bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oberflächenstrukturierung polymerer Fasern durch UV‐Laserbestrahlung. 1. Grundlagen der UV‐Laserbehandlung von Polymeren
Authors: Bahners Thomas , Schollmeyer Eckhard 
Published: April 2003

AbstractDie Oberflächenstruktur stellt ein herausragendes Merkmal einer textilen Faser dar. Sie beeinflußt Gebrauchs‐ und Verarbeitungseigenschaften wie Reibungsverhalten, Benetzungseigenschaften, Adsorptionsvermögen von Farbstoffmolekülen und vor allem Haftungsverhalten von Partikeln, Pasten und Pigmenten. Die Möglichkeit, diese vielfältigen Eigenschaften durch gezielte Oberflächenmodifikation zu beeinflussen, machen Technologien für die Textilveredlung wünschenswert. Als neuartiges Verfahren soll in dieser Artikelfolge die Bestrahlung von Synthesefasern mit gepulsten UV‐Lasern (Excimerlasern) vorgestellt werden. Diese Technologie wird für die mikrolithographische Bearbeitung und auch für das Schneiden und Bohren von polymeren Werkstoffen eingesetzt. Dabei hat sich gezeigt, daß gezielte, hochpräzise Oberflächenbehandlungen möglich sind, ohne das Grundmaterial zu schädigen. Im ersten Beitrag zur Oberflächenstrukturierung von Synthesefasern mit UV‐Lasern sollen Grundlagen der UV‐Laserbehandlung betrachtet werden.
Oberflächenstrukturierung polymerer Fasern durch UV‐Laserbestrahlung. 2. Phänomenologische Untersuchung der durch Laserbestrahlung erzeugten Oberflächenstrukturen
Authors: Bahners Thomas , Schollmeyer Eckhard 
Published: April 2003

AbstractDieser Beitrag berichtet über die Bestrahlung von Synthesefasern mit gepulster UV‐Laserstrahlung (Excimerlaser) als neuartige Technologie zur Erzeugung regelmäßiger Oberflächenstrukturen. Dabei werden Laserwellenlängen von 193 und 248 nm eingesetzt. Am Beispiel verschiedener Synthesefasern werden die Kenndaten der Oberflächenstrukturen in Abhängigkeit von den Bestrahlungsbedingungen rasterelektronenmikroskopisch untersucht. Anhand der Meßdaten werden phänomenologische Gesetzmäßigkeiten ermittelt.
Oberflächenstrukturierung polymerer Fasern durch UV‐Laserbestrahlung. 3. Synergetisches Modell für das Entstehen der Oberflächenstrukturen
Authors: Bahners Thomas , Schollmeyer Eckhard 
Published: April 2003

AbstractEin synergetisches Modell wird vorgeschlagen für die Entstehung der Oberflächenstruktur von UV‐laserbestrahlten Polymeren und speziell Synthesefasern. Dabei wird angenommen, daß durch thermische Beiträge zur UV‐Laser‐Polymer‐Wechselwirkung eine sehr dünne, hocherhitzte Schmelzschicht an der Ablationsgrenze entsteht. Das Zusammenwirken von Marangoni‐Konvektion und Schrumpfverhalten aufgrund innerer Spannungen ist dann für das Entstehen der typischen Struktur verantwortlich. Parameter für das Auftreten des Effekts sind hierbei der Absorptionskoeffizient für die jeweilige Wellenlänge, der die Dicke der Schmelzschicht bestimmt, sowie die Existenz des Schrumpfes.
Oxygen transport and surface active properties of silicone containing copolymers of methyl methacrylate II
Authors: Erbil H. Yildirim 
Published: April 2003

AbstractNew organofunctional siloxanes from γ‐methacryloxypropyltrimethoxysilane (MPTMS) were synthesized by transesterification of methoxy groups with linear high alcohols, ether alcohols, and α‐hydroxyacids. The factors affecting the substitution ratios were determined.These siloxanes were copolymerized with methyl methacrylate (MMA), crosslinked with ethylene glycol dimethacrylate (EGDM) in order to examine the effect of substituted groups to the oxygen permeability coefficient (Pd) and surface free energy properties of the resultant copolymers.The substitution of the oxygen containing polar groups decreased the oxygen permeability due to the interactions between polar groups decreasing the free volume. However, these groups increased the polar component of surface free energy (γ) and thus total surface free energy (γS). The hydrophilicity of the carbitol and 2‐ethoxyethanol containing siloxane‐MMA copolymers was found to be suitable for biomedical applications.
Chemical reactions of an epoxy‐functional silane in aqueous solution
Authors: Xue Gi 
Published: April 2003

AbstractChemical reactions of the functional epoxy group of γ‐glycidoxypropyltrimethoxysilane in aqueous solution have been studied by Fourier transform infrared spectroscopy (FT‐IR). It was found that the epoxy group reacts with the silanol group forming a SiOCC structure, and concurrently reacts with water. The kinetics of these reactions were studied.
A model for predicting elongational viscosity of polymer blends
Authors: Saini D. R. , Shenoy A. V. 
Published: April 2003

AbstractA model has been proposed to correlate the elongational viscosity of blends with the free volume theory so that the elongational viscosity of a blend at any composition can be determined from the elongational viscosity and the weight fractions of the individual components. The predictions of the model are compared with experimental data in four cases and found to give reasonable good agreement.
Untersuchungen zur thermodynamischen verträglichkeit von polyethylen hoher dichte (HD PE) und polyethylen niederer dichte (LD PE) im schmelzezustand, I. Die bestimmung der löslichkeitsparameter
Authors: Freytag Ulrich , Radusch Hans‐Joachim 
Published: April 2003

AbstractFür HD PE und LD PE wurden oberhalb der Kristallisationstemperaturen die Löslichkeitsparameter auf der Basis gaschromatographischer Retentionsdaten bestimmt. Als Meßverfahren wurde die Methode der Inversen Gaschromatographie angewendet. Es zeigte sich, daß die Löslichkeitsparameter der untersuchten Polyethylentypen innerhalb der Fehlergrenzen nahezu gleich sind. Aus der Beschreibung der Temperaturabhängigkeit der Löslichkeitsparameter folgt, daß das thermodynamische Verhalten der Polyethylenkomponenten in Mischungen durch ihre unterschiedlichen freien Volumina determiniert ist.
Synthesis and thermal studies of bisitaconimide‐methacrylic acid copolymers
Authors: Rao K. Vijaya Chandra , Nema Suresh K. , Kumar Velayudhan Nair G. , Mathew Suresh 
Published: April 2003

AbstractA copolymer of 3,3′‐bisitaconimido‐m,m′‐diphenyl sulfone and methacrylic acid was synthesized by free radical polymerization. The copolymer was characterized and the copolymerization parameters were evaluated. The reactivity ratios determined by three different methods were in good agreement and the values suggest an alternating copolymer. The thermal degradation of the bisitaconimide homopolymer and the copolymer were compared and the structural implications on the thermal behaviour are discussed. The activation energies for the different stages of thermal decomposition of both the homopolymer and the copolymer were evaluated from the Coats‐Redfarn plots.
Influence of synthesis conditions of porous copolymers of 1,4‐di(methacryloyloxymethyl)‐naphthalene with divinylbenzene on their structure, 2. Influence of diluent composition
Authors: Gawdzik B. , Matynia T. 
Published: April 2003

AbstractThe influence of diluent composition on the internal structure of porous copolymers of 1,4‐di(methacryloyloxymethyl)naphthalene (1,4‐DMN) and divinylbenzene (DVB) was studied.A set of copolymers containing 0.5 mole fraction of 1,4‐DMN and 0.5 mole fraction of DVB obtained in the presence of various amounts of toluene in the mixture with n‐decanol was investigated. In order to establish the influence of toluene concentration on the internal structure of 1,4‐DMN and DVB copolymers, surface areas, pore size distributions, and polarities of sorbents were investigated.
Reaction of poly(vinyl alcohol) with n‐butyl isocyanate. Chemical hydrolysis of the resulting polymers
Authors: Arranz F. , Sánchez‐Chaves M. , Martínez R. 
Published: April 2003

AbstractThis study is concerned with some kinetic features of the reaction of n‐butyl isocyanate with poly(vinyl alcohol) without any catalyst and using triethylene diamine as catalyst. 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 butyl urethane (VAL‐VBU) copolymers were obtained. It has been found a linear dependence of reaction rate on polymer, n‐butyl isocyanate, and triethylene diamine concentrations. Reaction rate constant decreases as reaction time increases. It can be explained by steric hindrance phenomena due to urethane groups incorporated along the polymeric chain. The activation energy was found to be 49.9 kJ/mol. A kinetic study of the homogeneous hydrolysis of VAL‐VBU copolymers has been made as a function of the base concentration, the temperature, and the VBU content. The homogeneous hydrolysis was found to be first order with respect to both hydroxyl ion and VBU contents. The activation energy for the base catalyzed homogeneous hydrolysis was found to be 79.3 kJ/mol. The heterogeneous hydrolysis of VAL‐VBU copolymers in basic medium showed that no hydrolysis takes place under the conditions employed.
Studies on 50/50 natural rubber/styrene butadiene copolymer blend
Authors: Joseph Rani , George K. E. , Francis D. Joseph 
Published: April 2003

AbstractA carbon black filled 50/50 natural rubber (NR)/styrene‐butadiene rubber (SBR) blend is vulcanized using several conventional curing systems designed by varying the amounts of sulphur and accelerator. The cure characteristics and the properties of the vulcanizates are compared. The quantity and quality of crosslinks in each case are evaluated by chemical probes to correlate them with the vulcanizate properties.
Radiation initiated grafting of styrene and methyl methacrylate onto wool
Authors: Kumar Manmohan , Rao M. H. 
Published: April 2003

AbstractRadiation initiated grafting of hydrophobic monomers styrene and methyl methacrylate onto wool (dyed and undyed) and dyed carpet has been carried out. The importance of swelling in obtaining appreciable amounts of grafting has been stressed. The rate of grafting with dyed wool and carpet is found to be less than for undyed wool and the results are explained on the basis of protection offered by aromatic moieties of the dye. Efficiency of monomer utilization has been found to be as high as 98% at low concentrations of the monomer since the accompanying (parasitic) homopolymerisation is almost negligible in the presence of scavengers. Reasonable hydrophobicity is achieved in ca. 80% styrene grafted and ca. 150% methyl methacrylate grafted wool.
Synthesis of hydrophilic elastomers by radiation grafting
Authors: Soebianto Yanti S. , Yoshii Fumio , Makuuchi Keizo , Ishigaki Isao 
Published: April 2003

AbstractRadiation grafting of acrylic acid (AAc) onto ethylene‐propylene rubber (EPR) to obtain hydrophilic elastomers has been investigated. It was found that by addition of alcohol (methanol and 1‐propanol) into water as solvent for grafting the degree of grafting increased and formation of homopolymer was retarded. The grafting by addition of alcohol occurred even in deeper portions of the film compared with no addition of alcohol. Grafting rate differed largely with propylene contents in the EPR. Graft polymerization occurred easily in EPR of lower propylene contents such as 22%. Before introducing AAc in grafting the stability of EPR radicals of lower propylene contents was higher in comparison with other components. Water absorption of EPR increased linearly with increasing grafting yield.
Kernresonanz‐untersuchungen an isophorondiisocyanat/diamin und röntgenstrukturanalyse des cis‐isophorondiamins
Authors: der Heyde W. Auf , Hübel W. , Boese R. 
Published: April 2003

Abstract1‐Amino‐(3‐aminomethyl)‐3,5,5‐trimethylcyclohexan 1 (IPDA) und 1‐Isocyanato‐(3‐isocyanatomethyl)‐3,5,5‐trimethylcyclohexan 2 (IPDI), die im technischen Hüls‐Produkt jeweils im Isomerengemisch mit 25 und 75% (1a, 1b und 2a, 2b) enthalten sind, wurden durch 1‐H/13‐C‐NMR‐Spektroskopie in ein‐ und zweidimensionaler Technik untersucht und die Konfiguration und Konformation festgelegt. Dabei ergab sich für das zu 75% vorliegende Isomere von IPDA und IPDI eine Sesselkonformation mit cis‐Anordnung des equatorialen NCO bzw. NH2 Substituenten und der equatorialen CH2NH2‐ bzw. CH2NCO‐Gruppe. Die Röntgenstrukturanalyse eines bei tiefer Temperatur gezogenen Einkristalls des flüssigen Hauptisomeren von IPDA bestätigte die NMR‐Befunde (Raumgruppe Pl̄; Zelldimensionen: a = 5,864(2); b = 8,107(3); c = 11,505(5) Å; α = 87,63(3)°; β = 88,85(3)°; γ = 73,34(3)°).
Bismaleimide resins. Effect of aliphatic amines on properties
Authors: Varma I. K. , Gupta S. P. , Varma D. S. 
Published: April 2003

AbstractBis(p‐maleimidophenyl) methane (BM) resin was chain extended by nucleophilic addition with aliphatic diamines having 2,4, or 6 methylene groups (EDA, DAB, HMDA) and diethylene triamine (DETA) and triethylene tetramine (TETA). Chain extension of BM with aliphatic amines significantly reduces the curing temperatures. Increasing the methylene content of the aliphatic amines leads to slight reduction in onset temperatures of curing (∼6°C). Heat of polymerization (ΔH) decreases significantly by chain extension with diamines. Further decrease in ΔH is obtained by the addition of triallylcyanurate (TAC) to the chain extended BM. Thermal stability of cured (180 ± 5°C) resin in nitrogen atmosphere was found to be independent of the methylene content of diamines used for chain extension. Mechanical properties of glass fabric reinforced chain extended BM resins were evaluated. Ageing behaviour of these laminates was investigated at 220 ± 10°C for 500 h and changes in mechanical properties were determined.
Zur Morphologie von peroxidisch vernetztem Polyethylen
Authors: Bongardt J. , Michler G. H. , Naumann I. , Schulze G. 
Published: April 2003

AbstractDas Vernetzen von LDPE mittels Peroxiden hat neben einer Abnahme der Kristallinität eine Veränderung der übermolekularen Struktur zur Folge. Mit steigender Vernetzung nimmt der Durchmesser der Sphärolithe bzw. der garbenförmigen überstrukturen ab. Dieses Ergebnis ist auf eine rückläfige Kristallwachstumsgeschwindigkeit zurückzuführen, bedingt durch eine fallende Kristallisationstemperature und einen Anstieg der Schmelzviskosität infolge zunehmender Vernetzungsdichte. Durch die Vernetzung entstehen zusätzliche konstitutionelle Störungen in der PE‐Kettenstruktur, wodurch die Abmessungen der Lamellenkristalle und die Größe der Mosaikblöcke beeinflußt werden.
Photoconductive properties of cadmium sulfide encapsulated in polymers
Authors: Haga Yutaka , Nakajima Masahisa , Yosomiya Ryutoku 
Published: April 2003

AbstractCadmium sulfide (CdS) was encapsulated in poly(methylmethacrylate), poly(styrene) or poly(vinylcarbazole) by the encapsulating polymerization process, and its photoconductivity was investigated. As result, it was observed a remarkable light‐sensitive effect. The light sensitive effect of CdS encapsulated in poly(methylmethacrylate) (C‐MMA‐CdS) is particularly marked and depends largely on the encapsulation rate. The photosensitive mechanisms of encapsulated cadmium sulfide (C‐CdS), CdS material, and CdS/polymer dispersion composites were discussed and compared. Furthermore, the temperature dependence of the dark current and the initial rising rate of the sensitizing photocurrent were studied.
Spectroscopic study of gangue of coal and its application as filler in PVC compounds
Authors: Xue Gi , Fu Qiang , Ding Jianfu , Jiang Shagen , Liu Shiying , Xi Yuinxia 
Published: April 2003

AbstractFillers for PVC compounds have been made from coal gangue. FT‐IR studies show that it contains aromatic components with phenolic groups. Application of gangue as a filler in rigid PVC compounds gives rise to materials of good mechanical properties, high heating and chemical resistance, and lower cost.
Styrene‐divinylbenzene copolymers, V. Inhomogeneity in the structure and the average degree of swelling
Authors: Okay Oǧuz 
Published: April 2003

AbstractThe compositional inhomogeneity and the average degree of swelling of heterogeneous styrene‐divinylbenzene (S‐DVB) copolymers were investigated using two morphological features of porous copolymers. At a fixed volume fraction of a nonsolvating diluent, the extent of inhomogeneous crosslinking increases with increasing DVB concentration. In addition, the crosslinking density of less crosslinked regions of the network decreases as the DVB concentration increases. The experimental results can be explained by the microgel‐model of the network formation. The average degree of volume swelling can be predicted from the composition of the starting monomer mixture and from the porosity of the final copolymer dried from water. Depending on these parameters, the changes in the value of v2, the volume fraction of copolymer in the swollen gel, and the conditions for the pore stability are discussed.
Eine rheo‐optische Apparatur für die Durchführung homogener, einfacher Dehnungen an Polymerschmelzen mit simultaner Aufzeichnung der Deformation, der mechanischen Spannung und der Doppelbrechung
Authors: Dinkel Alfred , Hoppler Hans Ulrich , Tomka Ivan , Vancso Gyula 
Published: April 2003

AbstractEs wird über eine rheo‐optische Apparatur zur Verstreckung von Polymerschmelzen mit rotierenden Klemmen berichtet, die mit einer Doppelbrechungs‐Meßeinrichtung ausgerüstet ist. Mit dieser Einrichtung können einfache Dehnungen an Polymerschmelzen bis zu hohen Verstreckgraden unter homogenen Bedingungen durchgeführt werden. Während des Deformationsvorganges können die Spannung, die Doppelbrechung und die Probendicke mit einer Meßrate von 20 Hz, sowie die Probenbreite mit ca. 3 Hz erfaßt werden.Wir haben Messungen an Polyisobutylen bei Raumtemperatur mit verschiedenen Dehngeschwindigkeiten (0,01 s−1 < \documentclass{article}\pagestyle{empty}\begin{document}$\dot \varepsilon$\end{document} < 1 s−1) bis zu einem Verstreckgrad von λ ≈ 200 durchgeführt. Dabei wurden Spannungen bis zu 2 · 106 Pa erhalten. Das spannungsoptische Gesetz war bei homogener Versuchsführung stets erfüllt. Es wird gezeigt, daß ohne Kontrolle der Dehngeschwindigkeit und insbesondere bei inhomogener Dehung nicht nur Abweichungen vom spannungsoptischen Gesetz, sondern auch große Fehler bei der Spannungs‐ bzw. Viskositätsberechnung auftreten. Deshalb wurde großer Wert auf die Prüfung der Homogenität der Dehnung gelegt.
About the influence of filler particle size on toughness of filled polypropylene
Authors: Švehlová Vítězslava , Polouček Eduard 
Published: April 2003

AbstractThe content of the largest filler particles and their agglomerates has been evaluated in polypropylene‐calcium carbonate composite. A strong decrease of tensile impact strength was noted with the increasing value of Av, i.e. the ratio of area belonging to inclusions greater than about 10 μm to the overall area. A similar dependence was observed for three different types of polypropylene matrix and different ways of composite preparation.
Correlation between the porous structure of polystyrene and its discolouring ability
Authors: Simitzis Johannis 
Published: April 2003

AbstractPorous polystyrene was prepared according to the following methods by variation of the production parameters: (A) Method based on the suspension polymerization using a nonsolvent of the polymer. (B) Method based on the dissolution of polystyrene in a solvent and then precipitation using a nonsolvent of the polymer. The molecular weight of the polymer, its structure using Hg‐porosimetry, and the microscopic pattern of the polymer grains were determined. The ability of the produced polystyrene to discolour aqueous solutions of different dyes (mainly methylene blue) was also examined.From the correlation between porous structure and discolouring ability in comparison with corresponding discolouring examination of other adsorptive agents (activated carbon) the importance of the following parameters was found out and evaluated: (a) total value of pore volume or pore volume distribution, (b) intermediate part of pore distribution 10000 – 100 Å for the adsorption of the given dyes, (c) shape of pores, which are different in method A and B (the comparison of produced polystyrene by different production parameters should be done only by independent methods and not between A and B method). It also resulted that it is necessary to introduce appropriate groups into the molecules of the porous polystyrene in order to increase the adsorption rate of an ionic or a polar substance. In conclusion, by appropriate choice of the production parameters of porous polystyrene a product with the desired characteristics of porosity could be produced.
Cashewnut shell liquid: Characterization and studies of PVC degradation in solution
Authors: Varma I. K. , Dhara S. K. , Varma M. , Biddapa T. S. 
Published: April 2003

AbstractCashewnut shell liquid (CNSL), which is basically a mixture of several alkyl substituted phenols was characterized using 1H and 13C‐NMR, FT‐IR, and mass spectroscopic techniques. The major constituent was found to be cardanol having one, two, or three double bonds in the alkyl side chain. Presence of one hydroxy group was confirmed by acetylation and 1H‐NMR studies. Distillation of CNSL under atmospheric conditions resulted in partial oxidation of the side chain. Such an oxidation was confirmed by elemental analysis and FT‐IR studies. Thermal degradation of poly(vinyl chloride) (PVC) in CNSL was studied in nitrogen atmosphere in the temperature range of 180–220°C. Rate of dehydrochlorination of PVC was found to be lower in CNSL in comparison to the degradation in ethyl benzoate. An induction period ranging from 23 min to 55 min was observed in CNSL and was found to depend on the concentration of PVC in solution and temperature of dehydrochlorination. Activation energy for dehydrochlorination of PVC in CNSL was found to be 43 ± kcal/mol. Compatibility studies of PVC in CNSL were done using differential scanning calorimetry (DSC). Good plasticization was observed by blending PVC up to 10% of CNSL. Overall thermal stability of PVC was not altered by the presence of CNSL in these low concentrations.
Graft copolymerization of starch with alkylene methacrylates
Authors: Sandle N. K. , Singh Om Pal , Varma Indra K. 
Published: April 2003

AbstractGraft‐copolymerization of 2‐hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA) onto starch using cerium (IV) as an initiator was investigated. The rate of graft copolymerization had a first order dependence on monomer concentration suggesting that grafting followed the typical free radical polymerization kinetics. In the infrared spectra of graft copolymers a very sharp and strong band at 1730 cm−1, which is characteristic for the vCO stretching of esters, was present. The grafting of HEMA or EDMA onto starch reduced the density of starch. Thermal behaviour of graft copolymers having different % graft‐on was investigated by thermogravimetric analysis. An increase in % graft‐on of EDMA from 19.7 to 95.7% resulted in an increase in thermal stability. However, at high % graft‐on (i.e. 163.4%) a reduction in thermal stability was observed.
Einfluß von Weichmachern auf die Löschung der Lumineszenz von Pyronin B in Polymerfilmen
Authors: Müller Franz Werner , Schiller Kurt , Marx Jörg , Klein Norbert 
Published: April 2003

AbstractDen polymeren, transparente Schichten ergebenden Bindemitteln Cellulosediacetat und Polyvinylalkohol wurden verschiedene Weichmacher zugesetzt, um spezifische konzentrationsabhängige Wechselwirkungen zwischen Polymerem und Weichmacher zu analysieren. Als Untersuchungsmethode dient dabei die Verfolgung der Löschung der verzögerten Fluoreszenz der Sonde Pyronin B in diesen Polymerfilmen. Es wird gezeigt, daß kleine Weichmacherkonzentrationen die Matrix verfestigen und damit beispielsweise die Sauerstoffpermeabilität einschränken. Dieser Effekt ist besonders in Cellulosediacetat ausgeprägt, für einige Weichmacher bis in den Bereich von 30%.