bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of composition and plastifier on the light scattering of polymer glasses and properties of polymeric optical fibers made from styrene‐methyl methacrylate copolymers
Authors: Dvořánek Ladislav , Koňák Čestmír , Neuhäusl Tomáš , Machová Lud'ka , Šorm Miloslav
Published: April 2003

High optical purity polystyrene (PS), poly(methyl methacrylate) (PMMA) and styrene‐methyl methacrylate statistical copolymers (S‐MMA) were prepared. Light scattering measured on polymeric glasses depends on the chemical composition of the polymer and on the refractive index of the plastifier added. An isorefractive plastifier reduces considerably the scattering values for the copolymers S‐MMA, while having no significant effect on the scattering of PMMA. A plastifier with a refractive index different from that of the polymer raises distinctly the light scattering values in all cases. It has been shown that the isorefractive plastifier has a favourable effect on attenuation loss of polymeric optical fibers (POF) obtained from the copolymer S‐MMA 2/1.
Thermostable polyesters containing imide and phenylquinoxaline units
Authors: Bruma M. , Sava I. , Hamciuc E. , Hamciuc C. , Belomoina N. M. , Krongauz E. S.
Published: April 2003

Thermostable, heterocyclic polyesters containing imide and phenylquinoxaline units have been synthesized by solution polycondensation of bis(hydroxyphenylquinoxaline) derivatives with diacid dichlorides containing preformed imide rings or by the reaction of bis(aminophenylquinoxaline) derivatives with dianhydrides containing ester groups. The thermal stability of these compounds is discussed and compared with related heterocyclic polymers. Electrical properties of the polycondensates were also studied.
On the effect of water on the durability of PP and PC/acrylic adhesive joints
Authors: Di Ruocco V. , Morra M. , Occhiello E. , Garbassi F.
Published: April 2003

The stability of PP and PC/acrylic adhesive joints has been assessed using a thermodynamic method based on surface tension components.

Surface characterization showed that plasma treatment induces the formation of an oxygen‐rich layer on treated surfaces. In the case of PP this layer does not change its composition upon immersion in water, while for PC leaching of oxidized species with low molecular weight was observed.

Both untreated and plasma treated PP joints showed reasonable stability against immersion in water. A small reduction of shear strength was observed, but the fracture remained adhesive for untreated PP and cohesive for plasma treated PP.

In the case of PC, only joints made from untreated PC showed fair sensitivity against immersion in water, while those made from plasma treated specimens degraded dramatically. In the latter case the locus of failure moved to the adhesive/adherend interface, the presence of a very hydrophilic, low molecular weight layer being suggested as responsible for this behavior.
Antioxidants and stabilizers, 116 Influence of the carbon black chezacarb EC on polyolefin thermooxidation: A model study with cyclohexene doped with chain‐breaking antioxidants
Authors: Rotschová Jitka , Pospíšil Jan
Published: April 2003

The ageing of polyolefins is accelerated by carbon black Chezacarb EC used as a filler. Conditions for selection of suitable chain‐breaking antioxidants protecting against degradation were simulated using cyclohexene doped with various amounts of carbon black and oxidized at 60°C. The results obtained reveal an acceleration of cyclohexene oxidation in the phase following the induction period (IP). The oxidation acceleration is similar to the effect caused by powdered copper(0) or copper(II) ions. Polynuclear phenolic antioxidants are able to stabilize cyclohexene for periods longer than 120 h only in the presence of low amounts of Chezacarb (up to 0.5 wt.‐%). At higher Chezacarb concentrations, merely a prolongation of IP may be achieved. Arylene diamines are efficient stabilizers only if combined with a high concentration of Chezacarb (10 wt.‐%). None of the chain‐breaking antioxidants used was able to diminish the oxidation rate of cyclohexene in the phase after IP.
Synthesis, characterization, and glass‐reinforcement of poly(oxysilane imide)s
Authors: Patel Hasmukh S. , Vyas Hemant S.
Published: April 2003

Poly(oxysilane imide)s were prepared via Diels‐Alder (DA) intermolecular polymerization of bis(2‐furylmethyloxy)‐dimethyl silane (1) with different bis(maleimido)‐compounds (2a–h). The DA reaction was carried out in tetrahydrofuran as solvent as well as in bulk followed by dehydration (aromatization) of poly(tetrahydrophthalimido)‐intermidiates (3a–h) in the presence of acetic anhydride. All poly(oxysilane imide)s (4a–h) were characterized by elemental analyses, IR spectral studies, and thermogravimetry. 1 and 2 were polymerized (at 130 ± 10°C) by in‐situ Diels‐Alder intermolecular reaction into poly(oxysilane imide)s‐glass fibre composites (i.e. laminates) without evolution of by‐products. The prepared composites were characterized by chemical resistivity and mechanical properties.
Correlation between microscopic structural parameters and macroscopic flow behaviour of some polymer‐surfactant systems suitable for tertiary oil recovery
Authors: Aust Nicolai , Meyer‐Kolshorn Uwe , Schreiber Axel , Zugenmaier Peter
Published: April 2003

Some materials, suitable for application in polymer‐surfactant flooding used in tertiary oil recovery (EOR), have been characterized by static and dynamic light scattering and studied in respect to their suitability in various model brines by measuring their rheological and dynamic‐rheological behaviour. Xanthan and polyacrylamides of different degree of hydrolysis have been used as polymers, an ethylene glycol sulfonate as surfactant.

Correlations have been established between microscopic structural parameters (Hydrodynamic radius, radius of gyration, molar mass, shape of the polymers) and the macroscopic behaviour, such as viscosity and elasticity, being important rheological parameters for EOR application. Additional investigations on surface tension and long term viscosity study lead then to a judgement for the efficiency and long term stability of polymer‐surfactant slugs in various reservoirs of different salinity.
Functional polyamides. 3. Synthesis and chelating properties of a new poly(amide thioether)
Authors: Yagci Yusuf , Denizligil Selcuk , Bicak Niyazi , Atay Tulay
Published: April 2003

Polymerization of β,β′‐(ethylenedithio)dipropionitrile

IUPAC name: 4,7‐dithiadecane dinitrile.

with formaldehyde in the presence of sulfuric acid was carried out in order to permit the synthesis of polymides containing thioether groups. The obtained poly(amide thioether)s were characterized; they coordinate mercury (II) with a high degree of selectivity.
Synthesis and characterization of bifunctional cellulose‐g‐poly(glycidyl methacrylate) based cation exchangers containing both sulfonic and carboxylic acid groups
Authors: Abo‐Shosha M. H.
Published: April 2003

Cellulose‐g‐poly(glycidyl methacrylate) copolymer was reacted with aqueous solutions containing mixtures of both sodium sulfite and citric acid, in order to synthesize bifunctional cation exchangers containing both sulfonic and carboxylic acid groups. Factors affecting the reaction, such as percent neutralization of citric acid with sodium carbonate, time, temperature, liquor ratio, reagents‐to‐epoxide molar ratio, and monosodium salt of citric acid‐to‐epoxide molar ratio were studied. Reaction conditions were selected to prepare five kinds of cation exchangers of different sulfonic and carboxy contents. These exchangers were characterized by potentiometric titrations, durability tests, and water solubility.
Preparation of prepolymers from diglycidylether of bisphenol A containing imide groups
Authors: Cádiz Virginia , Mantecón Ana , Serra Angels , Thepaut Christophe
Published: April 2003

Epoxy resins derived from Bisphenol A have been modified with new diphenols containing imide moieties in order to improve their thermal properties. The diphenols have been synthesized from dianhydrides and aminophenols by condensation reactions. Diphenols as well as modified resins have been characterized by IR and NMR spectroscopy. The thermal characteristics were evaluated by DSC and TGA.
Chromatographic properties of macroporous beads from poly(GMA‐co‐EDMA)
Authors: Horák D. , S̆vec F. , Tennikova T. B. , Náhånek M.
Published: April 2003

A series of macroporous glycidyl methacrylate‐ethylene dimethacrylate copolymers have been prepared by the suspension polymerization according to a statistical design of experimental approach in which concentration of ethylene dimethacrylate and time needed for raising the polymerization temperature from 20 to 70°C have been varied. The porous properties of hydrolyzed copolymers have been characterized by means of size exclusion chromatography using polystyrene standards in tetrahydrofuran. Pore volume, specific surface area, and pore size are affected by the crosslinking agent concentration rather than by the rate of temperature increase during the polymerization reaction.
Photolytic crosslinking of poly(p‐hydroxystyrene)
Authors: Nakabayashi Kenichi , Schwalm Reinhold , Schnabel Wolfram
Published: April 2003

Light‐induced crosslinking of poly(p‐hydroxystyrene) (PPHS) is significantly enhanced by O2. This was evidenced by molar mass (light scattering measurements) and by gel content determinations which were performed on various polymer samples before and after continuous irradiation at λinc = 254 nm. The following mechanism was elucidated with the aid of flash photolysis studies: Crosslinking in the absence or presence of O2 is mainly due to the combination of phenoxyl type radicals. In the absence of O2 the latter are exclusively formed by OH bond cleavage of singlet excited phenolic groups. Triplet excited phenolic groups which are also formed do not deactivate via OH bond cleavage but react very effectively with O2. This reaction leads to the formation of HO and additional phenoxyl type radicals. All Commercial and most laboratory‐prepared PPHS samples contain chemically bound impurities of quinoid nature. On the basis of results performed with model compounds of low molar mass, it is concluded that triplet excited quinoid groups react effectively with phenolic groups forming phenoxyl type radicals and that they are quite unreactive with respect to the abstraction of alphatic hydrogen atoms. Irradiation of PPHS at λinc = 254 nm causes the formation of quinoid groups which absorb strongly at this wavelength. Light absorption by these groups becomes a determining factor with respect to photochemical alteration in the course of further irradiation.
Multipurpose woven cotton and cotton/polyester blends containing crosslinked polyols affixed by a low temperature cure
Authors: Vigo Tyrone L. , Hao Ping , Bruno Joseph S.
Published: April 2003

Woven cotton and cotton/polyester blend fabrics of similar construction were treated with solutions of poly(ethylene glycol) (PEG, Mn of 600, 1000 and 1450 g/mol) containing tetrafunctional dimethyloldihydroxyethyleneurea

Systematic name: 1,3‐Bis(hydroxymethyl)‐4,5‐dihydroxyimidazoline‐2‐one.

(DMDHEU) and a mixed acid catalyst. Subsequent curing of these fabrics under selected mild conditions produced fabrics containing bound and crosslinked polyols with several improved functional properties (thermal storage and release, flex and flat abrasion resistance, soil release and hydrophilicity). These functional property improvements are due to structural aspects of the crosslinked polyol. These structural aspects are high latent heat due to energy required to break intra‐ and intermolecular hydrogen bonds and the elastomeric and hydrophilic nature of the polymer in the fiber matrix. When the fabrics were cured under the mildest conditions, these enhanced functional properties were obtained without adversely affecting the softness or hand and the air permeability of these fabrics. Best results were obtained with the PEG‐1000/DMDHEU solutions for an overall balance of improved fabric properties. Relative to untreated fabrics, treated 100% cotton fabrics had the most dramatic increase in their flex life, sometimes over an order of magnitude greater than before treatment and curing.
Alternierende copolymerisation von butadien und ethen
Authors: Arnold M. , Reußner J. , Wohlfarth L.
Published: April 2003

Es wurde die Copolymerissation von Butadien und Ethen in Gegenwart des katalysatorsystems Dineopetyloxyvanadiumoxychlorid/Aluminiumtriisobutyl untersucht. Die Variation der grundlegenden Reaktionsparameter [A1]/[V]‐Verhältnis, Zusammensetzung der Monomermischug und Polymerisationstemperature ergab einen signifikanten Einfluß auf den Verlauf der Reaction, den Umsatz der Moomeren die, Molmasse und die Polydispersität der erhaltenen Copolymeren. NMR‐Untersuchngen belegen einen hohen Alternierungsgrad.

Bei der Variation des Verhaltnisses der Katalysatorkomponenten wurde ein Maximum für Umsatz und die Molmasse bei einem Verhältnis [A1]/[V] ≈︁ 7 ermittelt. Die Erhöhung des Ethengehaltes in der Moomermischung führt ebenfalls zu einer Erhöhung des Umsatzes. Dabei werden die Molmassen jedoch erniedrigt. Die Variation der Polymerisationstemparatur im Bereich von −25°C bis +40°C ergab für den Umsatz und die Molmasse Abhängigkeiten mit Minimum bzw. Maximum. Bei Polymerisationstemperaturen oberhalb +20°C ist ein Anwachsen der 1,2 ‐Addition des Butadiens und eine zunehmende Vernetzung der Produkte zu verzeichnen.
Synthesis and chemo‐physical properties of hydrogels
Authors: Chen C. M. , Lee T. Y. , Niu Gregory C. C.
Published: April 2003

Hydrogels are synthesized from methyl methacrylate (MMA) and N‐vinyl‐2‐pyrrolidone (NVP) with 1,1,1‐trimethylol propane trimethacrylate (TPTA) as a crosslinking agent. It was polymerized under UV radiation (365nm) with a small amount of photosensitizer, diethoxy acetophenone (DEAP), acclerator and diluent, triethanol amine (TEA). The hydrogels were characterized by measuring the water retention, dissolved oxygen diffusivity and permeability, mechanical strength, and light transparency. The hydrogels can retain water up to 80 wt.‐% and the mechanical strenght is weakened as the water content is increased in the gel. The dissolved oxygen diffusivity and permeability in the swelling hydrogels are determined to be 10−6 cm2/sec and 1013 cm2s−1 Pa−1, respectively. The light transparency is over 90% in the wave lenght ranging from 500 to 700 nm.
Time temperature equivalence in plasticized PVC
Authors: Patel N. K. , Kansara Sujata , Patel C. K.
Published: April 2003

The viscoelastic response of plasticized PVC was determined from stress‐relaxation data over a wide range of time at different temperatures. The relaxation modulus as a function of time was determined from these data. The relaxation curves were then shifted horizontally to obtain a master curve at a reference temperature. The amount of shift was evaluated using the WLF equation. The coefficients C and C used in the equation for the PVC were determined according to the method of reduced variables.
Tough thermoplastic polyesters by reactive extrusion with epoxy‐containing copolymers
Authors: Hert Marius
Published: April 2003

Poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) are brittle polymers with poor notched impact strength. Their toughening can be achieved by melt blending with different types of rubbery ethylene copolymers containing functions having potential reactivity with the hydroxy and carboxy end groups in polyesters.

Two types of ethylene copolymers were investigated: ethylene/ethyle acrylate/glycidyl methacrylate (E/EA/GMA) and ethylene/ethyl acrylate/maleic anhydride (E/EA/MAH) copolymers. The blends were obtained by reactive extrusion of PBT with 10 to 25% of copolymers.

PBT blends undergo a brittle to ductile transition by toughening with GMA copolymer between 10 and 20% of rubbery phase. The most effective toughening could be achieved by a partial crosslinking of the rubbery particles obtained by associating GMA and MAH copolymers and a reaction catalyst.
Reaktionsverhalten des Natriumallylsulfonats in der Lösungscopolymerisation des Acrylnitrils in Dimethylformamid
Authors: Fritzsche Peter , Abel Christiane
Published: April 2003

Im Copolymerisationssystem Acrylnitril (AN)/Methylacrylat(MA) mit Natriumallylsulfonat (NaAS) in Dimethylformamid wurde die relative Übertragunskonstante zum NaAS Cx = 0,04 ± 0,01 unabhängig vom verwendeten Initiator (Azoisobuttyronitril, Ammoniumperoxodisulfat) ermittelt. Die Übertragunsreaktion beschreibt den Einfluß des NaAS auf den Polymerisationsgrad, sie beeinflußt jedoch den Copolymerisationsparameter r1 nur in der Größenordung von 1 bis 5% und kann damit die Konzentrationsabhängigkeit von r1 nicht erklären.

Mit Hilfe der erweiterten Debye‐Hückel‐Theorie für verdünnte Elektrolyte wird die Abhängigkiet des r1‐Wertes von der NaAS‐ Konzentration beschrieben. Der sich daraus für unendliche Verünnung des NaAS ergebende r10‐Wert ist offensichtlich noch gerinfügig von der Acrylnitrilkonzentration abhägig. Er liegt beispielsweise für [AN] = 4, 26 mol/1 bei r10 = 0, 32. Damit wurde zum ersten Mal das nichtideale Copolymerisationsverhalten im untersuchten System erkärl. Das Vorgehen sollte verallemeinerungsfähig sein und generell auf das Copolymerisationsverhalten von Monomeren mitdissoziierten Gruppen angewendet werden können.
Effect of ring size on the oxidizability of lactams
Authors: Lánská Božena , Makarov Genadii G. , Šebenda Jan
Published: April 2003

The initial stage of oxidation of lactams was studied in the temperature range 70–120°C. It was found that pyrrolidone and piperidone are oxidized essentially more easily than the seven‐, eight‐, nine‐ and thirteen‐membered lactams as well as linear N‐alkylamides. The high oxidizability of the five‐ and six‐membered lactams may be attributed to the easier homolytic splitting of the N‐vicinal CH bond and to the different reactivity of lactam radicals in the propagation step of the chain oxidation.
Photosynthetic membranes, 21. Immobilization of catalase by photochemically grafted ultrafiltration membranes
Authors: Selli Elena , Bellobono Ignazio Renato , Raimondi Maria Luisa
Published: April 2003

Catalase has been immobilized in membranes prepared by photoinduced grafting onto microporous polymeric supports and its catalytic activity on hydrogen peroxide decomposition has been studied under ultrafiltration conditions by means of a recirculation apparatus. The membranes showed a very good catalytic performance and the enzyme reaction took place exclusively within the membrane structure. Initial reaction rates measured in the temperature range 5 – 35°C as a function of both substrate concentration and enzyme amount immobilized per unit membrane surface indicate that the mechanism of action of catalase is not altered after immobilization.
Untersuchungen zum Netzwerkbildungsprozeß bei der Reaktion von Bisphenol A‐Diglycidylether mit 4,4′‐Diaminodiphenylmethan
Authors: Strehmel Veronika , Fryauf Kerstin , Sommer Claudia , Arndt Karl‐Friedrich , Fedtke Manfred
Published: April 2003

Der Aufbau von Netwerken aus Bisphenol A‐Diglycidylether und 4,4′‐Diaminodiphenylmethan wurde durch Messung des Drehmomentes, der Leitfähigkeit und durch Bestimmung der löslichen Anteile des vernetzenden System untersucht. Aus den Gelzeiten wurden die Aktivierungsenergie für den Vernetzungsprozeß bestimmt. Außerdem wurde die während der Vernetzung aufretende Volumenschwindung gemessen. Der Einfluß von N, N‐Dimethylbenzylamin als Beschleuniger auf den Vernetzungsprozeß wird diskutiert.
Crystallization and thermal behaviour of isotactic polypropylene blended with an alicyclic random co‐oligomer
Authors: Canetti Maurizio , Bonfatti Anna Maria , Siciliano Antonio , Seves Alberto
Published: April 2003

A fully saturated, alicyclic hydrocarbon resin (IST) was blended with isotactic polypropylene (iPP). IST is a random co‐oligomer of low average molecular weight obtained by oligomerization of indene, α‐methyl styrene and vinyl toluene, followed by hydrogenation.

The crystallization and thermal behaviour of iPP/IST blends were analyzed by microscopy and differential scanning calorimetry (DSC). The influence of blend composition on the spherulite growth rate and on the overall crystallization rate suggests that the two components form a miscible blend in the amorphous phase, as confirmed by the following observations: All blends show a single glass transition temperature (Tg); its value, depending on composition, lies between the iPP and IST Tg values (–14°C and 82°C, respectively), and is in good agreement with the theoretical values calculated by the Fox equation. The equilibrium melting temperature calculated for pure iPP was equal to 187°C; this value decreases with blending to 175°C for the iPP/IST 50/50 (w/w) blend. The χ12 parameter of the iPP/IST system was equal to −0.435, the negative value should suggest that the two components can form a compatible mixture which is thermodynamically stable above the equilibrium melting temperature.
Synthesis and thermal properties of copoly(1,4‐arylene‐1,2,4‐oxadiazole)s with dimethyl substituent
Authors: Jung Jin Chul , Choi E.‐Joon
Published: April 2003

2,5‐Dimethyl terephthalamide oxime (DTD) was prepared from 2,5‐dimethyl terephthalonitrile, and various mixtures of DTD and terephthalamide oxime (TD) were condensated with terephthaloyl chloride in dimethyl acetamide. The obtained homo‐ and copoly(terephthaloyl terephthalamide oxime)s with two methyl substituents were characterized and cyclodehydrated to give rise to corresponding homo‐ and copoly (1,4‐arylene‐1,2,4‐oxadiazole)s with two methyl substituents as the side branch.

Thermal properties of the homo‐ and copoly(1,4‐arylene‐1,2,4‐oxadiazole)s were investigated and the effects of the methyl groups were determined and discussed. The introduction of methyl substituents improved the solubility of the copoly(1,4‐arylene‐1,2,4‐oxadiazole)s greatly, but lowered their thermal resistance. All the copolymers and the homopoly [1,2,4‐oxadiazole‐5,3‐diyl‐(2,5‐dimethyl‐1,4‐phenylene)‐1,2,4‐oxadiazole‐3,5‐diyl‐1,4‐phenylene] were found to be amorphous with no observable glass transition.
Metal complexation of poly[1‐(2‐hydroxyethyl)aziridine‐co‐2‐methyl‐2‐oxazoline] in aqueous solution
Authors: Geckeler Kurt E. , Zhou Rongnong , Rivas Bernabé L.
Published: April 2003

The metal complexation of water‐soluble poly[1‐(2‐hydroxyethyl)aziridine‐co‐2‐methyl‐2‐oxazoline] with Co(II), Zn(II), Ni(II), Cu(II), Cr(III), Fe(III), Cd(II), Pb(II), and Sr(II) ions was investigated in aqueous phase using Liquid‐Phase Polymer‐Based Retention (LPR). The study shows that all metal ions are complexed at pH 5, except Co(II) and Zn(II). In contrast to Sr(II), which showed only a slight interaction over a pH range of 3 to 7, 94% of Co(II) and 88% of Zn(II) were retained at pH 7. At pH 3, only Cu(II) and Cr(III) ions interacted with the copolymer with retention values of 76% for Cu(II) and 52% for Cr(III). Viscosimetric measurements of the copolymer were performed in the presence of metal ions at different pH values.
Glass fiber‐reinforced epoxy composites
Authors: Patel Sandeep R. , Patel Ranjan G.
Published: April 2003

Glass fiber‐reinforced epoxy composites were prepared from the matrix resins tetraglycidyl diaminodiphenylmethane

Systematic name: N,N,N′,N′‐Tetrakis(2,3‐epoxypropyl)‐4,4′‐diaminodiphenylmethane.

(TGDDM) and tetraglycidyl bis(o‐toluidino)‐methane

Systematic name: N,N,N′,N′‐Tetrakis(2,3‐epoxypropyl)‐4,4′‐bis(o‐toluidino)methane.

(TGMBT) using various amines like 4,4′‐diaminodiphenylmethane (DDM), 4,4′‐diaminodiphenylsulfone (DDS) and diethylene triamine (DETA) as curing agents. The fabricated laminates were evaluated for their mechanical and dielectrical properties and chemical resistance. The composites prepared using an epoxy fortifier (20 phr) showed significant improvement in the mechanical properties.
Investigation of synthesis and light stability of polymeric azo dyes. II. Polymeric acrylate‐azo dyes
Authors: Lewandowsky Ekkehart , Mayer Roland , Marx Jörg , Böttcher Horst
Published: April 2003

Different 4′‐substituted 4‐[N‐ethyl‐N‐(2‐acryloyloxy)ethyl]aminoazobenzenes were used as starting monomers for homopolymerization and copolymerization reactions with styrene and methyl methacrylate. The photofading behaviour of the obtained polymeric azo dyes (M̄n 4200 – 9000) was investigated by means of a Xenotest device and compared with that of the corresponding monomers. The decreased photostability in the order monomer — copolymer — homopolymer was assumed to be caused by an increasing energy transfer in the matrix.
Crystallization of poly(aryl ether ketones). 2. Double peak melting behavior of PEEKK
Authors: Könnecke K.
Published: April 2003

Annealing poly(ether ether ketone ketone) (PEEKK) between glass transition and melting temperature generally results in a pronounced double peak melting behavior as obtained by DSC. Detailed investigations of the dependence of this double peak melting behavior on annealing conditions and experimental parameters clearly reveal that the crystallization can be described by a two‐stage process occurring on different time scales. A recrystallization model as origin for the double peak melting curves can be disproved.
m‐Bromophenolic epoxy resins for electronic packaging
Authors: Wang Chun‐Shan , Lin Yong‐Sheng , Fritz David B.
Published: April 2003

Meta‐halogenated phenols are generally known to be more chemically and thermally stable than their ortho‐ or para‐halogenated counterparts. A reactive intermediate, produced by the bromination of 2,4,6‐trimethylphenol is being used as an alkylating agent to incorporate this stable m‐bromophenol moiety into varieties of organic compounds and polymers. In electronic encapsulation applications, epoxy derivatives of novolacs containing m‐bromophenol have exhibited superior hydrolytic and thermal stability as compared with the conventional tetrabromo bisphenol‐A epoxies which are ortho‐brominated phenolics. The m‐bromophenol moiety contributes to the extended device reliability while meeting flame retardency requirements as well.
Bonding of rhenium(V) to diethylenetriaminepentaacetate functional groups of a polymethacrylate support
Authors: Hoskovcová I. , Kálalová E.
Published: April 2003

The bonding of rhenium to diethylenetriaminepentaacetic acid functional groups of a polymeric methacrylate matrix was studied. Diamagnetic complexes were formed of Re(V) with the heterogeneous coordination sphere containing atoms of chlorine and multiply bonded oxygen in addition to carboxylic groups, which are the only groups of the polymeric support functioning as ligands in the bonding to the metal. The rhenium complexes were examined by IR and UV‐VIS spectroscopy and by magnetic moment measurements.
Investigation of phase equilibria in mixtures composed of ethene, 1‐butene, 4‐methyl‐1‐pentene and a polyethylene wax
Authors: Wohlfarth Christian , Finck Udo , Schultz Ronald , Heuer Tilo
Published: April 2003

Some measurements of the vapour‐liquid and/or the demixing equilibrium at moderate pressures were carried out in systems containing the monomers ethene, 1‐butene, 4‐methyl‐1‐pentene and a polyethylene wax. A group‐contribution‐modified chain‐of‐rotators (COR) equation of state was used to calculate the phase diagrams in all binary and ternary subsystems and in the whole quarternary mixture. The calculations lead to a satisfying description of the vapour‐liquid equilibrium and its intersection by a liquid‐liquid region at higher pressures and temperatures. The miscibility gaps in both mixtures of the polyethylene wax with 1‐butene and 4‐methyl‐1‐pentene, respectively, were observed again after adding ethene to these binary mixtures. The calculations indicate a small three phase triangle in all corresponding ternary mixtures. A liquid‐liquid demixing region intersecting the vapour‐liquid surface could also be found in the whole quaternary system by calculation with the modified COR model. This surprisingly complicated phase behaviour has properly to be taken into account during the separation of the monomers after the co‐ or terpolymerization process.
Influence de la quantité d'un sel de sulfonium sur la coupure des liaisons OSi et sur la solubilité d'un mélange renfermant le sel et le poly(p‐triméthylsiloxystyrène) et irradié par des UV
Authors: Bonfils Frédéric , Giral Louis , Montginoul Claude , Sagnes René , Schué François
Published: April 2003

Si on laisse vieillir les solutions d'enduction obtenues en solubilisant le poly(p‐tri‐méthylsiloxystyrene) et l'un des sels (C6H5)2(C6H5SC6H4)SSbF6 ou (C6H5)3SAsF6 dans un solvant tel que la 3‐pentanone, on constate que le pourcentage de coupure des liaisons OSi(CH3)3 obtenue après irradiation (λ = 254 nm) avec une dose donnèe et après postcuisson dèpend de la quantitè de sel introduit. I1 en est de même de la solubilité de la rèsine ainsi traitee dans le solvant basique MF 319.
Readily hydrolyzable cellulose esters as intermediates for the regioselective derivatization of cellulose, 1. Synthesis and characterization of soluble, low‐substituted cellulose formates
Authors: Schnabelrauch Matthias , Vogt Sebastain , Klemm Dieter , Nehls Irene , Philipp Burkart
Published: April 2003

A new procedure was developed for the synthesis of low‐substituted, soluble cellulose formates. In a mixture containing cellulose, formic acid, phosphoric acid and water, cellulose can be dissolved within several hours, and after 24 h cellulose formates with a DS of about 0.6 that are soluble in DMSO could be obtained. By adding sulfuric acid as a dehydrating agent to the formylating system, formates with DS‐values up to 1.2 that are soluble even in DMF and N,N‐dimethylacetamide are formed after a very short reaction time of 15 min. 13C‐NMR studies show a strongly preferred formylation of the primary hydroxy groups of cellulose. Furthermore, the extent of depolymerization during the formylation reaction was investigated for various cellulose materials.
Synthesis and transition metal complex binding of amines and amides covalently bound to crosslinked polystyrene
Authors: Nicolaus Volker , Wöhrle Dieter
Published: April 2003

Polymers containing moieties of amides covalently bound to highly crosslinked polystyrene by CC connections were prepared via a polymer‐bound malonic ester group in the reaction with open‐chain diamines. The reaction of crosslinked, chloromethylated polystyrene with macrocyclic and open‐chain amines results in covalent binding by CN‐connection. The synthesized functionalized polymers were investigated for uptake of Cu(II), Ni(II) and Co(II) ions from aqueous solutions.
Sorptionsverhalten von nativer und thermoplastischer stärke
Authors: Sala R. M. , Tomka I. A.
Published: April 2003

Es wurden Wasserdampf‐Sorptionsisothermen von nativer und thermoplastischer Stärke gemessen. Die thermisch‐mechanische Behandlung der Stärke und das Einfähren von Glyzerin als Weichmacher fährt zum Verschwinden der Hysterese und zum Übergang von der Typ II in eine Typ III Isotherme. Eine Theorie, welche das Sorptionsverhalten von quellbaren Sorbentien gut beschreibt, wird kurz eingeführt und anhand der experimentellen Daten ihre Aussagen diskutiert. Die vorgestellte Theorie erlaubt wegen der physikalischen Bedeutung der Parameter Rückschlüsse auf die molekularen Vorgänge während der Sorption. Die Motivation zur Untersuchung des Sorptionsverhaltens von thermoplastischer Stärke ist deren möglicher Einsatz als biologisch abbaubarer Kunststoff.
New unsymmetrical cycloaliphatic epoxypolyesterimides
Authors: Roig Antoni , Serra Angels , Cádiz Virginia , Mantecón Ana
Published: April 2003

New bisepoxy unsymmetrical cycloaliphatic derivatives have been synthesized. The different reactivity of both oxirane rings (cycloaliphatic and glycidylic) has been tested against carboxylic acids giving rise to normal and abnormal opening to the glycidyl group. Homopolymerization reaction was also observed. Polymer structures were identified by 13C‐NMR spectroscopy. Thermal analysis carried out allowed to confirm their good thermal properties.
Mutual correlations between parameters characterizing the miscibility, structure and mechanical properties of polymer blends
Authors: Fekete Erika , Pukánszky Béla , Peredy Zoltán
Published: April 2003

Polymer blends were prepared in the whole composition range using polymers of different polarity. Mechanical properties were characterized by tensile measurements. Surface and interfacial properties were measured and calculated and parameters characterizing the miscibility were determined. A correlation was found between the yield stress and the thermodynamic quantities characterizing the degree of miscibility. Since both the degree of miscibility and morphology are influenced by the interfacial tension, it can be regarded as the best candidate to correlate polymer/polymer interaction and mechanical properties in polymer blends.
Kupferdesaktivierende wirkung von chelatkomplexbildnern in strahlenvernetztem polyethylen niedriger dichte
Authors: Schipschack Klaus , Beger Jörg , Neumann Renate , Wagner Harald
Published: April 2003

Komplexbildner für Kupfer, die als Nachweisreagenzien in der Analytik und als Reagenzien für die Flüssig‐Flussig‐Extraktion interessant sind, wurden als Kupferdesaktivatoren in vernetztem Polyethylen niedriger Dichte (XLDPE) durch Bestimmung der Induktionszeiten der Sauerstoffaufnahme von XLDPE/Cu/XLDPE‐Sandwichproben bei 165 °C getestet. Neben acylierten Hydrazinen, einer für wirksame Metalldesaktivierung bereits bekannten Stoffklasse, wurden mehrere Gruppen von Chelatkomplexbildnern untersucht, wobei sich vor allem die 2‐(2‐Hydroxyphenyl)imidazole als wirksame Kupferdesaktivatoren in XLDPE erweisen. 2‐(2‐Hydroxyphenyl)oxazol, ‐thiazol und ‐oxadiazol, denen bei sehr ühnlicher chemischer Struktur der bewegliche Wasserstoff am Fünfring fehlt, sind dagegen unwirksam.
High performance polyamide‐6 and blends of poly(ethylene terephthalate) and poly(butylene terephthalate) through ultraquenching
Authors: Avramova Nadka , Fakirov Stoyko , Avramov Issak
Published: April 2003

Polyamide‐6 (PA6) and blends of poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) characterized by amorphous initial structure and improved mechanical properties are obtained by means of an ultraquenching technique. In the case of polyamide‐6, erasure of the structural memory is achieved by melt annealing above the equilibrium melting point. This procedure is applied in order to restrict the crystallization process. After quenching, further orientation of the amorphous polymers and annealing with fixed ends lead to a significant improvement of the mechanical properties. The tensile strength and elasticity modulus increase three to five times and the elongation at break decreases by half as compared with conventionally obtained polyamide‐6, PET and PBT.
Synthesis of epoxy resins based on bisphenol‐S and its derivatives
Authors: Liaw Der‐Jang , Shen Wen‐Chang
Published: April 2003

Bisphenol‐S derivatives of five kinds such as bis[4‐(β‐hydroxyethoxy)‐phenyl]sulfone (HEPS), bis[4‐(β‐hydroxy(iso)propoxy)‐phenyl]sulfone (HPPS), 3,3′,5,5′‐tetrabromobisphenol‐S (TBS), bis[3,5‐dibromo‐4‐(β‐hydroxyethoxy)‐phenyl]sulfone (HEETBS) and bis[3,5‐dibromo‐4‐(β‐hydroxy(iso)propoxy)‐phenyl]sulfone (HPETBS) were successfully prepared by the reaction of bisphenol‐S with ethylene carbonate, 1,2‐propylene carbonate or bromine, respectively. Several sulfone‐containing epoxy resins were obtained by alkaline condensation of bisphenol‐S (bis(4‐hydroxyphenyl)‐sulfone) or its derivatives with epichlorohydrin using sodium hydroxide. The epoxy resins thus obtained were characterized by elemental analysis, IR and 13C‐NMR spectra. All epoxy resins are solid products except HPPS epoxy which contains oxypropylene units. The melting points (Tm) and glass transition temperatures (Tg) of epoxy resins which have flexible oxyethylene or oxypropylene units were lower than that of epoxy resin derived directly from bisphenol‐S. The increase of melting point which has been observed in brominated epoxy resins is attributed to the bulky bromine atom. The molar‐mass distributions of epoxy resins made by the direct addition of epichlorohydrin to bisphenol‐S (so‐called “taffy” process) or by the reaction of epoxy resin of low molar mass and of which the main constituent is the diglycidyl ether of bisphenol‐S in melt (so‐called “advancement” process) have also been compared. The “taffy” process leads to products containing both odd‐ and even‐numbered diepoxide oligomers in contrast to the “advancement” process which leads to products containing predominantly even‐numbered diepoxide oligomers. Epoxy equivalent and melt viscosity of epoxy resins increased with increasing amount of bisphenol‐S. This result is in accordance with the theoretical distribution calculated according to Flory statistics.
Ion exchanger resins, I. Anion exchangers with tertiary amine groups on poly(acrylonitrile‐co‐divinylbenzene) networks
Authors: Drǎgan Stela , Grigoriu G.
Published: April 2003

Macroporous copolymers of poly(acrylonitrile‐co‐divinylbenzene) were synthesized in the presence of 2‐ethyl‐1‐hexanol (2EH) and toluene as diluents. The copolymers were characterized by acrylonitrile content and from morphological point of view. Samples with a minimum content of homopolymer were transformed into weak base anion exchangers by the aminolysis‐hydrolysis reaction of the nitrile groups with N,N‐dialkylaminoalkylamines. The reactions were investigated by the exchange capacity variation and IR‐spectral analysis. It was emphasized that the reactivity of asymmetrical diamines depends on the nucleophilicity of the primary amine group.
An ATR‐FTIR study on penetration of resins in wood
Authors: Jensen Eirik S. , Gatenholm Paul , Sellitti Claudio
Published: April 2003

Wood samples were treated with allylic ether resins having various molecular weights, various structures and with the use of different solvents. Using a technique based on Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR‐FTIR), differences in the characteristic bands of wood and resin were monitored throughout a piece of wood treated with resins and thus a penetration profile was demonstrated.

ATR‐FTIR showed that there were differences in the chemical composition of the wood itself at different depths from the surface. The resins could be detected at a depth of more than 3 mm into the wood after 4 days of penetration by gravity. Using a characteristic band for wood as an internal standard, it could be demonstrated that penetration depends upon the solvent used, molecular weight of the resin and also morphology of the wood.
Synthesis and properties of porous ion‐exchange membranes, I. Polymer‐polymer‐filler system
Authors: Bryjak Marek , Poźniak Gryzelda , Trochimczuk Witold
Published: April 2003

A method of preparation of porous ion‐exchange membranes (PIEM's) with sulfonic groups is presented. One of the four studied polymer blends is recommended for PIEM's preparation. It is the ternary blend of polyethylene with poly(styrene‐co‐divinylbenzene), isotactic polypropylene, and calcium carbonate. The effect of blend composition on membrane properties is also discussed. Both blend components, PP and CaCO3, affected the membrane porosity while only PP governed the pore diameter. A model of PIEM's creation is suggested. The antifouling behaviour of PIEM's was evaluated by means of ultrafiltration of bovine serum albumine or poly(ethylene glycol) solutions as well as skimmed‐milk and an active sludge designated for bioconversion of aldehydes. It was found that membranes with ion‐exchange capacity higher than 1 mmol/g offer antifouling effect. PIEM's have also higher solute rejection parameter and are easier to regenerate than membranes without sulfonic groups.
Lokale mischbarkeit von isotaktischem polypropylen (iPP) und trans‐polyoctenylen (TOR) in grenzschichten von iPP/TOR‐blends
Authors: Wenig W.
Published: April 2003

Blends aus isotaktischem Polypropylen (iPP) and trans‐Polyoctenylen (TOR) wurden mit Differentialkalorimetrie, Röntgenweit‐ und ‐kleinwinkelstreuung, Torsionsschwingungsanalyse und Polarisationsmikroskopie (Keimbildung und Kristallisationskinetik) untersucht. Schmelz‐ und Kristallisationstemperaturen ändern sich nur wenig als Funktion der Komponentenzusammensetzung; auch die Überstruktur ist nahezu invariant gegenüber der Konzentration des zugemischten TOR. Die aus den Verlustmodulmaxima der Torsionsschwingungskurven bestimmten Glastemperaturen zeigen jedoch interessante Abhängigkeiten. Durch Berechnung der Schiefe der G″‐(T)‐Maxima wird gezeigt, daß iPP‐Moleküle in die TOR‐Komponente diffundieren, in geringerem Maße auch TOR‐Moleküle in die iPP‐Matrix. Dadurch bildet sich ein Grenzschichtvolumen, in dem beide Komponenten lokal gemischt sind. Dieses Grenzschichtvolumen ist verantwortlich für den gemessenen erhöhten Anteil der heterogenen Keimbildung.
Antioxidants and stabilizers, 117. Contribution to the transformation mechanism of 2,6‐di‐tert‐butyl‐4‐methylphenol, a processing stabilizer for polyolefins
Authors: Pilař Jan , Rotschová Jitka , Pospíšil Jan
Published: April 2003

2,6‐Di‐tert‐butyl‐4‐methylphenol (1), a polyolefin processing stabilizer, is transformed during the stabilization process primarily into 2,6‐di‐tert‐butyl‐4‐methyl‐phenoxyl (2). The important consecutive transformation pathway of 2 involves irreversible CC coupling giving 4,4′‐ethylenebis(2,6‐di‐tert‐butylphenol) (8) and reversible CC coupling accounting for formation of 2,6‐di‐tert‐butyl‐4‐methyl‐4‐(3,5‐di‐tert‐butyl‐4‐hydroxybenzyl)‐2,5‐cyclohexadiene‐1‐one (9). The stepwise transformation of 9 into the parent phenol 1, the stable dimer 8 and a variety of other products was found in EPR and chromatographic studies of free radical and molecular products generated from 9 in oxidative environment. It follows that compounds 1, 8 and 9 are stepwise transformed into coloured quinoide and quinonemethinoide compounds in the ultimate phase, and the antioxidant chain‐breaking character of 1 is thus lost. It is considered that most of the free radical species formed transiently during transformation of 1 and/or of derived phenolic coupling products disappear from the system via disproportionation and alkylperoxy radicals (RO2) or oxygen trapping. Labile, cross‐conjugated, peroxidic species generated by the latter process contribute to the fragmentation of coupling products.
Synthesis of polyacrylamide flocculants with poly(ethylene glycol) segments by redox polymerization
Authors: Erciyes A. Tuncer , Erim Melek , Hazer Baki , Yagci Yusuf
Published: April 2003

The polymerization of acrylamide (AAm) initiated by polyazoesters (PAE) possessing poly(ethylene glycol) (PEG) segments and azo functions was investigated in aqueous solution at 70°C. Polymerization of AAm initiated by PAE yields polymers with PEG segments and appropriate hydroxy functions for the subsequent redox polymerization. Polymerization of AAm induced by these polymers in conjunction with Ce(IV) provided increase in the molecular weight of the initial polymer without formation of insoluble polymer. The water‐soluble polymers obtained at various stages were tested in the flocculation of suspension of tincal concentrate and showed good flocculating properties.
Preparation of modified styrene‐divinylbenzene copolymers having different physical structures and their adsorption characteristics of nonionic surfactants
Authors: Fujita Itsusei , Nagano Yuko , Harada Kumiko , Nakayama Morio , Sugii Atsushi
Published: April 2003

Several α‐oxoethylated and α‐hydroxyethylated styrene‐divinylbenzene (St‐DVB) resins having different degrees of crosslinking and porosity were prepared and their adsorption behaviour toward a nonionic surfactant, decaethyleneglycol nonylphenyl monoether, was investigated. The increment of the adsorption capacity caused by the introduction of the α‐hydroxyethyl groups was remarkable in the less crosslinked resin. The α‐hydroxyethylated resin derived from the St‐DVB resin synthesized with 10 vol.‐% DVB and 100 – 120 vol.‐% of 2,2,4‐trimethylpentane showed the highest capacity among the resins tested. The significance of both macroporosity and gel porosity in the effective adsorption of the nonionic surfactant was elucidated. A column operation using proposed resins was carried out and versatility was evaluated in terms of the breakthrough capacity.
Fracture mechanics analysis of rubber‐modified polyamide‐6: Temperature and rate effect with varying rubber content
Authors: Ricco Theonis , Pavan Andrea
Published: April 2003

Elasto‐plastic fracture mechanics has been applied to a series of EPDM‐modified polyamide‐6 samples with varying rubber content, in order to characterize properly their fracture behaviour. J‐testing has been carried out to determine the J‐resistance (JR) curve and to evaluate therefrom the fracture initiation resistance, JIC, and the fracture propagation parameter dJ/da. The results obtained are analyzed and discussed as a function of rubber content, temperature, and strain rate.
Relations between physical parameters and kinetics of photo‐induced radical polymerization in polymer binders: Radical polymerization of acrylamide
Authors: Timpe Hans‐Joachim , Müller Franz Werner , Strehmel Bernd , Panzner Gerit , Schiller Kurt , Reuter Hardy
Published: April 2003

The photo‐induced radical polymerization of acrylamide has been investigated in combinations of two polymers containing carboxy groups. The kinetic parameters of this polymerization, measured with a calorimetric method, depend on the proportion of the two polymers in the system. In mixtures with the lowest glass transition temperature, the polymerization rates are the highest. These transition temperatures have been determined with a special fluorescene technique using crystal violet as probe. Presumably, the effects measured in the systems are based on the strong polar interactions between the carboxy groups of both polymers.
Molecular aspects of rubberlike elasticity
Authors: Mark J. E.
Published: April 2003

Molecular theories of rubberlike elasticity are surveyed, starting with the earliest attempts carried out in the 1930's and ending with work still very much in progress. The models are variously based on phenomenological arguments, affinely‐deforming networks, phantom networks, constrained junctions, constrained chains, slip‐links, molecular tubes, van der Waals concepts, or rotational isomeric chains. Most of the theories are analytical, but some involve computer simulations based on Monte Carlo methods. The theories are generally for networks of Gaussian chains, but there have been significant advances for non‐Gaussian networks as well, and these are particularly important with regard to a better understanding of ultimate properties. The major outstanding problem on the theory side, however, seems to be a quantitative treatment of chain entanglements.

There have also been numerous advances on the experimental side. These include preparation of model networks of known structure, accumulation of elasticity data for deformations other than the much‐studied simple elongation, development of new characterization techniques (such as fluorescence polarization, and X‐ray and neutron scattering), investigation of the phenomenon of gel collapse, borrowing of ideas from the area of bioelastomers, and preparation of novel reinforcing fillers.