfone (DDS) curing agent and evaluated for their physical properties (density, void content) and mechanical properties (flexural strength and interlaminar shear strength). Thick films of the neat resin were also prepared and their flexural strength has been studied. It is observed that DGEBC‐curing agent system shows improved properties compared to DGEBA‐curing agent system.
Preparation and characterization of new synthetic noncross‐linked anion exchange membranes
Authors: Lin Mei‐Chih , Takai Nobuharu 
Published: April 2003

AbstractNew synthetic noncross‐linked anion exchange membranes have been prepared by casting a solution of quaternized chloromethylstyrene‐methyl methacrylate copolymers containing 64.0, 42.9, 19.7, 12.9 and 11.0 mol‐% chloromethylstyrene. The ion exchange capacity, water content and physicochemical properties (membrane potential and transport number) of these membranes were studied. The results showed that the copolymers can be fabricated in membrane form after treatment with tertiary amine, of which the membranes produced from the 12.9 and 11.0 mol‐% copolymer exhibited excellent dimensional stability and mechanical strength towards dilute alkali solution, dilute acid solution and salt solution, and were soluble in a variety of organic solvents, such as acetone, methyl ethyl ketone and methanol. Their anion transport numbers determined from the membrane potential measurements in 0.01 N and 0.3 N KCI solution were 0.96 and 0.97, respectively.
Facilitated oxygen transport in (polystyrene‐block‐polyisoprene‐block‐polystyrene)‐graft‐poly(1‐vinylimidazole) containing three cobalt‐containing schiff bases
Authors: Hsiue Ging‐Ho , Hsu Wey‐Leun 
Published: April 2003

AbstractMembranes of (polystyrene‐block‐polyisoprene‐block‐polystyrene)‐graft‐poly(1‐vinyl‐imidazole) (SIS‐g‐VIm) reacted with three cobalt‐containing Schiff bases (CoS) were prepared and studied. SIS‐g‐VIm was obtained by radiation‐induced graft copolymerization of 1‐vinylimidazole onto poly(styrene‐block‐isoprene‐block‐styrene) triblock copolymer. Membranes of SIS‐g‐VIm reacted with three cobalt‐containing Schiff bases (SIS‐g‐VIm‐CoS) were prepared by the solution casting method. The co‐ordination numbers and formation constants of these reactions were determined. Equilibrium constants and thermodynamic parameters of SIS‐g‐VIm‐CoS membranes for binding and dissociation of oxygen were determined by UV/VIS spectroscopy. The permeability and O2/N2 permselectivity of the SIS‐g‐VIM‐CoS membranes were measured at various upstream gas pressures and temperatures. Oxygen permeation through the SIS‐g‐VIm‐CoS membranes can be explained by dual‐mode‐facilitated transport theory.
Preparation of multiphase block copolymers by redox polymerization process, 2. Polymerization of acrylonitrile by the Mn(III)‐poly(ethylene glycol) redox system
Authors: Cakmak Ismail 
Published: April 2003

AbstractRedox polymerization of acrylonitrile (AN) with poly(ethylene glycol) using Mn(III) as catalyst was carried out to yield poly(ethylene glycol‐block‐acrylonitrile). The principal parameters (concentration of reactants, temperature) affecting the synthesis were examined. Successful blocking has been confirmed by infrared and 1H nuclear magnetic resonance spectroscopy as well as gel permeation chromatography.
Poly(sulfide sulfone) by activated nucleophilic displacement polymerization
Authors: Dutta Pradip K. , Maiti Sukumar 
Published: April 2003

AbstractA poly(sulfide sulfone) was synthesized by activated nucleophilic displacement reaction between bis(4‐nitrophenyl)sulfone and anhydrous sodium sulfide at 200°C in N‐methyl‐2‐pyrrolidone (NMP). The polymer is soluble in NMP, dimethylformamide, dimethylsulfoxide and other highly polar solvents. The molecular weight of the polymer (M̄n = 2.500) having an inherent viscosity of 15 mL/g at 30°C in DMF was determined by 1H‐NMR spectroscopy. The polymer has a glass transition at approx. 73°C and char residue of 36% at 600°C in air. The limiting oxygen index of the polymer is ∼37.
Modelling the polymerization of 1,3‐butadiene in solution with a neodymium catalyst
Authors: Proß Alexander , Marquardt Peter , Reichert Karl‐Heinz , Nentwig Wolfgang , Knauf Thomas 
Published: April 2003

AbstractThe batch polymerization of butadiene in hexane with an in‐situ‐activated Ziegler‐Catalyst containing neodymium versatate, ethylaluminium sesquichloride and triisobutylaluminium was studied at 45°C. The rate of polymerization was determined by online density measurements. A mathematical model has been developed which is able to describe the kinetics of polymerization at different catalyst ratios. At molar ratios of aluminium/neodymium above 40 a bimodal molar mass distribution can be observed by gel permeation chromatography which leads to the assumption of more than one active species being present in the polymerization system.
Fluorine‐containing polyimides with phenylquinoxaline units
Authors: Sava Ion , Bruma Maria , Belomoina Nataliya , Mercer Frank W. 
Published: April 2003

AbstractA series of new polyimides with phenylquinoxaline units have been synthesized by solution polycondensation of 2,2‐bis(1,3‐dioxo‐1H,3H‐isobenzofuran‐5‐yl)hexafluoropropane (hexafloroisopropylidene‐diphthalic anhydride) with aromatic diamines containing preformed phenylquinoxaline units. These polymers are soluble in polar amidic solvents and can be processed into transparent, flexible films, having low dielectric constants and high thermal stability with decomposition temperatures above 400°C.
A route to preparation of bromomethylated poly(2,6‐dimethyl‐1,4‐phenylene oxide)
Authors: Líška Juraj , Borsig Eberhard , Tkáč Ivan 
Published: April 2003

AbstractBromination of poly(2,6‐dimethyl‐1,4‐phenylene oxide)Systematic name: Poly(oxy‐2,6‐dimethyl‐1,4‐phenylene).
(PPO) in halogenated aromatic hydrocarbons has been investigated in order to find optimum conditions for preparation of bromomethylated polymer when using either molecular bromine or N‐bromosuccinimide as brominating agent. It was found that bromination of the methyl group of PPO took place in chlorobenzene with dicumyl peroxide initiator at 132°C and no phenyl‐brominated product was obtained. The parallel bromination of the phenyl group and the methyl group of PPO, however, occurs at temperatures below 130°C with either molecular bromine or N‐bromosuccinimide. At temperatures above 150°C, cross‐linking of PPO accompanying the bromination starts to play the important role in PPO modification.
The free‐radical terpolymerisation of ethylene, methyl acrylate and vinyl acetate at high pressure. Polymerization tests
Authors: Luft Gerhard , Stein Franz , Dorn Maximilian 
Published: April 2003

AbstractIn this study, the terpolymerisation, under high pressure, has been examined for the ethylene‐methyl acrylate‐vinyl acetate system. The polymerisations were carried out in a high pressure polymerisation facility designed for continuous operation. To assess the effect of pressure and temperature on the reaction, polymerisation was carried out at two different pressures of 1 900 and 1 100 bar and at temperatures of 180 and 230°C. By varying the concentration of the ethylene, methyl acrylate and vinyl acetate monomers in the feed, polymers of different composition were obtained. The ratio of the monomer concentrations in the reactor was calculated from the amount of polymer weighed out and its comonomer content as well as the composition of the feed, using the mass balance for the ideal stirred tank reactor. The result was used to determine the reactivity ratios of the three possible binary copolymerisation systems ethylene/methyl acrylate, ethylene/vinyl acetate and methyl acrylate/ vinyl acetate. This made it possible to predetermine, by calculation, the composition of a product obtained by continuous polymerisation in a stirred autoclave.
Preparation of optically active polymer layers by after‐glow plasma polymerization
Authors: Hartwig Andreas , Steinhauser Hermann , Ellinghorst Guido 
Published: April 2003

AbstractAfter‐glow plasma polymerization is described as a new method to prepare polymeric layers from unsaturated monomers. An optically active acrylic monomer is used in this investigation. The deposition rates are given as functions of plasma power, pressure, distance between plasma and deposition zone, flux and kind of auxiliary gas (He, Ne, Ar, Kr) and of monomer flux. The polymers prepared are optically active, the IR spectra comply with those of polymers synthesized in bulk. Mostly the polymers prepared by after‐glow plasma polymerization are cross‐linked and therefore insoluble. NMR spectra of soluble samples show that the polymers are atactic. After‐glow plasma polymerization occurs by a radical chain growth mechanism. Membranes made from these polymers are able to separate racemates.
Effect of α‐methyl styrene on properties of epoxy‐novolac based vinyl ester resins
Authors: Padma G. , Varma I. K. , Sinha T. J. M. , Patel D. M. 
Published: April 2003

AbstractThe paper describes the synthesis of vinyl esters using epoxy‐novolac resin. The curing behaviour of the resins containing different portions of styrene and α‐methyl styrene (α‐MS) as reactive diluents was studied by gel time determination. Delayed curing was observed in samples containing increasing proportions of α‐MS. An increase in the α‐MS content resulted in a decrease in the tensile strength and increase in heat deflection temperature of the cured sheets. The flexural strength and flexural modulus of both resin and glass fibre‐reinforced composites (resin content approx. 41 wt.‐%) increased. Treatment with boiling water (12 h) of laminates resulted in a decrease in interlaminar shear strength with an increase in α‐MS content.
Photocrosslinkable polymers based on maleimidemodified acrylates
Authors: Nair C. P. R. 
Published: April 2003

AbstractNovel photocrosslinkable polymethacrylate systems with enhanced thermal stability and solvent resistance were synthesized. Copolymers of methyl methacrylate (MMA) or butyl acrylate (BuA) with 4‐maleimido benzoic acid (MBA) were synthesized and photocrosslinkable methacrylic functions were incorporated through the pendent COOH groups. Photofunctional groups were introduced by the acid chloride route and by the epoxy‐carboxy reaction. Photocrosslinking was performed using UV radiation of 350 nm in the presence of a photo‐initiator. The kinetics of photocuring was studied with a model multiacrylate. The imide‐modified photocured acrylate polymer exhibited enhanced solvent resistance and thermal stability, compared with the unmodified polymer.
Polybenzpinakole als Initiatoren für die radikalische Polymerisation
Authors: Braun Dietrich , Meid Holger 
Published: April 2003

AbstractDurch Photopolymerisation von 4,4′‐Dibenzoyldiphenylmethan und 4,4′‐Bis(aαhydroxybenzy1)‐diphenylmethan mit UV‐Licht in benzolischer Löisung lassen sich Polybenzpinakole herstellen. Die Polymeren können durch Fällungsfraktionierung in Fraktionen mit Molekulargewichten bis etwa 20000 aufgetrennt werden. Polybenzpinakole zerfallen ebenso wie Benzpinakol thermisch in Diarylhydroxymethyl‐Radikale. Diese initiieren bei 60 bis 100°C die radikalische Polymerisation von Styrol direkt und teilweise auch durch Wasserstoffübertragung von den Initiatorradikalen auf das Monomere. Mit steigender Temperatur nimmt dabei der Anteil der Wasserstoffübertragung an der Initiierung ab, was aus den Reaktionsordnungen bezüglich der Monomerkonzentration geschlossen werden kann. Soweit die Polymerisation von Styrol mit Oligo‐Benzpinakol direkt durch Diarylhydroxymethyl‐Radikale ausgelöst wird, entstehen Polystyrolketten mit eingebauten Oligo‐Benzpinakol‐Segmenten, die thermisch spaltbar sind, was durch die Abnahme der Molekulargewichte beim Erhitzen in toluolischen Lösungen bestätigt wird.
Methodological investigations on the thermal stability of polypropylene
Authors: Wallius Satu 
Published: April 2003

AbstractThe correlation between different methods of measuring thermo‐oxidative stability of polypropylene has been studied. The oxidation induction times were measured using differential scanning calorimetry (DSC) in the temperature range from 160°C to 240°C up to 10000 min. The same samples were oven‐aged in the temperature range from 130°C to 160°C up to 13000 h.The dynamic experiments performed by DSC show different results for differently stabilized samples. At slow heating rates the results of the dynamic experiments corresponded best to the results of the isothermal experiments.The straight‐line Arrhenius plots of the isothermal DSC measurements do not correlate with the straight‐line Arrhenius plots of the oven‐aging tests. The Arrhenius plots obtained by these two methods either intersect close to the melting temperature of polypropylene or show jumps towards longer times when switching from DSC to oven‐aging. It was found that the apparent activation energies obtained from the oven‐aging tests are much lower than these obtained by DSC measurements. Almost the same activation energies were obtained for all the samples in oven‐aging, while for the differently stabilized samples the activation energies from DSC measurements showed different results.Antistatic additives and colour pigments influence the thermal stability of polypropylene. Especially red pigment acts like a stabilizer for polypropylene, which is noticed at oven‐aging testing, but at higher temperatures it loses this stabilizing effect.
Free‐Radical stabilizers for the thiol/ene‐systems
Authors: Klemm Elisabeth , Sensfuß Steffi , Holfter Uta , Flammersheim Hans Jürgen 
Published: April 2003

AbstractBy means of calorimetric investigations it is shown that dithiol/diene‐mixtures show a more or less distinct spontaneous dark reaction, without light and in the absence of initiators. Pyrogallol, hydroquinone and catechol were tested as stabilizers. The efficacy of the stabilizer to transform the radicals resulting from charge transfer interaction of the thiol with the ene component into an inactive species decreases in the order mentioned above.
The participation of block copolymers in the increase in the number of tie molecules
Authors: Kučera Miloslav 
Published: April 2003

AbstractThree‐block copolymers polyamide‐block‐polyX‐block‐polyamide (where X is styrene, ethylene‐co‐1‐butene, and others) are able to improve substantially the toughness of poly(ϵ‐caprolactam). Outer blocks of these copolymers are able to take part in folding lamellae of semi‐crystalline polyamide, inner blocks are not. They operate as a spacer, meaning that the end blocks of copolymers capable of folding become parts of different lamellae, or that the unfoldable part of a block copolymer is pushed out of a folding lamella with a certain probability of the remaining outer block taking part in folding another lamella.This increases the number of tie‐molecules.