bluuebunny/crossref_metadata_2025 huggingface dataset:
Beiträge zur galvanisierung von polymeren, 7. Metallisierung von epoxidharzen mit hilfe von haftvermittlern
Authors: Springer Jürgen , Förster Frank , Sezi Recai , Sirinyan Kirkor
Published: April 2003

Epoxidharze lassen sich mit einer haftfesten Metallschicht überziehen, wenn sie zuvor mit einem metallisierbaren Haftvermittler beschichtet worden sind. Ein solcher Haftvermittler besteht z.B. aus einem partiell epoxidierten Styrol‐Butadien‐Styrol‐Triblockcopolymeren, einem Epoxidharzvorprodukt und einem Aminhärter.

Das Mischungsverhältnis dieser Komponenten sowie die Art des Amins beeinflussen die Abzugsfestigkeit der galvanisch aufgebrachten Metallschicht. Der höchste Wert wurde bei der Verwendung eines niedermolekularen Amins mit ca. 45 N/25 mm erreicht, während beim Einsatz von höhermolekularen Aminen nur Werte bis ca. 10 N/25 mm erzielt werden konnten.
A comparative study of the kinetic theories of the glass transition phenomenon in high polymers
Authors: Vijayakumar Chinnasamy Thangavel , Kothandaraman Harimurthi
Published: April 2003

The effect of thermal history on the glass transition temperature (Tg) of poly(vinyl chloride) was studied. The parameters like the hole energy (Eh), the activation energy for the disappearance of holes (Ej), the activation enthalpy for the structural relaxation (Δh1* and Δh2*) and the activation energy for the glass transition process (E) were calculated. The increase of Eh value with the increase in Tg value shows that there exists a holesize distribution. The Ej (26.9 ± 0.5 kcal/mol) value calculated according to Wunderlich's treatment, the Δh1* (27.8 ± 0.6 kcal/mol) value obtained by Moynihan's procedure and the E (35.3 kcal/mol) value from Barton‐Critchley's method agree well with one another in the poly(vinyl chloride) system. The Δh2* quantity, obtained through Moynihan's formulations, increase as the rate of heating was increased, a result similar to the variation of Eh value with the rate of heating.
Thermal properties of nylon 6 fibres grafted with acrylic monomers
Authors: Mukherjee A. K. , Goel H. R.
Published: April 2003

Thermal Properties of methyl methacrylate (MMA), ethyl methacrylate (EMA) and n‐butyl methacrylate (n‐BMA) grafted onto nylon 6 fibre with various graft levels were investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) and the results compared with that of parent nylon 6 fibre. It was found that the initial decomposition temperatures (IDT) of the grafted samples were lower than that of the parent nylon 6 fibre. On the other hand with all the three monomers, there was an increase in overall thermal stability followed by subsequent decrease with increase in the graft level. Among the grafted samples both the IDT and IPDT (initial procedural decomposition temperature) followed the order MMA‐g nylon > EMA‐g nylon < n‐BMA‐g nylon

Differential thermal analysis shows a depression in glass transition temperature (Tg) as well as in melting temperature (Tm). In the case of the MMA and EMA grafted samples, the depression is small over a wide range of graft level. In the case of the n‐BMA grafted samples, the depression is higher. A wide melting range was obtained in the grafted samples. Flammability studies also showed that with an increase in the graft level as well as an increase in the alkyl chain the ease of flammability increased as expressed by limiting oxygen index (LOI) values. The possible reasons for the phenomena occurred have been discussed.
A calorimetric investigation of suspension and emulsion polymerization of vinyl chloride
Authors: Nilsson Holger , Silvegren Christer , Törnell Bertil
Published: April 2003

An isothermal calorimeter for studying radical polymerization in heterogeneous systems is presented. The calorimeter was used for investigation of suspension and emulsion polymerization of vinyl chloride at 50°C. The results from the suspension polymerization experiments showed that the termination rate constant in the PVC phase was diffusion controlled and very sensitive to the vinyl chloride activity. During suspension polymerization the pressure started to drop at a much lower conversion than in emulsion polymerization. Mass balance calculations showed that this was due to entrapment of a large amount of liquid vinyl chloride in the fine capillary system of the suspension particles. The results from emulsion polymerization experiments in which the particle number spanned the range from 0.094.1018 to 1.7.1018 dm−3, were analyzed according to the kinetic model developed by Ugelstad et al. Using the concentration‐dependent termination rate constant obtained from the suspension experiments and assuming proportionality between the radical adsorption and desorption rate constants, this model gave a very good fit of the experimental rate over the entire interval II and most of interval III. The results strongly indicated that termination in the aqueous phase was of measurable importance during interval II and became the dominating termination in interval III.
Polymerization of lactams, 49. Hydrolytic polymerization of 6‐caprolactam in the presence of its cyclic dimer
Authors: Krajník Václav , Kondelíková Jaroslava , Králíček Jaroslav , Mössinger Ivan
Published: April 2003

The hydrolytic polymerization of 6‐caprolactam has been studied at 260–280°C in the presence of 5, 10 and 15 mol‐% of cyclic dimer of 6‐caprolactam and 2 mol‐% of 6‐aminocaproic acid as an initiator. The content of monomer and cyclic oligomers, including pentamer, was determined by HPLC. It has been proved that the rate of polymerization decreases with increasing content of cyclic dimer in the initial mixture and the time required to attain the equilibrium content of polymer increases as much as by an order of magnitude. The cyclic dimer is incorporated into the polymer above all in the final reaction stage.
Poly(vinyl alcohol) modification with n‐alkyl chloroformates
Authors: Arranz F. , Sánchez‐Chaves M. , Molinero A.
Published: April 2003

This work deals with the modification reaction of poly(vinyl alcohol) with n‐alkyl chloroformates using pyridine as catalyst. The structure of the modified polymers was determined by means of IR, 1H and 13C‐NMR spectroscopy as well as by chemical analysis. Vinyl alcohol‐vinyl n‐alkyl carbonate copolymers were obtained. The presence of cyclic carbonates has not been observed. It has been found a linear dependence of reaction rate on polymer, n‐alkyl chloroformates, and pyridine concentrations, respectively. The activation energy found was of 15.4 kcal/mol. The water absorbed in the copolymers made it reasonable to conclude that the hydrophilic character of the copolymers decreased progressively when either the carbonate groups content or the side chain length increased. Water insoluble alcohol‐vinyl n‐alkyl carbonate copolymers were hydrolyzed in an alkaline medium. They were found to recover their solubility in water after a certain hydrolysis extent was reached.
Solubility parameters of poly(di‐n‐alkyl cyclohexyl‐) and poly(di‐n‐alkyl phenyl itaconates)
Authors: Veličković J. , Petrović‐Djakov D. , Filipović J.
Published: April 2003

Solubility parameters of poly(dicyclohexyl‐), poly(diphenyl itaconate) and of the first three members of the poly(dialkyl cyclohexyl‐) and poly(dialkyl phenylitaconate) homologous series were determined from limiting viscosity numbers in various solvents and solvent mixtures, differing in structure, polarity and composition. The values obtained are within limits of 19.0 and 16.7 (J1/2. cm‐3/2). Phenyl groups in the substituents lead to slightly higher values than cyclohexyl rings and the introduction of alkyl groups in both series results in a progressive decrease of the solubility parameter. The experimental values are slightly lower than those obtained by calculation from molar attraction constants.
Organic solvent treatment of isotactic polypropylene films, 1. Effects of organic solvent treatment on proton spin‐lattice and spin‐spin relaxation times
Authors: Tanaka Hiroshi , Yoshida Yoshio
Published: April 2003

An isotactic polypropylene film was treated with cyclohexane, toluene, 1‐chloronaphthalene, and glycerin. The morphological changes were characterized by measurements of weight loss, density, molecular weight, and spin‐lattice and spin‐spin relaxation times. There is a relatively narrow temperature range at which a sharp increase in weight loss occurs corresponding to the kind of the solvent. The change in density occurs almost linearly with treatment time for all solvents. Molecular weight also increases as the weight loss is increased. There is a considerable increase in T1 with increasing treatment temperature. T2 of the amorphous region, T2a, also increases as the treatment temperature is increased, but some decrease in T2a is found in the samples treated with toluene and cyclohexane at higher temperatures. The fraction of the rigid region, Fc, increases and that of the mobile one, Fa, decreases with proceeding solvent extraction. The value of Fc is considerably different from the crystallinity calculated from the density in the early stage of the treatment followed by the gradual approach to the value calculated from the density, although some different behaviour was found with the samples treated with cyclohexane.
Anionic polymerization using rotating disk reactor (I)
Authors: Yamaguchi Tadashi , Nozawa Masayuki , Egashira Akihiko , Kumagai Hiroshi , Imai Hideki
Published: April 2003

Anionic polymerization of styrene with sodium naphthalene was carried out using the rotating disk reactor. The mode of disintegration of the polymerization mixture changed from dropwise to filamentwise and finally to filmwise within a few minutes of reaction at low speed revolution and a large amount of flow. Under the condition of high speed revolution and a small amount of flow, only dropwise disintegration was observed and a beadlike polymer was obtained having a unimodal molecular weight distribution. The polymer was found to have a bimodal distribution when the polymerization was terminated on the rotating disk. These results are explained by assuming that a highly viscous layer was formed near the disk surface.
Attempts to prepare regularly sequenced polyamides containing oxyethylene and iminoethylene units
Authors: Kern Werner , Kämmerer Hermann , Böhmer Volker , Bhagwat Madhusudan M.
Published: April 2003

Water soluble polyamides with iminoethylene and oxyethylene units in the main chain were obtained by condensation polymerization of diethylenetriamine and triethylenetetramine with suitable dimethylesters containing two or three oxyethylene units. The molecular weights were in the range of M̄n = 5000–7000. By potentiometric and conductometric titration only 80–85% of the expected amount of basic groups was found which was probably caused by branching.
Study of the reactions of phenol, 2,5‐ and 3,5‐dimethylphenol with acrolein
Authors: Šebenik Anton , Osredkar Uči
Published: April 2003

The reactions of phenol, 2,5‐ and 3,5‐dimethylphenol with acrolein in neutral medium were studied by means of 13C NMR. The addition of the double bond of acrolein seems to be the dominant reaction, although from the spectra small amounts of cyclic compounds and polymeric acrolein were detected. This indicates side reactions of the double bonds and of the carbonyl groups. Acrolein reacts with phenols mainly at the para position. The ratio of CH2‐signals bonded at the ortho and para positions was found to be 1:6 for 2,5‐dimethylphenol and 1:1.4 for 3,5‐dimethylphenol.
Primary processes of the thermal degradation of HET acid containing unsaturated polyester cured with styrene
Authors: Vijayakumar Chinnasamy Thangavel , Fink Johannes Karl , Lederer Klaus
Published: April 2003

The primary processes of thermal degradation of 1,4,5,6,7,7‐hexachloro‐5‐norbornene‐2,3‐dicarboxylic (HET) group containing unsturated polyesters cured with styrene were investigated. DTA traces in nitrogen atmosphere showed a much more pronounced endothermic reaction as the chlorine content in the unsaturated polyester resin decreased. This could be associated to the unzipping of the polystyrene units which is interfered by hexachlorocyclopentadiene ejected during degradation. Actually the styrene formation is prevented in a certain range of temperature due to the interaction with hexachlorocyclopentadiene. This was proved by on‐line mass spectroscopic analysis of the degrading polymer.
Poly(vinylalcohol) as polymeric support for metal chelating phosphoric acid and derivatives
Authors: Bayer Ernst , Grathwohl Paul‐Anton , Geckeler Kurt
Published: April 2003

Synthesis and application of several polymeric agents based on poly(vinylalcohol) with phosphorus containing functional groups were investigated. Monomer and polymer syntheses of phosphoric acid and derivaties with poly(vinylalcohol) are described. Multifunctional derivaties of the hydrophilic polymer were obtained by polymer‐analogous reactions with mono and diethyl esters of phosphoric acid. Studies on chelating properties of the polychelatogenes at different pH values for nickel were carried out by means of membrane filtration. Metal determination in filtrate and retentate yielded typical chelating curves. Differences of the polymer supports and influences of the functional groups are discussed.
Pestizide Polymere, 1. Herstellung und Untersuchung endosulfanhaltiger LDPE‐ und EVA‐Folien
Authors: Bahadir Müfit , Pfister Gerd , Herrmann Rainer , Moza Prannath , Korte Friedhelm
Published: April 2003

Mischungen aus Endosulfan mit LDPE‐ bzw. EVA‐Granulaten wurden unter unterschiedlichen Bedingungen zu Flachfolien extrudiert und diese untersucht. Es konnte gezeigt werden, daß bei Extrusionstemperaturen bis 190°C keine Veränderung des Endosulfans erfolgt. Additive wie Benzophenonderivate und Ölsäureamid hatten ebenfalls keinen Einfluß auf das Extrusionsverhalten des Endosulfans. Bedingt durch die unterschiedlichen Löslichkeiten der Isomeren des Endosulfans betrugen die Sättigungskonzentrationen in der LDPE‐Folie für α‐Endosulfan ca. 0,8% und für β‐Endosulfan ca. 0,2%. Bei EVA‐Folien mit ≥ 10% VAC‐Anteil konnten ≥8% (α + β) Endosulfan homogen gelöst werden.
Immobilisierung von Corynebakterium simplex durch Photovernetzung von vinyliertem Polyvinylalkohol zur mikrobiologischen Steroidumwandlung
Authors: Manecke Georg , Beier Wilfried
Published: April 2003

Die Steroidumwandlung von Hydrocortison zu Prednisolon wurde mit immobilisierten Corynebakterium simplex‐Zellen (A.T.C.C. 6946) untersucht. In partiell mit Acrylsäure verestertem Polyvinylalkohol wurden die Zellen durch Bestrahlung des Polymeren mit sichtbarem bzw. UV‐Licht in Gegenwart von Riboflavin‐5′‐monophosphat durch Photovernetzung immobilisiert. Die Steroid‐Δ1‐Dehydrogenase‐Aktivität der immobilisierten Zellen ließ sich durch Enzyminduktion erhöhen.

Die Abhängigkeit der Steroid‐Δ1‐Dehydrogenase‐Aktivität von der Zell‐, Substratund Cofaktorkonzentrtion, der Reaktionstemperatur und der Lösungsmittelkonzentration wurde untersucht. Die Halbwertzeit der Immobilisate wurde mit und ohne Nährmedium bestimmt. Die Aktivität der Corynebakterium simplex‐Immobilisate betrug 169 μmol/gImm h mit einer relativen Aktivität von 246%.
Quantitative determination of antioxidants and ultraviolet stabilizers in polymers by high performance liquid chromatography
Authors: Francis Vadakkoott C. , Sharma Yoginder N. , Bhardwaj Ishwar S.
Published: April 2003

The quantitative determination of antioxidants and ultraviolet (UV) stabilizers in a polymer matrix has been standardized using HPLC. The additives were extracted out of the matrix using low boiling solvents in order to minimize the degradation of additives at elevated temperatures. Carbon tetrachloride and tetrahydrofuran have been found to be most suitable solvents for low density polyethylene and polypropylene respectively. The method has been found to be highly reproducible and the standard deviation is very low. This method does not suffer from the problems like overlapping frequencies as observed in spectroscopic methods.
High‐temperature oxidation of polymers
Authors: Shlyapnikov Yu. A. , Serenkova I. A.
Published: April 2003

Above the certain temperature which depends on the composition of the polymer and usually exceeds 200°C the mechanism and regularities of polymer oxidation markedly change: the main reaction of peroxide radicals RO becomes decomposition with formation of low‐molecular radicals, activation energy decreases and the rate of oxygen consumption becomes directly proportional to the oxygen pressure.
Einfluß der mechanischen spannung und der temperatur auf die photooxidation von polyethylen
Authors: Peewa L. , Ewtimowa S.
Published: April 2003

The tensile stress and temperature effects on the Polyethylene photooxidation kinetics have been investigated. Subjects are light stabilized and not stabilized high density Polyethylene films. The tensile stress used were 10% and 20% of the breaking stress. Temperatures of 50°C, 30°C, 5°C were realized in a chamber for an artificial climate with an irradiation source mercury ark lamp type 𝔫PK‐2. The duration of exposure was up to 1500h. The oxidation degree has been appreciated by the carbonyl index determined by means of a IR spectrophotometer.

It was established that the photooxidation process rate depends on the temperature as well as on the mechanical stress. At the tensile stress used it was found a decrease of the oxidation rate in comparison with the unloaded samples. The mechanical stress influence was stronger when testing unstabilized Polyethylene.
Influencing parameters in the accelerated weathering of pigmented plastics and paints – new findings and possible progress
Authors: Kämpf G. , Papenroth W.
Published: April 2003

A report is given of recent studies into the influence of spectral energy distribution, irradiation intensity, moisture, oxygen pressure and specimen temperature on the results obtained during the accelerated weathering of unpigmented and pigmented polymers. In particular, a “radiation‐related spectral energy absorption” is defined and its possibilities for providing information on the sequence of the degradation processes that take place during weathering is discussed; in this respect it is possible to differentiate between the degradation of the polymer matrix by UV‐degradation, degradation by photocatalytic oxidation of the polymer when photoactive pigments are used and the protective action of high‐grade inorganic pigments. Finally, the possibilities for improving the process and equipment used in accelerated weathering are discussed.
Alterung von copolymeren, die ketogruppen enthalten
Authors: Nenkov G. , Bogdanzaliev T. , Stoyanov A. , Kabaivanov W.
Published: April 2003

Polymers of polystyrene and polyoelefine, containing covalently linked keto groups, are obtained. Polystyrene polymers are prepared by polymerization of styrene and unsatured ketones in the presence of polybutadiene while polyolefines are obtained by grafting unsatured ketones to the polymer. Films of copolymers, thus prepared, undergo photochemical degradation when exposed to natural and artificial light. The rate of degradation is considerably higher, as compared to the analogical polymers without keto groups, and it depends on the type and concentration of the ketone used. The reaction of degradation is propably mainly Norish II‐type which has the effect of decreasing the molecular weight of copolymers. That assumption is confirmed by the observed alteration in carbonyl and hydroxyl range ‐ 1720 cm−1 and 3450 cm−1 respectively in the polymer chains when they are irradiated.
Über die wirkung der breite des spektralbereichs auf die alterung von kunststoffen
Authors: Nyitrai Zs. , Lovas I. , Ocskay Gy. , Wein T.
Published: April 2003

The effect of the short wavelength range of the UV spectrum and the influence of elevated temperatures to the degradation of the plastics were measured in three different artificial weathering devices.
Beurteilung von lichtschutzsystemen bei polyolefinen in der natürlichen und künstlichen bewitterung
Authors: Schaaf R.
Published: April 2003

Vestolen A 6016 and Vestolen P 5200 were acceleratedly weathered in a Xenotext 1200 and a Xenotest 450. By variation of operating conditions of Xenotest 1200 different spectral distributions in the UV region (with and without UV filter) were obtained. In Xenotest 450 polyethylene and polypropylene showed approximately the same process of damage, wheras polyethylene and polypropylene showed clear different “spectral sensitivities” in Xenotest 1200. The maximum of UV capacity which is possible in Xenotest 1200 enables a maximum of time accelerating effect ‐ also when light protecting systems are used ‐ but it does not admit a more exact evaluation of the quality of a light protecting formulation. The test of light protecting formulations based on UV absorber, HALS and combinations thereof showed, that evaluation can be very different and does not always conform with the results of out door weathering.
Ein beitrag zur beurteilung der alterung von kunststoffen mit hilfe der raster‐elektronenmikroskopie
Authors: Reuß S.
Published: April 2003

After open‐air weathering water and moisture proof sheetings made of polyvinyl chloride show cracks in some cases. Changes in the characteristics, determined by mechanical testing procedures, doe not explain the reason and the mechanism of crack formation. Therefore scanning electron microscope‐studies have been carried out and evaluated in connection with the results of infrared spectroscopy investigations. Resulting from microcracks and notch impact defects knowledge of age‐depending crack formation has been achieved.
Grundsätzliche gedanken über bewitterung und stabilisierung von polyethylen niederer dichte
Authors: Nikolowa Zi. , Georgiewa M. , Kostow G. , Mladenow Iw.
Published: April 2003

Ageing test was done on low density‐polyethylene (tubular type). The tests under combined influence of atmospheric factors started for one year in May. Changes of chemical structure of the polymer are studied by means of infrared spectroscopy.
Eigenschaften von PE‐erzeugnissen nach der bewitterung
Authors: Komitov P. G.
Published: April 2003

In the last years in a joint action with Institute of Chemical Industry ‐ Sofia wide research work was completed on lightstabilized (atmospheric resistant) types of polyethylene high density creation and its implementation in transport packaging production.

Quite interesting and unexpected result in relevant improvement of tested articles operating properties in the initial stages of the natural ageing after which they regularly change for the worse. Dynamic properties optimum of the polyethylene articles is reached in one to three months of the production date and direct open exhibition. It is found out that main influence on the results got is by some additives existance and concentration in the polyethylene composition.

Available data and influences found out are mainly of quality nature but allow assumption that processes as recrystallization and disorientation in unbalanced structure created in treatment process are carried out which in the initial stages of operation predominate over ageing processes.

An research is made on determination of exact quantity ratio between composition of the polyethylene (type and quantity of the additives) and treatment conditions (articles configuration and process parameters). Results with essential implementation value are expected.
Reactive polymers, 45. Use of macroporous glycidyl methacrylate—ethylene dimethacrylate copolymer modified by diethylamine for the separation of pt(IV), pd(II) and rh(III)
Authors: Kálal Jaroslav , Kálalová Eliška , Jandová Lenka , Švec František
Published: April 2003

Sorbents based on the macroporous copolymer of glycidyl methacrylate—ethylene dimethacrylate modified with diethylamine sorb in a strongly acid solution Pt(IV), Pd(II) and Rh(III) as chloro complexes. By gradual desorption with variously concentrated nitric and hydrochloric acid, it is possible to desorb selectively platinum or rhodium ions and to separate them virtually quantitatively from palladium ions which later on are desorbed only at a high HCl concentration.
Oxygen‐ascorbic acid‐ferric ion initiating system. Kinetics of polymerization of methyl methacrylate
Authors: Reddy G. Gangi , Nagabhushanam T. , Rao K. Venkata , Santappa M.
Published: April 2003

The kinetics of polymerization of methyl methacrylate (MMA) in dilute nitric acid medium at 40°C initiated by the three component initiating system, oxygen‐ascorbic acid (AA)‐ferric ions was investigated. The rate of polymerization, Rp, was found to be proportional to [MMA]1.5 under different experimental conditions. Rp, was independent of [Fe3+] in the concentration range 2 to 5 − 10−5 M, but decreased slightly at higher values. Rp was also independent of [AA] and a dependence on [O2]0.6 was noticed with [O2] < 6.5 × 10−4M. After an initial increase, Rp became independent above [HNO3] ≈ 0.3M. Ionic strength, μ, of the medium had no effect on Rp. A rate increase up to 42°C followed by constancy and decrease with further increase in temperature (>46°C) was noticed. The chain lengths of the polymers were determined to be in the range 102 — 103 by viscometry. A plausible reaction mechanism with initiation by the primary radical and termination by mutual interaction was proposed.
Reactivity ratios of some substituted aromatic amines by linear graphical methods
Authors: Chatterjee S. K. , Singh B. P. , Pachauri L. S.
Published: April 2003

Reactivity ratios of some halogen substituted aromatic amines have been determined by using Kelen‐Tüdős and Fineman‐Ross linear graphical methods. On copolymerization with p‐toluidine or p‐nitrophenol as comonomer, the reactivity of halogen substituted aromatic amines was found to be in the order of their basic strength. However, this order of reactivity gets reversed when these halogen substituted amines are copolymerized with p‐nitroaniline. This reversal of reactivity has been interpreted in terms of polarization and resonance stabilization of the monomeric species.
Formaldehyde release and cellulose crosslinking with N‐methylol agents: A delicate balance
Authors: Andrews B. A. Kottes , Simoneaux Jacqueline M. , Harper Robert J.
Published: April 2003

In addition to the etherification of cellulose by N‐methylol and N‐alkoxymethyl agents that results in crosslinking, hydrolysis reactions that liberate formaldehyde can also occur. The hydrolysis of representative reactants was followed under acidic and basic conditions, through deetherification and demethylolation, to formaldehyde release. Functional groups were identified by the use of nuclear magnetic resonance spectroscopy. Results were used to interpret the behavior of finishes from these agents on cotton fabrics, particularly with respect to the special influence of alcohols.
Untersuchungen zum Verschleiß beim Spritzgießen von monomerfreien ungesättigten Polyesterformmassen
Authors: Braun Dietrich , Tretner Hartmut
Published: April 2003

Die beim Spritzgießen zweier mineral‐ und glasfasergefüllter, monomerfreier ungesättigter Polyesterformmassen entstehenden flüchtigen Zersetzungsprodukte wurden isoliert und identifiziert. Hauptbestandteil der Flüchte ist in beiden Fällen Wasser mit einem Anteil von über 96 Gew.‐%, daneben geringe Mengen des Polymerisationsinitiators und seiner Abbauprodukte. Substanzen, die auf einen Abbau des ungesättigten Polyesters hinweisen, wurden nicht gefunden.
Neue photoreaktive Polymere mit seitenständigen Dimethylmaleinimid‐Gruppen. I. Radikalische homo‐und copolymerisation von N‐(5‐methyl‐3‐oxa‐4‐oxo‐hexen‐5‐yl)‐dimethylmaleinimid
Authors: Berger Joseph , Zweifel Hans
Published: April 2003

Die Homopolymerisation von N‐(5‐Methyl‐3‐oxa‐4‐hexen‐5‐yl)‐dimethylmaleinimid (DMI‐MA) führt zu linearen Polymethylmethacrylaten mit seitenständigen lichtvernetzbaren Dimethylmaleinimid‐Gruppen. Dabei nimmt die CC Doppelbindung des Imidylrestes infolge sterischer Hinderung durch die beiden Methylsubstituenten, selbst bei Umsätzen von über 90%, nicht an der Reaktion teil. Für die Homopolymerisation wurde die Polymerisationsgeschwindigkeitskonstante bestimmt zu kp/k = 2,0 – 2,2·10−2(65°C, Toluol, AIBN); die Aktivierungsenergie beträgt Ea = 62,36 ± 2 kJ/mol−1.

Aus den Copolymerisationen der Monomerpaare DMI‐MA/Methacrylsäure (MAS), DMI‐MA/Methylmethacrylat (MMA) und DMI‐MA/Ethylacrylat (EA) ergaben sich folgende Copolymerisationsparameter: DMI‐MA (r1) : MAS (r2) = 1,36 ± 0,06 : 0,77 ± 0,06; DMI‐MA (r1) : MMA (r2) = 1,16 ± 0,17 : 0,475 ± 0,17 und DMI‐MA (r1) : EA (r2) = 1,60 ± 0,15 : 0,44 ± 0,15.
Gas chromatography/mass spectroscopy analysis of resols and etherified resols
Authors: Anthony Geoffrey M. , Kemp Graham
Published: April 2003

The characterisation of two resols which had been etherified with methanol under acidic conditions is described for the first time. The resins were converted into trimethylsilyl derivatives and the individual components were separated by means of capillary gas chromatography. Structural assignments were made using mass spectrometry measurements and with the aid of model compounds. The precursor resols have also been analysed by the same technique.
Viskosität hochkonzentrierter Lösungen eines ungesättigten Polyesters in p‐Xylol
Authors: Lešek František , Eichler Josef , Šimek Ludvík , Gajda Josef
Published: April 2003

Die Abhängigkeit der Viskosität eines Polyesters auf der Basis von Maleinsäureanhydrid (MA), Phthalsäureanhydrid (FA) und 1,2‐Propylenglykol (1,2 PG) vom Polyveresterungsgrad M̄0 im Säurezahlbereich 30–240 (mg KOH/g) ließ sich in Verdünnung mit 2–10% p‐Xylol durch η = k1M̄ beschreiben. Als Beziehung zwischen Temperatur und Viskosität ergab sich log η = A + B/(T–T0). Für die Korrelation der Viskosität mit dem Polyestergehalt im Temperaturbereich 55–130°C war die Gl. η = C exp(Dx) maßgebend, wobei C und D spezifische Konstanten für den Polyveresterungsgrad und die Temperatur und x der Polyestergehalt der Proben in Gew.−% sind. In der Gl. log η = x1 log η1 + x2 log η2 + Δ, wobei x1 und x2 die Molenbrüche von Polyester und p‐Xylol und η1 bzw. η2 ihre Viskositäten sind, war das Glied Δ eine lineare Funktion von M̄ und dem Polyestergehalt der Proben. Meßwerte der Systeme bei 100°C werden angeführt.
Die Medienabhängigkeit der alkalischen Hydrolyse von Methylmethacrylat‐Polymeren
Authors: Sandner Barbara , Bischof Claus
Published: April 2003

Die Geschwindigkeit der alkalischen Hydrolyse von Polymethylmethacrylat (PMMA) und Methylmethacrylat (MMA)‐Ethylacrylat‐Copolymeren erhöht sich mit steigender Dielektrizitätskonstante und abnehmendem OH−‐Ionen‐Solvatationsvermögen der als Lösungsmittel verwendeten aliphatischen einwertigen Alkohole und in aprotischen Lösungsmitteln. Aus dieser Abhängigkeit ergeben sich in der Alkoholreihe maximale Geschwindigkeiten bei den Propanolen. Höhre Wassergehalte führen zur starken Verminderung der Hydrolysegeschwindigkeit. Die Geschwindigkeitskonstanten der Hydrolyse von Ethylacrylat‐ und MMA‐Einheiten im Copolymeren unterscheiden sich bei den untersuchten Reaktionsbedingungen um eine Größenordnung. In Ethanol bilden Hydrolysemischungen von MMA‐Ethylacrylat‐Suspensions‐copolymeren bei 80°C bei niedrigem Alkalihydroxid‐ und Wassergehalt homogene Lösungen, bei mittlerem Alkalihydroxid‐ und Wassergehalt hochgequollene Gele und bei hohem Alkalihydroxid‐ und Wassergehalt unter bestimmten Bedingungen Dispersionen. Für die partielle Hydrolyse ergeben sich technisch interessante Varianten.
Cellulose containing block copolymers. 4. Cellulose triester macroinitiators
Authors: Mezger T. , Cantow H.‐J.
Published: April 2003

The preparation of monofunctional 1‐hydroxy cellulose triesters—propionate‐acetate and tributyrate — and subsequent coupling with bis‐(4‐isocyanatophenyl)‐disulfide is described, thus yielding a macrophotoinitiator for radical threeblock copolymer syntheses. Cellulose triester blocks were obtained by hydrogen halide cleavage of fully substituted cellulose esters under esterification conditions. The terminal halide function introduced in this way yields hydroxyl after hydrolysis at medium pH conditions. Evidence of strict monofunctionality has been demonstrated by analysis of molecular weights as well as of molecular weight distributions before and after coupling with stoechiometric amounts of difunctional coupling agents. Viscosity‐molecular weight relationships were extended towards low degrees of polymerization, applying vapour pressure and membrane osmometry for calibration.
Polymerisation von Vinylchlorid bei Atmosphärendruck. 2. Chemische und spektroskopische Methoden zur Charakterisierung von U‐PVC
Authors: Braun D. , Holzer G.
Published: April 2003

Bei Atmosphärendruck hergestelltes PVC (sog. U‐PVC) enthält gegenüber normalem PVC relativ hohe Konzentrationen an Strukturanomalien. Die ozonolytisch bestimmten Spaltstellenzahlen x̄ pro 100 Monomereinheiten als Maß für die internen Doppelbindungen der untersuchten U‐Polymeren schwanken zwischen 0,026 und 0,058.

Die gemeinsame Bestimmung von allylischem und tertiärem Chlor erfolgte durch die selektive Umsetzung von U‐PVC mit Phenol und 1H‐NMR‐spektroskopische Untersuchung der phenolisierten Polymeren. Mit ca. 0,65 labilen Chloratomen pro 100 VC‐Einheiten wurden vergleichsweise hohe Gehalte dieser Fehlstellen gefunden.

Die beim Initiatorzerfall aus K2S2O8 gebildeten OH‐Radikale führen zu alkoholischen Endgruppen im U‐PVC, die durch eine Absorption bei 3580 cm−1 im IR‐Spektrum sichtbar werden. Beim Kettenabbruch mit OH‐Radikalen entsteht eine Chlorhydrinsktruktur, die unter Chlorwasserstoffabspaltung in einen ß‐Chloraldehydrest übergeht, was durch eine Bande bei 1720 cm−1 im IR‐Spektrum angezeigt wird.

U‐PVC‐Rohprodukte enthalten im Mittel zwei Verzweigungsstellen pro 100 Monomereinheiten. In den mit CCl4 extrahierten niedermolekularen Anteilen liegt die Zahl der Verzweigungen um den Faktor 10 höher. Die olefinischen Strukturen CHCHCHCl und CHClCHCH2 sind in Konzentrationen von jeweils 0,25 bis 0,3 pro 100 VC‐Einheiten NMR‐spektroskopisch nachweisbar. Die für U‐PVC typische Enddoppelbindung CHCHCH2Cl findet sich vor allem in den niedermolekularen Anteilen der Ausgangsprodukte.
Modification of polyethylene with methacrylic acid, I. Grafting of methacrylic acid onto polyethylene
Authors: Bryjak Marek , Trochimczuk Witold
Published: April 2003

Three different methods for grafting methacrylic acid onto polyethylene have been investigated. These were carried out in melt, in the swollen gel, and in solution. It has been found that the membranes obtained by pressing the blends are optically homogeneous when the products obtained in melt or in solution were used, but grafting in gel led to a macroheterogeneous product. For further studies the product containing a relatively high content of grafted methacrylic acid obtained in solution was chosen.
Beitrag zur Problematik der theoretischen und experimentellen Festigkeit von Polyesterfasern
Authors: Kalousková V. , Všianský J.
Published: April 2003

In der vorliegenden Arbeit wird das Problem der Wirkung von Kräften zwischen den Makromolekülen in idealen 100proz. kristallinen und vollständig orientierten Polyesterfasern behandelt und daraus die theoretische Festigkeit berechnet. Bei der Berechnung der theoretischen Festigkeit wurde von der Vorstellung ausgegangen, daß es bei einer Deformation durch Zug sowohl zum Bruch der Makromolekülketten als auch zum gegenseitigen Abgleiten bei Störungen der Kohäsionskräfte kommen kann. Auf Grund der erhaltenen Ergebnisse wird das schwächste Glied der Struktur der idealen Polyesterfasern bestimmt und daraus die Vorstellung über den Mechanismus ihres Bruches abgeleitet.

Der experimentelle Teil der Arbeit beschäftigt sich mit der Fraktographie von Polyesterfasern durch mechanischen Abrieb in der Quer‐ und Längsrichtung. Dabei wird die Raster‐Elektronenmikroskopie (REM) eingesetzt. Die Schlußfolgerungen aus dem theoretischen und dem experimentellen Teil der Arbeit ergeben einen eindeutigen Zusammenhang.
Coordination polymers, III. Synthesis and properties of chelate polymers of Cr(III), Fe(II), Co(II), Ni(II), Cu(II) and UO2(II). With schiff base of 4,4′‐(4,4′‐biphenylylene bisazo) disalicylaldehyde with aniline
Authors: Deshpande U. G. , Shah J. R.
Published: April 2003

Polychelates of Cr(III), Fe(II), Co(II), Ni(II), Cu(II) and UO2(II) were prepared from Schiff base of 4,4′‐(4,4′‐Biphenylylene bisazo) disalicylaldehyde with aniline. All the chelate polymers are dark coloured and insoluble in common organic solvents. They are characterized on the basis of electronic reflectance spectral and magnetic measurements in conjunction with infrared measurements. Elemental analyses indicate a metal ligand ratio of 1:1 for all the polychelates except polychelate of UO2(II) for which the ratio is 2:3. The various ligand field parameters have been evaluated for Cr(III), Ni(II) and Co(II) polychelates. Except Cu(II) and Co(II), polychelates, the other polychelates show six coordinated structure. Cu(II) and Co(II) polychelates may have a square planar and tetrahydral structure, respectively. The thermal stability of all the polychelates was determined from their thermogravimetric analyses.
Osmotic pressures of concentrated polymer solutions in good solvents
Authors: Kok C. M. , Rudin Alfred
Published: April 2003

The hydrodynamic radii of solvated polymer molecules can be estimated with a theory which has been reported earlier. These radii are employed in a hard sphere model to predict osmotic pressures of polymer solutions. Calculated and experimental osmotic pressures are in quite good agreement even for solutions with concentrations appreciably higher than the critical concentrations for overlap of polymer coils. The theory presented here is limited to good solvents.
Reactive polymers, 46. The effect of diluents on the surface reactivity of polymers obtained from glycidyl methacrylate
Authors: Horák Daniel , Pelzbauer Zdeněk , Švec František , Labský Jiří , Bleha Miroslav
Published: April 2003

Macroporous copolymers of glycidyl methacrylate and ethylene dimethacrylate were synthesized under equal conditions in the presence of different solvents as porogenic agents. The products obtained differ in the porosity, specific surface area, content of oxirane groups, and shape. The reactivity was measured using three substrates having low, medium, and high molecular weight (HCl, 4‐amino‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl, human serum albumin). The fraction of the reacted amount of reagent to the amount which would fill in the measured specific surface area in a monomolecular layer was calculated and found to reach a minimum for polymers with the best developed porous structure, although in all cases it is higher than unity. This shows that the reaction proceeds not merely on the available surface and that a new approach to the description of reactions on macroporous polymers is necessary.
Epoxy resins VIII. Thermal properties of 4,4′‐sulfonyldiphenol and bisphenol a epoxy resins
Authors: Bansal R. K. , Agarwal R. , Keshav K.
Published: April 2003

Epoxy resins of different molecular weights were prepared from epichlorohydrin and 4,4′‐sulfonyldiphenol (SDP) and from epicholorohydrin and bisphenol A (BA). They were cured at high temperatures with four different crosslinking agents, including aliphatic and aromatic amines. The thermal behaviour of these cured epoxy resins was studied. From the IPDT and IDT data it was observed that sulfone epoxy resins were thermally more stable than bisphenol A epoxy resins. The activation energies of thermal degradation of the resins were calculated and the implications of these results are discussed.
The oxidation of poly(vinyl pyrrolidone) with Ce(IV)
Authors: Staszewska Danuta Urszula
Published: April 2003

It was established that commercial poly(vinyl pyrrolidone) (PVP) may contain hydroperoxides, hydroxyl groups, carbonyl groups and double bonds in the main chain, and substances of low molar mass such as hydrogen peroxide and 2‐pyrrolidone, products of PVP oxidation during processing, handling and/or storage. In a scheme PVP reacting sites with Ce(IV) used as an initiator in the reaction of copolymerization of PVP with vinyl monomers were shown. It was concluded that PVP hydroperoxides were responsible for the formation of a respective homopolymer, whereas PVP hydroxyl groups may form radicals capable of the polymerization of a comonomer. The influence of molar mass of mother PVP on the course of the reaction of copolymerization of PVP was also discussed.
Miscibility of poly(vinyl chloride)/ethylene‐acrylic rubber blends
Authors: Kalfoglou Nikos K.
Published: April 2003

The compatibility behaviour of blends of poly(vinyl chloride) with an ethyleneacrylic rubber was investigated at five compositions. Phase‐contrast microscopy revealed submicron heterogeneities at intermediate compositions, however, on the basis of the dynamic mechanical properties, one concludes that the pair is miscible at the segmental level, throughout the composition range. These properties were studied between 143 and 383 K at 110 Hz. Tensile properties are characteristic of a miscible system and modulus enhancement supports the view that synergistic effects are present. Models proposed for miscible systems accurately predict the compositional variation of Tg. Also, mechanic models suitable for two‐phase systems, fail to predict the modulus dependence on composition. Fire retardancy becomes considerable already at intermediate levels of PVC.
A study of synthesis and characterization of compatibilizers for thermosetting‐thermoplastic polymer blends
Authors: Jayabalan M. , Balakrishnan T.
Published: April 2003

Modified copolymers or compatibilizers were prepared to blend thermosetting (phenol formaldehyde resin) and thermoplastic (PMMA/PS) polymers. Two compatibilizers, modified phenol formaldehyde‐(s‐triazine)‐polystyrene, P(PF‐g‐S) and poly‐(cinnamaldehyde‐co‐oxypropyleneoxyisophthaloyl‐co‐oxypropyleneoxyfumaroyl), P(C‐g‐E), were synthesized and characterized. The behaviour of the compatibilizers towards UV vacuum irradiation and heat was studied with low molecular weight P(PF‐g‐S) and P(C‐g‐E). Crosslinking was found to occur during the initial 20 h of UV vacuum irradiation, which was confirmed by solubility and swelling data. Thermal degradation of thermoplastic segments in P(PF‐g‐S) was found to occur initially during thermal exposure. Crosslinking of the degraded radical fragments and phenolic segments took place in the continued thermal exposure.

A method yielding a simultaneous interpenetrating network (SIN) was adopted to increase the molecular weight of P(PF‐g‐S) and its allied copolymers which is a prerequisite for the present polymer blends. Condensation reaction in phenolic segments and addition reaction in thermoplastic segments were carried out simultaneously, the former reaction was carried out thermally and the latter by photo irradiation.
Trennung von PUR‐Ionomeren mit Sulfonatgruppen und nichtionischen Prepolymeren mittels Gelpermeations‐Chromatographie
Authors: Lorenz O. , Rose G.
Published: April 2003

Mischungen aus Polyurethanionomeren mit SO3‐ ‐Gruppen und ionenfreien Prepolymeren können mittels Gelpermeations‐Chromatographie unter Verwendung von ß‐Bondagel als stationärer Phase und wasserhaltigen Elutionsmitteln getrennt werden. Derartige Mischungen wurden durch Umsetzung von dünngeschichteten NCO‐Prepolymeren mit N‐(2‐Aminoethyl)‐2‐aminoethansulfonsaurem Natrium bei variiertem Stoffmengenverhältnis erhalten. Die für Ionomere und prepolymere ermittelten Massenbrüche sind mit denen identisch, die sich aus der wahrscheinlichsten Molmassenverteilung ergeben.
Einfluß des reckprozesses auf die struktur von polyethylenterephthalatfasern
Authors: Koukol Ludvîk , Kalousková Vera
Published: April 2003

In der Einleitung wird eine kurze übersicht über die Literatur gegeben, die sich mit der Untersuchung der strukturellen Veränderungen der Polyesterfasern durch das Recken befaßt. Dann wird die Entstehung der orientierten Fibrillenstruktur von Tesil 11 anhand von Rasterelektronenmikroskopaufnahmen beschrieben.

Die Strukturparameter von verschiedenen gereckten Fasern wurden mit Hilfe der Röntgenweit‐ und ‐kleinwinkelbeugung und der Doppelbrechung bestimmt . Abschließend wird eine Modellvorstellung von den Veränderungen der übermolekularen Struktur der amorphen Fasern während des Reckprozesses entwickelt.
Modification of polyethylene with methacrylic acid, II. Molecular structure of the grafted copolymer
Authors: Bryjak Marek , Trochimczuk Witold
Published: April 2003

A modified method for the investigation of the molecular structure of polyethylene grafted with methacrylic acid (PE‐g‐MA) using the statistical analysis of the grafting process has been presented. On this basis a model for the structure of PE‐g‐MA has been proposed, in which one PMA chain is attached to one PE chain. It has been found that benzoyl peroxide does not influence the molecular weight distribution of the parent polyethylene under modification conditions used.
Rheological properties of carbon black‐extended compounds of polyisoprene and polybutadiene
Authors: Dschagarova E. , Piralkova S.
Published: April 2003

The rheological properties of carbon‐black‐extended mixtures of polyisoprene and polybutadiene were investigated. Investigations were carried out at 70, 80, 90, and 100°C at wall adjacent shear rates of 0.8 to 3.2·105 Pa. Values of the flow index ‘n’ were found between 0.16 and 0.23, showing the non‐Newtonian character of the mixtures. The constant K of the Ostwald‐de Waele function varies with the composition ratio of the two incorporated rubbers in a non additive and non monotonous way. At a 1:1 ratio of the rubbers a minimum value of K was found. Effective viscosities of the mixtures are lower than expected in an additive case. The energy of activation shows an essential positive deviation from the straight line of additivity. The rheological properties were interpreted in terms of phase model, including a continuous and a discontinuous phase as well as an intermediate layer between these phases.
Effect of pre‐extension on the electrical conductivity of styrene‐butadiene rubber loaded with FEF carbon black. I. Dependence on temperature and swelling
Authors: Amin M. , Hassan H. H. , Nasr G. M.
Published: April 2003

The effect of pre‐extension on the electrical conductivity of SBR (1502) filled with 70 phr FEF carbon black was studied. The anomalous behaviour of conductivity, manifested as a minimum in the temperature dependence of the electrical conductivity curve began to disappear on approaching a certain characteristic value of pre‐extension. Moreover, the shape of the electrical conductivity vs. temperature curve was found to change appreciably with increasing pre‐extension.

The effect of swelling in kerosene on the electrical conductance of the same samples at constant pre‐extension was also studied.

A correlation between the effect of both, pre‐extension and swelling in kerosene on the electrical properties of SBR filled with 70 phr FEF carbon black was found.
Study of electrochemical properties and formation of some phenolic block copolymers
Authors: Chatterjee S. K. , Katyal Anita
Published: April 2003

Phenolic block copolymers have been prepared by condensation of p‐cresol‐formaldehyde and p‐toluidine‐formaldehyde homopolymer chains. The compositions of the copolymers have been determined by electrometric titrations in non‐aqueous solvents. Efforts have been made to correlate structural features of the copolymers, such as intramolecular hydrogen bonding, and the probable number of phenolic and aromatic amine units in the respective blocks of the copolymer chain with their titration curves.
Heterogene ultrafiltrationsmembranen zur fixierung von enzymen, II
Authors: Ansorge Wolfgang , Staude Eberhard
Published: April 2003

Eine neue heterogene Ultrafiltrationsmembran zur kovalenten Kupplung von Enzymen wird beschrieben. Die Membranmatrix besteht aus Polysulfon, die aktive Kupplungskomponente ist ebenfalls ein Polyarylether mit entsprechendem Substituenten. Das Verhalten als reine Ultrafiltrationsmembran sowie als aktive Enzymmembran wurde untersucht. Die kovalente Immobilisierung erfolgte durch Diazotierung der aktiven Komponente. Das Enzym Dextranase ist nur in der Stützschicht der asymmetrischen Membran fixiert. Damit ist das Model1 eines idealen Membranbioreaktors realisiert.