bluuebunny/crossref_metadata_2025 huggingface dataset:
Activity of carbon black as a filler in different elastomeric matrices
Authors: Ślusarski L. , Zaborski M. , Donnet J. B.
Published: April 2003

Activity of carbon black toward natural, butyl, butadiene, butadiene‐styrene and butadiene‐acrylonitrile rubber has been evaluated. Peroxide, sulfur donor, sulfur/accelerator systems and also tris(2‐methyl‐1‐aziridinyl)phoshine oxide as crosslinking substances were used. Different activity parameters were taken into consideration. From the results it follows that activity of carbon black depends not only on its properties but also on the type of the elastomer matrix. An effect of chain flexibility, unsaturation degree, crosslinking density and chemical structure of the network has been observed.
Modification of melamine‐formaldehyde moulding compounds with ethylene/vinyl acetate copolymers
Authors: Braun Dietrich , Unvericht Reinhard
Published: April 2003

Melamine‐formaldehyde moulding compounds (MF) were modified by mechanical mixing with ethylene/vinyl acetate copolymers (EVA) and with partially hydrolysed EVA. Ether linkages between the hydrolysed material and the MF resin improve the mechanical properties of the transfer moulded parts containing the hydrolysed material compared to those made with EVA. The use of both modifying polymers improves the ductility and, in case of the partially hydrolysed material, the postshrinkage of the extremely rigid MF matrix, as long as the modification polymer content is kept low. On the contrary, Young's modulus and the heat deflection temperature are deteriorated. The improvement in impact strength by use of those uncrosslinked polymers is still insufficient.
Synthesis of highly porous styrene‐divinylbenzene copolymers prepared in the presence of 2,2,4‐trimethylpentane
Authors: Djahièche Abderrahim , Rabia Idir , Revillon André
Published: April 2003

A large number of styrene‐divinylbenzene copolymers (St‐DVB) were synthesized using 2,2,4‐trimethylpentane as pore‐forming agent. Diluent and crosslinking agent (DVB) contents were varied in the ranges 20–60 vol.‐% and 2–40 vol.‐%, respectively, to generate various St‐DVB networks. Network features as apparent and skeletal densities, pore volume, mean pore diameter, specific surface area and pore size distributions were measured by mercury porosimetry. A compressing process occurring at the beginning of each measurement has been revealed and measured. Depending on the two synthesis parameters, the changes in pore diameter distributions are discussed. Those results, combined with the calculated average pore diameter and microscopy observations, allow to conclude that the synthesized matrices have a microspheres‐based structure with a network‐overlapping process occurring over 50 vol‐% of dilution. A macroporosity domain has been defined for networks having specific surface areas greater than 130 m2/g.
Synthesis and characterization of N‐alkylated polyamide‐imides
Authors: Choi Kil‐Yeong , Yi Mi Hie
Published: April 2003

New aromatic polyamide‐imides (PAI) containing various alkyl substituents were prepared by the substitution reaction of Torlon® 4203L (commercialized PAI resin) with the corresponding alkyl halides such as methyl iodide, ethyl iodide, and n‐butyl bromide. The resulting amorphous PAIs with glass transition temperatures ranging from 238 to 276°C had inherent viscosities in the range of 51 to 53 mL/g. These polymers were readily soluble in aprotic polar solvents such as N‐methylpyrrolidone, dimethylformamide, dimethyl acetamide, etc. Furthermore, the incorporation of various alkyl substituents into amide groups of the PAI resin increased the melt processability, but slightly decreased the thermal properties compared with conventional PAI resin. The melt viscosities of resulting PAIs determined at 330°C under the frequency of 10‐1 rad/sec were in the range of 103–105 Pa.s. On the other hand, the modified PAIs showed significantly lower melt viscosities than Torlon® 4203L, which was almost comparable to the conventional polyetherimide, Ultem‐1000.
Synthesis and properties of biodegradable copolyesteramides: Nylon 6,6/ϵ‐caprolactone copolymers, 1
Authors: Arvanitoyannis Ioannis , Nakayama Atsuyoshi , Kawasaki Norioki , Yamamoto Noboru
Published: April 2003

A series of copolyesteramides based on adipic acid/1,6‐hexane diamine/ϵ‐caprolactone and Nylon 6,6 salt/ϵ‐caprolactone were synthesized. Their molecular weights, determined by gel permeation chromatography and NMR spectroscopy, were found to lie within the range from 1000 up to 7000. Their thermal properties (glass transitions, melting points and heats of melting, and decomposition temperatures) were recorded with diferential scanning calorimetry and thermogravimetry, respectively, and correlated to the comonomer feed composition. The FT‐IR and NMR spectra were also recorded in order to confirm the composition of the copolyesteramides and to compare them with that of the comonomer feed. The biodegradability of the synthesized copolymers was tested by enzymatic hydrolysis.
Study of the condensation products of abietic acid with formaldehyde at high temperatures
Authors: Bicu Ioan , Mustaţǎ Fǎnicǎ
Published: April 2003

New condensation products have been synthesized by heating abietic acid and formaldehyde at high temperatures in the presence of sulfonic‐type acid catalysts. The main polycondensation reaction is associated with a secondary one which leads to a ketonic compound, carbon dioxide and water. The carboxylic groups of abietic acid participate in this condensation reaction. The behaviour of the abietic acid‐sulfonic acid catalyst system was studied in absence of formaldehyde to acquire additional information about the reaction. The process is defined by the reaction temperature and chemical nature of the catalyst. A possible mechanism of the condensation reaction is discussed on the basis of the obtained results.
Deposition of hydrophobic layers onto acrylic fibers by plasma polymerization
Authors: Occhiello Ernesto
Published: April 2003

Experiments aimed at the deposition of hydrophobic coatings on acrylic fiber surfaces are described. The effects of utilizing fluorine‐containing and siloxane monomers and of varying plasma parameters have been assessed by measuring deposition rates, observing surface chemistry and determining water contact angels.
Tailored polymers by cationic ring‐opening polymerization
Authors: Goethals Eric J. , Van Caeter Peter , Geeraert Jan M. , Du Prez Filip E.
Published: April 2003

After a general classification of the cationic ring‐opening polymerizations (CROP's) according to their polymerization mechanism, a number of examples of tailored polymers based on CROP are presented. The monomers used for the synthesis of these tailored structures are tetrahydrofuran (THF), N‐tert‐butyl aziridine (TBA), 2‐methyl‐1,3‐oxazoline (MeOX) and 1,3‐dioxolane (DXL).

The polymer structures include different block and graft copolymers, macromonomers, star‐shaped polymers, polymer networks and interpenetrating polymer networks (IPNs).
Dendritische und “hyperbranched” Polymere. Beispiele für die Beeinflussung von Polymereigenschaften durch gezielte Synthese von dreidimensionalen Strukturen
Authors: Voit Brigitte I. , Turner S. Richard
Published: April 2003

Dendritic polymers are highly branched structures with globular shape and high number of functionalities. In a divergent or convergent stepwise synthesis perfect macromolecules with controlled size and architecture are obtained. From the broad variety of dendrimer structures some examples are given and the properties of these unusual polymers are illustrated. For comparison the hyperbranched polymers, dendritic structures with defects made in a one‐pot polycondensation reaction, are discussed. Differences and conformities of properties like molecular weight distributions, functionalities, solubility, viscosity behavior and glass transition temperatures for both globular polymer structures are explained.
Massgeschneiderte Polymere. Synthesestrategien für Telechele, Makromonomere, Block‐ und Pfropfcopolymere
Authors: Nuyken Oskar
Published: April 2003

New developments in the synthesis of telechelics, macromonomers, block‐ and graftcopolymers are presented. Synthetic strategies for them are demonstrated with examples from different fields such as polycondensation, radical, anionic, and cationic polymerization, chain cleavage and criss‐cross‐cycloaddition.
Progress in synthesis and application of segmented polymers
Authors: Mülhaupt Rolf , Buchholz Udo , Rösch Joachim , Steinhauser Norbert
Published: April 2003

Tailor‐made segmented polymers play a key role in the development of novel polymeric materials exhibiting unsual bulk and surface properties. As a function of molecular architectures of segmented polymers, it is possible to control polymer morphologies and to achieve property synergisms. Selected examples are presented to illustrate basic concepts and recent developments. Segmented reactive liquid rubbers, containing an immiscible silicone segment flanked by two miscible oligo(caprolactone) segments, are efficient epoxy toughening agents. In such nano‐phase‐separated silicone‐modified IPNs impact strength is improved without sacrificing dimensional stability. Compatibilized blends of segmented phenolic polyurethane and nitrile liquid rubbers produce rubber blend microphases dispersed in epoxy prepregs which are used to bond aluminum sheets in structural laminates. Reactive blending technologies are developed to produce segmented polymers as blend compatibilizers during melt processing, e.g., of polypropylene/polyamide 6 blends. Incorporation of oligo(tetrafluoroethene) segments into various condensation polymers modifies thermal and mechanical properties as well as surface tension and gas permeabilities.
Neuartige Einkomponenten‐Reaktiv‐Systeme auf basis von festen Polyisocyanaten
Authors: Kopp Richard , Grögler Gerhard , Heß Heinrich , Prolingheuer E. Christoph , Casselmann Holger
Published: April 2003

Lagerstabile Polyurethan‐Einkomponentensysterne auf Basis von flüssigen oder ver flüssigbaren NCO‐reaktiven Kornponenten und festen, feinteiligen, mit einer Diffusions sperrschicht umhullten TDIH‐Partikeln lassen sich therrnisch zu Elastomeren mit hohem Eigenschaftsniveau, insbesondere hoher thermomechanischer Stabilität, ausharten.

Die Eigenschaften der Endprodukte lassen sich in einem weiten Bereich durch die Auswahl der NCO‐reaktiven Aufbaukomponenten steuern. Je nach Viskosität bzw. Schmelzverhalten der Ausgangskomponenten erhält man bei Raumtemperatur gut gießbare, rakelfähige oder auch feste, leicht aufschmelzbare reaktionsfähige Gemische, die, abhängig von ihrer Viskosität und dem Verwendungszweck, nach verschiedenen Methoden verarbeitet werden können (Spritzen, Gießen, Rakeln, Spritzguß, Schleuderguß, Slush‐Molding u.ä.)

Die Kombination aus praktisch unbegrenzter Lagerzeit und Verarbeitungszeit, rascher. Härtung bei Temperaturen ab ca. 100°C und breiter Variationsmoglichkeit der mechanischen Eigenschaften eröffnen diesen neuen Polyurethan‐Systemen ein weites. Einsatzgebiet mit interessanten, neuen Möglichkeiten.
Olefinpolymerisation mittels metallocenkatalysatoren
Authors: Kaminsky Walter
Published: April 2003

Metallocenes have gained widespread interest as catalysts for olefin polymerization due to their high activity and versatility. A large range of new polymers with narrow molecular weight distribution and different microstructures can be produced with these “single‐site” catalysts. These highly active catalysts which are able to produce 40 tonnes of polyethylene per gram zirconium per hour are even capable of incorporating remarkable amounts of sterically demanding olefins and dienes in copolymerization with ethylene. Isotactic, syndiotactic, stereoblock and isoblock polyolefins are accessible by variation of the metallocene ligands. Similarly, the isotacticity and molecular weight of the generated polyolefins are influenced by the ligand structure. By heterogenization of the metallocene on metal powder or silica polymers with substantially higher molecular weight, higher melting points and other new properties may be attained. Cyclic olefins like cyclopentene, norbornene or dimethanooctahydronaphthalene polymerize without ring‐opening to yield highly melting and poorly soluble polymers. By separation of the racemic catalyst into enantiomers, optically active alkanes and alkenes are accessi‐ble. Trimers are obtained with ee of 95%. These results provide new insights into the mechanism of Ziegler‐Natta catalysis.
Cycloolefin‐copolymere: Eine neue klasse transparenter thermoplaste
Authors: Cherdron H. , Brekner M.‐J. , Osan F.
Published: April 2003

Investigation of the polymerization process and property modification of metallocene‐based cycloolefin copolymers (COC) shows that this monomer‐catalyst combination enables synthesis of a new class of transparent thermoplastic polymers. Metallocene catalysis offers much opportunity to vary the composition and microstructure of the copolymers. The breadth of the polymer spectrum which can be further widened by polymer modification enables many applications for this new class of thermoplastics. The key parameters that control structure and properties in the COC family are discussed in this paper.
Übergangsmetall‐katalysierte kondensations‐ und polykondensationsreaktionen
Authors: Heitz Walter
Published: April 2003

While metal‐catalysed polymerizations are chain reaction with constant valence of the metal, metal‐catalysed polycondensations are step polymerizations with changing valence of the metal. Taking as examples the Pd‐catalysed vinyl polymerization of norbornene, the alternating copolymerization of ethylene and carbon monoxide, and the Heck reaction, the essential structural prerequisties of the catalyst to control those reactions are presented. Metal‐catalysed polycondensations may occur as one‐ or two‐electron processes. The oxidative polymerization of 2,6‐dimethylphenol, the Heck reaction, and the Ni‐catalysed polyphenylene synthesis are discussed.
Polymersynthesen durch repetitive N‐alkylierungen
Authors: Schulz Rolf C. , Hochberg Gerd , Walter Frank
Published: April 2003

The repetitive N‐alkylation reaction, at first used by Marvel, turned out to be a very versatile method for the synthesis of polycations. Rembaum introduced the name “ionenes” for this type of polymers. In the first part of the lecture some examples of single‐stranded ionenes are described. The second part shows how the repetitive N‐alkylation can be used for the synthesis of spiro polymers. In these double‐stranded polymers two spiro‐conjugated rings of the main chain have a central quaternary nitrogen in common (spiro‐ionenes or spiro‐azonia polymers). Starting from tetrabromides (for instance 1,2,4,5 tetrabromomethylbenzene) and different cyclic diamines soluble polymers (with more or less stretched shape) with the typical properties of polyelectrolytes are obtained.
Intramolekular vernetzte poly(organosiloxan)partikel
Authors: Geck Michael , Deubzer Bernward , Weis Johann
Published: April 2003

Intramolecularly crosslinked poly(organosiloxane) particles are prepared by means of emulsion polycondensation or emulsion polymerization of alkoxysilanes or cyclic organic siloxanes. Starting from these intramolecularly crosslinked poly(organosiloxane) particles, graft copolymers are obtained by free‐radical emulsion polymerization of unsaturated olefinic monomers (e.g. acrylates, styrene) in the presence of (functionalized) organosiloxanes. Intramolecularly crosslinked poly(siloxane) particles and their graft copolymers are characterized by means of light scattering (in dispersion), electron microscopy and thermal analyses (DSC, DMTA).
Preparation of multiphase block copolymers by redox polymerization process, 3. Polymerization of methyl methacrylate and acrylamide by the Mn(III)‐poly(ethy1ene glycol) redox system
Authors: Cakmak Ismail
Published: April 2003

Redox‐initiated free‐radical polymerization of methyl methacrylate (MMA) and acrylamide (AAm) with poly(ethy1ene glycol) (PEG) using Mn(III) as reduction agent was carried out to yield PMMA‐block‐PEG‐block‐PMMA and AAm‐block‐PEG‐block‐AAm triblock copolymers. The principal parameters (concentration of the reactants, temperature) affecting the synthesis were examined. Block copolymers were characterized by 'H‐NMR and infrared spectroscopy.
Aminosiloxane‐modified epoxy resins as microelectronic encapsulants
Authors: Shieh Jeng‐Yueh , Ho Tzong‐Hann , Wang Chun‐Shan
Published: April 2003

Amine‐terminated poly(dimethylsiloxanes) (ATPDMS) were used to improve the toughness of a cresol‐formaldehyde novolac epoxy resin cured with a phenolic novolac resin for electronic encapsulation application. The effect of molecular weight of amine‐terminated polysiloxanes on the phase separation of the resultant elastomers from epoxy matrix were investigated. Mechanical and dynamic viscoelastic properties of siloxane‐modified epoxy networks were also studied. The dispersed silicone rubbers effectively improve the toughness of cured epoxy resins by reducing the coefficient of thermal expansion and flexural modulus, while the glass transition temperature was hardly depressed. Electronic devices encapsulated with the dispersed silicone rubber‐modified epoxy molding compounds have exhibited excellent resistance to the thermal shock cycling test and have resulted in an extended device use life.
The effect of the processing steps on the oxidative stability of polyethylene tubing crosslinked by irradiation
Authors: Iring M. , Fodor Z. , Bődy M. , Baranovics P. , Kelen T. , Tüdős F.
Published: April 2003

Some chemical and mechanical properties of intermediate products obtained in the production of PE heat‐shrinkable tubes were studied at different compositions of the material containing PE, antioxidant (aromatic amime or phenol) and, in some cases, flame retardant and/or an elastomer.

In the course of the production phase, the thermooxidative stability decreases compared to that of compounded granulate. The greatest decrease is caused by irradiation. The aromatic amine seems to be a more effective antioxidant at similar compositions than the phenol derivative, and it shows a better resistance against irradiation. The oxidative stability of the finished shrinkable tubes is not affected by the quality of commercial granulate (initial polyethylene).

Mechanical properties change slightly upon ageing, and the introduction of the elastomer did not alter the tensile strength and elongation at break. The remaining stability of the end product was still high enough to bear the stress of shrinking in use, and the good tensile strength of the material did not decrease upon thermal ageing either.

In the extrusion of the granulated compound no significant change in the distribution and average molecular weight took place. Irradiation produced more than 50% insoluble fraction and the thermooxidative properties of the crosslinked sample changed significantly compared to the original PE and to the compound prepared from it.
Preparation of multiphase block copolymers by redox polymerization process, 4. Polymerization of methyl methacrylate by the redox system Mn(III)‐poly(ethylene glycol) containing azo groups
Authors: Cakmak Ismail
Published: April 2003

Redox polymerization of methyl methacrylate using Mn(III) with poly(ethylene glycol) having azo and hydroxy functions was carried out to yield ethylene glycolmethyl methacrylate block copolymers with labile azo linkages in the main chain. These prepolymers were used to initiate free‐radical polymerization of styrene through thermal decomposition of the azo groups, resulting in the formation of multiblock copolymers. Successful blocking has been confirmed by fractional precipitation, a strong change in the molecular weight, and spectral measurements.
Benzylcellulose als thermoplastischer kunststoff, II. Stabilisierung und weichmachung.
Authors: Braun D. , Bahlig K. H.
Published: April 2003

Durch Zusatz eines Stabilisators (4‐Benzyloxyphenol) kann die oxidative thermische Schädigung von Benzylcellulose bei deren Verarbeitung aus der Schmelze vermindert werden. Die notwendige Mindestkonzentration an Stabilisator beträgt 5 Gew.‐%. Durch äßere Weichmachung mit Diethylphthalat können die Glas‐ und die Verarbeitungstemperatur herabgesetzt und eine zufriedenstellende Weichheit und Flexibilität der ansonsten hart‐spröden reinen Benzylcellulose erzielt werden. Die erforderliche Weichmacherkonzentration liegt bei 5 bis 10 Gew.‐% und ist damit wesentlich niedriger als für andere Cellulosederivate wie z. B. Ethylcellulose (10–20 Gew.‐%) oder Celluloseacetate (20–30 Gew.‐%).
Thermogravimetrie als brennbarkeitsbestimmungs‐methode für lineare polyurethane
Authors: Pielichowski Krzysztof , Pielichowski Jan , Altenburg Horst , Wiegmann Marc
Published: April 2003

In der vorliegenden Arbeit wurden für eine Serie von Polyurethanen auf der Basis von Diol und Isocyanat der Sauerstoffindex (SI) gemessen und die thermische Zersetzung mittels thermogravimetrischer Analyse (TG) untersucht. Dabei wurde ein Zusammenhang zwischen einigen Parametern der thermischen Zersetzung und den SI‐Werten gefunden. Die Auswertung der experimentellen Ergebnisse zeigte, daß die Höhe des Massenverlustes bei 250°C und die SI‐Werte direkt proportional zueinander sind. Derselbe Zusammenhang besteht auch zwischen dem Logarithmus der Temperatur bei der maximalen Zersetzungsgeschwindigkeit und den SI‐Werten.
Studies on thermal stability of modified polycarboxylate cements
Authors: Bansal R. K. , Tewari U. S. , Singh P. , Murthy D. V. S.
Published: April 2003

Dental cement compositions made by mixing poly(acrylic acid‐co‐acrylamide) and mixtures of zinc oxide and cryolite (Na3AIF6) in various proportions of 10–50 wt.‐% (w/w) were cured at room temperature. From thermogravimetric analyses of the samples, the integral procedural decomposition temperatures (IPDT), maximum decomposition temperatures, activation energies and frequency factors were evaluated. The cured cement sample containing 20 wt.‐% cryolite in the filler mixture is thermally very stable.
Synthesis and polymerization of hydrophobic iodine‐containing methacrylates
Authors: Moszner Norbert , Salz Ulrich , Klester Alfred Michael , Rheinberger Volker
Published: April 2003

Starting from 2,4,6‐triiodophenol, 2,3,5‐triiodobenzoic acid and 3,5‐bis(acetylamino)‐2,4,6‐triiodobenzoic acid, polymerizable methacrylates were synthesized and characterized by elemental analyses, IR, 1H‐NMR and 13C‐NMR spectroscopy. The iodine‐containing methacrylates show a different radical polymerization behaviour. 2,4,6‐Triiodophenyl methacrylate gives only oligomeric products in the presence of azoisobutyronitrile (AIBN), whereas 2‐methacryloyloxyethyl 2,3,5‐triiodobenzoate yields polymers. On the basis of mixtures of isomeric 1,3‐dimethacryloyloxy‐2‐ and 1,2‐dimethacryloyloxy‐3‐(2,3,5‐triiodobenzoyloxy)propane with usual crosslinking monomers, radiopaque materials were prepared.
Peroxid‐induzierte thioladdition an polybutadien
Authors: Gorski Ute , Klemm Elisabeth
Published: April 2003

Die radikalische Addition von 1‐Octanthiol oder 3‐(Trimethoxysily)‐1‐propanthiol an die 1,2‐ bzw. 1,4‐cis‐Doppelbindungen des Polybutadiens erfolgt redox‐induziert mit Dibenzoylperoxid (DBPO) bei Raumtemperatur ohne nachweisbare Nebenreaktionen. Trans‐konfigurierte Doppelbindungen reagieren unter gleichen Bedingungen nicht. Die Molmassenverteilung der Additionsprodukte ist ähnlich eng wie die des reinen Polybutadiens.
Synthesis and characterization of water‐soluble diazonium salts as contrast‐enhancement materials
Authors: Liu Jui‐Hsiang , Her Chi‐Fon , Liu Hung‐Tsai , Chung Yi‐Chang
Published: April 2003

Water soluble aromatic diazonium double salts, p‐diazodiphenylamine chloride zinc chloride (DZS‐1) and p‐diazoanisol chloride zinc chloride (DZS‐2), have been evaluated as photobleachable dyes for contrast enhancement lithography. After testing the bleaching characteristics, aqueous solutions of DZS‐1 and poly(vinyl alcohol) were used as a contrast enhancement material. Thermal stability, resist contrast, exposure parameters and other bleaching characteristics of the photobleachable membranes were investigated. A. commercial i‐line photoresist was used to evaluate the contrast ratio of the DZS‐1/PVA CEL layer. The contrast ratio obtained in this investigation is 1.67.
Antistatic modification of synthetic fibers by blend‐spinning of polymers containing zwitterionic antistatic modifiers and their copolymers
Authors: Sano Yoshiyuki , Saegusa Takeo , Kimura Yoshiharu
Published: April 2003

New poly(oxyethylene) derivatives (S‐betaine) having a zwitterionic structure of ammoniumsulfonate were prepared by the reaction of oxirane (EO) adducts of stearylamine with sodium chloromethanesulfonate and examined as blending antistatic modifiers for poly(ethylene terephthalate) (PET) and polyamide 6 (PA6) fibers. The blend PET and PA6 fibers containing 2.0 wt.‐% of S‐betaine exhibited a decreased half‐life time of leakage of electrostatic charge (t1/2) and a surface area resistivity (Rs) compared with those of the control PET and PA6 fibers. However, their antistatic properties were almost lost after repeated washings, because of the extraction of the agents. To increase the resistivity to washing, copolyester‐type modifiers comprising both S‐betaine and poly(ethylene glycol) were synthesized and incorporated into PET fibers. It was found that the antistatic properties of the blend PET fibers obtained can be retained even after dyeing and repeated washings.
Comparison of the coupling behaviour of diisocyanate and bisoxazolines in modification of liquid crystalline poly(ethylene terephthalate‐co‐oxybenzoate)s
Authors: Böhme Frank , Leistner Dirk , Baier Angela
Published: April 2003

Methylene‐4,4′‐diphenyldiisocyanate and two different bisoxazolines were used for coupling reactions in carboxy‐terminated liquid crystalline poly(ethylene terephthalate‐co‐oxybenzoate). In order to guarantee defined conditions, copolyesters with different carboxylic group concentrations were synthesized. The determination of the carboxylic group content is described.

The coupling behaviour of both types of chain extenders has been compared. It was evidenced that the bisoxazolines reacted significantly faster than the diisocyanate. A slight excess of bisoxazoline in the reaction mixture prevented thermomechanical degradation. Depending on the amount of coupling agent added, an oxazoline termination of the copolyester was observed. Additionally, probable crosslinking reactions and the thermal stability have been discussed.
Studies on the mechanical degradation of cellulose
Authors: Marx‐Figini Marianne , Figini Rubén Victor
Published: April 2003

The mechanical degradation by high‐speed stirring of cellulose in dilute n‐butanol suspensions was investigated on six different samples with degrees of polymerization (DP) between 300 and 7500. The degrees of polymerization were determined viscosimetrically in CuEn (copper ethylendiamine complex) at different times of mechanical action. The distributions of the DP were measured on the polymer‐analogous nitrates by size exclusion chromatography (HPSEC) in THF.

The investigations reveal that only high‐molecular‐weight cellulose undergoes degradation, whereas celluloses with a starting DP0 < 3000 remain undegraded. In the case of degradation the decrease of the DP with time is exponential, reaching a “limiting” DP (DP∞) of about 3200 which does not diminish further.

The narrowing with degradation time of the distributions of DP of the degraded samples allows to assume that the bonds splitting by the action of mechanical forces are the so‐called “weak links” present in high‐molecular‐weight cellulose. The course of the nonuniformity U with decreasing DP, could be confirmed by mathematical derivation of the relationship between U and the degree of degradation DP0/DPt, considering the scission of only “weak links”.
Graft polymerization of acrylonitrile onto chemically modified bleached jute fibers
Authors: Mohanty A. K. , Misra M.
Published: April 2003

The graft polymerization of acrylonitrile (AN) onto chemically modified bleached jute fibers has been studied using potassium peroxydisulfate‐ferrous ammonium sulfate redox initiating system. The effects of time of reaction, variation in concentration of monomer, peroxydisulfate, ferrous ammonium sulfate and sulfuric acid on graft yield have been studied. The effects of temperature, amount of jute fibers, some inorganic salts and organic solvents on graft yield have also been investigated. Grafted jute has been characterized by IR spectra. Grafting has improved the light fastness of jute dyed with Rhodamine B dye.
Lichtinduzierte Polymerisation, 4. Pfropfcopolymerisation von Methylmethacrylat auf Polyethylenoxid in Gegenwart von Chinolinderivaten
Authors: Braun Dietrich , Hettig‐Rupaner Claudia
Published: April 2003

Bei Verwendung von Polyethylenoxid (PEO) als polymerem Wasserstoffdonator werden bei der lichtinduzierten Polymerisation von Methylmethacrylat mit Chinolinderivaten Pfropfcopolymere erhalten. Die Abtrennung dieser Pfropfcopolymeren von dem ebenfalls entstehenden homopolymeren Polymethylmethacrylat (PMMA) und Resten an nicht umgesetztem PEO kann durch aufeinander folgende Extraktionen mit Ethyl‐acetat und Methanol erreicht werden. Damit ist eine Bestimmung von Pfropfausbeute, Pfropfungsgrad, Pfropferfolg und Pfropfhöhe möglich.
Zur Häurtung von Bisphenol‐A‐diglycidether mit Dicyandiamid in Gegenwart von Beschleuniger‐Addukten
Authors: Sanftenberg Heike , Fedtke Manfred
Published: April 2003

Einkomponentige Epoxidharzsysteme mit effizienten Reaktionsbeschleunigern müssen lagerstabil sein. Daher wurden Versuche unternommen, Beschleuniger auf Basis von tertiären Aminen mit modifizierten Phenolnovolaken zu blockieren. Das Ausmaß der Blockierung ist sowohl von der Basizität der Amine, die mit der beschleunigenden Wirkung korreliert, als auch von der Acidität und dem strukturellen Aufbau der modifizierten Phenole abhängig. Die Bewertung der Härtungseigenschaften erfolgte über Gelzeitbestimmungen und Viskositätsmessungen.
Comparison of the crack growth method and the crack stress whitening zone method for the fracture toughness determination of phenolphthalein poly(ether ketone)
Authors: Han Yanchun , Yang Yuming , Li Binyao , Feng Zhiliu
Published: April 2003

Fracture toughness values of phenolphthalein poly(ether ketone) (PEK‐C) at 190°C were determined by two different methods, i.e. the conventional crack growth method and the crack stress whitening zone method, which show consistent results. This indicates that the crack stress whitening zone method can be used to determine the crack initiation of some polymers for which the blunting line concept is unsuitable.
Thermodynamic studies on some interpolymer interactions and stability of polycomplexes
Authors: Chatterjee S. K. , Nigam Shalini , Chhabra Mamta
Published: April 2003

Stability constant and related thermodynamic parameters (ΔH° and ΔS°) of a multicomponent intermacromolecular complex consisting of poly(acrylic acid‐coacrylamide), poly(methacrylic acid‐co‐acrylamide) and poly(N‐vinylpyrrolidone) have been determined using known methods. A distinct stepwise disintegration of the complex at different temperatures has been observed, and this could be correlated with the stability constant and thermodynamic parameters calculated at various temperatures.
Synthesis and characterization of cellulose/N‐methylolacrylamide/glycidyl methacrylate/methacrylic acid cation exchange resins
Authors: Abo‐Shosha M. H. , Ibrahim N. A.
Published: April 2003

New cation exchange resins based on cellulose/N‐methylolacrylamide (NMA)/glycidyl methacrylate (GMA)/methacrylic acid (MA) were prepared by polymerizing highly concentrated mixtures of NMA/GMA/MA in the presence of cellulose using a sodium persulfate/sodium sulfite redox system under different conditions including the concentrations of the redox system components, NMA and GMA as well as the polymerization temperature. Polymerization conditions were selected to synthesize three resins of different carboxy and nitrogen contents. Potentiometric titration showed that these resins were weakly basic cation exchangers of different strength. Water solubility and swellability as well as durability of these resins were examined.
Diffusion characteristics of vinyl chloride from PVC in slurry phase
Authors: Erbay Erol , Bilgiç Tülin
Published: April 2003

The porous nature of poly(vinyl chloride) (PVC) brings along the problem of residual vinyl chloride in the final product. Stripping techniques are developed to eliminate vinyl chloride to the desired levels. After a certain extent of monomer removal, the stripping rate of vinyl chloride is limited by diffusion. Therefore, the diffusion characteristics of vinyl chloride from PVC slurries was investigated. Stripping was carried out at the boiling point of water where the generated steam was used as a carrier substance. The boiling point of water was changed by elevating the pressures. The dependence of diffusion on concentration is put forward and the activation energy of diffusion was calculated.
Ein neues niedrigviskoses nichtreaktives verdünnungsmittel für epoxidharze
Authors: Večeřa Miroslav , Mleziva Josef
Published: April 2003

Für manche Anwendungsgebiete liegt die Viskosität von Epoxidharzen zu hoch. Sie läßt sich jedoch durch den Zusatz von verschiedenen Verdünnern herabsetzen. Der Einfluß von 1,1‐Diphenylethan (DPE) auf die Viskosität und Reaktivität entsprechender Harzmischungen sowie auf die Eigenschaften gehärteter Proben wurde untersucht und mit anderen Verdünnungsmitteln verglichen. Epoxidsysteme mit DPE zeigten eine wirksame Erniedrigung der Viskosität, hohe chemische Beständigkeit und weitgehend unveränderte mechanische, thermische und elektrische Eigenschaften.
Interpenetrating polymer networks derived from epoxide‐amine adducts in either polymer network
Authors: Klee Joachim E. , Leube Walter , Mülhaupt Rolf
Published: April 2003

A new type of interpenetrating polymer network was synthesized via photoinitiated free‐radical polymerization of α,ω‐methacryloyl terminated macromonomers prepared from epoxide‐amine‐adducts, followed by thermal addition polymerization of bisphenol‐A diglycidyl ether and 4,4′‐diaminodiphenylsulfone or 3(4),8(9)‐bis(aminomethyl)tricyclo[5.2.1.0.2,6]decane. The interpenetrating polymer networks are optically transparent and show only one glass transition temperature ranging from ‐10 to 130°C, as a function of the macromonomer/addition polymer mixing ratio. The presence of a single phase was confirmed by scanning electron microscopy (SEM).
Purification of soybean trypsin inhibitors by means of chromatographic methods
Authors: Bryjak Marek , Bryjak Jolanta
Published: April 2003

The paper presents comparative studies on chromatographic purification of soybean trypsin inhibitors (STI) applying various polymer matrices. Two types of copolymers were tested: a copolymer of butyl acrylate with ethylene glycol dimethacrylate, and a terpolymer of acrylonitrile and butyl acrylate crosslinked with divinylbenzene. The investigations revealed that a similar purification extent is achieved in affinity chromatography with trypsin attached to both copolymers and in ion exchange chromatography when the matrices are aminated with ethylene diamine. The purification phenomenon was not so high for both unmodified matrices, and quite negligible for matrices hydrophilized by end‐capping with tris(hydroxymethyl)aminomethane.
Polyurethanes and polyurethane cationomers bearing nitroaromatic groups and their photobehavior
Authors: Buruianǎ T. , Airinei A. , Buruianǎ E. C. , Robilǎ G.
Published: April 2003

Elastomer‐type polyether urethanes and polyether urethane cationomers with nitroaromatic groups were prepared and the effect of UV irradiation on their characteristics was evaluated comparatively with a model compound. The photobehavior by UV irradiation with a high‐pressure Hg lamp was studied in solution, following the change of absorption bands characteristic for nitro structures as a function of irradiation time. UV irradiation causes diminution of the intensity of characteristic UV absorption bands and a decrease of molecular weight.
Synthesis and copolymerization of vinyl cobalt(III)porphyrins
Authors: Anaç Olcay , Sezer Özkan , Daut Ayşe
Published: April 2003

2‐Diazopropane and 1‐diazo‐1‐phenylethane were reacted with meso‐tetraphenyl‐porphin cobalt(III) bromide (Co(III)TPPBr), and the resulting vinyl Co(III)TPP derivatives were copolymerized with MMA to give alkyl Co(III)TPP complexes, covalently bound to macromolecules.
Poly(esterbenzoxazinone)s derived from 4,4′‐diaminodiphenylmethane‐3,3′‐dicarboxylic acid
Authors: Hamciuc Corneliu , Bruma Maria , Popescu Florin , Gaspar Mariana
Published: April 2003

Poly(esterbenzoxazinone)s were prepared in two successive steps from 4,4′‐diaminodiphenylmethane‐3,3′‐dicarboxylic acid and aromatic diacid dichlorides which contained preformed ester groups, via polyamic acids as intermediates. The poly(esterbenzoxazinone)s are soluble only in concentrated sulfuric acid. They thermally decompose in a single step between 400 and 500°C.
Poly(phenylquinoxaline‐imide‐amide)s containing perfluoroisopropylidene units
Authors: Hamciuc Elena , Bruma Maria , Mercer Frank W. , Belomoina Nataliya M. , Simionescu Cristofor I.
Published: April 2003

Poly(phenylquinoxaline‐imide‐amide)s have been synthesized by solution polycondensation of aromatic diamines containing preformed phenylquinoxaline units with diacid dichlorides incorporating preformed imide rings and perfluoroisopropylidene units. These polymers show high thermal stability; they decompose above 400°C and have glass transition temperatures in the 225–290°C range. Comparison of these compounds with related heterocyclic polymers leads to the conclusion that the decomposition of the former ones begins with the destruction of amide groups. Films prepared from polymer solutions showed good electrical insulating properties, comparable to those of a standard film (Film H). The highest quality of these poly(phenylquinoxaline‐imide‐amide)s is their remarkable solubility in polar aprotic solvents, which is very important for practical applications.
Removal of polymerization inhibitors from styrene based on adsorption
Authors: Matsas G. M. , Faliagas A. C. , Simitzis J. C.
Published: April 2003

Use of adsorptive materials for the removal of polymerization inhibitors from styrene is studied. The adsorptive materials selected cover a wide range of properties and structure. The most important inhibitors that are used in laboratory and industrial scale were studied. The effectiveness of the adsorptive materials was assessed by determining the inhibitor uptake at equilibrium. It was found that activated carbons are the most effective adsorbents for the removal of inhibitors from styrene and that the factor most affecting adsorption is the polarity of the adsorbent and the adsorbate. The possible importance of removing the inhibitor before industrial‐scale polymerization is demonstrated.
Kinetic study and crosslink density in styrenebutadiene rubber compounds filled with boron‐amine‐modified silica
Authors: Elvira M. Rosario , Macías Antonio , Oteo José Luis , Royo Joaquín , Rubio Juan
Published: April 2003

Vulcanization kinetics and crosslink density of styrene‐butadiene rubber compounds have been studied with two vulcanization systems, an efficient (EV) and a conventional (CV) one. A surface‐modified silica with boron‐amine groups (SiOB(NH2)2) was employed as filler. Untreated and modified silica with two silanes (γ‐mercaptopropyl‐trimethoxysilane and γ‐aminopropyl‐triethoxysilane) have been used as reference.

The best kinetic parameters, such as highest vulcanization rate, longest induction time and lowest activation energy, were obtained for the compound with boronaminated silica. The crosslink density, achieved with this compound, is similar to that with silane‐modified silica, probably because of the better surface distribution of boron‐amine groups on the silica. These facts lead to important technological improvements: better processing safety, faster vulcanization rate and improved physical properties.
Hyper‐crosslinked sorbents for hemoperfusion
Authors: Kolarz Bozena N. , Jermakowicz‐Bartkowiak Dorota
Published: April 2003

Pore structure changes of swelling sorbents, which were obtained from styrene and divinylbenzene (DVB) by additional crosslinking with α,α′‐dichloro‐p‐xylene in the presence of tin chloride catalyst and in dichloroethane solution, were examined. It was found that the amount of dichloroxylene influences the swelling decrease and the increase of sorption ability of sorbents for chemical compounds with low molecular weight. Hemocompatibility was imparted to the sorbent and it was useful for hemoperfusion when a small amount of sulfonyl groups (about 0.2 mmol/g) had been introduced.
Epoxidation of poly(cis‐1,4‐isoprene) microgels
Authors: Hallensleben Manfred L. , Schmidt Henning Rüdiger , Schuster Robert H.
Published: April 2003

Poly(cis‐1,4‐isoprene) microgels and crosslinked natural rubber latex as well as noncrosslinked poly(cis‐1,4‐isoprene) were epoxidized by means of 3‐chloroperbenzoic acid and H2O2, respectively.

Epoxidation of the latex leads to homogeneous functionalized polymer particles whereas the feature of the microgels which were obtained from the reaction in organic phase is a shell‐like profile of epoxidation. By variation the time of exposure of the microgels to the organic solvent prior to the epoxidation reaction, different profiles of epoxidation in the microspheres could be achieved.
Synthesis and properties of a cellulose exchanger with the crown ether diaminodibenzo‐17‐crown‐5 as anchor group
Authors: Beck E. W. , Lieser K. H.
Published: April 2003

A new cellulose exchanger was synthesized from “o‐aminophenolcellulose” by diazotation and coupling with diaminodibenzo‐17‐crown‐5. The distribution coefficients for Ca2+, Sr2+, Ba2+, Na+ and K+ were determined in water/methanol mixtures as a function of the water content. Separation of Ca2+, Na+ and K+ and fractionation of the calcium isotopes 48Ca and 40Ca were investigated. The enrichment factor ε = 4.9 · 10−3 for 48Ca2+ is appreciably higher than that found for cation exchange resins with SO3H groups, but lower than that reported for certain cryptands.
Adhesion promotion for epoxy resin/copper and polyimide/copper joints by a two‐component coupling system of poly(4‐vinylimidazole) and cystamine
Authors: Dai Q. , Lu Y.
Published: April 2003

A two‐component coupling agent layer on copper, produced by immersion of copper in poly(4‐vinylimidazole) solution and then in cystamine solution, showed better anticorrosive performance and higher adhesive strength for epoxy resin and polyimide than each single component even at high temperature.
The izod impact fracture behaviour of phenolphthalein poly(ether ketone)
Authors: Han Yanchun , Li Binyao , Yang Yuming , Feng Zhiliu , Wang Xuhui
Published: April 2003

The Izod impact fracture behaviour of notched specimens of phenolphthalein poly(ether ketone) (PEK‐C) has been studied over a temperature range from room temperature to 240°C by using an instrumented impact tester. The temperature dependence of the maximum load, total impact energy, initiation energy, propagation energy, ductility index (DI) and the relationships between these parameters and the relaxation processes have been investigated.
Cross‐linking reactions on polyamides by bis‐ and tris(maleimide)s
Authors: Kossmehl Gerhard , Nagel Hans‐Ingo , Pahl Andreas
Published: April 2003

12 bis‐ and tris(maleimide)s were synthesized and characterized and their reactions with polyamides in the melt were examined. It was found that the double bonds of the maleimides react with terminal amino groups of the polyamides to form elastomeric networks. The chemical and physical properties of these elastomers were examined. Mixtures of bis‐ and tris(maleimide)s with amino‐terminated polyamides can be applied as hot melt adhesives with high tensile and shear strength, with high thermal stability and high chemical resistance.
Synthesis and characterization of liquid‐crystalline polyesters based on biphenyl‐4,4′‐diol
Authors: Haridas K. R. , Radhakrishnan Ganga
Published: April 2003

The syntheses of liquid‐crystalline polyesters of biphenyl‐4,4′‐diol and 1,4‐butanediol with adipic acid were carried out by varying the mole ratios of the two diols, keeping the total mole ratio of diacid to diols constant. Adipic acid was first converted into adipoyl dichloride, which was then reacted with the diol(s) in dimethylformamide. The resultant polyesters were characterized by means of 1H NMR and FT‐IR spectroscopy, elemental analysis, thermogravimetric analysis and gel permeation chromatography. The liquid‐crystalline behavior of the polyesters was studied by differential scanning calorimetry and hot‐stage polarization microscopy.
Differential scanning calorimetry and thermal gravimetric analysis of lignin blended with triglycidyl isocyanurate
Authors: De Chirico Aurelio , Audisio Guido , Provasoli Francesco , Schieroni Alberto Giacometti , Focher Bonaventura , Grossi Barbara
Published: April 2003

The thermal behaviour of lignin blended with triglycidyl isocyanurate (TGI) was investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) over a range of lignin contents from 0 to 85 wt.‐%.

DSC thermograms of lignin/TGI blends show two exothermic peaks at about 250 and 355°C while TG analysis in nitrogen bears evidence of a single loss of weight at about 360°C. The first exotherm is suggested to correspond to the heat of bulk reaction between epoxy groups of TGI with phenolic hydroxy groups of lignin, and the second one to the heat of char formation of lignin. TG and infrared analyses suport this conclusion.
Hydrogels based on 3‐O‐acryloyl‐1,2;5,6‐di‐O‐iso‐propylidene‐α‐D(‐)‐glucofuranose
Authors: Koßmehl Gerhard , Volkheimer Jürgen , Schäfer Horst
Published: April 2003

Hydrogels (crosslinked polymers with a defined water content) based on 3‐O‐acryloyl‐1,2;5,6‐di‐O‐isopropylidene‐α‐D(‐)‐glucofuranose and 2‐hydroxyethyl methacrylate were prepared by radical copolymerization and acid hydrolysis of the isopropylidene protecting groups. The obtained hydrogel samples were examined for linear expansion to hydration, weight‐percent hydration, refractive index, extractables, percent transmission of visible light and oxygen permeability as typical properties for contact lens materials.
Poly(diaryl diazosulfide)s — synthesis and photolysis. Photopolymers, diazosulfides, interfacial polycondensation, photolysis
Authors: Nuyken O. , Lang A. , Staško A. , Wokaun A.
Published: April 2003

Poly(diaryl diazosulfide)s were synthesized from aromatic bisdiazonium ions and benzene‐1,3‐dithiol via interfacial polycondensation. Number‐average molecular weights Mn in the range of 3400 to 11700 were determined by gel permeation chromatography (GPC).

The new polymer class is distinguished by high photosensitivity and low thermostability. First order kinetics during photolysis of nearly all polymers and model compounds under investigation was observed by means of UV spectroscopy. Polymer degradation upon irradiation was verified by GPC measurements. Thermal decay was followed by differential scanning calorimetry (DSC).