bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiblock copolymers by polymeric initiators via free radical mechanism
Authors: Hazer Baki
Published: April 2003

Polymeric peroxycarbamate initiators containing polyazoester or polyethylene adipate blocks were synthesized. They can be used to prepare multiblock copolymers by radical polymerization in a procedure involving several steps. Bulk and solution polymerizations are suitable techniques in these steps.

The polymerization of styrene with these initiators was investigated over a wide range of conversion. Longer polymerization times led to an expected decrease in peroxygen contents of the active polystyrenes.

Styrene/methyl methacrylate/n‐butyl methacrylate, polyethylene adipate/styrene/methyl methacrylate, polyethylene adipate/styrene/methyl methacrylate/n‐butyl methacrylate and polyethylene adipate/styrene/methyl methacrylate/acrylonitrile multiblock copolymers were obtained in this way.
Application of di‐functional organic peroxides in the polymerization of ethylene under high pressures
Authors: Luft Gerhard , Seidl Hans
Published: April 2003

The suitability of difunctional organic peroxides for the synthesis of low density polyethylene (LDPE) was examined with a view to improve the results. Polymerization tests were carried out in a stirrer autoclave pilot plant using three different difunctional compounds with different levels of thermal stability at a pressure of 1700 bar and temperatures of between 180 and 290°C. The conversion and the specific peroxide consumption were measured and the average molar masses of the polymers obtained were determined. The solubility of the peroxides in isododecane was also examined.
The polymerization of hexachloro cyclotriphosphazene by molybdenum silicate and tungsten silicate
Authors: Kajiwara M.
Published: April 2003

Solution and bulk polymerizations of hexachloro cyclotriphosphazene (NPCl2)3 were carried out using molybdenum silicate and tungsten silicate as catalysts. The polymer did not form by the solution polymerization, but was obtained by the bulk polymerization. When tungsten silicate was used, a linear polymer was predominantly formed.
Etude des propriétés des films préparés par evaporation des solutions d'un polymére dans différents solvants
Authors: Grognet Annick , Papantoniou Christos
Published: April 2003

Films of a plasticized random terpolymer were prepared by evaporation of solutions in several solvents. The glass transition temperatures of the films were determined and were found to follow the Fox's equation. Their tensile modulus, measured just below the glass transition temperature, was found to depend on the residual solvent content of the films.
Preparation and optical properties of polymer films having lamellar structure and cylindrical air bubbles
Authors: Cha Younsik , Tsunooka Masahiro , Tanaka Makoto
Published: April 2003

Polymer films displaying lustrous, iridescent colors were obtained by irradiation of poly(methyl methacrylate) films containing 1,4‐benzoquinone with a medium pressure mercury lamp followed by solvent treatment. The colors were not produced by visible light‐absorbing species in the polymer films because the color seen in reflection was complementary to that seen in transmission.

It was found from optical and scanning electron microscopic studies of the polymer films that they have two characteristic optical structures; a great number of microcylindrical air bubbles oriented perpendicularly to the film surface and periodic lamellas with planes parallel to the film surface. The colors of the polymer films were thought to be produced by this periodic lamellar structure which would act as a three dimensional optical reflection grating. Continuous color change on tilting the sample could also be explained by the Bragg equation.
Grafting of acrylonitrile onto different cellulose forms by the xanthate method
Authors: Shukry Nadia , El‐Ashmawy Ahmed E. , El‐Saied Houssni
Published: April 2003

Wood pulp and regenerated cellulose (viscose fibres) were grafted by the xanthate method. In some cases, the regenerated cellulose was more accessible towards grafting than wood pulp. Grafting of incompletely regenerated viscose fibres which were obtained by changing the spinning conditions in order to spare the step of partial xanthation caused more orientation of the filaments. The mechanical properties of these filaments were in general poor.
Diffusion de l'eau dans le polyuréthanne par spectrometrie micro‐ondes
Authors: Henry François , Berteaud André‐Jean
Published: April 2003

Parmi les nombreuses méthodes permettant de suivre la circulation de l'eau libre dans un matériau, les méthodes diélectriques (région des micro‐ondes) semblent à la fois particulièrement sensibles et appropriées.

A 9 GHz nous avons pu étudier et déterminer, au moyen d'une technique de perturbation d'une cavité résonnante, les coefficients de diffusion de films de polyuréthanne. Des mesures simultanées de perméabilité à la vapeur d'eau ont aussi été entreprises.

Les résultats mettent en évidence d'une part un faible comportement Fickien et d'autre part une augmentation du coefficient de diffusion et de perméabilité avec l'épaisseur. Le caractère hydrophile des constituants du film et le manque d'aération de la surface sont pris en compte comme élément d'interprétation.
Study of crosslinking of unsaturated polyester resins by relaxation methods
Authors: Jelcic Zelimir , Hedvig Péter , Ranogajec Franjo , Dvornik Igor
Published: April 2003

Radiation and thermal curing of unsaturated polyester resins with styrene were investigated by combining differential thermal analysis with electric and mechanical relaxation techniques. A microprocessor controlled combined relaxation equipment of special construction was used. By radiation initiated curing the reaction was interrupted at different stages and the products were analyzed. Relaxation and simultaneous differential thermal measurements were also made during the course of gamma radiation and peroxide initiated thermal curing. By this way the shift of the characteristic transitions of the resin as a function of conversion could be studied. Also the change of the phase‐structure of the resin caused by the reaction was monitored. By deconvolution of the dielectric spectrum band the physical structure was found to become heterogeneous by crosslinking.

Besides the shift of the transition temperatures the oscillator strength of the dielectric transition was found to decrease with conversion. Electrical polarization and depolarization studies were also performed. A special intermittent load thermomechanical technique was used for separating elastic from viscous response of the sample subjected to external mechanical force. The transitions exhibited by the thermomechanical curves were found to shift to higher temperatures by crosslinking and the compliance plateaus decreased.
Charakterisierung von styrol‐acrylnitril‐copolymeren durch ausschlußchromatographie und turbidimetrische titration der dabei erhaltenen fraktionen. II. Untersuchung einer probe mit breiter chemischer verteilung
Authors: Glöckner Gottfried , Albrecht Victoria , Francuskiewicz Frieder , Ilchmann Dieter
Published: April 2003

Eine Probe eines Styrol‐Acrylnitril‐Copolymeren mit etwa 40 mol‐% Acrylnitril wurde mit Hilfe der Trübungstitration (TT), der Ausschlußchromatographie (SEC), der TT von SEC‐Fraktionen und der Hochdruck‐Fällungschromatographie (HPPLC) der SEC‐Fraktionen untersucht. Während die TT und die SEC für das unfraktionierte Copolymere zwar breite, aber scheinbar homogene Verteilungen nach der Molmasse und der Zusammensetzung lieferten, offenbarten Kreuzuntersuchungen (TT von SEC‐Fraktionen/HPPLC) das Vorliegen von drei ziemlich unterschiedlichen Komponenten. Dieses Ergebnis wurde zuerst durch die TT der SEC‐Fraktionen mit n‐Hexan als Fällungsmittel gefunden. Nachfolgend wurde es mit der HPPLC unter Verwendung eines Elutionsgradienten mit n‐Hexan und Tetrahydrofuran als Komponenten bestätigt. In einem topographischen Bild wurde die Zusammensetzung der untersuchten Copolymerprobe dargestellt.
Stability constants and thermodynamic parameters of some intermacromolecular complexes of acrylic copolymers and poly(vinyl pyrrolidone)
Authors: Chatterjee S. K. , Yadav J. B. , Sethi K. R.
Published: April 2003

Stability constants and thermodynamic parameters (e.g. ΔH0 and Δ0) have been determined for intermacromolecular complexes of methacrylic acid‐methacrylamide and acrylic acid‐acrylamide copolymers with poly(vinyl pyrrolidone) (PVP). The presence of nonionic units in the copolymers greatly enhances the stability of the complexes with PVP. The enthalpy and entropy changes of the systems with temperature have been interpreted in terms of various modes of interaction between the components.
Effect of thermal treatment on the electrothermographic and electrical properties of poly(acrylonitrile butadiene styrene)
Authors: Pillai P. K. C. , Gupta A. K. , Sharma S. K.
Published: April 2003

Studies on the electrothermographic and conductivity behaviour of poly(acrylonitrile butadiene styrene) (ABS) films of different thermal pretreatments were carried out. The resistivity in ABS layers stored at 50°C was found to be low (∼ 1015 Ω · cm). The charge acceptance and its retention also is poor. The reason for that is the adsorption of water molecules. The layers, when thermally treated at 100°C or more for 5 h, show an enhanced resistivity (∼ 1017 Ω · cm at 50°C) and hence an improvement in charge acceptance as well as in charge retention. Environmental and storage conditions as well as thermal treatment during layer preparations have no effect on the temperature dependence of the resistivity beyond 110°C.
Studies on structural aspects of cellulose acetate
Authors: Suthar J. N. , Patel M. J. , Patel K. C. , Patel R. D.
Published: April 2003

In the present investigation an attempt has been made to throw light on the structure of stiff chain amorphous polymers. For this purpose cellulose acetates (CA) having different degrees of substitution (DS) were prepared. The samples were characterised by IR‐spectroscopy, Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). Scanning electron micrographs of the cryogenically fractured surfaces of these polymers showed that along with lamellar structures, nodular structures were also observable.
Radiation induced copolymerization of hydroxyalkyl methacrylate — vinyl acetate networks. Physico‐mechanical properties
Authors: Ramakrishna M. S. , Deshpande D. D. , Babu G. N.
Published: April 2003

Radiation induced copolymerization of hydrogel networks based on hydroxyalkyl methacrylates, vinyl acetate, and dimethacrylates was reported. The equilibrium water content of copolymers was compared for the uncrosslinked, and crosslinked materials. The effect of composition of comonomer, nature, and concentration of crosslinker on the mechanical properties of HEMA‐co‐VAc and HPMA‐co‐VAc was discussed.
Beiträge zur galvanisierung von polymeren, 11. Metallisierung von mischungen aus epoxidharzen und acrylnitril‐butadien‐copolymeren
Authors: Springer Jürgen , Förster Frank , Hadiwinoto Siauw Ling
Published: April 2003

Die Metallisierung von Mischungen aus Epoxidharzen und Acrylnitril‐Butadien‐Copolymeren hängt von der Wahl des geeigneten Mischungsverhältnisses sowie von dem Härter ab, mit dem das Epoxidharzvorprodukt in Gegenwart des Copolymeren zur Reaktion gebracht wird. Bei der Verwendung von Triethylentetramin als Härter werden die höchsten Werte für die Abzugsfestigkeit erzielt, die durch kurzzeitige Ozonbehandlung auf bis zu 150 N/25 mm gesteigert werden können. Längere Ozonisierungszeiten führen zu geringeren Haftfestigkeiten und zur Schädigung des Materials.

Kavernen treten nur bei epoxidharzreichen Mischungen auf und vergrößern sich mit zunehmender Ozonisierungszeit. Diese Proben besitzen relative geringe Abzugsfestigkeiten.
Polystyrene‐supported aluminium silver chloride as selective ethylene adsorbent
Authors: Hirai Hidefumi , Hara Susumu , Komiyama Makoto
Published: April 2003

Polystyrene‐supported aluminium silver chloride was prepared as a solid and selective adsorbent for ethylene by refluxing silver chloride, aluminium chloride, and macroreticular‐type polystyrene resin in carbon disulfide, followed by removal of the solvent in vacuo. The adsorbent rapidly adsorbed ethylene about equimolar to aluminium silver chloride under 1 atm at 20°C. Almost all the ethylene adsorbed was released by subjecting the adsorbent to a reduced pressure 8 mm Hg at 20°C for 10 min. The adsorbent, however, showed no adsorption of carbon monoxide under 1 atm at 20°C.
Chemistry and application of organic isocynates, VII. Conversion of hexamethylene diisocyanate into biuret and urea derivatives by means of hexamethylenediamine
Authors: Balewski Andrzej , Lesiak Tadeusz , Ciemniak Grażyna
Published: April 2003

Attempts of the conversion of hexamethylene diisocyanate (HDI) into biuret and urea derivatives by treatment with hexamethylene diamine (HDA) at 140°C, 155°C, and 170°C at different molar ratios of the reactants have been described. By means of gel permeation chromatographic analyses, the approximate contents of the mainly formed prepolymers were estimated. Also a scheme of the formation of all obtained oligomers has been proposed. On the basis of the results of physico‐chemical measurements, the influences of temperature and molar ratios of the reagents on the properties of the resulting products have been interpreted. It has been shown, that about 30 prepolymers of molecular weights (MW) up to 1300 having a biuret or a urea structure, are formed.
Improving the dyeing properties of textiles via utilization of redox systems. I. Dyeing of wool and wool/polyacrylic blend fabrics with acid dye
Authors: Ibrahim N. A. , Haggag K. , Hebeish H.
Published: April 2003

Dyeing of wool and wool/polyacrylic fabrics with an acid dye, namely, Kiton Scarlet 4 R, was carried out in absence or presence of different redox systems. The latter were based on sodium, potassium, or ammonium peroxodisulphate or potassium periodate as oxidant and glucose, sodium thiosulphate, potassium pyrosulphite or thiourea as reductant. Regardless of the redox system used, the colour strength was far greater in presence than in absence of the redox system. Except in case of potassium periodate/glucose redox system, increasing the oxidant concentration up to 0.03 mol/l caused significant enhancement in colour strength. The same was observed upon increasing the temperature from 30 to 60°C as well as the time from 10 to 40 minutes. It is postulated that presence of the redox system alters the mode of dye attachment to the substrate. Association of the dye with the substrate, wool in particular, seems to involve covalent bonding beside the usual salt‐linkage. Hence the approach presented is advantageous in producing dyeings with much higher colour strength and dye fixation at relatively low temperature.
Liquid crystal polymers. 20. Poly(1,4‐cycloalkylhydroquinone terephthalates) with flexible hexamethylene spacers in the main chain
Authors: Dicke Hans‐Rudolf , Lenz Robert W.
Published: April 2003

A series of cycloalkylhydroquinone terephthalate copolyesters containing varying amounts of 1,6‐hexanediol flexible spacers were prepared by a two‐step reaction procedure and characterized for their liquid crystalline properties. Included in the series were hydroquinone monomers containing norbornyl, cyclohexyl, cycloheptyl, and cyclooctyl substituents. The norbornylhydroquinone series formed nematic melts at 1,6‐hexanediol contents of 30 mol‐% or less, but not at 40 mol‐%. The glass temperatures and melting points were higher than expected in the norbornylhydroquinone series, but analysis of dyad contents by 13C‐NMR indicated that the comonomers were randomly distributed.
A DSC study of the polymerization of 2‐Vinylpyridine in dimethylformamide
Authors: Alberda van Ekenstein Gert O. R. , Held Bert‐Jan , Tan Yong Y.
Published: April 2003

The polymerization of 2‐vinylpyridine (2VP) in dimethylformamide (DMF) with azobisisobutyronitrile (AIBN) as initiator was studied with a differential scanning calorimeter. By taking an appropriate amount of AIBN and after correction for its decomposition, the following values could be obtained:

Heat of polymerization ΔHp,o = −68 ± 4 kJ/mol; overall Arrhenius activation parameters Ea = 90.0 ± 4 kJ/mol and ln A = 24 ± 1.0 (A = 2.6 × 1010 dm3/2/mol1/2. s).
Humidity dependence of the electric characteristics of quaternized poly(vinylpyridine)‐perchlorate complexes
Authors: Hirata Mitsutoshi , Inoue Shozo , Yosomiya Ryutoku
Published: April 2003

The dependence of electrical characteristics of polymer complexes on ambient humidity was studied for complexes of quaternized poly(2‐vinylpyridine) and of quaternized poly(4‐vinylpyridine) with perchlorates (HClO4, LiClO4, KClO4). The electric resistance decreased linearly with the increase in ambient humidity for both types of complexes. The complex containing the perchlorate with the larger ionic radius showed a lower electric resistance. No change was observed in the humidityresistance relationship for more than ten months.
8‐Hydroxy quinoline‐furfural polymers
Authors: Patel A. U. , Patel H. S. , Patel M. N.
Published: April 2003

Poly(8‐hydroxyquinoline‐furfural) (8HQ‐Fu) was prepared by condensing 8‐hydroxyquinoline with furfural in the presence of aqueous K2CO3 and NaOH as catalysts using equimolar proportions of the two reactants. The polymer samples were characterized by elemental analysis, IR spectra, and thermogravimetric analysis. The number average molecular weight (Mn) was determined both by vapour pressure osmometry and by non‐aqueous titration. Intrinsic viscosities of all the polymer samples were measured in DMF.

Polymeric metal chelates of Cu2+, Fe3+, Co2+, Zn2+, Mn2+, Ni2+ with the 8HQ‐Fu polymer were prepared and characterized.
Chemische charakterisierung von elektronen‐bestrahltem polypropylengranulat
Authors: Klee D. , Gribbin D. , Kirch D.
Published: April 2003

In jüngster Zeit wird der Einsatz von elektronen‐bestrahltem Polypropylengranulat als Nukleierungsmittel bei der Extrusion vorgeschlagen. Die vorliegende Arbeit beschäftigt sich mit der chemischen Charakterisierung der elektronen‐bestrahlten Granulate. Da die Bestrahlung unter atmosphärischen Bedingungen stattfindet, werden nicht nur der Zusammenhang von Abbau und Vernetzung, sondern auch Oxidationsprodukte bestimmt. Die oxidative Schädigung findet hauptsächlich in den oberen Moleküllagen statt und führt über peroxidische Zwischenprodukte zur Entstehung von Carbonylgruppen. Neben für funktionelle Gruppen spezifischen Nachweismethoden wird die oberflächen‐spezifische ESCA‐Methode zur Erfassung des Oxidationsgrades und zur indirekten Vinylgruppenbestimmung nach der Bromierung eingesetzt.
Emulsionspolymerisation von vinylchlorid, 10. Einfluß wasserlöuslicher oligomerer auf das dehydrochlorierungsverhalten des polymeren
Authors: Tauer Klaus , Behnisch Jürgen
Published: April 2003

Die Dehydrochlorierung unterschiedlicher PVC‐Proben wird mit Hilfe eines Thermoanalyzers, der mit einer konduktometrischen Meßzelle gekoppelt ist, untersucht. Die Messungen erfolgen nichtisotherm. PVC‐Proben unterscheiden sich synthesebedingt in dem Gehalt an niedermolekularen wasserlöslichen Oligomeren. Mit steigender Konzentration der oligomeren Produkte in den Pulvern wird eine erhöhte HCl‐Abspaltung bei niedrigen Temperaturen gemessen. Die Bildung der Oligomeren in Abhängigkeit von der Polymerisationsrezeptur, dem Umsatz und der Monomerkonzentration wird diskutiert.
Modification of gelatin by grafting
Authors: George Anne , Radhakrishnan Ganga , Joseph K. Thomas
Published: April 2003

Graft copolymerization of butyl acrylate onto gelatin has been carried out using potassium persulphate as initiator both in aqueous and in water‐acetic acid medium. Kinetic parameters like rate of grafting, percent grafting, and grafting efficiency were determined for the two systems. The grafting was proved by IR spectra of the isolated graft chains which showed amide absorption bands characteristic for the amino acids.
Acetylation behaviour of cotton and bagasse celluloses. III. Upgrading pulps by extraction with sodium hydroxide‐borax solutions
Authors: Abou‐State M. Amine , Helmy Samia A. , El‐Din Nabil M. Safy
Published: April 2003

The presence of borax during alkali refining of pulps increased the solubility of the short‐chain celluloses and hemicelluloses and thus improved their chemical characteristics. Small improvements in the chemical characteristics of cotton linters took place. A stronger effect was observed in case of the dissolving pulp and a more pronounced effect took place in case of the kraft pulp. Cold 20% NaOH refining was more effective than hot 5% NaOH refining. The physical and sub‐microscopic characteristics of linters were mainly affected. Refining lowered the D.P., increased the affinities towards water and alkali, decreased the crystallinity, and improved the reactivity towards xanthation. The presence of borax resulted in a more open and accessible fine structure and better reactivity. Cold refining of the dissolving and kraft pulps resulted in lower reactivity than hot refining and the presence of borax improved the reactivity. It also increased the yield of cellulose acetate. The increase in the solubility of the short‐chain celluloses and hemicelluloses resulting from the presence of borax resulted in better homogenisation of the pulp. This was reflected in better chemical and physical characteristics of the acetate.
Zum einfluß hochdispersen polyvinylchlorids auf die polymerisation aminhaltiger monomerer der acrylreihe
Authors: Eliseeva V. I. , Aslamazova T. R. , Morozova E. M. , Göurnitz E. , Wulf K. , Bischof C.
Published: April 2003

Die radikalische Polymerisation von aminhaltigen Acrylmonomeren wird in Anwesenheit von PVC als Füllstoff beschleunigt. Zur Klärung des Effekts wird der Einfluß der PVC‐Konzentration auf die Polymerisationskinetik von Acrylmonomeren mit und ohne Aminogruppe bestimmt sowie durch viskosimetrische und Quellungsmessungen die Immobilisierung der Monomeren am Füllstoff untersucht. Die Ergebnisse bestätigen die Vorstellung von einer spezifischen chemischen Wechelwirkung zwischen PVC und aminhaltigem Monomeren.
Improving the dyeing properties of textiles via utilization of redox systems. II. Dyeing of nylon‐6 with acid dye
Authors: Ibrahim N. A. , Haggag K. , Hebeish A.
Published: April 2003

Redox systems based on potassium, sodium or ammonium peroxodisulphate or potassium periodate as oxidant and glucose, thiourea, sodium thiosulphate or potassium pyrosulphite as reductant were incorporated in the dyeing bath of nylon‐6 under a variety of conditions. An acid dye, namely Kiton Scarlet 4 R was used. The colour strength and dye fixation enhanced outstandingly in presence of the redox system, depending upon kind and concentration of the redox components. Raising the dyeing temperature from 30 to 60°C caused significant improvement in colour strength. The same holds true for duration of dyeing up to 60 min. Beside association of the dye with nylon‐6 by salt‐like bond, a free radical mechanism was suggested.
Reactive polymers, 50. The use of porous polymers in the sorption of tricyclic antidepressant in vitro
Authors: Horák D. , S̆vec F. , Kálal J.
Published: April 2003

Three types of chemically different macroporous copolymers were investigated with respect to the possibility of their application as potential drug sorbents in blood detoxication and compared with activated charcoal which is used for this purpose in most cases. The measurements with a model drug solution were carried out in a dynamic arrangement under conditions resembling haemoperfusion. The effect of particle size of the sorbent on the rate of sorption and actual capacity of the column was detected and elucidated.
The structure of blends of polyethylene and polypropylene with EPDM elastomer
Authors: Fortelný Ivan , Kovář Josef , Sikora Antonín , Hlavatá Drahomíra , Kruliš Zdeněk , Nováková Zuzana , Pelzbauer Zdeněk , Cbreve;efelín Pavel
Published: April 2003

The structure of polyethylene/ethylene‐propylene‐diene (PE/EPDM) and polypropylene/ethylene‐propylene‐diene (PP/EPDM) blends prepared in the whole concentration range of components by mixing in the melt was investigated. The dependence of the torque in mixing on the composition of the blend is more complicated than reported in the literature. The dependence of morphology on composition is similar for both types of blends. According to the X‐ray scattering measurement EPDM considerably reduces the crystallinity of both PE and PP in the blend.
Die modifikationsspezifische wirksamkeit von keimbildnern in polypropylen
Authors: Moos K.‐H. , Jungnickel B.‐J.
Published: April 2003

Es wird über kristallisationskinetische Untersuchungen an isotaktischem Polypropylen berichtet, das mit dem Farbstoff γ‐Chinacridon in unterschiedlichen Konzentrationen versetzt wurde. Durch geeignete Wahl der Präparationsbedingungen konnten Proben mit vorgegebenem Massenverhältnis zwischen kristalliner α‐ und kristalliner β‐Modifikation hergestellt werden. Aus der Analyse des Kristallisations‐ und Schmelzverhaltens konnte, für beide Kristallmodifikationen getrennt, auf die Lamellenseiten‐ und ‐deckflächenenergien der Kristalle gegenüber der eigenen Schmelze sowie gegenüber dem zugesetzten Farbstoff geschlossen werden. Die Ergebnisse belegen, daß durch das γ‐Chinacridon bevorzugt die Bildung von β‐Kristallen gefördert wird; die Stabilität entsprechender Sekundärkeime bis weit über die Gleichgewichtsschmelztemperatur hinaus wird experimentell und theoretisch nachgewiesen.
Poly(oxyethylene) diglycolic acid: A novel blending antistatic agent for polyamide fibres
Authors: Zhao Yao M. , Kimura Yoshiharu , Taniguchi Isoji , Sano Yoshiyuki , Muraoka Youichiro
Published: April 2003

Poly(oxyethylene) diglycolic acids (PEO acids) with average molecular weights of Mn = 8 400 (Ia), 3 300 (Ib), and 1 000 (Ic) were used as blending anti‐electrostatic agents for nylon 6 (Ny6) fibres. The blended fibres containing 2.0 and 5.0 wt.‐% of the PEO acids were successfully spun by the melt‐blend spinning process at 260°C. Processabilities of the spinning and the drawing of the as‐spun filaments were little deteriorated compared with those of the Ny6 control. During the spinning block condensation of I and Ny6 occurred by reaction of their mutual end‐groups. The block copolymers produced were distributed in the filament matrix as coarsely dispersed spheres to form sea‐island structures. These fibres showed good antistatic properties; their performances were in the order of Ia > Ib > Ic, which was parallel to the size, not the number, of the islands. The tensile properties of the fibres containing 2.0 wt.‐% of Ia and Ib were comparable with those of the control. The dyeabilities examined for their knits were not seriously affected, either. In addition, it was indicated that the performance of antistatic property was not lost at all after the dyeing and the subsequent repeated washings. This is because I is anchored covalently to the Ny6 fibre matrix by the condensation above.
Preparation and properties of dialysis membranes prepared from a ternary solution of cellulose acetate/acetone/dimethylformamide
Authors: Schauer J. , Pelzbauer Z. , Vacík J.
Published: April 2003

Dialysis membranes were prepared by casting a solution of cellulose acetate in a mixed solvent acetone/dimethylformamide (1:1) followed by partial evaporation of the solvent from the cast solution at room temperature and by coagulation in icewater. The effect of the polymer concentration in solution and evaporation time of the solvent on tensile strength, morphology, and permeability of the membranes was investigated. Membranes possessing the best mechanical properties are formed from solutions containing 20–28 wt.‐% cellulose acetate and at evaporation times longer than three minutes. The membranes contain the minimal amount of cavities in their lower layer. The permeability of the membranes for low molar mass compounds increases with decreasing polymer concentration in the casting solution and with extension of the evaporation time of the solvent up to ca. 2 min.
Morphologie und eigenschaften schlagzähmodifizierter teilkristalliner polymerer
Authors: Kloos Friedrich
Published: April 2003

Es wurden Untersuchungen über die Zusammenhänge zwischen der Morphologie und den Eigenschaften von schlagzäh modifiziertem Polypropylen und Polyoxymethylen durchgeführt. Durch Bestimmung der Volumendilatation bei uniaxialer Deformation wird beim schlagzäh modifizierten Polypropylen ein Übergang von einem Scherfließprozeß zum Crazing festgestellt, wenn die Einfriertemperatur der amorphen Bereiche des Polypropylens unterschritten wird. Beim schlagzäh modifizierten Polyoxymethylen laufen beide Prozesse gleichzeitig ab, wobei das Scherfließen die Kinetik der Deformation festlegt. Durch Beeinflussung der Morphologie bei der Herstellung der Legierungen über Schmelzmischverfahren und über Blockcopolymerisationsverfahren kann ihr Einfluß auf die Deformationsvorgänge überprüft werden. Es ergeben sich ähnliche Gesetzmäßigkeiten, wie sie für amorphe schlagzähe Polymere gefunden werden.
Study on formation, morphology, and properties of Si3N4 and SiC fibers
Authors: Hanna S. B. , Abdel‐Mohsen F. F.
Published: April 2003

Silicon nitride and silicon carbide fibers were prepared by firing silicon resin mixed with iron under NH3 flow at 1 500°C. The effect of preparation variables, iron content, flow rate of NH3 gas, and time of heating, on the yield and Si3N4/SiC ratio was studied. The yield of reaction increases considerably with increasing the iron content up to 1.7 wt.‐% iron and decreases slightly beyond this value. The Si3N4/SiC ratio in the yield is affected in the same direction. Heating for a longer time at 1 500°C favours the formation of silicon carbide instead of silicon nitride. The conversion reaction remains constant for the gas flow rates greater than 0.5 1/min.

The product has grown dominately in the form of smooth and uniform fibers of a mean diameter of less than 0.3 μm. The electrical resistivity and hardness of silicon nitride and carbide composite material were measured and discussed on the basis of its composition.
Modification of polyethylene with methacrylic acid, III. Wide angle X‐ray scattering and small angle light scattering study of the modificates
Authors: Bryjak Marek , Trochimczuk Witold
Published: April 2003

The structures of membranes obtained from low‐density polyethylene (LDPE) grafted with methacrylic acid (MA) have been studied. Using WAXS and SALS methods it has been shown that introduction of up to 0.5 mol/dm3 of poly(methacrylic acid) (PMA) does not affect the initial structure of PE. It was concluded from SALS measurements that the PMA domains are located in the interspherulite regions of PE.
Synthesis, characterization, and thermal behaviour of new epoxy polyesterimides
Authors: Martínez Pedro‐Alberto , Cádiz Virginia , Mantecón Ana , Serra Angels
Published: April 2003

New epoxy resins have been synthesized by the reaction of diimide‐diacids trimellitimide derivatives containing different aliphatic and aromatic fragments in N‐methyl pyrrolidone (NMP) with their corresponding diglycidylesters, using several molar ratios. The polymer composition has been determinated by chemical and elemental analyses. Their IR, 1H, and 13C NMR spectral data allowed to confirm the structural unit. Epoxy polyesterimides are soluble in polar organic solvents and show good thermal resistance. Differences on the basis of the introduced aliphatic or aromatic fragments were observed.
Thermodynamic properties of poly(butylene terephthalate)
Authors: Aleman J. V.
Published: April 2003

Specific heat of poly(butylene terephthalate) was measured in a Mettler TC 10 differential thermal analyzer. Its glass transition, melting behaviour, as well as its enthalpy, entropy, Gibbs free energy, and the rigidity of the chains are described.
A new class of photopolymers with pendent dimethylmaleimide groups. III. Comparative study of different photopolymers with pendent olefinic structures including dimethylmaleimide groups
Authors: Finter Jürgen , Haniotis Zeppos , Lohse Friedrich , Meier Kurt , Zweifel Hans
Published: April 2003

A series of photopolymers with the same polymer backbone but with different pendent chromophors including four imidyl structural units — dimethylmaleimide, 4‐methyl‐3,4,5,6‐tetrahydrophthalic acid imide, 3,4,5,6‐tetrahydrophthalic acid imide, and 3,4‐dihydro‐1,2‐naphthalene dicarboxylic acid imide — as well as trans‐3‐phenyl propenoyl (cinnamoyl) and 1,3‐diphenyl‐2‐propenonyl (chalcone) units were synthesized by polymer analogous reaction of the corresponding carboxylic acid chloride derivatives with poly(vinyl alcohol). The polymers, sensitized with thioxanthone, were characterized by their minimal exposure energies derived from gel point as well as photographic sensitivity measurements. Quantitative relations between chromophore conversion and exposure were established for unsensitized films of the chalcone and the 3,4‐dihydro‐1,2‐naphthalene dicarboxylic acid imidyl polymer. Upon irradiation with monochromatic 365 nm light the sensitized and unsensitized imidyl polymers proved to be one order of magnitude more sensitive than the chalcone and cinnamoyl polymers.
Tensile deformation of regenerated and native cellulose fibres
Authors: Northolt M. G. , De Vries H.
Published: April 2003

The tensile deformation of well‐oriented cellulose fibres has been reexamined. It is demonstrated that not only the fibre structure but also the deformation mechanism is similar to that found in high performance aramid fibres. An explanation is proposed for the difference between the elastic moduli of cellulose I and II. In view of these results it is possible to assess the prospect for improving the mechanical properties of cellulose fibres.
Étude des propriétés rhéologiques des mélanges de polypropylène‐polystyrène et de polystyrène‐polyéthylène basse‐densité
Authors: Deri Fawaz , Genillon René , May J. F.
Published: April 2003

Le but de ce travail est d'examiner les propriétés rhéologiques à l'état fondu des mélanges à base de PP/PS et LDPE/PS. Les mélanges ont été examinés dans le domaine des températures 160–210°C. Les courbes des variations de la viscosité apparente en fonction de la composition à tension et vitesse de cisaillement constante pour le PP/PS présentent un minimum, les courbes des variations du facteur de Barus en fonction de la composition passent par un maximum. Il semble que le domaine de faible viscosité est associé à un domaine de forte élasticité pour les matériaux viscoélastiques examinés.
Theoretical reactivity of tolylene‐2,4‐diisocyanate and tolylene‐2,6‐diisocyanate, and structures of oligomers contained in the products of conversion of tolylene‐2,4‐diisocyanate into urethane and biuret derivatives
Authors: Czerwiński Wojciech , Ciemniak Grażyna
Published: April 2003

By the methods of quantum chemistry it is possible to calculate a number of theoretical quantities dependant on the structure of chemical compounds. In this paper quantum chemical calculations have been done in order to explain quantitatively the differences in the reactivity of isocyanate groups in tolylene diisocyanates and for the account of directions of oligomer formation with definite structures. These quantities have been connected in a simple way with the chemical reactivity of the molecules. The results of calculations made with the INDO semiempirical method are in a very good correlation with results of experimental investigations.
Synthesis of poly(acrylic acid)‐and poly(styrene)‐cyanoethylated cotton graft copolymers using gamma radiation
Authors: Hebeish A. , Zahran A. H. , Rabie A. M. , El‐Naggar A. M.
Published: April 2003

Six substrates, untreated cotton (substrate I), alkali‐treated cotton (substrate II), and cyanoethylated cottons having 0.12% N (substrate III), 0.55% N (substrate IV), 0.77% N (substrate V) and 1.24% N (substrate VI) were graft copolymerized with either acrylic acid or styrene at different monomer concentrations and radiation dosages. The effect of using water/methanol mixtures at different ratios as polymerization media for graft copolymerization of the six substrates with styrene on the graft yield was also investigated. Furthermore, moisture regain and dyeability of the six substrates before and after copolymerization were examined. It was found that the graft yield increases by increasing monomer concentration and radiation dose irrespective of the monomer or substrate used. Using water/methanol mixtures as polymerization media was advantageous for grafting of styrene onto the six substrates. Nevertheless, for a given set of polymerization conditions, the graft yield follows the order: substrate VI > substrate V > substrate IV > substrate III > substrate II > substrate I, indicating that presence of cyanoethyl groups in the molecular structure of cotton cellulose affords additional sites for graft polymerization. Poly(acrylic acid)‐cyanoethylated cotton graft copolymers show much higher moisture regain than cyanoethylated cottons particularly when the carboxylic groups of the graft were in the sodium form. The opposite holds true for poly(styrene)‐cyanoethylated cotton graft copolymers which exhibit much lower moisture regain as compared with cyanoethylated cottons. The colour strength of cyanoethylated cotton dyed with direct or reactive dyes decreases significantly after copolymerization with poly(acrylic acid) prior to dyeing. On the other hand, this copolymerization improves the affinity of cyanoethylated cottons for the basic dye and brings about perceptible shade. With respect to poly(styrene)‐cyanoethylated cotton graft copolymers, they acquire higher colour strength than the cyanoethylated cottons when dyed with direct, disperse, and basic dyes but lower colour strength upon dyeing with the reactive dye. Also reported were the moisture regain and dyeability of untreated and alkali‐treated cotton before and after copolymerization with acrylic acid or styrene for comparison.
Viscoelastic behaviour of molten polypropylene/polyethylene blends
Authors: Santamaría A. , Muñoz M. E. , Peña J. J. , Remiro P.
Published: April 2003

Some aspects of the viscoelastic behaviour of 10 blends of polypropylene and long branched polyethylene have been studied. Shear viscosity measurements have been carried out at temperatures from 180 to 220°C and shear rates from 1 s−1 to 1 000 s−1. The elasticity has been studied in terms of the extrudate swell, entrance pressure losses, and shrinkage effects. The most striking results are the enormous shrinkage effects observed on the extrudates at 180°C: for some blend compositions the reduction of the initial length of the sample attains a value of 800%.
Systèmes réactifs polyuréthannes bloqués, 4. Cinétique de réaction en présence de tissus de renforcement. Propriétés des matrices correspondantes
Authors: Viollaz François , Lam Thanh My , Pascault Jean‐Pierre , Camberlin Yves
Published: April 2003

Die Reaktion von geblockten Isocyanat‐Präpolymeren mit einem aliphatischen Diamin wurde in Gegenwart von faserverstärkenden Materialien (Carbonfasern und Glasfasern mit unterschiedlicher Oberflächenbehandlung) untersucht. Die Molekulargewichte der Polyurethanharnstoffe wurden durch Gelpermeationschromatographie als Funktion der Reaktionszeit gemessen. Niedrigere Molekulargewichte wurden in Gegenwart von Glasfasern erhalten, mit einem einschneidenden Abfall bei rohem Glas.

Diese Ergebnisse können durch komplexierende Aminfunktionen auf der Faseroberfläche erklärt werden.
New block copolymers. 1. Synthesis and characterization of an (a–b)n type block copolymer
Authors: Mahato Beni Madhab , Shit Subhas Chandra , Maiti Mrinal M. , Maiti Sukumar
Published: April 2003

A new (A–B)n type block copolymer has been synthesized by polycondensation of acidchloride terminated poly(ethylene‐terephthalate) with amine‐terminated butadiene acrylonitrile rubber (ATBN). The acid chloride terminated poly(ethylene‐terephthalate) was synthesized by reacting terephthaloyl chloride with ethylene glycol using N,N‐dimethyl formamide as the solvent. The resulting polymer was characterized by nitrogen analysis, IR and NMR spectroscopy. The solubility characteristics, solution viscosity behaviour, crystallinity, and phase characteristics of the polymer have been studied.
The dielectric behaviour of shellac‐urea‐formaldehyde resins
Authors: Goswami D. N.
Published: April 2003

The Cole‐Cole method has been employed for an analysis of the dielectric relaxation data, obtained by Bhattacharya, of a shellac‐urea‐formaldehyde resin (SUF) in the temperature range 30–100°C. Three relaxation processes were observed for temperatures 30 to 50°C. At 60°C, two relaxation processes were noticed. The relaxations at 70°C and above represented typical Cole‐Cole type. The static dielectric constant, relaxation time and distribution parameter of SUF were found to be greater than those of the unmodified shellac. Marked changes in the above mentioned parameters were observed during a rise of temperature from 70 to 100°C. The results of the present study indicate that some rearrangement in the tertiary disposition of the resin molecules takes place during the rise of temperature from 30 to 100°C.
Re‐analysis of extensional flow data of polymer melts
Authors: Shenoy A. V. , Saini D. R.
Published: April 2003

Extensional flow behaviour is very important in polymer processing operations such as fiber spinning and film blowing but there is scanty experimental data in the literature due to inherent difficulties in measurement of the relevant flow parameters. In the present paper, an attempt has been made to correlate the existing available data on the extensional flow of three generic types of polymer melts through a logarithmic plot of modified extensional viscosity function, ηE · MFI, and a modified extension rate, (ε/MFI)2. The method may be extended to other polymeric systems.
Reactive polymers, 51. The temperature behaviour of macroporous methacrylate sorbents
Authors: Hradil J. , Švec F.
Published: April 2003

The behaviour of macroporous methacrylate copolymers was investigated in the temperature range between 20 and 270°C. On the basis of retention of methyl alcohol and n‐decane a discontinuity at 40°C was recorded in all cases, interpreted by the increasing mobility of chains of surface layers of the polymer globules. This temperature agrees with the reported Tg value of poly(glycidyl methacrylate) and is independent of further substitution of the polymer chain with ionogenic groups. At 210–250°C depolymerization takes place; in the case of methacrylic acid copolymers cyclic anhydrides are formed, while in the case of esters alkyls are eliminated. Modified copolymers of 2,3‐dihydroxypropyl methacrylate with ionogenic groups are more stable thermally — the depolymerization proceeds under the same conditions to a smaller degree. Heating is connected with changes in the morphology of particles and pores, and also in the polarity of the polymers noticeable by the ratio of retentions of alcohols and paraffins and by the heat of dissolution.
Use of a design for the optimization of rheological properties of mixtures of lauryl acrylate‐stearyl methacrylate copolymers and a resinic ester
Authors: Perillon J. L. , Lanteri P. , Longeray R. , Dreux J. , Mathieu D. , Feneuille D. , Luu R. Phan Tan
Published: April 2003

The use of modern methods of building optimal experimental matrices is especially suitable for optimization of properties of polymeric compound mixtures. We show how, with a limited number of well defined experiments, we optimized rheological properties of a mixture of a lauryl acrylate‐stearyl methacrylate based copolymer and a resinic ester. The methodology is founded upon the determination of coefficients of a mathematical model postulated a priori, describing the property studied in function of variables of composition. This model is then used for forecasting purposes to determine simultaneously the copolymer composition and the ratio of different ingredients to obtain a mixture possessing the expected rheological properties. These mixtures were studied to elaborate a truly polyvalent cross‐country ski‐wax.
Photo‐induced polymerization of diethyleneglycol diacrylate in the presence of poly(methyl methacrylate). 3. Structure of the resulting polymer network
Authors: Braun D. , Gehrisch R.
Published: April 2003

In view of the manufacture of printing plates, films consisting of diethyleneglycol diacrylate and poly(methyl methacrylate) acting as a binding agent were cured by UV‐radiation. 9‐Phenyl acridine was used as the photoinitiator.

During polymerization of the diacrylate a highly crosslinked polymer network is formed, having strong inhomogeneities concerning crosslink density. Because of incompatibility between poly(diethyleneglycol diacrylate) and poly(methyl methacrylate) phase separation occurs. However, entanglements of the PMMA chains with the polymer network cause the formation of a semi‐interpenetrating polymer network, thus preventing a two‐phase morphology with a typical domain structure.
Chemical heterogeneity of a partially modified dextran with ethyl carbonate groups
Authors: Arranz F. , Sánchez‐Chaves M.
Published: April 2003

A sample of a partially modified dextran with ethyl carbonate groups was fractionated by cross‐fractionation. Two systems THF/hexane and DMF/0.5% aqueous NaCl were selected on the basis of cloud‐point determinations. The chemical composition distribution (CCD) and molecular weight distribution (MWD) curves were constructed from fractionation data. The chemical heterogeneity observed may be correlated with the pattern of reaction of dextran with ethyl chloroformate. The cumulative data were fitted by the two‐parameter MWD functions of Tung and of Wesslau.
Celluloseaktivierung: Geeignete behandlungen und strukturveränderungen
Authors: Focher B. , Sarto V. , Prati G.
Published: April 2003

Die Passivität der Zellstoffe wird verschiedenen Faktoren zugeschrieben: Der Regularität der primären Struktur der Celluloseketten, deren steifer Beschaffenheit sowie deren Fähigkeit, während der Biosynthese die Gestalt von langen Bändern anzunehmen, welche in hohem Maße zur Bildung eines Wasserstoffbrückennetzes neigen. Das Ergebnis ist ein hochgeordnetes und dicht gepacktes Polymeres.

Es wird über die Aktivierung von Zellstoffausschuß berichtet, der infolge Derivatisierungsreaktionen und biologischer Konversion als Rohstoff für die Herstellung von Erzeugnissen mit hohem Mehrwert verwendet werden kann.

Die Auflösung der Abfallstoffe in nichtwäßrigen Lösungsmitteln wird als mögliche Alternative gegenüber den üblichen Verfahren zur Herstellung von Kunstfasern besprochen.

Zwecks Aktivierung der Zellstoffe wurden physikalische (γ‐ und UV‐Bestrahlung), physikalisch‐chemische (Quellung, Entkristallisation und Auflösung) sowie chemische Verfahren (Copolymerisation) angewendet. Die Aktivierung der Zellstoffe wurde mittels Untersuchung ihrer Struktur (Röntgenstrukturanalyse, Festkörper‐NMR‐Spektroskopie, Doppelbrechung) ermittelt. Außerdem wurde die Geschwindigkeit der enzymatischen Hydrolyse bestimmt.
Anionic polymerization of isoprene with n‐butyllithium in n‐heptane in a continuous stirred tank reactor
Authors: Bandermann Friedhelm , Tappe Ralf
Published: April 2003

The living anionic polymerization of isoprene with n‐butyllithium in n‐heptane in a continuous stirred tank reactor was investigated. It is shown that there exist no multiple steady states for monomer and initiator conversions and for molecular weights at monomer and initiator feed concentrations >4 mol/1 and >0,02 mol/1, respectively, as postulated by Porter et al.6, but that the results may well be described by the known model of Sinn1.