bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of copolymers modifying PVC on its physical and mechanical properties and its UV‐radiation resistance. VI. Photodegradation and crosslinking of PVC films containing MMA/MA, VC/VAC, MBS or ABS
Authors: Kamińska A. , Kaczmarek H.
Published: April 2003

The degradation and crosslinking induced by 253.7 nm wavelength radiation was investigated in pure PVC films and in films containing 1–10 wt.‐% of modifying copolymers (ABS, MMA/MA, VC/VAC or MBS).

It has been found that these copolymers decrease the efficiency of PVC crosslinking. Especially ABS and 3–10 wt.‐% MBS clearly hamper this reaction. The induced changes of the limiting viscosity number (LVN) and solubility observed in samples containing MBS and VC/VAC suggest that these copolymers increase or decrease the efficiency of photodegradative or crosslinking processes, depending on the concentration of the copolymers in the samples.
Contribution à l'etude des propriétés rhéologiques, à l'etat fondu, de matériaux composites à base de fibres de cuir et de polyéthylène basse densité ou de copolymères d'ethylène. I. Etudes en rhéomètre à capillaire
Authors: Ayad D. , Genillon R. , May J. F.
Published: April 2003

L'étude des propriétés rhéologiques, à l'état fondu, de matériaux composites à base de fibres de cuir et de polyéthylène basse densité, ou de copolymères d'éthylène, a été effectuée à diverses températures et à différentes vitesses de cisaillement. Le comportement des mélanges, dont la matrice est le polyéthylène basse densité, est différent de celui des mélanges à base de copolymères. Une interprétation de cette différence de comportement, basée sur les intéractions fibre matrice, a été proposée. Un minimum de la viscosité, observé sur les courbes d'écoulement des mélanges à base de polyéthylène basse densité, a été attribué à une séparation de phase du composite.
Crosslinkable copolyisophthalamides
Authors: Serna Felipe J. , De la Campa José G. , de Abajo Javier
Published: April 2003

Copolyisophthalamides with nadimide pendent groups have been prepared by polycondensation of 5(5‐norbornene‐2,3‐dicarboximido)isophthaloyl chloride (NCIC) and isophthaloyl chloride with bis(4‐aminophenyl)methane, the ratio between both diacid chlorides being 0/100, 10/90, 15/85, 20/80, 25/75, 50/50, and 100/0. By 1H‐NMR it has been proved that the composition of the copolymers closely coincided with the ratio of monomer's feeds.

Properties such as solubility, glass transition temperatures, and thermal resistance have been measured and related to the copolymer's composition. Crosslinking studies have been carried out by DSC, and a comparison of properties of copolymers before and after thermal crosslinking has been made. The effect of crosslinking on the mechanical strength of copolymer films has also been measured.
Chlorination of polypropylene in suspension
Authors: Puszyński Andrzej , Dwornicka Jadwiga
Published: April 2003

It is shown that both, potassium chloride and ammonium molybdate, accelerate the chlorination of isotactic polypropylene up to the content of 15 wt.‐% Cl, while sodium chloride speeds up the process up to 25 wt.‐% Cl. At the same time, no effect of salts on the chlorination of atactic polypropylene was observed. From IR analysis followed that chlorine substitution occurred not only at the ternary carbon atom but occasionally at primary and secondary ones as well.
Solubility of poly(n‐alkylmethacrylate)s in hydrocarbons and in alcohols
Authors: Sander Uwe , Wolf B. A.
Published: April 2003

Poly(methylmethacrylate) (PMMA), poly(butylmethacrylate) (PBMA), and poly(decylmethacrylate) (PDMA) are completely miscible with toluene at normal pressure from room temperature up to the boiling point of the solvent. In alkanes (C6 to C10) and 1‐pentanol the solubility increases with the length of the side chain of the polymer: PMMA always exhibits a solubility gap within the above temperature range, PBMA shows upper critical solution temperatures (except n‐hexane, which is a non‐solvent), and PDMA mixes completely with all alkanes under consideration. Alcohols (up to C4) are non‐solvents for PMMA but theta solvents for PBMA and PDMA (except ethanol which is a non‐solvent for the latter). The low temperature demixing of ethanol/PBMA is shifted towards lower temperatures by pressure.
Trocknung als verfahren zur charakterisierung von asymmetrischen ultrafiltrationsmembranen
Authors: Paßlack Jürgen , Staude Eberhard
Published: April 2003

Strukturen von und Wasserzustände in Membranen lassen sich auf einfache Weise durch Trocknung erfassen, vorausgesetzt, die Membranen kollabieren nicht. Anhand der Trocknungskurven von Ultrafiltrationsmembranen aus Polyamid, Polysulfon und Polyethersulfon kann sowohl die Asymmetrie nachgewiesen als auch der Anteil an freiem und gebundenem Wasser in der Membran quantititativ bestimmt werden. Vergleichende DSC‐Messungen zeigten eine gute Übereinstimmung der Wasserwerte. Unterschiedliche Trocknungskurven lassen sich eindeutig unterschiedlich hergestellten Membranen zuordnen. Mit steigendem Sulfonierungsgrad nimmt die Hydrophilie von substituierten Polyethersulfonmembranen zu; die jeweiligen Trocknungskurven weisen auf zunehmenden Wassergehalt und auf Änderungen in der Membranstruktur hin.
Anionische lösungspolymerisation von glycolid
Authors: Braun Dietrich , Kohl Paul R.
Published: April 2003

Die anionische Lösungspolymerisation von Glycolid zu Polyglycolsäure mit verschiedenen Lösungsmittel‐Initiator‐Systemen wurde untersucht. Das Polymerisationsverhalten in Toluol mit den tertiären Aminen Triethylamin und N,N‐Dimethylbenzylamin als Initiatoren und in Sulfolan (Tetrahydrothiophendioxid) mit N,N‐Dimethylbenzylamin wird in Abhängigkeit von Initiatorkonzentration und Reaktionszeit beschrieben.
Changes in the dynamic properties and in the crystallization of polypropylene by incorporation of surface treated and untreated sepiolite
Authors: Acosta José Luis , Ojeda Maria Carmen , Linares Amelia , Romero Mariano
Published: April 2003

In the present work, the changed properties of isotactic polypropylene caused by adding untreated sepiolite and n‐decylaldehyde treated sepiolite were analyzed by studying the isothermal crystallization processes and the dynamic properties of the resulting composites. Variations in the surface activity of the n‐decylaldehyde treated sepiolite leads to significant changes in the measured properties compared to those observed in the composites containing untreated sepiolite. This allows the assumption that the structure of the interface filler/polymer is modified as a function of filler activity.
Modification of polyacrylonitrile fibers with hydrazine and hydroxylamine in aqueous medium
Authors: Karaivanova S. , Badev A.
Published: April 2003

The interaction between polyacrylonitrile (PAN) fibers and hydrazine and/or hydroxylamine in aqueous medium was investigated. The kinetics of the reaction was studied and a step‐like effect was found, testifying to a diffusion‐controlled stage. The Michaelis‐Menten kinetics was used for the description of the initial stage of the reaction. On the basis of the results and the analytical data the mechanism of the process was discussed. By studying the basic physical and physico‐mechanical indices of the fibers it was found that the chemical modification with these bases and a subsequent processing with aqueous solutions of copper salts takes place with notable changes in structure and properties of the fibers. The results obtained lead to improved methods for the production of fibers with chemical resistance and improved fire resistance.
The reaction of sodium silicate with dichlorotetrakis(dimethylamino cyclotriphosphazene)
Authors: Kajiwara M. , Yamamoto N.
Published: April 2003

The reaction of sodium silicate with dichlorotetrakis(dimethylamino cyclotriphosphazene) was carried out under various experimental conditions. The products were white colored, adhesive materials and were soluble in high polar solvents. It was found that the dichlorotetrakis(dimethylamino cyclotriphosphazene) used reacted with silanol. It did not act as middle but as end group because the molecular weight of the product was not increased compared to that of the product derived from sodium silicate alone.
Calorimetric study of partially crosslinked poly(butylene terephthalate) and poly(ethylene terephthalate)
Authors: Fakirov Stoyko , Avramova Nadka , Schultz Jerold
Published: April 2003

An attempt is made for partial crosslinking (i.e., only in the amorphous regions) of films of poly(ethylene terephthalate) (PETP) and poly(butylene terephthalate) (PBTP) by diffusion of molten dicumyl peroxide. It is demonstrated that because of steric and structural reasons this technique is applicable only to PBTP. A series of crosslinked and non‐crosslinked samples of drawn and undrawn PBTP films annealed at various temperatures were investigated. The average crystallite sizes have been determined by wide angle X‐ray diffraction and the melting temperatures of crosslinked samples have been measured using DSC. Applying the Gibbs‐Thomson equation, the equilibrium melting temperature of PBTP is found to be Tm0 = 250 ± 4°C.
Modifizierung der integralen form der Mayo‐Lewis‐Gleichung zur berechnung der copolymerzusammensetzung bei der semikontinuierlichen polymerisation
Authors: Matějíček Alois , Horký Jaroslav
Published: April 2003

Es werden Gleichungen für eine mathematische Simulation der mehrstufigen chargenweisen Copolymerisation zweier Monomerer vorgeschlagen. Mit Hilfe dieser Beziehungen ist es möglich, den Verlauf der Zusammensetzung der Monomerphase und des gerade entstandenen Polymeren sowie die integrale Zusammensetzung des Polymeren in Abhängigkeit vom Monomerumsatz zu berechnen. Die vorgeschlagenen Beziehungen bilden ein System von Differentialgleichungen, deren schrittweise Integration numerisch durchgeführt wird. Der vorgeschlagene Berechnungsvorgang wird an einer semikontinuierlichen Emulsionspolymerisation des Systems Styrol/Acrylnitril demonstriert. Aus den berechneten Abhängigkeiten geht die Bedingung hervor, daß nach Erreichen eines quasistationären Zustandes die Reaktionsgeschwindigkeit der Polymerisation größer sein muß als die Dosierungsgeschwindigkeit des Monomergemisches.
Chlorocarboxylation of polyethylene. I. Preparation and structure of chlorocarboxylated polyethylene
Authors: Joshi Shashikant G. , Natu Arvind A.
Published: April 2003

Chlorocarboxylated polyethylene (CCPE) is produced by simultaneous reaction of chlorine and maleic anhydride (MA) with polyethylene (PE). Low concentrations of the carboxyl groups in CCPE have been quantitatively estimated by dye interaction method and non‐aqueous titration procedure. IR spectroscopic data are presented for the structural characterization of CCPE. During chlorocarboxylation, maleic anhydride can be anchored to the backbone chlorinated PE (CPE) chain as a chlorinated single monomeric unit without forming any graft copolymer of short branches.
Chemical reactions in the bulk of the epoxy‐functional silane hydrolyzate
Authors: Xue G. , Ishida H. , Koenig J. L.
Published: April 2003

Chemical reactions in the epoxy‐functional silane hydrolyzate bulk have been studied by Fourier transform infrared spectroscopy (FT‐IR). It was found that the silanol group opened the epoxy ring upon heating, concurrently with the silanol condensation. The kinetics of these reactions were studied, and the relative reaction rates were obtained.
Propriétés viscoélastiques à l'etat fondu de matériaux composites à base de fibres de cuir et de polyéthylène basse densité ou de copolymères d'ethylène. II. Etudes en balance rhéomètre
Authors: Ayad Djamel , Genillon René , May Jean‐François
Published: April 2003

L'étude des propriétés viscoélastiques à l'état fondu, de matériaux composites à base de fibres de cuir et de polyéthylène basse densité ou de copolymères d'éthylène, a été réalisée à la balance rhéomètre. Elle confirme les interprétations proposées, basées sur les interactions fibres‐matrice, de l'influence de la charge et de la nature de la matrice. Elle permet également de connaître les variations de la composante élastique qui joue un rôle important en transformation.
End‐groups in poly(methyl methacrylate) and polystyrene prepared by radical polymerization in the presence of derivatives of stilbene
Authors: Bevington John C. , Breuer Stephen W. , Huckerby Thomas N.
Published: April 2003

Polymers of methyl methacrylate and styrene have been prepared in the presence of low concentrations of various para‐derivatives of stilbene, using 13C‐benzoyl peroxide as the source of the initiating radicals. Examination of the 13C‐NMR signals due to benzoate end‐groups showed that in each case a high proportion of the initiator fragments was attached to a stilbene unit. The results indicate that each of the stilbenes has very high reactivity towards the benzoyloxy radical, depending upon the nature of the substituent. Radical polymerization involving benzoyl peroxide and a stilbene provides a method for the preparation of polymers with special end‐groups.
Spaltprodukte bei der verarbeitung von phenol‐formaldehyd‐formmassen
Authors: Braun Dietrich , Wolde‐Giorgis Kashai
Published: April 2003

Bei der Verarbeitung von Phenol‐Formaldehyd‐Harzen mit Asbest und mit Holzmehl als Füllstoff entstehen neben ca. 98% Wasser niedermolekulare phenolische Spaltprodukte, die durch Dünnschichtchromatographie, Gaschromatographie und Hochdruckflüssigchromatographie isoliert und identifiziert werden. Gefunden wurden Phenol, m‐ und o‐Kresol, verschiedene Dimethylphenole sowie 2‐ und 4‐Hydroxybenzylalkohol.
Photo‐induced graft copolymerization. XV. Graft copolymerization of methyl methacrylate onto nylon‐6 using erythrosin as photoinitiator
Authors: Lenka Subasini , Mohanty Indu B.
Published: April 2003

The photo‐induced graft copolymerization of methyl methacrylate onto nylon‐6 was investigated using erythrosin as the photoinitiator. The systems were buffered with phosphate citrate buffer (Na2HPO4/citric acid). The graft copolymerization was carried out within the temperature range of 35–50°C and from the corresponding Arrhenius plot, the energy of activation was evaluated. The effect of monomer, initiator, ascorbic acid, etc. on the graft yield has been investigated. Further, the effect of solvent on the rate of grafting has been investigated and the chain transfer constant (Cs) of the solvent has been evaluated. The kinetic data and other events indicate that the overall polymerization takes place by a radical mechanism. A suitable mechanism has been suggested and rate expressions have been derived.
A study of polystyrene‐polyvinylmethylether blends by excimer fluorescence
Authors: Qian Renyuan , Gu Xiaohong
Published: April 2003

Studies of interchain excimer interaction in semi‐dilute and concentrated solutions of polystyrene (PS) in a good solvent have been extended to polystyrene/polyvinylmethylether (PS/PVME) polymer‐polymer compatible blends. The constant fluorescence intensity ratio R ≡ IE/IM for blends with a PS content lower than 5 wt.‐%, which is smaller than the value of PS in a dilute solution implies a mixing of PS and PVME chain segments down to molecular level in the compatible blend. The fluorescence intensity has been found to serve as sensitive criterion for phase separation. The cloud point curve for the used PS/PVME system has been obtained showing an LCST at 113°C at ca. 20 wt.‐% PS. It was shown that the one‐phase PS/PVME system is thermodynamically stable at room temperature presumably over the entire concentration range.
Development of a polyimide resin matrix for composites
Authors: Dolui Swapan K. , Maiti Sukumar
Published: April 2003

The low molecular weight polyimides (PI) end‐capped with bismaleimide or amine terminated monomaleimide of six different compositions were synthesized by reacting benzophenone tetracarboxylic dianhydride, hexamethylene diamine, and maleic anhydride. These low molecular weight reactive imide prepolymers were characterized by infra‐red spectra, 1H‐NMR, elemental analysis, vapour pressure osmometry (VPO) technique, solution viscosity (0.5 g/dl in NMP), density and X‐ray measurements. With these resins carbon cloth reinforced laminates were fabricated by the hot press moulding method. These laminates were evaluated by their flexural strength, interlaminar shear strength, density, void content, and fibre content. Optimization studies in mechanical and thermal behaviour of such composites were also carried out.
Effect of moulding pressure on crystallinity in powder processing of semicrystalline polymers
Authors: Radhakrishnan S.
Published: April 2003

The crystalline content in high pressure compacted polymeric powders has been investigated as a function of moulding pressure. It has been noted that the crystallinity Cp varied with the pressure as [C0 — βPα] where α and β were material dependent constants. There also appears a correlation between α, β, and an empirically defined factor which is related to the glass transition temperature, melting point, and compressive yield strength for all the polymers studied. The results have been discussed in terms of various processes taking place during the high pressure compacting step.
Reaction products of polyacrylonitrile with dicyandiamide — new flocculation agents —
Authors: Gohlke Ulrich , Dietrich Klaus
Published: April 2003

A new flocculation agent is prepared by reaction of polyacrylonitrile with dicyandiamide in alkaline solution, followed by acid hydrolysis. The polymer contains guanamine‐, N‐carbimidoyl‐N′‐cyanoguanidine‐, amido‐, hydronaphthiridine‐, and carboxylic‐groups. In consequence of the alkaline and acidic groups present, the polymer shows polyampholytic properties and can be used as a primary flocculation agent. Fields of application are removal of contaminants dispersed in water, like waste, algae, bacteria and also in some cases dissolved substances like dyes, etc. Concepts of the flocculation activity and suggestions of application are discussed.
Studies on the polymerization of methyl methacrylate using ylide as an initiator and degradative transfer agent
Authors: Shukla A. K. , Saini S. , Kumar P. , Nigam S. K. , Srivastava A. K.
Published: April 2003

The polymerization of methyl methacrylate (MMA) initiated by α‐picolinium‐p‐chlorophenacylide in CCl4 at 30, 35, and 40°C for four h was investigated dilatometrically. The orders of reaction with respect to the concentrations of ylide and MMA are 0.22 ± 0.01 and 1.0, respectively. The overall energy of activation and an average value of k/kt are 21.0 kJmol−1 and 0.37 ± 10−2, respectively. The results are explained in terms of radical mode of polymerization with initiator dependent transfer besides bimolecular termination.
Preparation of vinyl chloride‐ethylene copolymers by partial reduction of poly(vinyl chloride)
Authors: Braun Dietrich , Mao Weiyou , Böhringer Bertram , Garbella Rüdiger W.
Published: April 2003

Reductive dechlorination of poly(vinyl chloride) with tri‐n‐butyltin hydride was used to prepare a series of vinyl chloride‐ethylene copolymers covering the complete range of comonomer composition from poly(vinyl chloride) to polyethylene. Osmotic measurements of the molecular weight showed that polymeranalogous products were obtained by the reduction. IR spectra of the copolymers and UV‐VIS spectra of thermally degraded copolymers were utilized to verify the statistical distribution of comonomer units in the polymer. The copolymers containing more than 73 mol‐% ethylene units show appreciable melting during thermal analysis with differential scanning calorimetry. The relationship between the melting temperature and the composition of the copolymers with a high content of ethylene can be expressed by Flory's equation. The reciprocal glass transition temperatures of vinyl chloride‐ethylene copolymers with high contents of vinyl chloride units change linearly with the weight fraction of vinyl chloride in the copolymers. The influence of the composition and the glass transition temperature on the thermal dehydrochlorination is discussed.
Gloss as an inner morphology characteristic of ABS polymers
Authors: Lednický F. , Pelzbauer Z.
Published: April 2003

The connection between inner morphology and gloss was investigated using a series of model samples of ABS polymers processed in the same way. A relation was derived for the dependence of gloss on particle size, and a rule of mixing was suggested for the eventual gloss of a sample containing a mixture of various rubber particles. The logarithm of gloss decreases linearly with particle size; this dependence was verified also using reported data on coating films.

The suitability of the characterization of inner morphology by surface gloss was illustrated using the dependence of impact strength on gloss. The cause of the correlation between the surface properties (gloss) and volume properties (inner morphology, impact strength) is seen in the influence upon the structure of the surface and subsurface layer by the material of the sample's interior.
High‐pressure polymerization of ethylene using methyl isobutyl ketone peroxide as initiator
Authors: Luft Gerhard , Henning Wolfgang , Dorn Max
Published: April 2003

An investigation was carried out into the suitability of methyl isobutyl ketone peroxide (MIKP) as initiator for the high pressure polymerization of ethylene. For this purpose, polymerization tests were carried out in a stirred autoclave at a pressure of 1000 to 2000 bar and a temperature of 195 to 310°C. The initiator concentration of the feed was varied between 6.5 and 42 mol ppm while the residence time was kept at a constant 30 s. Apart from the rate of polymerization, the conversion and the initiator consumption were also determined. The characteristic properties of polyethylene (PE) were determined by measuring the melt flow index, the density and, in some cases, the molecular weight distribution.

Conversion levels of 5 to 27% were achieved with rates of polymerization between 1 and 5.5 kg PE l−1 h−1. The initiator consumption at 1700 bar was in the region of 1 to 2 g I kg−1 PE−1 over a temperature range of 220 to 315°C.

In view of these results, MIKP can be considered as suitable to initiate ethylene high pressure polymerization at 220 to 310°C, particularly in the tubular reactor.

The density of the polyethylene thus prepared is ranging between 0.910 and 0.927 g ml−1. Without the addition of modifiers or cross‐linking agents, the melt flow index varies considerably. The polydispersity of the polymers prepared at a pressure of 1700 to 2000 bar was between 6 and 8 and therefore within the range to be expected for stirred autoclaves. Reducing the pressure to 1000 bar resulted in surprisingly low polydispersity values of 2.4 to 3.7.
Chemical reactions of poly(vinyl pyridine)s with epoxy compounds
Authors: Xue G. , Ishida H. , Koenig J. L.
Published: April 2003

Chemical reactions of poly(vinyl pyridine)s and epoxy compounds were studied both in homogeneous solution and in solid state by Fourier transform infrared spectroscopy and other techniques. The pyridine side group was found to react with the epoxy group, forming networks which contain pyridone and cyclic amide structures. This reaction was observed also in the interfacial region of poly(vinyl pyridine) and γ‐glycidoxypropyltrimethoxysilane hydrolyzate coatings on poly(ethylene terephthalate) fiber substrates.
Studies of etching mechanism of polyimide films on silicon chips
Authors: Xue G.
Published: April 2003

The etching mechanism of polyimide films on silicon chips has been studied. As the film contacts with alkaline solution, the imide bonds hydrolyze quickly, resulting in the formation of polyions. The polyion coils are expanded by electrostatic repulsion. Within the etching time, most part of the polyimide dissolves into solution. The remaining gel contains 10% of original imide bonds and has a molecular weight of 12,000. The gel is not a classical one, but a physical gel which contains relatively small polymer molecules jointed by secondary forces.
Retardation of V5+‐thiourea initiated polymerization of acrylonitrile by phenol
Authors: Mohanty A. K. , Misra M. , Singh B. C.
Published: April 2003

Studies have been made on the kinetics and mechanism of the retardation of V5+‐thiourea initiated polymerization of acrylonitrile by phenol in the temperature range 40 – 50°C. The effects of retarder (phenol), metal ion, monomer, sulphuric acid, some inorganic salts, and organic solvents have also been studied. The most remarkable observation in the present investigation is the positive intercept obtained from the plot of [M]/Rp vs. 1/[M]. A reaction mechanism has been suggested and a suitable rate expression has been proposed and explained in the light of experimental findings.
Chemistry and application of organic isocyanates, VIII. Conversion of 5‐isocyanato‐1‐(isocyanatomethyl)‐1,3,3‐trimethylcyclohexane into biuret and urea derivatives by means of hexamethylenediamine
Authors: Balewski Andrzej , Lesiak Tadeusz
Published: April 2003

Attempts on the conversion of 5‐isocyanato‐1‐(isocyanatomethyl)‐1,3,3‐trimethylcyclohexane (IPDI) into biuret and urea derivatives by treatment with hexamethylene diamine (HDA) at 140°C, 155°C, and 170°C at different molar ratios have been described. By means of gel permeation chromatographic analyses, the approximate contents of the mainly formed prepolymers were estimated. On the basis of the results of physico‐chemical measurements, the influence of temperature and molar ratios of the reagents on the properties of the resulting products have been interpreted. It has been shown, that 12 prepolymers of molecular weights up to 1226 having a biuret or a urea structure are formed.
Thermogravimetrische untersuchung der dehydrohalogenierungspolymerisation von 4‐methylphenyl‐phenyldichlormethan. Untersuchungen über poly(arylenvinylene), 31
Authors: Opfermann Johannes , Scherf Ullrich , Raabe Dietrich , Nowotny Jürgen , Hörhold Hans‐Heinrich
Published: April 2003

Die Bildung von Poly(1,4‐phenylen‐1‐phenylvinylen) aus 4‐Methylphenyl‐phenyl‐dichlormethan wurde thermogravimetrisch im quasi‐geschlossenen System untersucht.

Für den beobachteten zweistufigen HCl‐Eliminierungsprozeß wurden durch Modellierung die Reaktionsordnungen ni, die Aktivierungsenergien Ei und die Geschwindigkeitskonstanten Zi zu n1 = 1,4; E1 = 105 kJ/mol und Z1 = 108,9 s−1 für die erste Stufe bzw. zu n2 = 1,3; E2 = 103 kJ/mol und Z2 = 106,7 s−1 für die zweite Stufe ermittelt. In der ersten Stufe wurden 77% des Gesamtgehaltes an HCl eliminiert. Der Mechanismus der Dehydrohalogenierungspolymerisation wird diskutiert.
Selective carbon monoxide adsorbent composed of polystyrene resin having amino groups and copper(I) chloride
Authors: Hirai Hidefumi , Wada Keiichiro , Kurima Kazunori , Komiyama Makoto
Published: April 2003

A carbon monoxide adsorbent composed of 10 g of a polystyrene resin having amino groups and 70 mmol of copper(I) chloride was prepared by refluxing the resin and copper(I) chloride in acetonitrile, followed by evaporation of the liquid phase at 5 mmHg, 80°C. The adsorbent rapidly adsorbs 15.9 mmol of carbon monoxide under 1 atm at 20°C. 11.4 mmol of adsorbed carbon monoxide are desorbed when the adsorbent is subjected to a reduced pressure (5 mmHg) at 80°C for 10 min. In the second and the later adsorptions, the amount of adsorbed carbon monoxide is virtually constant at 11.4 mmol. The amount of carbon dioxide adsorbed by the adsorbent under 1 atm at 20°C is 2.8 mmol, and the value for methane is 0.0 mmol. The prepared adsorbent is applicable to selective separation of carbon monoxide from gas mixtures containing both carbon dioxide and methane.
Mechanical properties of carboxyl terminated polybutadiene cured with epoxides
Authors: Schwartz Anders
Published: April 2003

Carboxyl terminated polybutadiene (CTPB) has been cured with two trifunctional epoxides, ERL‐0510 and EPON 812, by means of ferric acetyl acetonate (FeAA) and chromium chelates of isopropyl salicylic acid (CrDIPS) as catalysts. In CTPB cured with ERL‐0510 there have been incorporated a carbon black, Sterling MT, and a plasticizer, dioctyl adipate (DOA). Tensile tests have been made at different temperatures and strain rates. The results of maximum stress, strain at break, and modulus have been treated according to the WLF‐equation to give temperature and rate reduced master curves. Addition of carbon black decreases strain at break and increases maximum stress and modulus. Addition of plasticizer increases strain at break and decreases maximum stress and modulus. CrDIPS gives the mixtures shorter curing time than FeAA. Polymers cured with the two epoxides have approximately the same strength properties.
Synthesis of linear p‐dimethylaminobenzoylated polystyrene
Authors: Mateo José L. , Manzarbeitia José A. , Sastre Roberto
Published: April 2003

Linear p‐dimethylaminobenzoylated polystyrenes have been synthesized. Two routes, one of them by polystyrene lithiation and the other one by polystyrene‐amide formation, have been followed. With the first route, poly‐p‐iodostyrene → poly‐p‐lithio‐styrene and reaction of lithiated polystyrene with methyl‐4‐N,N‐dimethyl‐aminobenzoate, a crosslinked polymer was always obtained which contained hydroxylic groups and in some cases, in the presence of an excess of methyl‐4‐N,N‐dimethylaminobenzoate and low temperatures, dimethylaminobenzoyl groups. The second route, polystyrene‐amide formation and subsequent reaction of this linear functionalized polystyrene with POCl3 and dimethyl‐aniline, yielded a linear p‐dimethylaminobenzoylated polystyrene. Starting with cumene and following the same procedure described for the polystyrene, the model compounds N‐phenyl‐p‐isopropylbenzamide and 4‐isopropyl‐4′‐N,N‐dimethylaminobenzophenone were also obtained. Both model compounds and functionalized polystyrenes were characterized by IR, UV, 1H‐NMR and mass spectroscopy as well as molecular weight determinations. From polystyrene‐amide, polystyrene‐ester and polystyrene‐acid were also obtained.
Polystyrolaustauscher mit 5‐(4‐dimethylaminobenzyliden)‐rhodanin als ankergruppe für die abtrennung von silber, gold und quecksilber
Authors: Hofmann B. , Lieser K. H.
Published: April 2003

Die Verteilungskoeffizienten von Ag+, Au3+ und Hg2+ an dem Polystyrolaustauscher mit 5‐(4‐Dimethylaminobenzyliden)‐rhodanin als Ankergruppe werden als Funktion des pH‐Werts in 0,1 M NaNO3 als Grundlösung und unter Zusatz von NaCl, NH4NO3, Na2S2O3 oder NaCN bestimmt. Ag+‐Ionen werden mit verhältnismäßig hohen Verteilungskoeffizienten gebunden, sofern die Konzentrationen an NaCl, NH4NO3 und NaCN niedrig sind. Na2S2O3 stört auch in niedrigen Konzentrationen. Au3+‐ und Hg2+ ‐Ionen werden auch in Gegenwart von 0,5 M NaCl mit verhältnismäßig hohen Verteilungskoeffizienten gebunden.
Zur berechnung von molmassenverteilungen bei binären radikalischen copolymerisationen
Authors: Weickert Günter , Wagner Eberhard
Published: April 2003

Das vorgeschlagene Verfahren zur Berechnung der Molmassenverteilung binärer Copolymerisate auf Grundlage des „chemisch kontrollierten Modells”︁ ist allen bisher in der Literatur publizierten Verfahren bezüglich Rechengenauigkeit und/oder geringem Speicherplatzbedarf und/oder Rechengeschwindigkeit überlegen. Es ist auf Mikrocomputern programmierbar und ermöglicht durch den geringen Rechenaufwand die Prozeßsteuerung nach der Molmassenverteilung.
New accelerators for vulcanization of rubber, 4. Synthesis and characterization of polythiocarbamyl sulfenamides
Authors: Khamrai Asim K. , Adhikari Basudam , Maiti Mrinal M. , Maiti Sukumar
Published: April 2003

Polythiocarbamyl sulfenamides were synthesized by the reaction of different aliphatic and aromatic diamines with carbon disulfide and using iodine as oxidant. The polymerization proceeds by radical mechanism. All the polymers are soluble in polar solvents like N‐methylpyrrolidone (NMP), dimethylformamide (DMF), m‐cresol etc. The structure of the polymers was confirmed by elemental analysis (nitrogen and sulfur), IR, and 1H‐NMR spectral analysis. The effects of aliphatic and aromatic moieties in the diamines were reflected in their reactivities.
Chemistry and application of organic isocyanates, IX. Conversion of tolylene‐2,4‐diisocyanate into urethane derivatives by means of heptane‐1,4,7‐triol
Authors: Ciemniak Grażyna , Lesiak Tadeusz , Balewski Andrzej
Published: April 2003

Investigations on the conversion of tolylene‐2,4‐diisocyanate (2,4‐TDI or TDI) with heptane‐1,4,7‐triol 1,4,7‐HPT or HPT) at 55–85°C and various molar ratios of starting materials are described. By means of mass spectroscopic analysis and gel permeation chromatography, molecular weights of six oligomers and their percent contents in the products have been estimated. Moreover, a scheme of the formation of all prepared isocyanate prepolymers has been proposed. It has been shown, that apart from oligomers having the structures resulting from the reaction of 1,4,7‐HPT with the isocyanate group in the position “4”, reaction products contained oligomers, which confirmed the reactivity of isocyanate group in the position “2”, too.
Reaction of poly(vinyl alcohol) with diketene
Authors: Arranz F. , Sánchez‐Chaves M. , Jarrín C. M.
Published: April 2003

A study has been made on the modification of poly (vinyl alcohol) with diketene using tertiary amines as catalysts. The structure of the resulting polymers was determined by means of IR, 1H‐ and 13C‐NMR spectroscopy as well as by chemical analysis. Vinyl alcohol‐vinyl acetoacetate (VAL‐VAA) copolymers were obtained. It has been found a linear dependence of reaction rate on polymer, diketene and pyridine concentrations, respectively. The activation energy was found to be 35.5 kJ/mol (8.5 kcal/mol). 13C‐NMR spectroscopy was used for the determination of the sequence distribution in VAL‐VAA copolymers. The obtained results show that VAA units have a little alternating tendency in the copolymer chain. Polymeric chelates between VAL‐VAA copolymers and cupric ions have been prepared. It is noteworthy that not all the β‐keto ester groups in the VAL‐VAA copolymers participate in binding cupric ions.
Chlorocarboxylation of polyethylene. II. Reaction mechanism of the process
Authors: Joshi Shashikant G. , Natu Arvind A.
Published: April 2003

Chlorocarboxylated polyethylene (CCPE) is produced by simultaneous reaction of chlorine and maleic anhydride (MA) with polyethylene (PE). Hydrogen atoms on the PE chain are substituted either by chlorine atoms or by maleic anhydride moieties. The reaction mechanism involves creation of an active site, i.e. a radical on the PE chain. There is competition between chlorine and MA molecules for the reaction with this macroradical. Chlorine reacts to give chlorinated polyethylene (CPE) type segments, while MA reacts as a single unit (as chloro derivative) without forming any graft copolymer. There is a marked reduction in the rate of chlorination of PE due to the presence of MA. This is probably due to the competitive nature of the process and the radical scavenging action of MA.
Untersuchungen zur strahlenchemischen Polymerisation und Vernetzung verschiedener mehrfunktioneller Acrylate
Authors: Fürst Walter , Heusinger Helmut
Published: April 2003

Die Vernetzung verschiedener mehrfunktioneller Acrylate wird beschrieben und nach der Vernetzungstheorie von Charlesby untersucht. IR‐spektroskopische und gelchromatographische Untersuchungen führen zu Aussagen über den Netzwerkaufbau der mehrfunktionellen Acrylate. Die vernetzten Acrylate werden chemisch abgebaut. Die entstandenen Polysäuren werden zu Polyestern umgewandelt. Durch GPC‐, MS‐ und IR‐Untersuchungen werden die abgebauten Polyester charakterisiert und die Abhängigkeit der Polymerisation und Vernetzung von der Dosis und Dosisleistung untersucht.
Styrene — divinylbenzene copolymers, IV. Porosity changes during chloromethylation
Authors: Okay Oǧuz
Published: April 2003

The change in the porosity of styrene‐divinylbenzene (S‐DVB) copolymers during the chloromethylation reaction was investigated using apparent densities and equilibrium swelling in toluene. Maximum porosity of S‐DVB copolymers does not change appreciably with the chloromethylation reaction. Only a slight decrease in the maximum porosity was observed in rigid networks, probably due to the partial destruction of the pore structure. However, with the substitution by chloromethyl groups, the degree of swelling decreases, which results in an increase in the stability of the porous structure in chloromethylated copolymers.
Unvernetzte epoxid‐amin‐additionspolymere, 15. 15N‐NMR‐spektroskopie von DGEBA‐anilin‐additionspolymeren
Authors: Hörhold Hans‐Heinrich , Klee Joachim , Schütz Heidrun , Radeglia Reiner
Published: April 2003

15N‐NMR Spektren von Bisphenol‐A‐diglycidylether (DGEBA)‐15N‐Anilin‐Additionspolymeren und deren Acetylderivate zeigen nur das Signal für die tertiäre Phenylamino‐dialkyl‐Gruppe, so daß der lineare Verlauf der Additionspolymerisation bestätigt wird. Aus Signalaufspaltungen bei 15N‐ und einigen N‐benachbarten 13C‐Signalen ist ersichtlich, daß diastereomere Aminodiol‐Einheiten in annähernd gleicher Konzentration gebildet werden. Bei telechelen Präpolymeren mit Anilinüberschuß werden hohe Konzentrationen an sekundären Phenylamino‐Endgruppen gefunden.
Zu den ursachen des unterschiedlichen zähigkeitsverhaltens von polycarbonat, polyestercarbonat und einem polyester auf basis bisphenol A
Authors: Biskup Ulrich , Rathmann Dietrich , Tacke Peter
Published: April 2003

Polycarbonat (PC), Polyestercarbonat (PEC) und ein aromatischer Polyester auf Basis von Bisphenol A (APE) wurden hinsichtlich ihrer Schlagzähigkeit und Kerbschlagzähigkeit im Temperaturbereich von −50 bis 100°C verglichen. Während alle drei Polymere ein ähnlich duktiles Schlagbiegeverhalten zeigen, treten im Kerbschlagbiegeversuch charakteristische Unterschiede auf. Die Ursachen dieser Unterschiede wurden u. a. anhand des Relaxationsverhaltens, der Wärmetönung der Enthalpierelaxation nach Temperung und des beim Bruch auftretenden shear‐yieldings diskutiert.
Synthetic resins, IV. Preparation and characterization of resins prepared from hydroxyacetophenone
Authors: Patra Santosini , Lenka Subasini , Nayak Padma L.
Published: April 2003

New resins have been synthesized from o‐hydroxyacetophenone by reaction with substituted aromatic compounds and formaldehyde in the presence of various acids and bases as catalyst following two different techniques. The polymer samples are characterized by IR spectra. The solution, thermal, and chemical properties of the resins are investigated. The solubility parameters of the resins calculated according to the investigations of Small agree well with the experimental values. The resins are found to be fairly thermostable and the energy of activation is evaluated from TG curve by applying (i) Freeman‐Anderson method and (ii) Broido method.
Reactive polymers, 56. Interaction of reactive sites of macroporous copolymers glycidyl methacrylate‐ethylene dimethacrylate
Authors: Švec František
Published: April 2003

An analysis of the results obtained in a series of studies dealing particularly with the reactions and synthesis of macroporous copolymers of glycidyl methacrylate‐ethylene dimethacrylate showed that relatively freely mobile poly(glycidyl methacrylate) chains are bound on the surface of globules which form the basic unit of a bead structure. These chains, in turn, make possible the formation of products with requirements on the steric order of substituents, on the one hand, but impede an effective application of the macroporous polymer as a protecting group, on the other. Their presence is explained on the basis of kinetics and copolymerization mechanism of the monomers.
Investigation into the interactions of metals and metal ions in polymer matrices
Authors: Payne R. , Fritz G. , Naarmann H.
Published: April 2003

The dispersion of transition metal sols (gold, ferric hydrous oxide, chromium hydroxide) in a water soluble polymer (PVA 4–88) was investigated and from the films produced, a comparison made of their mechanical and electrical properties. Extending to non aqueous solvents (dimethylformamide, tetrahydrofuran) interactions of polyvalent metal ions (Fe(III), Al(III), Ti(IV), Zr(IV), Pd(0), Ag(0), Au sols) with a specific metal complexing polymer (poly(acrylamideoxime)) and a block copolymer containing styrene and butadiene (Buna BL 6533) were investigated.
Electronic processes in poly(p‐phenylene) and related compounds, II. Structure and electrical properties of polymers related to poly(p‐phenylene sulfide)
Authors: Czerwiński Wojciech
Published: April 2003

Poly(p‐phenylene sulfide) was prepared by polymerization of benzene with elemental sulfur in the presence of aluminium chloride as catalyst. The synthesis product was exactly purified from catalyst and oligomers. IR spectra of the resulting material and the application of other analytical methods indicated a structure like PPS. The polymer is thermally resistant up to 773 K and has a small degree of crystallinity. Conductivity of the pristine polymer is higher than that of the original poly(p‐phenylene sulfide). After doping with iodine the conductivity rises more than 6 orders in magnitude to a level of 10−4 Sm−1 and the spin concentration is from five to ten times larger than in the virgin polymer. The activation energy of the conductivity decreases from 0.11 eV for the original polymer to 0.03 eV for the doped one. I — V characteristics are ohmic for both the virgin and the doped materials. The barrier height of metal (Au) and polymer semiconductor junction for the doped sample is smaller than for the undoped substance.
Chlorocarboxylation of polyethylene, III. Kinetics of the process
Authors: Joshi Shashikant G. , Kulkarni Bhaskar D.
Published: April 2003

The paper presents the kinetic model and derives the values of the kinetic parameters for the simultaneous reaction of chlorine and maleic anhydride with polyethylene in tetrachloroethyane solution. The sites of attack in the investigated reaction being the hydrogen atoms in the polyethylene chain, the concept of occupied and vacant sites available for the reaction has been used to derive the kinetic model.

The temperature dependence of the ratio of rate constants (kCl/kMA) for the attack of chlorine and maleic anhydride is obtained by applying Arrhenius law. The analysis of the results reveals that the activation energy difference (ECl — EMA) is of the order of − 19 kcal/mol and the pre‐exponential factor ratio (ACl/AMA) is of the order of 735. The generalized form of the equations is also presented in order to extend this method of kinetic analysis to many other similar systems.
Polyphenylquinoxaline‐amide‐imides
Authors: Korshak V. V. , Krongauz E. S. , Belomoina N. M. , Brumă M. , Diaconu I. , Simionescu C. I.
Published: April 2003

New thermostable heterocyclic polymers containing phenylsubstituted quinoxaline and both amide and imide units have been synthesized by low temperature solution polycondensation of diaminophenylquinoxalines with diacid chlorides of certain aromatic acids containing preformed imide rings. The thermal stability as well as electrical properties of these polyphenylquinoxaline‐amide‐imides are discussed.
Effect of copolymers modifying PVC on its physical and mechanical properties and its UV‐radiation resistance, VII. The influence of structure of pvc chains on tensile strength of irradiated films
Authors: Kamińska A. , Kaczmarek H.
Published: April 2003

PVC films and films containing the modifying copolymers, irradiated by increasing dose of UV‐radiation of λ = 253.7 nm were investigated. It was previously stated1–3 that 1–10% content of modifying copolymers in PVC films distinctly change the resistance of PVC to UV‐radiation and this is the cause that photochemical processes have a different course. Thus it makes it easy to observe the effect of branching, crosslinking, dehydrochlorination, and oxidation processes on mechanical properties of the samples.

It was stated, that an introductory crosslinking of PVC has a positive influence on its tensile strength (σ) but only when the density of crosslinking is ≤ 1, i.e., when all the polymer is still soluble. Whereas with the increase of density of crosslinking above 1, i.e., when insoluble gel is formed in the samples, this process distinctly makes σ values of PVC worse.

The oxidation products of the occurring concentration range in the investigated samples do not have prevailing influence on the tensile strength of PVC.
Interaction of multi‐chain copoly(α‐amino acid)s with 2‐(4′‐hydroxyphenylazo) benzoic acid (HABA)
Authors: Kuramoto Noriyuki , Aoyama Tomoyuki , Yamaguchi Mieko , Nagai Katsutoshi , Hayama Shigeru
Published: April 2003

A number of multi‐chain Nε‐copoly(L‐lysine · HBr γ‐methyl‐L‐glutamate) copoly‐(L‐lysine γ‐methyl‐L‐glutamate)s with various intervals of the grafting sites in the core molecules were prepared in N,N‐dimethylformamide (DMF) containing dimethyl sulfoxide (DMSO) by the reaction of the N‐carboxy anhydride (NCA) of Nε‐carbobenzoxy(Cbz)‐L‐lysine and the NCA of γ‐methyl‐L‐glutamate with random copoly‐(L‐lysine · HBr γ‐methyl‐L‐glutamate)s of different composition with various anhydride‐initiator ratios. The interactions between anionic azo dye (HABA) and multichain copoly(α‐amino acid)s were investigated by means of difference UV‐VIS spectroscopic measurements. From the obtained binding constants and thermodynamic parameters, it was concluded that the hydrophobic moieties of γ‐methyl‐L‐glutamate units in the multi‐chain copoly(α‐amino acid)s have an important role on the HABA and multi‐chain copoly(α‐amino acid)s interaction.
Molecular weight‐intrinsic viscosity relationship of trans‐16‐hydroxy‐9‐enoate hexadecenoic acid polyesters
Authors: Gupta P. C. , Bhattacharya P. R. , Misra G. S.
Published: April 2003

The uncatalysed kinetics of self‐esterification of trans‐16‐hydroxy‐9‐enoate hexadecenoic acid has been found to follow third order. A relationship between intrinsic viscosity and molecular weight of its polyesters [η] = 14.2 · 10−5 M0.95 (25°C, chloroform) has been put forward. The polymolecularity studies of the polyester have shown usual characteristics of integral and differential curves.
Poly(vinyl chloride) blends. I. Aspects of processability
Authors: Rusu Mihai , Petraru Filip , Grămescu Livia
Published: April 2003

The paper deals with the influence of chlorinated polyethylene (CPE) as an impact modifier on the processability of unplasticized PVC blends, with and without clay as filling material, using the Brabender plastograph.

It was found that, for both types of blends, increase of the CPE content causes increase of the torque, fusion performance and fusion factors (Brabender and Böttner‐Rosenthal), and reduction of fusion time, fusion coefficient and, between limits, of the thermal stability of the blends. This behaviour may be explained by the reduction of the lubrication action brought about by this impact modifier.

By addition of CPE to the filled blends, a compensation of disadvantages caused by the introduction of the filling material into the compound is achieved.
Oriented supramolecular systems‐polymeric monolayers and multilayers from prepolymerized amphiphiles
Authors: Laschewsky A. , Ringsdorf H. , Schneider J.
Published: April 2003

Oriented polymeric membranes were originally prepared by polymerization or polycondensation of preoriented monomers. The introduction of hydrophilic spacer groups into the polymeric amphiphiles allowed the formation of highly ordered systems (monolayers, liposomes, multilayers) from prepolymerized amphiphiles: due to the partial decoupling of the different mobilities and orientation tendencies of the polymer chain and the amphiphilic side groups, these polymers are able to self‐organize. In monolayer experiments the high order of these membranes could be demonstrated by their surface pressure area‐diagrams. In addition the combination of order and mobility of these spacer groups containing polymeric amphiphiles allowed the formation of Langmuir‐Blodgett‐multilyers with a high layer correlation. Thus, disturbancies in highly oriented layers can be avoided normally taking place during the polymerization reaction (e.g. contractions) or oriented monomeric layers.