bluuebunny/crossref_metadata_2025 huggingface dataset:
Solvolyse‐ und umesterungsreaktionen bei der vernetzung von alkyd‐ und acrylatharzen mit melaminvernetzern
Authors: Pohl Horand Uwe , Traenckner Hans‐Joachim
Published: April 2003

Ein Acrylat‐ und unterschiedlich aufgebaute Alkydharze werden mit Melaminharz vernetzt. In Abhängigkeit von der Zeit werden bei einer Einbrenntemperatur von 130°C anwendungstechnische Eigenschaften, Quellgrade, relative IR‐Extinktionen und flüchtige Komponenten im Abgas quantitativ bestimmt und daraus der iso‐Butanolumsatz für die Fremd‐ und Selbstvernetzung berechnet. Zusätzlich zu den Vernetzungsreaktionen tritt beim Alkydharz eine Solvolyse‐ und beim Acrylatharz eine Umesterungsreaktion durch Reaktion der Estergruppen mit dem aus dem Melaminharz abgespaltenen iso‐Butanol auf. Die Solvolyse wird durch Untersuchung von spezifischen Spaltprodukten mittels IR, GPC und GC/MS abgesichert. Ein Reaktionsweg zum Ablauf der Solvolyse wird vorgeschlagen.
Morphologie und technologische eigenschaften von polycarbonat/ABS‐mischungen
Authors: Weber Gunter , Schoeps Jochen
Published: April 2003

PC/ABS‐Mischungen stellen ein ternäres Mehrkomponentensystem aus Bisphenol A‐PC, SAN und einem SAN gepfropften Polybutadienkautschuk dar. Die Morphologie der PC/ABS‐Mischungen wurde in Abhängigkeit vom PC:SAN‐Mengenverhältnis und von der Schmelzentemperatur bei der Verarbeitung mit Hilfe der Elektronenmikroskopie untersucht. Der Verteilungszustand der Elastomerkomponente und die partielle Mischbarkeit der Thermoplastkomponenten beeinflussen die technologischen Eigenschaften der PC/ABS‐Mischungen. Die Wärmeformbeständigkeit hängt von der Zusammensetzung der Mischungen ab und nimmt mit steigendem PC‐Anteil zu. Für ein hohes Kerbschlagzähigkeitsniveau sind eine mit PC angereicherte SAN‐Mischphase sowie eine gleichmäßige Dispergierung der Pfropfkautschukpartikel notwendig. Die Mischphasenbildung hängt von der Zusammensetzung und der Verarbeitungstemperatur der Mischungen ab. Steigende Verarbeitungstemperaturen führen zu einer PC/SAN‐Entmischung. Der Einfluß der Verarbeitungstemperatur auf die Zähigkeit ist bei denjenigen PC/ABS‐Mischungen gering, in denen die PC‐Komponente eindeutig die Matrix darstellt.
Simulated lightning tests on baymetex C protected graphite‐epoxy laminates
Authors: Ebneth Harold
Published: April 2003

Highly nickel‐coated graphite fabrics will provide adequate composite structure protection from zone 1 A and 2 A lightning strikes, as simulated lightning tests showed. The coating level used will depend on the damage tolerance and structural make‐up of the part to be protected. Mechanical tests show that the nickel‐coated graphite fabric has a positive effect in compression of the panels. The compressive strength is about 25% better than the panel with a non‐metallized fabric ply.
Effect of copolymers modifying PVC on its physical and mechanical properties and its UV‐radiation resistance. v. photooxidation of PVC in films containing mma/ma, vc/vac, mbs or abs
Authors: Kamińska A. , Kaczmarek H.
Published: April 2003

Photooxidation of PVC caused by 253.7 nm wavelength UV‐radiation in pure and modified PVC films has been investigated. The IR spectra analysis pointed out that the presence of modifying copolymers ABS, MBS, MMA/MA or VC/VAC in PVC films causes the increase of the efficiency of photooxidative processes which lead to the formation of hydroxy groups. ABS and MBS cause also the increase of the efficiency of these reactions which lead to the formation of carbonyl groups, while MMA/MA hampers these processes. VC/VAC has no definite influence on their course. With the increase of the copolymer content (1 – 10%) in PVC films, an increase of their influence on photooxidation was observed.
Einfluß von imidhydantoinpolymeren auf den reststrom modifizierter metalloxid‐halbleitertransistoren
Authors: Yokoyama Takashi , Kinjo Noriyuki , Wakashima Yoshiaki
Published: April 2003

Copolymere, die Hydantoin‐ und Imidgruppen enthielten, wurden hergestellt und auf die Oberfläche von MOSFET (Metalloxid‐Halbleitereffekt‐Transistor) aufgetragen, um den Einfluß des Copolymeren auf Halbleiteranlagen darzustellen. Der Einfluß der Polymeren auf den Reststrom der Anordnung wurde hinsichtlich des Gehalts an Verunreinigungen, der Erweichungstemperatur, der Zusammensetzung etc. untersucht. Es wurde beobachtet, daß der Reststrom bei Polymeren, die nur Imidgruppen enthielten, mit steigender Erweichungstemperatur sowie bei den Copolymeren mit steigendem Hydantoingruppengehalt ansteigt.
Temperature dependence of surface tension of poly(vinyl chloride)
Authors: Pigłowski Jacek
Published: April 2003

The thermal dependence of the surface tension of poly(vinyl chloride) (PVC) containing typical additives was determined below the glass transition temperature. From the results, the surface tension of PVC melts was evaluated and possible differences between the real value and estimate are discussed. It is suggested that the surface tension does not affect the wall‐slipping properties of PVC melts.
Processibility of starch‐graft‐polyacrylonitrile copolymers
Authors: Patel A. R. , Patel M. R. , Patel K. C. , Patel R. D.
Published: April 2003

Starch‐graft‐polyacrylonitrile (S‐g‐PAN) has been prepared from granular starch of common millet (Penicum miliaceum, L) and its processibility has been examined using the Brabender Plasticorder. Glycerine, a known plasticizer for starch does not work as plasticizer for S‐g‐PAN. A mixture of 1 : 1 starch : S‐g‐PAN and 25% glycerine can be processed and a film can be extruded. The strength of the film was less than that of pure starch. The film prepared from the mixed graft copolymer of S‐g‐PAN and S‐g‐PMA had high tensile strength. The data on flow activation energy obtained from the torque‐rheometer are also reported.
Zur variierung des diethylenglykolgehalts von PETP bei dessen synthese aus dimethylterephthalat und ethylenglykol
Authors: Mössner Wolfgang , Vollmert Bruno
Published: April 2003

Die Kontrolle über den Diethylenglykol (DEG)‐Gehalt ist sowohl bei der großtechnischen als auch bei der Labor‐Synthese von Polyethylenterephthalat (PETP) von Bedeutung. Im Rahmen der Reaktionsführung wurde die Synthese in drei Abschnitte unterteilt und die Abhängigkeit des DEG‐Gehalts von deren Dauer untersucht. Es wurden Präparate mit DEG‐Gehalten zwischen 2,6 und 10,4 mol‐% dargestellt. Die Ergebnisse werden in Zusammenhang mit den für die DEG‐Bildung in der Literatur vorgeschlagenen Reaktionen diskutiert.
Reactive polymers, 53. separation of platinum metals on the copolymer of glycidyl methacrylate—ethylene dimethacrylate modified with ethylenediamine
Authors: Švec F. , Kálalová E. , Kálal J.
Published: April 2003

A macroporous copolymer of glycidyl methacrylate — ethylene dimethacrylate, modified with ethylenediamine, is able to bind only ionic particles (PdCl4)2− from strongly acid solutions containing palladium‐ and copper salts. After washing the sorbent, the metal can be quantitatively desorbed with a concentrated hydrochloric acid solution. The procedure can be utilized for the regeneration of inactive palladium catalysts in industry. Moreover, using the same sorbent and the same principles, it is possible to separate a mixture of platinum metals in acid solutions as (RhCl6)3−, (PtCl6)2−, and (PdCl4)2− by eluting them with a solution of hydrochloric or nitric acid with increasing concentration, the efficiency being 100%.
The effectiveness of radiation as a function of angle of incidence on the surface of specimen
Authors: Trubiroha Peter
Published: April 2003

The effectiveness of radiation as a function of angle of incidence on polymer films has been calculated and examined by exposure tests. Theoretical considerations for different coefficients of transmission and different indices of refraction show that the radiation with normal incidence is the most effective. However, it is concluded that a photoreceptor which is cosine corrected for a solid angle of 2π sr does undervalue radiation with oblique incidence. The exposure tests confirm these theoretical results but also show an additional unexplained peak of effectiveness for radiation with angles of incidence of about 20°.
Formation and role of ester groups in the thermal stabilization of PVC
Authors: Lévai Gy. , Ocskay Gy. , Nyitrai Zs.
Published: April 2003

The stabilizing action of calcium‐zinc stearate and pentaerythritol systems in PVC cannot only be ascribed to the ability of binding hydrogen chloride, but also to the replacement of labile chlorine atoms of the PVC chain by stearate groups. In this way the growth of the polyene sequences is inhibited. On the other hand sufficient amounts of pentaerythritol and calcium stearate effectively inhibit the detrimental catalytic action of zinc chloride formed.

A mathematical equation was deduced based on this mechanism, which satisfactorily describes the correlations among the induction period, the stabilizer concentration and the ester groups formed during thermal ageing.
Variations in some of the properties of PVC sheets during natural and artificial ageing
Authors: Gantcheva T. , Marinova A. , Genova P.
Published: April 2003

We have investigated variations in mechanical properties such as tensile strength and specific elongation as well as the variations in electrical properties such as the dielectric loss angle, permitivity and surface resistivity of PVC sheets of various thicknesses exposed during 24 months in weathering and up to 400 h in a Xenotest‐1200. Using the test data, an evaluation of the influence of the scale coefficient during ageing was achieved. The test data showed that lower variations in the investigated properties were seen in the case of the thicker sheets.

After various ageing periods a correlation between the surface roughness, mechanical and electrical properties could be seen. More important variations could be seen during the ageing period ranging from 50 h to 6 months.

Speculations were made about the reasons causing the variations observed in the properties of PVC sheets during ageing.
Diffusion und alterung
Authors: Wurster T. , Franck A. , Eyerer P.
Published: April 2003

Die Rückdiffusion eines Testmediums (hier: Methan) nach unvollständiger Sorption erfordert ‐ im Vergleich zur Messung der Permeation ‐ eine wesentlich kürzere Priifzeit. Sie kann Veranderungen vorzugsweise in den oberflächennahen Bereichen anzeigen. Bei Polyethylen (PE) verringerte sich die Rückdiffusion nach Bewitterung. Dieser Effekt wird auf erhöhte Kristallinität zurückgeführt; denn bei der Alterung erhöht sich die dafür signifikante Dichte. Auch wenn dieser Kunststoff mit energiereichen Strahlen behandelt wird, vermindert sich die Rückdiffusion. Hier überlagern sich Wirkungen der Alterung (s.o.) und der Vernetzung. Bei allen Untersuchungen wurde die Trägergasmethode mit der Pneumatik und dem Detektor (FID) eines Gaschromatographen angewendet. Daraus ergeben sich empfindliche, spezifische Messungen bei einfachem apparativem Aufbau und die Möglichkeit zur zerstörungsfreien Kunststoffprüfung. Die Details der Meßzelle werden erläutert.
UV‐stabilization of ABS with sterically hindered amines. Results of an ESR‐study
Authors: Loelinger Hans , Gilg Bernard
Published: April 2003

ABS polymers have been limited in outdoor applications due to their poor weathering characteristics. On exposure to light the polybutadiene phase on the exposed side of the sample is photooxidized resulting in loss of impact strength and discoloration. We have found that the combination of a hindered amine light stabilizer (HALS) and a benzotriazole UV absorber dramatically outperforms either component alone. This L‐S blend provides a level of impact strength retention many times that of unstabilized ABS and also protects the polymer from discoloration. The present study describes the results of an E.S.R. investigation intented to explain the synergistic effect between HALS and benzotriazole UV absorber. Since the photostabilizing effect of HALS is associated with the reaction of the nitroxide radicals formed upon irradiation, the concentration of these radicals, as a function of light exposure time, was determined. Two types of . radicals were found. First, a broad . signal with an anisotropic hyperfine nitrogen interaction, was detected. This signal is characteristic of the . radicals localized in the SAN matrix. Second, a narrow . signal with an isotropic hyperfine nitrogen interaction, corresponding to nitroxide radicals localized in the polybutadiene phase, was also found. The . concentration in the SAN matrix and in the polybutadiene phase could, therefore, be determined separetely, as a function of light exposure time.

In both phases, a maximum of . is observed after approximately 50 hours exposures. However, the maximum . concentration is ten times higher in the polybutadiene phase of ABS stabilized with a blend 0,5% HALS/0,5% UV Absorber than in the BR phase of an ABS containing only 0,5% HALS. On the other hand, there is only a slight increase of . radicals in the SAN phase when 0,5% UV absorber is added on top of 0,5% HALS. A comparable effect is observed in the polybutadiene phase when 8% titanium dioxide is added to an ABS stabilized with 0,5% HALS.

Since the polybutadiene phase is the most sensitive toward photooxidative degradation, these results rationalize the observed synergistic effect of the combinations of HALS/Benzotriazole UV absorber.
Aspects of the stabilization mechanisms of phenolic antioxidants in polyolefins
Authors: Gugumus Francois
Published: April 2003

Kinetic factors as well as physical parameters such as volatility are often considered in explaining the different antioxidant efficiencies of monophenols and polyphenols. The objective of this work is to examine these factors in comparing the behavior of different sterically hindered phenols in processing stabilization and long term heat aging. For this purpose, mainly data relative to phenols of the 3,5‐di‐tert.butyl‐4‐hydroxyphenyl propionate type in polypropylene are examined. It is found that the stabilizing efficiency of phenolic antioxidants of the propionate type in processing of polypropylene is a function of the concentration of phenolic groups, regardless of the number of phenolic groups attached to a single molecule.

To explain the superiority of the polyphenols over the monophenol in long term heat aging, a reaction model involving chemical as well as physical aspects is proposed.

The kinetics of stabilization are applied to the interpretation of oven aging data. For this purpose, two concepts are considered, the well‐known critical antioxidant concentration and another one, the critical oxidation level. It is found that the results are best accounted for by the latter.
Study of photooxidative processes during the induction period
Authors: Tüdós Ferenc , Kelen Tibor , Bálint Gabriella
Published: April 2003

Various processes taking place during the induction period of the change of a property accepted as a measure of the photostability, were investigated in polypropylene, PVC and EPDM rubber.

In polypropylene containing stabilizer, changes in stabilizer concentration and in molecular mass could be detected before the end of the induction period of the carbonyl formation. Kinetics and other characteristics of these changes depend on the type and amount of the stabilizers applied.

Hydrogen chloride evolution in UV‐irradiated PVC is accompanied also by carbonyl formation. In the presence of a metal soap stabilizer, carbonyl formation can be detected even during the induction period of hydrogen chloride evolution.

In case of EPOM rubber compounds, the study of thermal stability gives information about the changes in the first period of photodegradation when mechanical stability still remains unchanged.
Wirksamkeit sterisch gehinderter amine bei anspruchsvollen applikationen von polypropylen
Authors: Pavol Čaučik , Marta Považancová , Júalius Durmis , Milan Karvaš
Published: April 2003

The influence of some types of antioxidants on the efficiency of low molecular hindered amine light stabilizers (HALS) has been investigated in a comparison with the behaving of high molecular HALS. Most of the antioxidants used exhibit favourable influence. Convenience of both low and high molecular HALS in compounds depends on the character of the stabilised product and the technological conditions for its production.
Artificial ageing of low density polyethylene film containing chemically bound UV ‐ stabilizer
Authors: Misǎk M. Mlinac , Ranogajec F. , Fleš D. , Jovanović D.
Published: April 2003

This paper deals with photostabilization of low density polyethylene films (LDPE) grafted with the UV‐stabilizer 2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxy‐propoxy) benzophenone (HMB). The influence of grafting yield and the other grafting conditions upon photostabilization efficiency of LDPE films were then studied. The chemically bound monomer (HMB) was localized mainly near the surface of an LDPE film.

The grafted LDPE film was exposed to an ultraviolet radiation source, and the degree of oxidation and other photooxidative changes were determined by transmission IR and ATR IR spectroscopy. Experimental results show that radiation grafting of a UV‐stabilizer upon LDPE films is an efficient photostabilization method.
On the mechanical ageing of polymers
Authors: Vassileva S. , Natov M.
Published: April 2003

The breaking of the polymers under operational conditions is a result of the simultaneous action of oxygen, humidity, and mechanical stresses. The mechanical ageing of a longtime life of the model polymer materials was investigated in function of the applied static stress. It was established that the time required for the breaking of the model polymers varies regularly as a function of the magnitude of the applied force. Expressed graphically, this dependence is S‐shaped. The action of the mechanical stress alters the tension of the valence bonds, hence also the vibration frequency, and consequently the energy term in the Arrhenius equation. The assumption that mechanical stress alters only the activation energy of the breaking processes does not lead to a dependence between longtime life and stress which corresponds to actual observations.
Transport phenomena in the system ion‐exchange membranes/sulfuric acid solutions. Non‐equilibrium thermodynamic approach
Authors: Ceynowa Józef
Published: April 2003

Transport processes in the systems sulfonic acid membranes (NAFION‐120 or MRF‐26)/sulfuric acid solutions are discussed applying non‐equilibrium thermodynamic approach.

For this purpose the phenomenological resistance and friction as well as coupling coefficients were calculated. The coefficients were extended to all the components, i.e. hydrogen ions, sulfuric acid anions, water, and polymer network.

As the most important feature determining transport phenomena, the interaction between anions and the polymer network, having a maximum at the same relative concentration of sorbed acid to that of fixed charges in both membranes, was recognized.

The second factor is the specificity of hydrogen ions, resulting in a small interaction of those ions with the polymer network, as well as essential coupling of large hydrogen ions and water streams.
Influence of different water soluble polymers and poly(ethylene oxide)/ionene complexes on sedimentation of suspended particles and filter cake resistance
Authors: Bortel Edgar , Stysło Maria
Published: April 2003

The objective of the investigations was to compare flocculating properties of three different water soluble resins: poly(ethylene oxide), PEO, with molecular mass Mv = 3.94 · 106 g/mol; polyacrylamide, PAAm, Mv = 2.1 · 106 g/mol, and tetramethyl‐2,6‐ionene bromide, ionene, Mw = 1500 g/mol. In each case the Healy‐La Mer theory proved to be valid due to the appearence of maximum points on both the subsidence w vs. polymer concentration c, and acceleration aQ vs. c curves. The ratios of these maximum values determined on aluminium silicate suspensions are as follows:

Contrary to aluminium silicate suspension dispersed TiO2 particles are not flocculated by PEO, although zeta potentials in both cases were found to be close up to each other, i.e. −16.68 and −16.38 mV, respectively. Nonetheless, the investigations carried out revealed the possibility to convert the high molecular weight PEO from being a stabilizer of the TiO2 suspension into a flocculant by means of interpolymer complexation with the ionene, i.e. a polyammonium salt. The ratios of maximum values related to complexes prepared with different unit mole ratios (u.m.r., values indicated in parantheses) are as follows:

and

Values at u.m.r. = 0 refer to uncomplexed PEO and at u.m.r. = ∞ to the uncomplexed ionene, respectively.
Effect of addition of sepiolite on the mechanical properties of glass fiber reinforced polypropylene
Authors: Acosta J. L. , Morales E. , Ojeda M. C. , Linares A.
Published: April 2003

Short glass fiber reinforced polypropylene is one of the composites with the widest range of applications in the plastics industry. The partial replacement of the glass fibers by sepiolite, brings forth a hybrid composite with better mechanical properties and, as a result, enhanced compatibility and better interfacial adhesion as a consequence of the surface properties of the sepiolite. The results obtained are also interesting from a practical point of view, as they allow for considerable reductions in the costs of the formulation.
Corrections des réponses des détecteurs placés à la sortie d'un CPG
Authors: Benchabane Mahmed
Published: April 2003

Le chromatographe par perméation de gel (CPG) muni du seul détecteur réfractomètrique est insuffisant pour la caractérisation des polymères. Une combinaison de trois détecteurs, un réfractomètre, un viscosimètre et un spectrophotomètre infrarouge, est nécessaire pour analyser un polymère présentant une hétérogénéité chimique et moléculaire. Malheureusement l'utilisation des réponses brutes de ces détecteurs conduit à des résultats erronés. Dans ce travail les différentes sources d'erreurs sont identifiées et puis corrigées.
Chemorheology of carboxyl terminated polybutadienes with different antioxidants
Authors: Schwartz Anders
Published: April 2003

An investigation of chemorheological properties has been made on two types of carboxyl terminated polybutadienes (CTPB), HC‐434, and Butarez CTL. Curing of CTPB has been done with an imine, MAPO. Films have been cast and cured and then cut into strips. Some of these strips have been extracted with acetone and then two types of antioxidants were added, phenyl‐beta‐naphthylamine (PBN) and methylenebis‐(4‐methyl‐6‐tert‐butyl)‐phenol (BKF). Continuous stress relaxation measurements and intermittent measurements of stress have been made at a temperature of 110°C. The results show that Butarez CTL seems to have better ageing properties than HC‐434 even when the same type of antioxidant has been added to the polymers. The most effective antioxidant of the two tested is BKF, which balances scission reactions and crosslinking reactions in a better way than PBN.
Studies on syntheses and permeabilities of special polymer membranes. 62. Active transport of alkali metal ions through poly(vinyl alcohol) membranes crosslinked with glutaraldehyde
Authors: Uragami Tadashi , Wada Tamaki , Sugihara Mizuho
Published: April 2003

The transport of alkali metal ion through poly(vinyl alcohol) crosslinked with glutaraldehyde without dissociating groups in a diaphragm cell, at one side being an alkaline and at the other an acidic solution, was investigated under various conditions. The active transport fraction of alkali metal ions from the alkaline side to the acidic side was significantly influenced by the degree of crosslinking of the membrane, size of anion species, initial pH on the acidic side, and the electric potential difference across the membrane.
An unexpected structure in the preparation of new epoxy resins
Authors: Serra Angels , Cádiz Virginia , Martínez Pedro‐Alberto , Mantecón Ana
Published: April 2003

Spectroscopic data of epoxy resins, derivatives of pyromellitimide, have shown two types of attack on the two carbons of the oxirane group, giving rise to normal and abnormal opening of the ring. Thus, primary and secondary hydroxy groups were obtained. The physical characteristics of the obtained new polymers and also their solubilities are reported. Thermal analysis of these epoxy polyesterimides showed their good thermal properties.
Approximierung des verlaufes des monomerenumsatzes für einige fälle der lösungspolymerisationen
Authors: Matějíček Alois , Seidl Josef , Horký Jaroslav
Published: April 2003

Die Approximierung des Umsatzkurvenverlaufs für einige Lösungscopolymerisationen im Batchverfahren wird mit Hilfe der empirischen Beziehung X = 1 − exp (−a1τa 2) durchgeführt. Die Übereinstimmung der gemessenen und berechneten Werte ist befriedigend. Aufgrund dieser Ergebnisse wird eine Methode der Approximierung des Umsatzverlaufs von Monomeren bei der semikontinuierlichen Copolymerisation vorgeschlagen. Sie geht von der Beschreibung der Copolymerisation im Satzbetrieb für dasselbe Reaktionssystem und dieselbe Reaktionstemperatur aus.

Das mathematische Modell der semikontinuierlichen Copolymerisation beruht auf der diskreten Zuleitung des Monomerengemisches, wobei jedem Teil des der Reaktionsmischung zugeleiteten Gemisches der mit Hilfe der oben angeführten Gleichung beschriebene Umsatzverlauf zugeschrieben wird. Der Gesamtumsatz der Monomeren ist dann durch die Summe der Umsatzkurven einzelner differentieller Volumen des Monomerengemisches gegeben, die nach bestimmten Zeitintervallen der Reaktionsmischung zugeführt werden.
Preparation and chelating properties of polychalcones derived from 8‐hydroxyquinoline‐5‐aldehyde
Authors: Patel Hasmukh S.
Published: April 2003

The polychalcones designated as poly(7‐acetyl‐8‐hydroxyquinoline‐5‐aldehyde) (PAHQ) were prepared by Friedel‐Crafts (F.C.) acetylation of 8‐hydroxyquinoline‐5‐aldehyde (HQA) in nitrobenzene using AlCl3 as F.C. catalyst. The polycondensation was carried out in a single step and under different experimental conditions. It was shown that the most likely mechanism of the reaction is F. C. acetylation of HQA followed by condensation of the acetyl and aldehyde groups leading to polychalcones. The polychalcone samples, designated as PAHQ, were characterized by determining nitrogen and hydroxy content, by IR spectroscopy, by bromination reactions, by number average molecular weights, by viscometric study, and by thermogravimetry.

Polymeric chelates of selected PAHQ polychalcone samples with various metal ions have been prepared and characterized. Ion exchanging properties of PAHQ polychalcones were also studied by employing the batch equilibration method.
Die oxidation von butadienstyrolkautschuk und daraus gewonnenem vulkanisat mit salpetersäure
Authors: Zaikova Stojanka , Bojadjiev Nikolaj , Bajdarov Dimiter
Published: April 2003

In vorliegender Arbeit wird die Reaktion zwischen Butadienstyrolkautschuk „Bulex‐1500”︁ (Handelsprodukt mit einem Gehalt von 25 bis 30% Styroleinheiten) bzw. Vulkanisat auf dessen Grundlage und Salpetersäure untersucht. Es wurde festgestellt, daß mehrere Reaktionsprodukte in meßbaren Mengen anfallen, nämlich aus Butadienstyrolkautschuk: Oxidierter Kautschuk, polyfunktionelles Oligomeres und Oxalsäure; aus dem Vulkanisat: Oxidiertes Vulkanisat, polyfunktionelles Oligomeres und Oxalsäure. Verfolgt werden die Reaktionsbedingungen der Oxidation von Kautschuk und Vulkanisat (Teilchengröße, Kontaktdauer, Temperatur) auf die Ausbeute an Reaktionsprodukten. Die Bedingungen für die Gewinnung der einzelnen Produkte mit optimaler Ausbeute werden angeführt. Weiterhin wird der Einfluß der Styroleinheiten des Butadienstyrolkautschukmoleküls auf die Ausbeute an Reaktionsprodukten untersucht. Die Ergebnisse werden mit den bei der Oxidation von Butadienkautschuk erhaltenen verglichen. Es wird festgestellt, daß die Oxalsäure das Produkt einer Reihe in dem salpetersauren Medium ablaufender oxidativ‐destruktiver Prozesse ist. Der Prozeßablauf wird in einem Schema veranschaulicht. Nachgewiesen wird, daß neben den oxidativ‐destruktiven Prozessen auch eine Nitrierung erfolgt. Es wird vorgeschlagen, die Reaktion zwischen Salpetersäure und Butadienstyrolkautschuk bzw. dessen Vulkanisat bei der Wiederverwendung von Kautschukabfällen einzusetzen.
Dielectric properties of styrene — butadiene rubber/silica mixtures
Authors: Louis N. Samson Maria , Banthia Ajit K.
Published: April 2003

Rice husk ash (RHA) obtained from rice mill and hydrated silica from RHA were used as a filler in vulcanized SBR 1502 and the dielectric properties were measured at a frequency of 1592 Hz at room temperature. The optimum hydrated silica content giving a good dielectric constant and conductivity was 125 parts/100 parts rubber and the dielectric loss was also high so that it could be a good insulater. There was no significant change in dielectric constant, dielectric loss and conductivity of SBR 1502 filled with RHA which could be used as high frequency dielectric due to low dielectric loss.
Copolymerization of acrylonitrile with N‐substituted maleimides
Authors: Sabaa Magdy W. , Mikhael Michael G. , Yassin Ahmady A. , Elsabeé Maher Z.
Published: April 2003

Acrylonitrile was copolymerized with three N‐arylmaleimides as well as with N‐octadecylmaleimide in dimethylformamide (DMF) using azobisisobutyronitrile (AIBN) as initiator. The monomer reactivity ratios were calculated by the Fineman‐Ross and the Kelen‐Tüdős methods from which the Q‐ and e‐parameters of these monomers were evaluated. The prepared copolymers were characterized by viscosity measurements and thermal analysis. The intrinsic viscosity decreases by increasing the maleimide content in the copolymer. Thermogravimetry TG and differential thermal analysis (DTA) data showed a remarkable improvement in the thermal behaviour of the investigated copolymers. A mechanism for the participation of the maleimide units in the nitrile oligomerization was also proposed. The investigation of the dyeing properties of the copolymers with the exception of those containing octadecylmaleimide, showed good affinity towards basic dyes as well as an appreciable improvement in their colour fastness towards UV light.
DSC‐untersuchungen an PUR‐ionomeren aus zwei makrodiolen
Authors: Lorenz O. , Haulena F.
Published: April 2003

DSC‐Untersuchungen wurden an Filmen aus Dispersionen von Polyurethan‐Ionomeren durchgeführt, zu deren Synthese zwei Makrodiole — Poly(tetramethylenoxid), Poly(propylenoxid) oder Polyester — Verwendung fanden. Das Mischen der beiden Komponenten erfolgte vor der Prepolymerherstellung, der Kettenverlängerung oder der Dispergierung, außerdem durch Verschnitt von zwei Latices aus jeweils einem Makrodiol.

Filme aus Latexmischungen ergaben immer ein zweiphasiges Weichsegment. Dies bestätigt, daß die Identität der Latexteilchen bei der Filmbildung erhalten bleibt. Unabhängig davon, ob die Makrodiole oder die entsprechenden NCO‐Prepolymeren miteinander mischbar waren, bildeten Mischungen aus den Ionomeren zweiphasige Weichsegmente. Dies spricht dafür, daß jeder Ionomertyp eine Sorte Latexteilchen bildet.
Polycarbonate mit dimerfettsäure‐polyester‐segmenten
Authors: Dhein R. , Nerger D. , Schreckenberg M. , Morbitzer L. , Nouvertné W.
Published: April 2003

Die Herstellung von neuen segmentierten Polykondensaten aus Dimerfettsäure‐Polyestern und Bisphenol A‐Polycarbonat wird beschrieben. Es werden Synthese und molekularer Aufbau der durch Kondensation in homogener Phase und in der Phasengrenzfläche hergestellten Produkte diskutiert. Die physikalischen Eigenschaften wie u. a. die Phasentrennung der Komponenten und anwendungsorientierte mechanische Festigkeitswerte, Wärmeformbeständigkeit und Spannungsrißkorrosion werden dargestellt. Die neuen Materialien zeichnen sich durch sehr gute Kälteflexibilität und hohe Wärmeformbeständigkeit aus.
The study of modified poly(styrene‐co‐divinylbenzene) by inverse gaschromatographic analysis
Authors: Sanetra Roman , Kolarz Boźena N. , Włochowicz Andrzej
Published: April 2003

For modified poly(styrene‐co‐divinylbenzene) the changes in supermolecular structure resulting from diluting the monomers during copolymerization with various amounts of inert diluents were studied. It has been found that the copolymers, obtained in the presence of substantial amounts of diluent, have a looser structure than those obtained with less diluent, as suggested by both the swelling measurements and the results of the inverse gas chromatographic (IGC) analysis. By this latter method it was found that the looser the copolymer structure, the broader was the range of adsorption‐absorption nonequilibrium region and the lower was the heat of adsorption of normal aliphatic alcohols by the copolymers. Since the copolymers had the same crosslinking degree, no difference in their apparent glass transition temperatures were detected.
Bestimmung der hydroxygruppen in oxycellulose
Authors: Franc Jaroslav , Černý Pavel , Blaha Jan
Published: April 2003

Es wurde eine Methode für die Bestimmung des Hydroxygruppengehalts in Oxycellulose ausgearbeitet. Die Methode beruht auf der Abspaltung von Chlorwasserstoff bei der Reaktion der Hydroxygruppen mit 3,5‐Dinitrobenzoylchlorid in inerter Atmosphäre bei höheren Temperaturen. Die Menge des abgespaltenen gasförmigen Chlorwasserstoffs wird in einem Azotometer bestimmt.
Bestimmung der zusammensetzung von copolymeren bei der mehrstufigen chargenweisen polymerisation durch modifizierung der Mayo‐Lewis‐Gleichung
Authors: Matějíček Alois , Horký Jaroslav
Published: April 2003

Die Bestimmung der Copolymerzusammensetzung bei der mehrstufigen chargenweisen Polymerisation mit Hilfe der Mayo‐Lewis‐Gleichung durch schrittweise Integration der entsprechenden Differentialgleichungen wird vorgestellt. Die Verwendung von zwei voneinander abhängigen Beziehungen für den Monomerumsatz, und zwar für den aktuellen sowie für den Gesamtumsatz, stellt eine Grundlage der vorgeschlagenen Methode dar. Der Integrationsschritt bleibt für die ganze Berechnung konstant. Das Ergebnis des angeführten Vorgangs ist ein Berechnungsschema für die Simulierung des Verlaufs einer mehrstufigen chargenweisen Polymerisation. Es ermöglicht, die Zusammensetzung der entstehenden Copolymeren annähernd zu berechnen. Die vorgeschlagene Berechnungsmethode wird anhand einer mehrstufigen chargenweisen Polymerisation des Gemisches Styrol/Ethylacrylat demonstriert.
Preparation and reactivity of new 3,3′,4,4′‐tetracarboxybenzophenone dianhydride glycidyl ester derivatives
Authors: Serra Angels , Cádiz Virginia , Martínez Pedro‐Alberto , Mantecón Ana
Published: April 2003

New diimidediacids coming from 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (TBPA) and their corresponding diglycidyl derivatives have been synthesized. Preparation of diglycidyl esters was carried out by reaction with epichlorohydrin (EPC) in excess and using a quaternary ammonium halide as catalyst. The obtained compounds were characterized by spectroscopic methods and employed as starting monomers in a stepwise polymerization. The presence of imide groups in the new epoxy resins confers them higher thermal stability and also acceptable processing possibilities, as they are soluble in high polar organic solvents.
Studies on oxidation of precursor carbon fibres of petroleum pitch by gas chromatography
Authors: Sanetra Roman , Włochowicz Andrzej , Wysocki Marian
Published: April 2003

Volatile products of precursor carbon fibres of petroleum pitch oxidized in oxygen were investigated.

Concentration changes in CO, CO2, and H2O as a function of temperature and oxidation time were determined quantitively by gas chromatrography. The oxidation of precursor pitch fibres is the most efficient in the temperature range between 453–498 K during 2–4 hours.
Chemorheology of carboxyl terminated polybutadienes. Effect of ammonium perchlorate
Authors: Schwartz Anders
Published: April 2003

An investigation has been made on chemorheological properties of carboxyl terminated polybutadienes (CTPB) with addition of small amounts of ammonium perchlorate (AP). Curing of the polymers has been done with the imine tris‐[1‐(2‐methyl)‐aziridinyl]phosphine oxide (MAPO), and with mixtures of MAPO and epoxides. AP has been dissolved in MAPO before addition to CTPB. Continuous stress relaxation measurements and intermittent measurements of stress have been made at 110°C on CTPB cured with MAPO and at 80, 88, 100, and 110°C on CTPB cured with MAPO and epoxides. The results show that AP increases the rate of scission reactions in all compositions. Mixtures of MAPO and epoxides as curing agents give better properties to CTPB than only MAPO as curing agent.
Curing of carboxyl terminated polybutadiene with epoxide. Effect of additives
Authors: Schwartz Anders
Published: April 2003

An investigation has been made of curing of carboxyl terminated polybutadiene with the epoxide EPON 812 and with a chromium chelate as catalyst. The effect on curing of some additives, ammonium perchlorate (AP) and boron, has been measured at three temperatures 323, 343, and 363 K. The results show that the polymer without additive and with AP cures very well. Addition of boron to the polymer decreases the curing reaction. Addition of boron and AP together inhibits the curing reaction almost completely.
Studies on carboxymethyl cellulose. Quantitative analysis of the huggins constant k′
Authors: Trivedi H. C. , Patel R. D.
Published: April 2003

The Huggins constant k′ was measured for sodium carboxymethyl cellulose (NaCMC) solutions by an isoionic dilution technique for various ionic strengths. The value of k′ is found to increase with decreasing ionic strength. The electrostatic potential at the effective surface of the macromolecule was calculated due to the method of Mason et al. and that of Lifson and it has been observed that there is an agreement between the two methods of deriving the potential.
Electrical properties of pre‐extended FEF carbon black loaded rubbers
Authors: Amin M. , Nasr G. M. , Khairy S. A. , Ateia E.
Published: April 2003

The electrical conduction was investigated in different rubber composites, subjected to various values of longitudinal extension. The study involves styrene‐butadiene‐rubber (SBR), butadiene‐rubber (BR), acrylonitrile‐butadiene‐rubber (NBR), butyl‐rubber (IIR), and natural rubber (NR). Each type was separately blended with 100 phr of fast extruding furnace black. The parameters of the model of Polley and Boonstra are recalculated for a specific example and good fitting is found.
Veränderung von fluorpolymeren durch gammastrahlen
Authors: Orth Helmut
Published: April 2003

Folien von Poly(tetrafluorethylen) (PTFE) und Poly(ethylen‐co‐tetrafluorethylen) wurden in Gegenwart von Luftsauerstoff der Einwirkung von Gammastrahlen ausgesetzt. Die IR‐analytische Untersuchung nach der MIR‐Technik (multiple innere Reflexion) zeigt, daß bei PTFE nur Kettenspaltung eintritt; eine oxidative Veränderung konnte nicht festgestellt werden. Die thermomechanische Analyse (TMA) zeigt, daß die Glasübergangstemperatur durch die Bestrahlung sinkt, offenbar als Folge einer Dichtezunahme der amorphen Phase. Im Gegensatz dazu unterliegt Poly(ethylen‐co‐tetrafluorethylen) einer Oxidation mit Ausbildung von Carbonylgruppen bis zu einer Strahlendosis von etwa 3 · 106 Gy, danach erfolgt Kettenabbau. Die Bildung der Carbonylgruppen ist eine Reaktion der ersten Ordnung.
Studies on some properties of poly(phenylene sulphide)
Authors: Kreja Ludwik , Warszawski Andrzej , Czerwiński Wojciech
Published: April 2003

Poly(phenylene sulphide) was synthesized by a direct method. Benzene and elemental sulphur were used as substrates, and aluminium chloride as a catalyst. The obtained final product was characterized by IR, VIS‐UV, wide angle X‐ray and mass spectroscopy, thermal, and elemental analyses. On the base of the analytical methods the molecular structure of the obtained polymer was discussed.
Continuous free‐radical polymerization of styrene in the stirred tank reactor: Effect of retarders
Authors: Kirchner K. , Rintelen T.
Published: April 2003

The influence of different retarders on the conversion and the molecular weight distribution of initiated styrene polymerization in a continuous stirred tank reactor (CSTR) was investigated. The retarders used were nitrobenzene, tert‐butylpyrocatechol (tBC) and tert‐butyl‐o‐quinone. The inhibition constant of the nitrocompound was taken from literature to test the mathematical model. For the other two substances the inhibition constant was determined experimentally. The effectiveness of tBC increases in the presence of oxygen. Our results indicate that oxygen transforms the normal alkyl radicals of the polymerization into peroxy radicals having a higher reactivity towards the retarder thus leading to an overall increase in efficiency.
Influence of atmospheric conditions on the properties of polyolefins
Authors: Peeva Lily B. , Tsveteva Vichra A.
Published: April 2003

Empirical relationships, describing the change in mechanical properties of polyolefins at natural ageing in a seaside climate at middle geographic latitudes are derived on the basis of experimental data collected in a long exposure period — more than 10 years. The empirical equations describe the experimental data with a good accuracy. A constant is introduced accounting for the period in which the properties remain unchanged (induction period). The empirical equations derived may be used in predicting the change in mechanical properties of the investigated polymers in outdoor applications.
Preparation and properties of copolymers of methyl‐2,3,3‐trifluoroacrylate with alkenes and alkyl vinyl ethers
Authors: Žůrková E. , Bouchal K. , Vacík J. , Kálal J. , Paleta O. , Dědek V.
Published: April 2003

Copolymers of methyl‐2,3,3‐trifluoroacrylate with isobutylene, propylene, ethylene, and n‐alkyl vinyl ethers, (the alkyl being ethyl, propyl, butyl) glycidyl vinyl ether, and 2‐methoxyethylvinyl ether were prepared by radical solution polymerization using di(isopropoxycarbonyl) peroxide as the initiator. Their structure was that of the alternating order of methyltrifluoroacrylate and the respective vinyl monomer units. The rate of copolymerization and molecular weights of the copolymers were determined by the ratio of both monomers and by the character of the vinyl comonomer. By means of the alkaline hydrolysis of trifluoroacrylate units, the corresponding copolymers of trifluoroacrylic acid were prepared. Their degree of dissociation was characterized by pK values. The rate of alkaline hydrolysis was considerably affected by the copolymer structure. The polymeric materials prepared in this study possessed good thermal stability, and their thermal decomposition did not occur below 300°C.
Untersuchungen zum reaktionsverhalten von polyacetylen mit dienophilen
Authors: Wilhelm D. , Strohmaier D. , Kleeberg W.
Published: April 2003

Versuche, die Langzeitstabilität von Polyacetylen durch Umsetzung mit Dienophilen zu erhöhen, ergaben keinen Hinweis auf eine Diels‐Alder‐Reaktion. Die bei Anwesenheit von Ziegler‐Natta‐Katalysatoren beobachtete Gewichtszunahme bei Umsetzungen in situ ist auf eine Reaktion zwischen Katalysator und Dienophil zurückzuführen, welche zu unlöslichen Produkten führt. Dies konnte durch IR‐spektroskopische Untersuchungen eindeutig gezeigt werden.
Antioxidants and stabilizers, 102. Transformation of 2,6‐dialkylphenols under gamma‐irradiation in benzene and isooctane solutions
Authors: Brodilová Jiřina , Chutný Bohumil , Pospíšil Jan
Published: April 2003

The mechanism of phenolic antioxidants participation in γ‐radiation initiated processes in polyolefins has been simulated under model conditions. The γ‐irradiation of benzene and isooctane solutions of 2,6‐dialkylphenols (I) in vacuum results in an antioxidant transformation. The latter involves CC, and presumably also CO couplings of radicals formed primarily from I and their combination with R° radicals generated from hydrocarbon substrate (RH). The CC coupling is suppressed at a lower concentration of I in RH. As a result, both the yield of the respective tetralkylated biphenyldiol V and the consecutive formation of diphenoquinone VI drop. 2,4,6‐Trialkylphenol III is the majority product formed in the aliphatic RH (isooctane).
Kernresonanzspektroskopische beiträge zur struktur und stereochemie von (cyclo)aliphatischen isocyanaten und deren folgeprodukten
Authors: Wendisch D. , Reiff H. , Dieterich D.
Published: April 2003

Es wird über 1H‐NMR‐Untersuchungen an Isophorondiamin (IPDA) und Isophorondiisocyanat (IPDI) sowie ausgewählter Folgeprodukte berichtet. Dem jeweiligen Hauptisomeren wurde zweifelsfrei die trans‐Konfiguration zugeordnet. Ebenso werden die 13C‐NMR‐Daten für eine Vielzahl von Folgeprodukten des n‐Butylisocyanats mitgeteilt. Mit Hilfe dieser Daten ist es nunmehr möglich, Abkömmlinge (cyclo)aliphatischer Isocyanate sicher zu charakterisieren. Das Datenmaterial ist auch in Hinblick auf die Analytik von Oligo‐ und Polymeren von Interesse.
Herstellung, struktur und mechanische eigenschaften von strahlenchemisch mit styrol gepfropftem polyethylen
Authors: Friese Klaus , Michler Goerg , Steinbach Helga , Hamann Bernd , Runge Jürgen
Published: April 2003

Von strahlenchemisch durch Gasphasen‐Pfropfung hergestellten Pfropfprodukten aus Polyethylen und Styrol wurden die Anteile an Homopolymerem und gepfropftem Styrol, die Struktur der Pfropfprodukte (an Hand von elektronenmikroskopischen Aufnahmen) sowie einige mechanische Eigenschaften in Abhängigkeit von der Pfropfausbeute untersucht. Es wurde festgestellt, daß die kristalline Struktur des Polyethylens selbst bei hohen Pfropfausbeuten kaum beeinflußt wird, was durch die sehr geringe Pfropfkettendichte in der Größenordnung von einer Pfropfkette pro 100 PE‐Moleküle erklärt wird. Der gute Verteilungsgrad der Polystyroldomänen in der PE‐Matrix ist die Ursache für die relativ hohe Festigkeit der Pfropfprodukte.
Kinetische messungen bei reaktionen technischer, höhermolekularer epoxidharze mit anhydriden
Authors: Matějíček Alois , Kaška Jiří , Sivoková Marta , Klaban Jiří , Horký Jaroslav
Published: April 2003

In dieser Arbeit wurde die Änderung der Konzentration der Reaktionskomponenten mit der Zeit bei der Reaktion eines höhermolekularen Epoxidharzes mit Tetrahydrophthalsäure‐ und 3‐Chlortetrahydrophthalsäureanhydrid in Anwesenheit von Lauryldimethylbenzylammoniumbromid verfolgt. Diese Messungen wurden im technischen Maßstab wie bei der Verarbeitung der Komponenten im Extruder gemacht. Die Reaktion wurde im Temperaturbereich von 363,2–403,2 K, d.h. in der Nähe des Erweichungspunktes des Harzes durchgeführt. Die gemessenen Konzentrationswerte der einzelnen reagierenden Gruppen im Reaktionssystem wurden in Abhängigkeit von der Zeit mit Hilfe der für die Folgereaktionen nach zweiter Ordnung geltenden kinetischen Beziehungen ausgewertet. Diese Auswertung wurde in der Anfangsphase der Reaktion durchgeführt. Es zeigte sich beim Vergleich aller drei bei 383,2 K gemessenen Systeme, daß das System mit 3‐Chlortrahydrophthalsäureanhydrid den größten Wert der Geschwindigkeitskonstante k1 = 8,397 · 10−3 kg s−1 mol−1 (gültig für die Bildung von Monoestern) und den niedrigsten Wert der Geschwindigkeitskonstante k2 = 1,345 · 10−3 kg s−1 mol−1 (gültig für die Bildung von Diestern und daher von der vernetzten makromolekularen Struktur) aufweist.
Scherung und degradation von polymerlösungen
Authors: Kulicke W.‐M. , Kniewske R. , Müller R.‐J. , Prescher M. , Kehler H.
Published: April 2003

Das Viskositätsniveau im Bereich der Ruhescherviskosität η0 (Newtonscher Bereich) sowie im schergeschwindigkeitsabhängigen Bereich (nicht‐Newtonscher Bereich (η = f(\documentclass{article}\pagestyle{empty}\begin{document}$$ \mathop \gamma \limits^. $$\end{document})) von Polymerlösungen kann auf der Basis molekularer Modellierungen bestimmt werden. Voraussetzung hierfür ist die Kenntnis der molekularen Parameter des Einzelmoleküls, welche in vielen Fällen Handbüchern entnommen werden könen, und das Ergebnis einer Einpunktmessung von η0 in konzentrierter Lösung. Darüber hinaus wurde ein Stabilitätskriterium erarbeitet, das den Grenzbereich zwischen einer scherstabilen und einer degradierten Polymerlösung vorhersagt. Dieses Kriterium ist sowohl für den laminaren als auch für den turbulenten Strömungszustand verwendbar, wodurch anwendungstechnologisch bedeutsame Fragestellungen bezüglich der Stabilität beantwortet werden können.

Die Ergebnisse sind unter einer modifizierten Betrachtungsweise auf Polymerschmelzen übertragbar.