bluuebunny/crossref_metadata_2025 huggingface dataset:
Optische Methoden zur Charakterisierung von hochpolymeren Fasern. 1. Methodik der Interferenzmikroskopie
Authors: Beier Manfred , Schollmeyer Eckhard
Published: April 2003

Dichte und Orientierung sind wichtige Größen für die Strukturaufklärung von Hochpolymeren. Diese lassen sich bei Fasern durch Brechwertmessung als Funktion des Radius gewinnen.

Der Einfluß der Lichtbrechung auf den Brechwertverlauf n(r) wird mit Hilfe eines optischen Modells der Faser berechnet. Er ist für Fasern mit einem Radius R < 30 μm und Brechwertschwankungen < 0,02 kleiner als ± 0,0002 und ist deshalb für textile Fasern im allgemeinen ohne Bedeutung. Wichtiger ist die genaue Anpassung der Einbettungsimmersion an den Faserrand: Der berechnete Brechwertverlauf nimmt am Faserrand stets den Brechwert der Einbettung an, wobei sich der Einfluß der Fehlanpassung ca. 0,2 · R in die Faser zurückverfolgen läßt.

Mit Hilfe einer Spline‐Funktion als Näherung für die Interferenzstreifenversetzung werden auch extreme Brechwertverläufe gut wiedergegeben; als Beispiel wird der Brechwert der Füllung einer Glashohlfaser untersucht.

Durch Verwendung eines HeNe‐Lasers als Lichtquelle des Interferenzmikroskopes ist die Anwendung der Interferenz‐Holographie möglich.
Characterization of the adhesion properties of polymers by electrokinetic measurements
Authors: Jacobasch Hans‐Jörg
Published: April 2003

Adhesion between polymers and other solids is predominately caused by dispersion, acid‐base, and electrical double layer forces. An overview is given on characterization of these force components by electrokinetic measurements. The theoretical approaches used, fields of application and apparative facilities are described. It has been shown that the most important force components acting in adhesion systems can be characterized by zeta‐potential measurements as well as the influence of adsorption layers on these forces. Therefore, results of electrokinetic measurements can be applied to control technical important adhesion phenomena.
Indirekte klassifikation von sechs oximierenden aldehydgruppen in oxycellulose nach dem polymerisationsgrad
Authors: Blaha Jan , Černý Pavel , Jahn Karel
Published: April 2003

Die stufenweise Oximierung bei 20, 23, 25, 28, 30 und 35°C ermöglichte die qualitative und quantitative Trennung von sechs verschiedenen Aldehydgruppen in Oxycellulose. Für die Berechnung des Gehaltes bn der n‐ten Aldehydgruppe bei einer bestimmten Oximierungstemperatur wurde eine modifizierte Berechnungsmethode nach einer verbesserten Gleichung angewandt. Das vorgeschlagene Verfahren ermöglichte die Charakterisierung der chemischen Strukturen von sechs verschiedenen Aldehydgruppen in Oxycellulosemakromolekülen. Es wurden lineare Abhängigkeiten zwischen den Gehalten an diesen Aldehydgruppen sowie den Aldehydsummenwerten und DP‐Werten bei logarithmischer Darstellung gefunden, die eine indirekte und schnelle Aldehydbestimmung in Oxycellulosen über den DP‐Wert ermöglichte. Für die indirekte Bestimmung der Aldehydgruppen über den DP‐Wert wurde ein Computerprogramm ausgearbeitet.
Autoxidation of thiols with cobalt(II)phthalocyanine‐tetra‐sodium sulfonate attached to poly(vinylamine), 6. Immobilized catalysts by crosslinking of poly(vinylamine)
Authors: Brouwer Wilfried M. , Traa Piet A. M. , de Weerd Teun J. W. , Piet Pieter , German Anton L.
Published: April 2003

Poly(vinylamine), being both carrier and promotor of the thiol oxidation catalyst cobalt(II)phthalocyanine‐tetra‐sodium sulfonate (CoPc(NaSO3)4), was crosslinked with α,α′‐dichloro‐p‐xylene, thus yielding porous hydrophilic networks. The effects of experimental parameters such as stirring speed, particle size, degree of crosslinking, distribution of catalytic sites (CoPc(NaSO3)4) in the catalyst particles, pH, temperature, and thiol concentration were investigated. Reaction rates observed for the immobilized catalyst system appeared to be 4–30 times lower as compared with the water soluble polymeric catalyst system but still higher than those of the polymer free CoPc(NaSO3)4 catalyst.

At a stirring speed around 3 · 103 rpm not the mass transfer from the bulk to the catalyst particles but intra‐particle diffusion limits the reaction rate. Accordingly, an uncrosslinked polymeric catalyst anchored to silica, with catalytic sites situated close to the particle surface, exhibited comparatively high activity, i.e. only four times lower than the soluble polymeric catalyst.

In addition, the heterogeneous catalyst systems showed resemblance in kinetic behaviour with the soluble polymeric thiol oxidation catalyst.
The homopolymerization and copolymerization of an azo dye, N‐methyl‐N‐[4‐(2,5‐dichlorophenyl) azophenyl]‐2‐aminoethyl methacrylate
Authors: Lokaj Jan , Morozova Elena Mikhailovna , Eliseeva Valentina Ivanovna , Hrabák František
Published: April 2003

The properties of a polymerizable dye, N‐methyl‐N‐[4‐(2,5‐dichlorophenyl)azophenyl]‐2‐aminoethyl methacrylate (I), its homopolymerization and the properties of the homopolymer were characterized. The copolymerization parameters (r1, r2) ofIwith styrene (St), methyl methacrylate (MMA), N,N‐dimethyl‐2‐aminoethyl methacrylate, 2,2,2‐trichloroethyl methacrylate and methacrylic acid and the rates of copolymerization were determined in benzene solution at 50°C with 0.01 M 2,2′‐azobisisobutyronitrile as initiator. The Alfrey‐Price e and Q constants were calculated forIusing the r1, r2values for the systemI/St. The retardative effect of the azo group in the homopolymerization and copolymerization ofIwas evaluated by determining the ratio of rate constants of addition of polymer radicals to the model azo compound and to the monomer in the homopolymerization of St and MMA. The relative permittivities of monomers and their solutions were measured, and the effect of the molecular interaction of comonomers on the composition of the copolymers was discussed.
Antioxidants and stabilizers, 98. An investigation of the synergism between N‐isopropyl‐N′‐phenyl‐1,4‐phenylenediamine and 2,6‐dialkylphenols
Authors: Taimr L. , Pospíšil J.
Published: April 2003

The rubber antidegradant, N‐isopropyl‐N′‐phenyl‐1,4‐phenylenediamine (I), after being oxidized to N‐isopropyl‐N′‐phenyl‐1,4‐benzoquinonediimine (II) may again be partly regenerated by a reaction with 2,6‐dimethylphenol with the simultaneous formation of a compound containing one fragment derived from 2,6‐dimethylphenol and two fragments derived from I. For this compound we suggest structure IV (a, b, or c). This compound readily decomposes, yielding a further molecule of antidegradant I. The cooperative effect between I and 2,6‐dimethylphenol can also be seen in the autoxidation of squalene. The behaviours of some further simple alkyl derivatives of phenol in a reaction with II are described.
A new temperature measuring device for rotating systems
Authors: Borchard W. , Hermanns B.
Published: April 2003

A new method to determine temperatures in rotating systems is described. The predicted relationship between signal displacement and temperature measurements at the place of the cell in an analytical centrifuge is presented.
Effect of carbon black and thermal aging on the conduction mechanism of natural and styrene butadiene rubbers
Authors: Ghani A. A. , Eatah A. I. , Hashem A. A. , Hassan H.
Published: April 2003

Two types of carbon black namely fast extrusion furnace black (FEF) and high abrasion furnace black (HAF) were incorporated with a concentration of 50 phr into styrene butadiene rubber (SBR) and natural rubber (NR). The effect of the time of aging and temperature on the electrical conductivity was studied. It was found that a thermal aging at 95°C leads to the appearance of minimum in conductivity (σ) in both FEF/NR and HAF/NR. This was explained by a competition between two factors: degradation and increase of crosslinking density in the rubber matrix. In case of FEF/SBR and HAF/SBR it seems that these factors have comparable effects on the conductivity after 10 days of aging. From the current‐voltage (I‐V) characteristics the carrier concentration, trap density, and the drift mobility were calculated. The minimum found in the temperature dependence of σ for FEF/NR is discussed and found to be controlled by the relative dimension of carbon and rubber aggregates.
Modification of polysaccharides: Degradation and graft copolymerization onto dextran
Authors: Samal R. K. , Sahoo P. K. , Ray S. S. , Nayak S. N.
Published: April 2003

A water soluble muco‐polysaccharide, “dextran”, was subjected to selective degradation and graft copolymerized with acrylamide and methylmethacrylate. Using ceric ions as initiator a low molecular weight model dextran and dextran‐g‐poly(acrylamide) as well as dextran‐g‐poly(methylmethacrylate) copolymers were prepared. The selective chain degradation and the graft copolymerizations were carried out at varying concentrations of Ce(IV) and monomer and varying temperatures. The course of degradative chain cleavage has been followed by viscometry. The low molecular weight model dextran and the copolymers were purified by usual methods. Their physical and chemical properties were tested and compared with the base. The energy of activation for the chain degradation and other related thermodynamic parameters have been evaluated.
Vinyl polymerization by carbon black, IV. Some properties of modified carbon black compared with its polymerization initiating activity
Authors: Haque Shah A. , Biswas Mukul
Published: April 2003

All grades of carbon black contain large amounts of unpaired electrons and organic functional groups. Polymerization reaction is possibly initiated by the unpaired electrons on the surface; the functional groups have promotional effect on the initiation process. All the properties like texture, geometry, surface area, pH of the aqueous slurry, ash content, and elemental composition have effects on the polymerization reaction. These pertinent physicochemical and surface properties of unmodified and modified N 220 carbon black have been studied in relation to N‐vinylcarbazole polymerization.
Proton magnetic relaxation times of isotactic polypropylene films treated with tetrachloroethylene
Authors: Tanaka Hiroshi
Published: April 2003

Proton spin‐lattice (T1) and spin‐spin (T2) relaxation times of isotactic polypropylene films with different thermal histories, treated with tetrachloroethylene, were measured with pulsed NMR. For the melt‐quenched sample T11 (the longer T1) increases and T2a (the longest T2) decreases with increasing treatment temperature. The mass fraction of mobile region (Fa) decreases and the mass fraction of rigid region (Fc) increases with increasing treatment temperature. T11 increases almost linearly with increasing Fc, indicating that the removal of the mobile amorphous region is mainly responsible for the change in T11.

For the annealed sample T11 also increases with increasing treatment temperature, although a slight decrease in T11 for the low treatment temperature is observed. There is a large decrease in T2a when the treatment temperature is raised, suggesting that a comparatively selective extraction occurs for the annealed sample.
Physical characterization of isotactic polypropylene/ethylene‐propylene copolymer blends
Authors: Kalfoglou Nikos K.
Published: April 2003

The properties of solution‐mixed blends of isotactic polypropylene (iPP) and an amorphous ethylene‐propylene copolymer (EPM), containing 40 wt.‐% of ethylene, were studied throughout the composition range. The techniques used were differential scanning calorimetry (DSC), dynamic mechanical spectroscopy, and optical microscopy. Morphological examination revealed a heterogeneous structure. The dynamic mechanical technique at isochronous conditions (110 Hz) between ‐120 and 160°C confirmed the heterophase nature of the blends and revealed limited phase mixing of the amorphous components of the two constituents. DSC measurements of specimens quenched at 0°C, indicated that EPM rubber promotes crystallization of the iPP phase.

Appropriate mechanics models tested in the complete composition range led to the conclusion that the system is incompatible, with rubber spherical inclusion strongly adhering to the iPP matrix, up to an EPM volume fraction Φ (EPM) ≃ 0.70. At higher EPM compositions, matrix reversal occurs — a fact corroborated by the available mechanical data for this blend.
Segmented copolyetherurethane‐ureas and semicarbazides for blood circulation systems, IV. Mass spectrometric investigations 2, linear‐temperature programmed pyrolysis (LTP‐Py)
Authors: Düssel H.‐J. , Wenzel N. , Hummel D. O.
Published: April 2003

Copoly(etherurethane‐urea)s (PEUU) from different polyethers with hydroxyl endgroups, with 4,4′‐diisocyanato‐dicyclohexylmethane and 4,4′‐diamino‐diphenylmethane (as a chain extender) were heated linearly within the ion source of a mass spectrometer. The analysis of the evolved gases allows the identification and detailed characterization of the investigated polymers. The building units of PEUU — polyethers, diisocyanates, and the diamine — can be identified by key fragments. These are formed during pyrolysis and can be identified with field ionization or low‐voltage electron impact ionization.

Furthermore, the polyethers with hydroxyl endgroups as well as the PEUU can easily be distinguished by their volatilization rate curves. Fragments resulting from cleavages of the different bond types present, e.g., urea, urethane, ether in this order, are generated during the linear increase of temperature; they are pinpointed by repetitive scanning of the mass spectra.
Organic sulfur compounds, III. Addition products of ethylene oxide to bis(2‐hydroxyethyl)disulfide
Authors: Sokołowski Adam , Burczyk Bogdan
Published: April 2003

The composition of products resulting from the reaction of bis(2‐hydroxyethyl)disulfide with ethylene oxide in the presence of sodium methoxide, dimethyl cyclohexylamine and boron trifluoride etherate as catalysts was determined. The addition reactions were carried out at 80°C, under normal and increased pressure, using the reagents in molar ratios of 1:1. Under these conditions the degree of disulfide conversion varied within the 70–80% range. Oxyethylene derivatives of bis(2‐hydroxyethyl)disulfide were the main products of the investigated reaction. Additionally, slight amounts of ethylene glycols (2–4%) and sulfides (2–4%) were found resulting from a reaction of ethylene oxide with the decomposition products of the starting disulfide.
On the polymerization of acrylamide in methanol in presence of poly(ethylene glycol)
Authors: Pantar A. V. , Atreyi M. , Rao M. V. R.
Published: April 2003

Acrylamide was polymerized in presence of poly(ethylene glycol)‐200 (PEG), with persulphate as initiator, in methanol as reaction medium, with varying monomer concentrations. The polymers obtained were finely divided powders and readily soluble in water, unlike pure polyacrylamide. The incorporation of PEG into the polymers was demonstrated by nitrogen determination, IR, and NMR studies. PEG does not covalently link to the polyacrylamide chains, but forms a blend with the polymer.
Single stage process for desizing, scouring, and bleaching of cotton fabric
Authors: Hebeish A. , El‐Bazza S.
Published: April 2003

The efficiency of a treating bath formulation consisting of H2O2, sodium hydroxide, chelating agents, wetting agent, metal ions, and MgSO4 · 7H2O in effecting combined desizing, scouring, and bleaching of cotton fabric using a winch beck system was investigated under different conditions. Presence of MgSO4 · 7H2O at a concentration of up to 3 g/l was essential for stabilization of the strongly alkaline H2O2 solutions (containing 10 g/l NaOH) at 95°C for 90 min to achieve complete starch removal and to bring about fabric with satisfactory whiteness and absorbency without seriously degrading the fibre substance. Chelating agents, namely EDTA and gluconic acid (2 g/l, each) assisted in stabilization of H2O2 even in presence of Fe3+, Cu2+ or both ions and resulted in improved whiteness and lower fibre degradation but had no effect on residual starch or on wettability of the fabric. The wetting agent used had no significant effect on stabilization of H2O2 and fibre degradation, but it helped starch removal and improved the wettability of the fabric. The decomposition of H2O2 increased by increasing its own concentration from 2 to 12 ml/l as well as the concentration of sodium hydroxide from 5 to 17.5 g/l. The same hold true for temperature (60 to 98°C) and duration (30 to 150 minutes). Combined desizing, scouring, and bleaching of loomstate cotton fabric could successfully be effected by using a treating bath consisting of sodium hydroxide (10 g/l), H2O2 (4 ml/l), MgSO4 · 7H2O (3 g/l), EDTA (2 g/l), gluconic acid (2 g/l), anionic/nonionic wetting agent (1.5 g/l) at 95°C for 90 min, and a material : liquor ratio of 1 : 25.
Photooxidation of polystyrene. Effect of stabilizers
Authors: Choudhary V. , Bhaskar V. U. , Varma I. K.
Published: April 2003

The effect of commercially available stabilizers such as Tinuvin‐327, Tinuvin‐770, and Irganox‐1024 on the photooxidation of polystyrene (PS) was investigated by following the changes in molecular weight and molecular weight distribution. Structural changes during degradation were studied by 1H‐NMR‐ and IR‐Spectroscopy and by Electron Spectroscopy for Chemical Analysis (ESCA). Neat PS films became very brittle and yellow on exposure to UV light. Tinuvin‐770 stabilized the PS films towards discolouration and brittleness.

The ESCA studies of surface photooxidation of polystyrene indicate the formation of ketonic and methylene ether groups in the initial stages (˜ 100 h). At later stages ester and carbonate groups are formed.
Kinetics of vinyl polymerization initiated by potassium permanganate/β‐hydroxybutyric acid redox system
Authors: Behari K. , Gupta K. C. , Verma Meena
Published: April 2003

The aqueous polymerization of acrylamide initiated by potassium permanganate/β‐hydroxybutyric acid has been studied volumetrically at 35 ± 0.01°C in an inert medium. The rate of polymerization shows nearly square root dependence on β‐hydroxybutyric acid at low concentration (3.12 – 12.5 · 10−3 mol dm−3). The order with respect to potassium permanganate has been found to be 0.6 indicating thereby a bimolecular mode of termination. The polymerization rate has been varied linearly at low monomer concentrations i.e. from 2.5 –7.0 · 10−2 mol dm−3. The dependence of number average degree of polymerization on the initial rate of polymerization and temperature has been determined. The over‐all activation energy has been found to be 51.66 kJ mol−1. A kinetic reaction scheme is proposed on the basis of experimental results.
Reactive polymers, 49. Changes in the porous structure of macroporous copolymers due to successive effects of solvents and temperature
Authors: Hradil J. , Švec F.
Published: April 2003

By drying at 78°C, the macroporous terpolymer 2,3‐dihydroxypropyl methacrylate‐co‐sodium methacrylate‐co‐ethylene dimethacrylate with a water retention of 3.78 g H2O/g loses porosity which is renewed by reswelling. Drying of this terpolymer at 0–25°C by which water or methyl alcohol is removed does not disturb its porosity. Less swelling copolymers such as 2,3‐dihydroxypropyl methacrylate‐co‐ethylene dimethacrylate with a water retention of 1.71 g H2O/g do not lose its permanent porosity when dried. Inversion gas chromatography has made possible the determination of the glass transition temperature of these macroporous terpolymers (Tg = 45°C) by using heptane and methyl alcohol as retention acids. With respect to this, and using scanning electron microscopy the loss of porosity due to drying was interpreted as sintering of macroporous copolymers whose polymer networks swell to a higher degree on heating above Tg.
Herstellung und eigenschaften von pfropfcopolymerisaten des vinylacetats auf ataktischem polypropylen
Authors: Schellenberg Jürgen , Hamann Bernd , Runge Jürgen
Published: April 2003

Die Verwendbarkeit von ataktischem Polypropylen als Pfropfgrundlage für die Pfropfcopolymerisation mit Vinylacetat wird untersucht. Die erhaltenen Pfropfprodukte werden hinsichtlich ihres Quellverhaltens und bezüglich ihrer Glasumwandlungstemperaturen und Pfropfparameter bei unterschiedlichen Pfropfproduktzusammensetzungen charakterisiert.

Nach Abmischung der Pfropfprodukte mit Polyvinylchlorid werden einige mechanische Eigenschaften sowohl in Abhängigkeit von der Menge des enthaltenen Pfropfproduktes als auch von der Zusammensetzung der Pfropfcopolymerisate dargestellt.
Dependence of soiling and soil release of easy care cotton on factors‐controlling the finishing treatment
Authors: Ibrahim N. A. , Hebeish A.
Published: April 2003

The conventional pad‐dry‐cure method was used for effecting crosslinking of cotton with N‐methylol finishing agents under different conditions. Factors studied include nature and concentration of finishing agent and softener, type and concentration of catalyst, and curing temperatures. Variation of soiling and soil release characteristics of crosslinked cotton with these factors were investigated. The effect of finishing agent on aqueous soiling followed the order:

Carbamate reactant‐fabric > Dimethylolethylene urea‐fabric > Dimethyloldihydroxyethylene urea‐fabric > Untreated fabric > Modified triazinone‐fabric ≥ Modified ethylene urea‐fabric. On the other hand, the effect of these finishing agents was to enhance the susceptibility of the fabric to oily soiling. Nevertheless, nature of the finishing agent governed the magnitude of this enhancement. Aqueous and oily soil release depended also upon the nature of finishing agent, soiling increased and soil release decreased by increasing finishing agent concentration. Type of catalyst exerted a considerable influence on aqueous and oily soil release without significantly affecting the degree of soiling. For aqueous soil release, the following order was found:
Al2(SO4)3 · 18H2O > MgCl2 · 6H2O > urea nitrate > ZnCl2 · 6H2O > Zn(NO3)2 · 6H2O > urea phosphate > urea oxalate > NH4 · H2PO4 ≥ NH4Cl.

A reverse order held good for oily soil release. Both aqueous and oily soil release were impaired by increasing catalyst concentration. Similarly, nature and concentration of the softener had no striking effect on soiling while they did on soil release. Raising the curing temperature from 80 to 140°C caused substantial reduction in case of soil removal of urea salts catalyzed‐crosslinked cotton samples while having the degree of soiling practically intact.
Graft copolymerization of perfluoroheptyl methacrylate/glycidyl methacrylate mixtures with cotton fabric using Fe2+‐thioureadioxide‐H2O2 redox system
Authors: El‐Alfy E. , Waly A. , Hebeish A.
Published: April 2003

The ability of Fe2+‐thioureadioxide‐H2O2 redox system to induce polymerization of perfluoroheptyl methacrylate (PFHMA) and glycidyl methacrylate (GMA) individually as well as in binary mixtures was investigated under different conditions. Results obtained indicated that (a) PFHMA monomer could substantially be polymerized with cotton cellulose only in presence of GMA, (b) maximum contribution of PFHMA in the polymer add‐on occurred upon using PFHMA mixture at a ratio of 50:50 at 80°C, (c) presence of PFHMA along with GMA offsets the fast termination rate of the latter as temperature increased from 60° to 90°C, (d) GMA activated PFHMA while the latter adversely affected GMA, (e) none of the PFHMA/GMA mixtures at ratios 2:8, 5:5, 8:2 showed synergetic effects, (f) H2O2 concentration of 0.01% and thioureadioxide concentration of 0.04% constituted the optimal concentrations for polymerization of PFHMA/GMA at a ratio of 5:5, and (g) the polymerization reaction proceeded initially very fast, then levelled off. (h) The water/oil repellency of the copolymerized cotton samples relied on the percent of PFHMA in total percent polymer add‐on; these properties attained maximum at 4.25% PFHMA in a total polymer add‐on of 22.5%.
Polychelates of a tetrafunctional bisoxime
Authors: Suthar H. B. , Shah J. R.
Published: April 2003

Mn(II)‐, Co(II)‐, Ni(II)‐, and Zn(II)‐polychelates of 4,4′‐(4,4′‐Biphenylylenebisazo)‐di(2‐hydroxy acetophenone oxime) have been synthesized and characterized on the basis of their physicochemical properties. An octahedral structure is suggested for all the polychelates. The order of thermal stability for all the polychelates was determined from their thermogravimetric analyses.
Interface distribution functions of isotactic polystyrene — poly(2,6‐dimethylphenylene oxide) blends
Authors: Wenig W. , Schöller T.
Published: April 2003

Morphological parameters of isotactic polystyrene (iPS) · poly(2,6‐dimethylphenylene oxide) (PPO) blends have been determined from measurements of the small angle X‐ray scattering by calculating interface distribution functions. Applied to the compatible system iPS/PPO this method yields a number of reliable parameters such as the long period and mean thicknesses of crystal lamellae and interlamellar spacings. A comparison of the results obtained from the calculation of the interface distribution functions with those derived from model calculations show that theoretical calculations using the density model yield essentially the same results.
Effect of styrene on properties of vinyl ester resins, I
Authors: Varma I. K. , Rao B. S. , Choudhary M. S. , Choudhary V. , Varma D. S.
Published: April 2003

The paper describes the effect of styrene on the properties of bis(methacryloxy) derivatives of epoxy resins (vinyl ester resins). The styrene concentration in the resin was systematically varied between 20–60 wt.‐%. The curing characteristics of vinyl ester resins changed only marginally on dilution with styrene. Dilution with styrene resulted in a decrease in tensile modulus and increase in elongation of neat resin castings and glass fibre reinforced laminates. The glass transition temperature of laminates was determined by dynamic mechanical analysis and was found to decrease with increasing styrene content.
A microhardness test for monitoring the thermal stabilization of solid PVC
Authors: Gonzalez Ana , Pastor Jose Maria , de Saja Jose Antonio , Perez Aurelio
Published: April 2003

The Vickers microhardness test has been found to be a new and attractive analytical tool for the study of the thermal degradation of rigid poly(vinyl chloride) sheets stabilized with different ratios of calcium/zinc carboxylates.
Computer‐simulation der polykondensation von phenol mit formaldehyd
Authors: Steffan Roland
Published: April 2003

Der zeitliche Verlauf der Polykondensation von Phenol mit Formaldehyd zu Resolen wird anhand eines kinetischen Modells mit einem Mikrocomputer simuliert. Durch Variation der Geschwindigkeitskonstanten und des Ausgangsmolverhältnisses von Phenol und Formaldehyd wird der Einfluß unterschiedlicher Reaktionsbedingungen auf wichtige Harzeigenschaften wie Restmonomergehalt, zahlenmittlerer Polymerisationsgrad, Verzweigungs‐ und Methylolierungsgrad untersucht. Die Eigenschaftsmerkmale der Endprodukte werden insbesondere durch das Ausmaß intramolekularer Vernetzungen, d. h., durch den Mikrogelanteil beeinflußt.
Acetylation behaviour of cotton and bagasse celluloses. II. Effect of hot alkali refining
Authors: Abou‐State M. Amine , Fahmy Abel M. , El‐Din Nabil M. Safy
Published: April 2003

The alkali pretreatments of cotton linters, bagasse dissolving pulp, and bagasse kraft pulp increased the accessibility of the cellulose hydroxy groups to acetylating molecules. The pretreatment with hot alkali resulted in a higher degree of esterification than with cold alkali.

The filterabilities of cellulose acetates obtained from alkali pretreated samples of cotton linters, dissolving pulp, and kraft pulp were better than in case of the untreated samples. Hot refining resulted in better filterability than cold refining, but resulted in stronger degradation and lower thermal stability than cold refining.

The presence of hemicelluloses in the untreated pulp lowered the reactivity towards acetylation but favoured the reactivity towards xanthation. In case of cotton linters both reactivities were improved by the alkaline pretreatments. The increase in reactivity resulting from the depolymerization of the cellulose overcame the increase in inaccessibility resulting from drying after the alkaline treatment.

The removal of hemicelluloses from the dissolving and kraft pulps by alkaline extraction deteriorated the reactivities towards xanthation, but had a favourable effect on the reactivity towards acetylation.
Graft copolymerization of methyl methacrylate with EPR and EPDM rubber. Effect of solvent and initiator
Authors: Severini Febo , Pegoraro Mario , Giudice Monica
Published: April 2003

The homopolymerization and graft copolymerization of methyl methacrylate with EPR and EPDM rubber was studied in a variety of solvents using benzoyl peroxide and azobisisobutyronitrile as initiators. Under the conditions of our experiments the yield of homopolymer and of graft copolymer for the solvents used increased in the order

cyclohexane > decaline > toluene > benzene

The grafting yield depends particularly on the concentration of the rubber solution. The grafting mechanism is discussed in terms of different initiators (AIBN and Bz2O2).
Migration of a representative additive from standard and from high‐impact polystyrene into test fat HB 307
Authors: Klahn J. , Figge K. , Meier F.
Published: April 2003

The migration of the antioxidant n‐octadecyl‐3‐(3,5‐di‐tert.‐butyl‐4‐hydroxyphenyl)‐propionate from standard polystyrene and selected high‐impact polystyrenes into the test fat HB 307 was investigated by means of radiotracer techniques, especially its dependence on contact time and temperature. Characteristic differences between the migration properties of the additive in standard polystyrene on the one hand and those in the high‐impact types on the other hand were found which obviously are caused by the different physical structures of these plastics. In the high impact types below 70°C the predominant migration process was found to be diffusion from the disperse rubber phase near the contact surface, whereas above this temperature the additive molecules are preferably diffusing through the polystyrene matrix.

Simple rules are given by which the procedure for calculating migration values — which we developed earlier for polyolefins — can be used to predict the migration of additives from high‐impact polystyrene into fat.
Compatibility and molecular structure of rubbers
Authors: Braun Hans‐Georg , Rehage Günther
Published: April 2003

Compatibility of 17 pairs of rubbers has been investigated by means of phase separation, glass transition measurements and electron microscopy. Influence of structural details like side chains, configuration of monomer units and distance between double bonds in the chain on the compatibility of polymers has been elucidated. Experimental data lead to following results:

Side chains have the strongest influence on compatibility; poly(isobutene) and poly(pentenamer), e.g., are highly incompatible. With decreasing influence on compatibility follows the configuration of the double bond in the polymer chain. Polymers with equal configuration are more compatible than polymers with different configuration. The structural detail with the weakest influence on compatibility is the distance between double bonds along the polymer chain. Poly(octenamer) and poly(pentenamer), e.g., with 6 and 3 methylene groups between the double bonds are less compatible than poly(butadiene) and poly(pentenamer) with a distance of 2 and 3 methylene groups.

Cis‐poly(pentenamer) and natural rubber were found to be highly compatible although electron micrographs show domains with an average diameter of 50 Å.
Radiation‐Induced graft copolymerization, I. Graft copolymerization of methyl methacrylate onto nylon‐6
Authors: Nayak P. L. , Lenka S. , Das A. P.
Published: April 2003

The radiation‐induced graft copolymerization of methyl methacrylate onto nylon fibers was investigated at room temperature. The homopolymer was separated by soxhlet extraction. The graft yield increases with increase of dose rate from 0.1768 to 0.7072 Mrad. The percentage of grafting increase with increasing monomer concentration. Addition of copper sulphate and a non‐ionic surfactant, sodium lauryl sulphate, supresses the formation of homopolymer. The value of Gb, the number of branches per 100 eV of energy absorbed in the substrate polymer, and the value of α, the fraction of substrate polymer grafted, have been computed. A kinetic scheme has been suggested.
Synthesis and characterization of resins from urea and acrolein
Authors: Šebenik A. , Osredkar U. , Vizovišek I.
Published: April 2003

The reactions of urea with acrolein in neutral and acidic media were studied by means of 1H‐ and 13C‐NMR spectroscopy. The addition of aldehyde groups to urea seems to be the first step of the reaction. In the second step in neutral medium the groups and the double bonds react with the amide groups. In the acidic medium the condensation of as second step was dominant. In the further course of the reaction highly crosslinked resins are formed which are insoluble and unmeltable. Chemical shifts of individual compounds are given. On the basis of these data, it was possible to set up tentative reaction schemes. The determination of the concentrations of reaction products as functions of reaction time allowed to establish the kinetics of individual reactions.
Aromatische polyphosphonate: Thermoplastische polymere von extremer brandwidrigkeit
Authors: Schmidt Manfred , Freitag Dieter , Bottenbruch Ludwig , Reinking Klaus
Published: April 2003

Durch alkalikatalysierte Polykondensation aromatischer Dihydroxyverbindungen mit Phosphonsäurediarylestern in Gegenwart geringer Mengen an speziellen verzweigenden Monomeren wurden verzweigte, hochmolekulare, thermoplastisch verarbeitbare Polyphosphonsäureester erhalten, die eine herausragende Flammwidrigkeit zeigen. Die mechanischen, thermischen, elektrischen und chemischen Eigenschaften eines typischen Vertreters dieser Thermoplastklasse — dem Poly[4,4′‐dioxydiphenylmethylphosphonat] — werden erstmals beschrieben. Es zeigt sich, daß das obengenannte Polymethylphosphonat zu den gut thermoplastisch verarbeitbaren, wärmeformbeständigen, äßerst schlag‐ und kerbschlagzähen Kunststoffen gerechnet werden kann, das innerhalb der halogenfreien Thermoplaste die höchste Flammwidrigkeit besitzt und sogar einen Großteil der hochhalogenhaltigen Kunststoffe in der Brandwidrigkeit übertrifft. Über den Verbleib des chemisch gebundenen Phosphors unter Pyrolysebedingungen an Luft wird eine Aussage gegeben: die Pyrolysegase enthalten ca. 2/3 des im Polymeren gebundenen Phosphors in Form von Phosphorsäure und Methylphosphonsäure. Die Anhebung der Wärmeformbeständigkeit der Polyphosphonate gelingt durch Einkondensation von Carbonat‐ und Arylestergruppen unter Bildung von thermoplastischen amorphen Polycarbonatophosphonaten und Polyesterphosphonaten — ebenfalls Kunststoffen mit signifikant verbesserten Brand‐widrigkeitseigenschaften.
Struktur und eigenschaften von mehrphasenkunststoffen. Deformations‐ und bruchverhalten von polycarbonat/ABS‐mischungen
Authors: Morbitzer L. , Kreß H. J. , Lindner C. , Ott K. H.
Published: April 2003

PC/ABS‐Mischungen haben als polymere Konstruktionswerkstoffe in den verschiedensten Anwendungsbereichen zunehmend an Bedeutung gewonnen, weil sie aufgrund ihres Legierungsaufbaues günstige Eigenschaftskombinationen besitzen. Obwohl diese Legierungen bereits seit längerem im Einsatz sind, liegen in der Literatur nur vergleichsweise wenige Untersuchungen über die grundlegenden physikalischen Aspekte vor. Mit den hier vorgestellten Untersuchungen wird der Einfluß unterschiedlicher Zusammensetzungen der Mischungen aus den Einzelkomponenten PC, SAN und Pfropfpolymerisat (SAN gepfropft auf Polybutadien) auf das Phasenverhalten sowie auf das Yield‐ und Bruchverhalten betrachtet und mit den Deformationsmechanismen in Verbindung gebracht. Eine nachfolgende Arbeit wird sich mit der Deformationsmorphologie befassen.
Emulsion polymerization of methyl methacrylate in presence of egyptian delta titano magnetite ore using different initiators
Authors: Moustafa Abdalla B. , Badran Ahmed S. , El‐Fettouh Abou , Abd‐El‐Hakim A. , Diab Moustafa A. , Shandy Sami M. M.
Published: April 2003

The emulsion polymerization of methyl methacrylate was carried out either emulsifier free initiated with NaHSO3 or with dodecylbenzene sodium sulphonate or potassium persulphate at different temperatures. The polymerization was carried out in aqueous media in absence and in presence of Egyptian Delta titano magnetite ore (EDTMO) (black sand). When small amounts of the ore were added the initial rate of polymerization was found to increase with the increase of the amount of ore. Larger amounts of the ore resulted in a decrease of the rate. When the reaction was initiated with sodium bisulfite the rate of polymerization was found to increase with the increase of EDTMO. In presence of 0.1 g/50 cm3 (reaction mixture) of the ore, the apparent activation energy Ea was found to decrease from 14.2 without EDTMO to 9.9 kcal/mol when the polymerization was initiated with sodium persulphate, and from 30.2 to 24.4 kcal/mol when initiated with potassium persulphate. The obtained average molecular weights were found to increase with the increase of EDTMO.
A hydroxyketone‐diamine poly schiff base and its polymeric chelates
Authors: Patel M. N. , Jani B.
Published: April 2003

The preparations of a poly(azomethine) (PSB) via condensation of 4,4′‐dihydroxy‐3,3′‐dibenzylbiphenyl with 4,4′‐diaminodiphenylmethane and its polychelates are described. PSB acts as a tetradentate ligand. A structure of the polymers is proposed. All the polychelates except those with Zn(II) as metal are paramagnetic, dark colored powdery solids which are insoluble in common organic solvents.
Synthesis and polymerization of a styryl terminated oligovinylpyrrolidone macromonomer
Authors: Akashi Mitsuru , Kirikihira Isamu , Miyauchi Noriyuki
Published: April 2003

The esterification of a carboxy group terminated vinylpyrrolidone oligomer with chloromethylstyrene under mild conditions resulted in a styryl terminated oligovinylpyrrolidone macromonomer. The purity of the obtained macromonomer was greater than 95%. Copolymerization of the macromonomer with styrene in ethanol using BPO as catalyst yielded a graft copolymer having a hydrophobic backbone and amphiphilic branches, which was found to have a spherical form and was dispersable in water and ethanol.
Blockcopolymere aus poly‐1,4‐benzamid und 6‐66‐copolyamiden. 1. Synthese und charakterisierung
Authors: Martin Roland , Götz Walter , Vollmert Bruno
Published: April 2003

Durch irreversible Polykondensation von 4‐Aminobenzoylchlorid‐Hydrochlorid in einer Lösung von Aminoendgruppen besitzenden 6‐66‐Prepolyamiden wurden Segmentcopolyamide aus Poly‐1,4‐benzamid und 6‐66‐Copolyamid (60/40) hergestellt. Die Molekulargewichte der eingesetzten aliphatischen Copolyamide, bestimmt durch photometrische Analyse nach Umsetzung mit 2,4‐Dinitrofluorbenzol, betrugen 5 000, 13 000 und 21 000. Die Molekuargewichte des Aramids wurden nach einer Näherungsmethode durch Viskosimetrie in konzentrierter Schwefelsäure bestimmt.

Der Nachweis des Blockcopolyamids gelang qualitativ durch Untersuchungen des Löslichkeitsverhaltens in NMP/LiBr/H2O‐Mischungen sowie quantitativ durch Kombination von Extraktionsversuchen mit Trifluorethanol mit Trübungstitrationen in H2SO4/H2O.
Electronic processes in poly(p‐phenylene) and related compounds I. Paramagnetic and electrical properties of doped poly(p‐phenylene)
Authors: Czerwiński W. , Bala W. , Kreja L.
Published: April 2003

Poly(p‐phenylene) (PPP) was prepared by polymerization of benzene and was exactly purified from oligomers and the catalyst. IR spectra of the resulting material indicated only para substitution and a DP about 20. PPP is a polycrystalline substance with a small degree of crystallinity and is thermally resistant up to 798 K. The annealing of pristine polymer produced a material with higher crystallinity and crystallite size. In our investigations we examined the electrical properties of doped (AlCl3) and undoped PPP at different temperatures. The mechanism of conductivity is explained assuming the existence of the Schottky barriers between polycrystalline grains and intergrain regions. The WAXS and ESR data are compared with the electrical results.
A simple method for evaluation of molar volumes Vu and V1 for polymer‐diluent systems
Authors: Patel K. C. , Patel R. D.
Published: April 2003

A simple method for the evaluation of the molar volume of the repeating unit Vu of a polymer and that of the diluent used for determining the thermodynamic parameters from the fusion of polymer‐diluent systems has been reported. The thermodynamic parameters calculated using these values are in fairly good agreement with those reported in the literature.
The polymerization of hexachloro cyclotriphosphazene by molybdenum phosphate and tungsten phosphate
Authors: Kajiwara M. , Saito H.
Published: April 2003

The polymer of (NPCl2)3 was obtained by bulk polymerization. Especially, linear polymer was predominantly formed when tungsten phosphate as catalyst was used.
Morphology and mechanical properties of silicate filled polyurethane elastomers based on castor oil and polymeric MDI
Authors: Varma A. J. , Deshpande M. D. , Nadkarni V. M.
Published: April 2003

Elastomers of castor oil and polymeric 4,4′‐diphenylmethane diisocyanate (PMDI; functionality 2.7) filled with clay, wollastonite, silica, talc, and calcium carbonate were prepared and their properties compared with the unfilled elastomer. It was found that clay and wollastonite fillers can be used for cost reduction without any detrimental effects on the mechanical properties. Scanning electron micrograph studies of freshly cut surfaces of the silicate filled elastomers showed that clay and wollastonite are much more compatible with the elastomer than silica, talc, and calcium carbonate. Results of gel time measurements in the castor oil — PMDI reaction are also presented as a help for the selection of processing parameters in the manufacture of the filled and unfilled elastomer.
Modification of polyethylene with methacrylic acid, IV. Diffusion of methanol vapour through modificate membranes
Authors: Bryjak Marek , Trochimczuk Witold
Published: April 2003

The diffusion of methanol vapour through membranes obtained from polyethylene and from polyethylene grafted with 5 · 10−4 mol/cm3 of poly(methacrylic acid) was studied. Different mechanisms of diffusion have been found in each type of membrane. The comparison of diffusion coefficients, activation energies and time lags suggested that methanol molecules diffuse through the poly(methacrylic acid) domains. A structural model of the modified polyethylene has been proposed.
The influence of sulphur and its mixtures with polyfunctional monomers on the efficiency of crosslinking of polypropylene initiated by dicumyl peroxide
Authors: Čapla Milan , Borsig Eberhard , Lazár Milan
Published: April 2003

Gel formation in crosslinking of isotactic polypropylene initiated by dicumyl peroxide (DCP) is increased by addition of sulphur at 170°C; the dependence of gel formation on sulphur concentration (cDCP = const.) has a maximum at DCP/S equal to one. The highest gel content at DCP/S = 1 is obtained in the presence of about 0.7% of sulphur. The addition of divinylbenzene influences slightly the gel content, while pentaerythritol tetrallylether decreases it considerably.
Competitive interaction of polyanions and 2‐(4′‐hydroxyphenylazo) benzoic acid with bovine serum albumin
Authors: Kuramoto Noriyuki , Sakamoto Munenori , Komiyama Jiro , Iijima Toshiro
Published: April 2003

The binding of the anionic dye 2‐(4′‐hydroxyphenylazo) benzoic acid (HABA) to bovine serum albumin (BSA) at pH 6.0–7.5 was studied by spectrophotometry. The values of the dissociation constants were obtained by use of a modified Langmuirtype equation for HABA. Competitive binding of the polyanions sodium poly(styrene sulfonate) (PSSNa), potassium poly(vinyl sulfate) (PVSK), poly(acrylic acid) (PAA), and poly(methacrylic acid) (PMAA), with HABA to BSA were evaluated by variations in the difference spectra of BSA‐HABA‐polymer systems.
Sauerstoffbeweglichkeit und photooxidativer zerfall von 1‐(4′‐N,N‐diethylaminophenyl)‐azo‐2‐naphthol in polymerfilmen
Authors: Müller Franz Werner , Schiller Kurt , Marx Jörg
Published: April 2003

Der photooxidative Zerfall von 1(4′‐N,N‐Diethylaminophenyl)‐azo‐2‐naphthol, das in 17 verschiedenen organischen polymeren Bindemitteln eingebettet war, wird wesentlich beeinflußt durch die Effizienz der Triplettbildung, die chemische Natur des Polymeren und die Diffusion des Sauerstoffs in diesem.

Untersuchungen zur Löschung der verzögerten Fluoreszenz von Pyronin B durch Sauerstoff in den verschiedenen Bindemitteln führen beim Vergleich mit den Ausbleichraten des Azofarbstoffs zu dem Schluß, daß der geschwindigkeitsbestimmende Schritt für den photooxidativen Farbstoffzerfall in den Polymeren die zeitlich und räumlich begrenzte Diffusion des Singulettsauerstoffs vom Ort seiner Entstehung zum Fänger ist.

Neben Darstellungen zur Meßmethode wird auf die kinetische Analyse der Fluoreszenzlöschversuche eingegangen.
Copolymerization of 4‐vinylpyridine macromers with butylacrylate
Authors: Severini Febo , Pegoraro Mario , Saija Leo
Published: April 2003

4‐Vinylpyridine macromers ending with methacryloyl functions have been prepared. Their reactivity in copolymerization with butylacrylate is considerably lower than that of 4‐vinylpyridine monomer. Graft copolymers with butyl acrylate have been prepared and characterized.
Blockcopolymere aus poly‐1,4‐benzamid und 6‐66‐copolyamid. 2. Haftvermittelnde eigenschaften in KEVLAR‐verbundsystemen
Authors: Martin Roland , Götz Walter , Vollmert Bruno
Published: April 2003

KEVLAR‐Filamente wurden mit der Lösung eines Blockcopolymeren aus Poly‐1,4‐benzamidsegmenten (M̄w= 28 600) und 6‐66‐Copolyamid (60/40)‐Segmenten (M̄w= 19 000) in 96proz. H2SO4imprägniert. Danach wurden die Filamente in Thermoplastfolien unterschiedlicher Polarität (Polyamid‐6, eine pfropfcopolymerhaltige Legierung aus Polyethylen und Polyamid‐6, ein Acrylester‐Acrylsäure‐Ethylen‐Terpolymeres (Ionomer) und LD‐Polyethylen) senkrecht zur Folienebene eingelagert. In Faserauszugsversuchen wurden zur Charakterisierung der Haftfestigkeit die Delaminierungsscherspannung, die Delaminierungsarbeit und die Reibungskraft beim Herausziehen der Faser gemessen.

Die Imprägnierung von KEVLAR‐Fasern mit Blockcopolyamid erhöhte die Haftfestigkeiten in polaren Matrixmaterialien erheblich. Bei Ionomer‐Folien war die relative Steigerung der Delaminierungsarbeit mit 670% bei weitem am höchsten. Bei Polyamid‐6 und bei der Polyamid‐Polyethylen‐Legierung betrug der Effekt 130%, während bei dem unpolaren Polyethylen praktisch keine Änderung festzustellen war.

REM‐Untersuchungen der herausgezogenen Fasern lassen erkennen, daß das Zerrißen der Verbundmaterialien nicht nur entlang der Faser‐Matrix‐Grenzfläche verlief, sondern daß dabei auch grenzflächennahe Bereiche von Faser und Matrix beteiligt waren.
Influence of solvent on the thermodynamic parameters and stability of some complexes of poly(ethylene oxide) and acrylic copolymers
Authors: Chatterjee S. K. , Yadav J. B. , Sethi K. R.
Published: April 2003

Stability constant and thermodynamic parameters (e.g. ΔH0, ΔS0) have been determined for interpolymer complexes of several acrylic copolymers and poly(ethylene oxide) in aqueous medium and water‐DMF mixtures. It has been observed that stability constant and thermodynamic parameters of the interpolymer complexes change with the composition of the medium. Some of these observations have been attributed to the change in the degree of solvation of component polymers, reduced hydrophobic interaction and dielectric constant of the medium.