bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on new non‐shrinking, thermally stable araldite®‐type photopolymers with pendent aryl acryloyl groups. IV. Syntheses and photoreaction of araldite®‐type photoresists with pendent aryl acryloyl groups
Authors: Müller H. , Nuyken O.
Published: April 2003

Addition polymers of bisphenol‐A and epichlorohydrin can easily be esterified with aryl acryloyl chlorides to yield photosensitive polymers. The photoresists are curable with UV‐irradiation (λ ≥ 280 nm). FT‐IR measurements indicate that the network formation fonforms to second order kinetics. DSC and TGA measurements were carried out. The glass transition temperature of irradiated material is up to 171oC; the material is thermally stable up to 350oC. Spectral data are given.
Interpenetrating polymer network films as piezodialysis membranes
Authors: Galip Hasan
Published: April 2003

In the present study, interpenetrating polymer network (IPN) membranes were investigated for their potential application as piezodialysis membranes. These IPN membranes are not mosaic membranes. It was found that some of these membranes did show piezodialysis effects. Two of the membranes tested under high pressure gave permeates which were found to be more concentrated in sodium chloride than the initial feed solution, when analyzed by differential refractometry. The permeates from one membrane were double checked by titrating the chloride ion with silver nitrate solution. The results of the titration also indicated a positive effect.
Asymmetric addition of n‐butyllithium to aldehydes by chiral polymers having acetoxybornyl moieties
Authors: Liu Jui‐Hsiang , Kuo Jue‐Cheng
Published: April 2003

Optically active (+)‐2‐endo‐acetoxy‐5‐endo‐bornyl methacrylate (ABMA) was prepared from (+)‐camphor. The free‐radical homopolymerization of ABMA and its copolymerization with achiral methyl methacrylate (MMA) or styrene (St) were carried out with 2,2′‐azoisobutyronitrile in benzene. Effects of temperature and reaction time on the copolymerization were discussed. The monomer reactivity ratios (r1, r2) for poly(ABMA‐co‐MMA) and poly(ABMA‐co‐St) as well as Q and e values for the chiral ABMA in the copolymerization systems were evaluated by the Fineman‐Ross method. It was found that the absolute value of the specific rotation of poly(ABMA‐co‐MMA) increased with increasing ABMA unit content. A small deviation from linearity was observed, which suggests that asymmetry is not introduced into the copolymer main chain. Temperature and solvent effects on the specific rotation of the chiral homopolymer and copolymers were investigated. The results suggest that the chiral polymers synthesized in this investigation did not show a strong preference for a particular helical conformation. Applications of the chiral polymers on the asymmetric addition of n‐butyllithium to aldehydes were investigated. The effect of temperature and aldehydes on the asymmetric addition were also discussed.
Untersuchungen zur übermolekularen Struktur in Polybutylenterephthalat/Polycarbonat‐Blends
Authors: Radusch Hans‐Joachim , Androsch René , Vogel Jürgen , Trempler Jörg , Fakirov Stoyko
Published: April 2003

Zur Charakterisierung der übermolekularen Struktur von schmelzegemischten Polybutylenterephthalat(PBT)/Polycarbonat(PC)‐Blends wurden lichtmikroskopische, rontgenographische und kalorimetrische Untersuchungen durchgeführt. Die polarisationsmikroskopischen Aufnahmen zeigen bis zu einer Konzentration von ca. 20 Gew.‐% PC eine rein sphärolithische Struktur. Bei höheren PC‐Konzentrationen wird eine zweite separate, amorphe Phase sichtbar. Mit der DSC‐Methode wurde eine Verschiebung der Glasübergangstemperatur beider Ausgangskomponenten, eine geringe Schmelzpunkterniedrigung der kristallinen PBT‐Phase und unterschiedliche Kristallisationstemperaturen in Abhängigkeit von der Konzentration der Ausgangskomponenten gemessen. Eine Erniedrigung des Kristallinitätsgrades des PBT und eine Kristallisation des PC, insbesondere bei thermischer Nachbehandlung der Blends, wurde mittels Röntgenbeugung und ergänzender Dichtemessungen nachgewiesen.
Kinetics of the free radical polymerization of dimethyl diallyl ammonium chloride, 5. Kinetic model with persulfate as initiator
Authors: Hahn M. , Jaeger W.
Published: April 2003

The polymerization of dimethyl diallyl ammonium chloride in concentrated aqueous solution with persulfate as an initiator can be described up to high conversion by a kinetic model including

formation of primary radicals by activated initiator decomposition as well as by redox reaction of S2O82− and Cl−,

chain propagation via monomer cation associates and

termination by combination of cyclized polymer radicals between each other or with chlorine atoms.

A kinetic expression for the rate of polymerization is presented; rate constants and model parameters have been determined.
Polymerization of acrylamide by electrolytically generated Ce(IV)‐organic acid redox systems
Authors: Saraç A. Sezai , Basak Hüseyin , Soydan A. Bahattin , Akar Ahmet
Published: April 2003

Ce(IV) salt‐malonic acid or citric acid initiator systems were used for the polymerization of acrylamide in the presence of electrolysis. This allowed Ce(III) to be converted to Ce(IV) during polymerization. Graphite, silver, chromium/nickel, lead, platinum and stainless‐steel electrodes were used. The highest polymerization yield was obtained with a stainless‐steel electrode.
Synthesis of a poly(terephthaloylphosphine)
Authors: Banerjee S. , Palit S. K. , Rahman S. , Maiti S.
Published: April 2003

Poly(phenylphosphinediylterephthaloyl), a novel phosphorus‐containing polymer, was synthesized by low‐temperature solution polycondensation of dilithio(phenyl)‐phosphine with terephthaloyl chloride. The resulting polymer is soluble in polar aprotic solvents, having inherent viscosity of 19 ml/g in DMF at 30°C. The polymer was characterized by elemental analysis, IR and 1H‐NMR spectroscopy. TGA data show that the polymer is stable up to 250°C in air. The polymer was found to be self‐extinguishing.
Extension of the measuring range in size exclusion chromatography to higher molar mass by use of a light scattering detector
Authors: Lederer Klaus , Höllwarth Peter
Published: April 2003

A new method for the extension of the measuring range of size exclusion chromatography coupled with light scattering (SEC/LALLS) to higher molar mass is presented. This method uses the fact that the light scattering signal can often be detected already at considerable smaller values of the elution volume (i. e. higher values of molar mass) than the concentration signal; furthermore, it takes into account the peak broadening effect in SEC. This procedure is tested for the case of a logarithmic normal distribution and a most probable distribution of molar mass. In the case of polypropylene with a logarithmic normal distribution (M̄w = 420 000, M̄n = 99 000), the range of molar mass covered by SEC/LALLS can be extended by a factor of about 10; with a most probable distribution (M̄n = 100 000), the attainable extension in molar mass assumes a factor of about 2.
Etudes microlithographiques de résines négatives renfermant des unités tétrathiafulvalènes sensibles aux UV
Authors: Giral Louis , Montginoul Claude , Mungroo Aumduth , Sagnes René , Schué François , Guibert Jean‐Charles
Published: April 2003

Pour résoudre le phéomène de gonflement qui limite la résolution des résines microlithographiques classiques, nous nous sommes intéressés à de nouvelles résines avec lesquelles ce phénomène n'apparait pas. Nous avons retenu pour notre étude les résines R qui renferment en mélange un polymère porteur de radicaux tétrathiafulvalénylcarbonyloxyméthyles et le dibromotétrachloroéthane. Afin de voir l'influence de la nature du radical porteur de l'unité tétrathiafulvalène dans le polymtrè sur les propriétés microlithographiques des résines R, nous nous sommes également intéressés aux polymères renfermant des radicaux tétrathiafulvalénylphénoxymethyles. Les résines R ont été testées sous irradiation UV. Leurs sensibilités dépendent en outre de la valeur de la masse molaire du polymèr.
Photoinitiated surface grafting of synthetic fibers, IV. Applications of textile dyes onto surface‐photografted synthetic fibers
Authors: Feng Zhenguo , Icherenska Magdalena , Rånby Bengt
Published: April 2003

High‐strength polyethylene (HSPE), polypropylene (PP), poly(ethylene terephthalate) (PET), and poly(vinyl alcohol) (PVA) textile yarns have been surface‐photografted with various functional monomers, such as acrylic acid (AA), acrylamide (AM), glycidyl acrylate (GA) and 4‐vinyl pyridine (VP), by means of the continuous presoaking process developed. The dyeing of these surface‐modified yarns with various textile dyes has been investigated. In general, considerable improvements of dyeability have been observed. The dye adsorption of the surface‐photografted fibers is influenced by many factors, such as type of fiber, amount and properties of the functional monomer grafted on the surface of the fibers, type of textile dye, etc. The fibers surface‐grafted with a monomer containing basic groups, such as acrylamide and 4‐vinyl pyridine, are efficiently dyed with an acid dye. Conversely, a fiber surface‐grafted with acidic functional monomer is easily dyed to deep shades with basic dyes. The dye adsorption increases monotonically with increasing grafting measured in ESCA spectra as relative intensities of relevant lines. The ungrafted HSPE, PP and PET fibers can be dyed to some extent with certain dyes. In the present work, the dye adsorption increased by 3.4 times for HSPE fiber grafted with GA and dyed with the metal complex dye IO, by 7.9 times for PP fiber grafted with AA and dyed with the basic dye MB, by 6.1 times for PET with AM and with the direct dye SL, and by about 15.3 times for PVA with VP and with the acid dye TE.
Study on the thermal behaviour of copolymers of acrylonitrile with halogenated carboxylic acids
Authors: Li Pei Ren , Jia Wei Dong , Liu Bai Jian
Published: April 2003

The thermal stability of AN copolymers was studied by DSC technique in order to get information on the influence of comonomers containing halogenated carboxylic acid on the stabilization of PAN. It is shown that the activation energy of cyclization is reduced in the case of the copolymer with bromoacrylic acid (BrAA, 86.2 kJ/mol) compared with chloroacrylic acid (ClAA, 158 kJ/mol), acrylic acid (AA, 128 kJ/mol) and itaconic acid (IA, 102 kJ/mol). Copolymer AN/BrAA permits the stabilization at higher temperature than AN/IA and AN/AA, helping to shorten the stabilization time. It is proved that comonomer ClAA is not superior to BrAA in the effectiveness of thermal stabilization. The mechanism of the cyclization reaction of AN copolymer containing halogenated carboxylic acid is discussed.
Dynamische kontaktwinkelhysterese an oberflächen von siliconcopolyestern
Authors: Grasnick Gerd , Kamusewitz Helmut , Zimmermann Heinz , Paul Dieter
Published: April 2003

Siliconcopolyester wurden als Copolymere oder als Mischung mit Phenyltrichlorsilan‐Hydrolysat hergestellt und aus der Lijsung zu Folien geformt. Durch Messung der dynamischen Kontaktwinkelhysterese wurde die für eine Diffusion von Gasen bei der Gastrennung relevante Phasenverteilung an der Oberfläche dieser Membranen untersucht. Sowohl in Copolymeren als auch in Mischungen wird die Oberfläche durch in Domänen aggregiertes Siloxan bestimmt.
Synthesis of phosphorus‐containing polymers with potential bioactivity
Authors: Trendafilova‐Gercheva D. , Troev K. , Georgieva M. , Vassileva V.
Published: April 2003

Phosphorylation of poly(N‐vinyl pyrrolidone‐co‐vinyl amine) and poly(N‐vinyl pyrrolidone‐co‐glycidylcrotonate

Systematic name: (2,3‐Epoxypropyl)crotonate.

) is realized by Atherton‐Todd and Fields‐Kabachnik reactions and by the means of direct interaction with phosphorus trichloride and phosphorus trichloride oxide. The composition and structure of the isolated final products was proved by NMR (1H and 31P), IR spectroscopy and elemental analysis.
Studies on new non‐shrinking, thermally stable araldite®‐type photopolymers with pendent aryl acryloyl groups. 5. Partially fluorinated photopolymers
Authors: Nuyken Oskar , Spiegel Sabine , Budde Klaus , Quella Ferdinand
Published: April 2003

Several partially fluorinated polymers with photosensitive groups have been synthesized and characterized. Their photocuring reaction was studied in detail. The effect of structural units on the dielectric properties and the glass transition temperature was of special interest. Therefore, van Krevelen's increment methods were applied to these novel polymers. New increments for CF2‐, CF3‐ and C6F5‐units have been calculated.
Polyesters with 1.4:3.6‐dianhydrosorbitol as polymeric plasticizers for PVC
Authors: Braun D. , Bergmann M.
Published: April 2003

Saturated aliphatic polyesters with 1.4:3.6‐dianhydrosorbitol units were mixed with poly(vinylchloride) (PVC). The mechanical properties of these mixtures were examined by differential scanning calorimetry, stress‐strain experiments, and torsion pendulum measurements. Polyesters containing more than four methylene groups in the acid component are compatible with PVC. These polyesters can serve as plasticizers for PVC. On the contrary, mixtures of PVC with poly(1.4:3.6‐dianhydrosorbitol adipate) are incompatible; in this case, at any blend composition, the two glass transition temperatures of the pure components are observed.
Adsorption of organic species by a cyclodextrin epichlorohydrin network polymer
Authors: Kiji Jitsuo , Konishi Hisatoshi , Okano Tamon , Terashima Takashi , Motomura Koji
Published: April 2003

The adsorption of 4‐methylbiphenyl, sodium dodecylbenzenesulfonate (NaDBS), and phenol on a β‐cyclodextrin epichlorohydrin network polymers at 25°C has been studied. The isotherm of 4‐methylbiphenyl fits well with the Freundlich equation at a concentration range from 10−5 to 10−4 mol/l. The isotherms of NaDBS and phenol deviate from a straight line in the investigated concentration range.
Study of three and four component intermacromolecular complexes involving acrylic copolymers, metal ions, and non‐ionic polymers
Authors: Chatterjee S. K. , Khan A. M. , Ghosh S.
Published: April 2003

Poly(methacrylic acid‐co‐methacrylamide) and poly(acrylic acid‐co‐acrylamide) have been synthesized and characterized by known methods. The respective comonomer units of the two copolymers enter into complex formation through hydrogen bonding and ion‐dipole interactions. The unreacted units in the intercopolymer complex also interact with homopolymers such as poly(N‐vinylpyrrolidone) and poly(oxyethylene) as well as transition metal ions to form three and four component intermacromolecular complexes. Formation of these complexes could be shown through several experimental techniques, e.g. viscometry, conductometry, potentiometry, IR and UV spectrophotometry.
Studies on LDPE/LLDPE blends
Authors: Abraham D. , George K. E. , Francis D. J.
Published: April 2003

Selected grades of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) were melt‐mixed and the physical, mechanical and rheological properties evaluated. The blends were found to combine the good mechanical properties of LLDPE and processing properties of LDPE. The effect of crosslinking the blends with dicumyl peroxide (1 phr

Parts per hundred rubber

) was also investigated. The level of crosslinking increased with increase in LLDPE content. While the mechanical properties of the crosslinked blends were more uniform, the physical properties controlled by the crystallinity of the polymer, such as density, hardness and volume loss on abrasion, decreased on crosslinking.
Synthesis and characterization of multifunctional initiators for preparation of four‐branch polymers
Authors: Menceloǵlu Yusuf́ Z. , Baysal Bahattin M.
Published: April 2003

Tetrafunctional initiators T4‐AZO4, T4‐TCE1 and T4‐IPDI4 have been synthesized by using insertion reaction of tetrakis(dimethylamino)‐titanium (T4) with 2,2′‐azoisobutyronitrile (AIBN), tetracyanoethylene (TCE) or isophorone diisocyanate (IPDI), respectively, in dry benzene under nitrogen at 35°C. T4‐AZO4 is useful for preparing four‐branch polymers from radically polymerizable monomers by decomposition of the azo groups incorporated in the related initiator. Four‐branch polyacrylonitrile can be synthesized by using the initiator T4‐TCE1. This initiator possesses titanium‐amino functionalities which are capable of initiating acrylonitrile polymerizations. The tetrafunctional isocyanate compound T4‐IPDI4 is found to be useful to prepare a model network of dihydroxy‐terminated polymers.
Synthesis, characterization and properties of oxyethylene‐oxypropylene‐styrene multiblock copolymers
Authors: Xie Hong‐Quan , Chen Xiao‐Yuan , Guo Jen‐She
Published: April 2003

Oxyethylene‐oxypropylene‐styrene multiblock copolymers were synthesized by coupling poly(ethylene glycol), poly(propylene glycol) and α, ω‐dihydroxy polystyrene with 2,4‐toluene diisocyanate. The purified copolymers were characterized by IR and 1H NMR spectroscopy and membrane osmometry and identified as multiblock copolymers. The multiblock copolymers exhibit good emulsifying properties, high water absorption capacity and good phase transfer catalysis properties in Williamson reaction. The mechanical properties of the multiblock copolymers show that they behave like a thermoplastic elastomer or a toughened plastic, depending on the composition.
Photovernetzung von siliconen, 8. Netzwerkcharakterisierung photovernetzter siliconacrylate
Authors: Müller U. , Jockusch S. , Häusler K.‐G. , Timpe H.‐J.
Published: April 2003

Die photoinduzierte radikalische Vernetzung von Siliconacrylaten bzw. ‐methacrylaten wurde mit Hilfe von Quellungsmessungen untersucht, wobei ein modifizierter Quellungstest erlaubt, die Netzwerkbildung als Funktion verschiedener Parameter zu betrachten. Die Ergebnisse zeigen, daß die Netzwerkdichte eine Funktion der Lichtintensität, der Bestrahlungszeit, des Acrylatgehalts, der Molmasse des unvernetzten Silicons und auch der Länge der Spacergruppe zwischen Acrylateinheit und dem Siliconrückgrat ist. Sauerstoff besitzt dagegen nur einen Einfluß auf die Polymerisationskinetik, nicht aber auf die Netzwerkdichte.

Aus dem Vergleich der δB, ‐Werte der vernetzten Siliconacrylate und der vernetzten Vinylsilicone kann geschlossen werden, daß die Netzwerkstruktur auch vom Typ der olefinischen Gruppen abhängt. Die χ‐Parameter besitzen jedoch im gleichen Konzentrationsbereich die gleiche Größe.

Kinetische Untersuchungen zeigen, daß die Netzwerkbildung nach einem Zeitgesetz erster Ordnung verläuft. Dieses Ergebnis steht im Einklang mit der Polymerisationskinetik.

Mit Hilfe der Quellexperimente ist es auch moglich, den Einfluß von H‐Siloxanzusätzen als Wasserstoffüberträger zu untersuchen.
Synthesis of novolac on the basis of bisphenol A as curing agent for epoxy resins
Authors: Strehmel Veronika , Strehmel Bernd , Arndt Karl‐Friedrich , Müller Gert , Fedtke Manfred
Published: April 2003

Bisphenol A novolacs were synthesized in a melting process using paraformaldehyde, and in a solution process using a formalin solution and oxalic acid catalyst. 1H‐NMR investigations show a higher content of methylene bridges in the novolacs synthesized in a melting process. These novolacs were analysed by HPLC, GPC, DSC and FT‐IR spectroscopy. The molecular masses were determined by vapour pressure osmometry. The results were shown to be related with the molar ratio of the components. The bisphenol A novolacs were used as curing agents for epoxy resins. There exists a dependence of the gel times on the content of methylene bridges; this dependence is influenced by temperature. The activation energy for gel formation is nearly the same in all curing reactions investigated. The networks synthesized were investigated by thermomechanical analysis.
Curing kinetics of epoxy resins based on bisphenol‐S and its derivatives
Authors: Liaw Der‐Jang , Shen Wen‐Chang
Published: April 2003

The curing reactions of several epoxy resins based on bisphenol‐S with amine have been investigated by differential scanning calorimetry. The overall kinetic parameters of the curing reactions, such as activation energy, curing range and the order of the reaction are estimated by using four computational methods based on a single dynamic scan over the temperature range 50 – 300°C. Epoxy resins containing oxyethylene or oxypropylene units have lower reaction order and activation energy than the diglycidylether of bisphenol‐S. This indicates that flexible epoxide resins are easier to cure.
Sulfobetaine polyurethane ionomers. Salts effects of the properties of dilute solutions and polymer films
Authors: Buruianǎ T. , Buruianǎ E. C. , Diaconu I. , Robilǎ G.
Published: April 2003

The viscosimetric behaviour of diluted DMF solutions of some sulfobetaine polyurethanes and also the influence of some mono‐ and bivalent metal salts were studied. The study showed that polyurethane zwitterionomers behave as polyelectrolytes.

Films of these polymers complexed with bivalent metals can form, in situ, particles of metal sulfides by exposure to slow H2S flow. Preliminary results show an increased conductivity of films treated with H2S, suggesting a microphase segregation structure.
Mixtures of poly(ethylene terephthalate) and liquid‐crystalline polyesters with Y‐shaped mesogens
Authors: Rötting Oliver , Hinrichsen Georg
Published: April 2003

Some liquid‐crystalline polyesters (LCP) with Y‐shaped mesogens, differing only in the length of their spacers, were blended with poly(ethylene terephthalate) (PET). Calorimetric measurements show significant influence of the LCP on the crystallization of PET even at low concentrations. The mixtures are spun into fibres and their mechanical properties are compared with fibres made from pure LCPs. The formation of LCP‐fibrils leads to improved values of Young's modulus and tensile strength.
Quantitative measurement of pigment dispersion and effect of processing on dispersion in high density polyethylene using a microscope photometer
Authors: Ogbobe Okoro
Published: April 2003

A microphotometer attached to a computer‐controlled darkfield microscopy system has been used for the quantitative measurement of the degree of pigment dispersion in high‐density polyethylene extruded at specified varying processing conditions. The method distinguishes levels of pigment dispersion in extrudates obtained from subtle changes in processing conditions. Since the set‐up is comparatively inexpensive, the technique promises to be particularly useful to small‐scale manufacturers.
Kinetik der Polyphenylensulfid‐Synthese
Authors: Koschinski I. , Reichert K.‐H. , Traenckner H.‐J.
Published: April 2003

Die Polykondensation von Na2S·3H2O und 1,4‐Dichlorbenzol im Lösungsmittel 1 ‐Methyl‐2‐pyrrolidon wurde in kleinen Hochdruck‐Kapseln aus Edelstahl mit einem Volumen von ca. 30 μl in einem Differentialkalorimeter im Temperaturbereich von 220°C bis 260°C kinetisch untersucht. Die Reaktion ist stark exotherm, bei 220°C beträgt die Reaktionsenthalpie ca. 180 kJ mol−1. Sie ist durch ein autokatalytisches Verhalten gekennzeichnet, welches mit einem Zeitgesetz 2. Ordnung in bezug auf die Konzentration der stöchiometrisch eingesetzten Monomeren und einer vom Umsatz abhängigen Reaktionsgeschwindigkeitskonstante des Kettenwachstums beschrieben werden kann. Die Aktivierungsenergie beträgt 95 kJ mol−1.
Synthesis of 2‐(2‐carboxybenzoyloxy)ethyl methacrylate and its radical polymerization and copolymerization with butyl methacrylate
Authors: Sedláková Zdena , Bouchal Karel , Ilavský Michal
Published: April 2003

Conditions of the synthesis of 2‐(2‐carboxybenzoyloxy)ethyl methacrylate (CEM) by the alcoholysis of phthalic anhydride (PA) with 2‐hydroxyethyl methacrylate (HEMA) were optimized. For the uncatalyzed, base‐catalyzed and acid‐catalyzed reaction of PA with HEMA at 50°C the respective second‐order rate constants were 4.7 × 10−6, 14.5 × 10−5 and 5.4 × 10−5 dm3 mol−1 s−1. Also, a consecutive esterification of CEM with formation of bis(2‐methacroyloxyethyl)phthalate took place under conditions of the acid catalyzed reaction. The emulsion polymerization of CEM (solubility in water 13 mmol dm−3 at 25°C) was carried out in the presence of sodium dodecyl sulfate as the emulsifier and of the redox initiation system based on K2S2O8–K2S2O5. Using the Smith‐Ewart model of emulsion polymerization, the growth rate constant of CEM, kp = 610 dm3 mol−1 s−1 at 25°C was determined. The monomer reactivity ratios and Q and e values determined for the radical copolymerization of CEM (M1) with butyl methacrylate (M2) were r1 = 0.85, r2 = 0.75, Q = 0.82, and e = 0.4.
Beeinflussung des eigenschaftsbildes von synthesekautschuk durch die polymerisationsparameter bei der emulsionspolymerization
Authors: Wendler Karin , Poltersdorf Steffi
Published: April 2003

Die Veränderung der Polymerisationsbedingungen (Polymerisationsgschwindigkeit, Emulgatorsystem) beeinflußt die Konzentration der Regler im Latexteilchen und damit die Molmassen, die Molmassenverteilung, Kettenverzweigungen und Gelgehalte der Polymeren. Die Speicher‐ und Verlustmodul‐Frequenzabhängigkeiten für die Kautschuke und ihre Netzwerke wurden aufgenommen und im Zusammenhang mit den Strukturparametern diskutiert.
Rubber‐extender interactions surface activity of fillers and filler/rubber interactions
Authors: Vidal A. , Haidar B.
Published: April 2003

The properties of filled elastomers are obviously dependent on the nature of the iller/matrix interface. However, one can expect the physical or chemical interactions which are able to take place between the surface of the solid and the polymeric matrix to be controlled by the surface activity of the filler. In this respect some of the methods, which have been devised for the characterization (identification and titration of surface functional groups, measurement of the surface free energy, determination of the distribution functions of energies,…) and the monitoring (activation, deactivation,…) of he surface reactivity of reinforcing fillers, are used in view of the establishment of relationships with the reinforcing ability of the corresponding fillers.
Verträglichkeit von kautschuken ein altes und ein aktuelles problem
Authors: Schuster Robert Hans
Published: April 2003

The utilization of rubber mixtures is to achieve a desired combination of properties and performance spectrum of elastomers is nowadays of a considerable technological and economical importance. The successful implementation of this concept requires the knowledge of the factors governing both the phase behaviour of rubber blends and the morphology of phase separated blends. Thermodynamic theories referring to miscibility and phase separation of polymers are briefly reviewed, with a specific focus on nonpolar polymers with high chain flexibility. It can be shown on the simple lattice that this theory works qualitatively for these systems. Reliable predictions are questionable due to the lack of equation of state parameters for the polymers of interest and temperature and concentration dependence of the interaction parameter χ.

Concerning the morphology of phase separated rubber blends the main influences governing the structure of the entire system (i) the interfacial tension, (ii) the viscosity of the matrix (iii) and the shear stress are discussed in more detail. It has been pointed out that for technological usability a better knowledge about the interdiffusion of polymers and the properties of the interphase, built in this would be not only of scientific interest but also beneficial for high performance elastomer blends. It would also be useful to know more about the dispersion of polymers at short mixing times and elevated temperatures. Because it has been considered until recently that polymer miscibility occurs only if strong specific segmental interaction are involved, emphasis was dedicated to oligomer/rubber‐ and rubber/rubber‐systems which exhibit miscibility and phase transitions through a convex coexistence curve into a homogeneous region. Consequences of phase transitions at high mixing temperatures for specific tire applications are suggested.
The essential role of network topology in rubber elasticity
Authors: Vilgis T. A. , Heinrich G.
Published: April 2003

This paper discusses various new aspects in the elasticity of rubbers and the statistics of elastomers. It is shown that the role of network topology is crucial in the statistics of rubbers. This is seen mostly on the influence of heterogeneities of crosslink density, which is also of practical interest. Strong heterogeneities lower the modulus, but do not change the stress‐strain behavior. It is also shown that if in a given network the flexible chains are replaced by rigid rods which are flexibly hinged the entropy is still of order of that of the flexible network and that the modulus is of the same order as the Gaussian one. This holds for lower functionalities, i.e. less than six. The phase behavior of crosslinked blends and interpenetrating networks is shown to be similar of the microphase transition of block copolymers. Semi IPNs demix at a critical crosslink density of the crosslinked part, or alternatively at a critical length of the free chains, even though if the chains are of the same chemical nature as the crosslink component.
Determination of crosslink densities of carbon black filled natural rubber sulfur vulcanizates by 13C NMR MAS spectroscopy and 1H NMR transversal relaxation
Authors: Hoffmann Uwe , Gronski Wolfram , Simon Gerald , Wutzler Andre
Published: April 2003

Two NMR spectroscopic methods were applied to carbon black filled NR vulcanizates to determine the chemical crosslink density. Both methods give corresponding results. Addition of carbon black leads to a decrease of crosslink density with increasing filler content. The influence is more pronounced at higher sulfur content.
Molekulares versagen bei der deformation von unvernetztem naturkautschuk
Authors: Fuhrmann J. , Hamel M.
Published: April 2003

On line investigation of molecular chain scission during mechanical loading of unfilled, unvulcanized natural rubber is possible using the “Exoemission” method. Especially, it can be shown that chain scission is force controlled, i.e. there is no significance for energy control. The emission rate, assumed proportional to the rate of chain fracture, can be described by the rate theory of Eyring[1]. The average molecular mass of a chain between two elastically effective entaglements MC, estimated by the theory of Mooney and Rivlin is linear correlated with the activation volume of the force controlled chain scission determined from the emission intensity.

The experimental data further indicated a strong dependence of crystallisation kinetics and associated molecular fracture processes on the velocity of loading.
Properties of rubber elastic systems at large strains
Authors: Göritz Dietmar
Published: April 2003

The large increase in tensile stress at high extension ratios has previously been treated by Kuhn und Grün in the theory of entropy elasticity by using non‐Gaussian chain statistics. This effect is caused by a non‐uniform distribution in the lengths of the network chains in a real network, such that short chains are highly orientated even at low strains and make an over‐propotionate contribution to the tensile stress.

It has been shown experimentally that the short chains lead to morphological changes during extension. This means that the deformation behaviour of networks may not be described correctly in terms of a homogeneous system.

The structure which arises on stretching both filled and unfilled samples has been investigated by electron microscopy. In both cases the material consisted of highly drawn ribbons which formed a super‐network. The degree of orientation of these ribbons was higher than would correspond to the macroscopic elongation. By means of this concept of a double network, a number of findings could be explained, such as the change in volume, the diffusion and adsorption of gas and, in the case of natural rubber, strain‐induced crystallization.

The load‐elongation behaviour could be described by the following relationship

in which the stresses due to the chemical network and the super‐network are additive. Φ is the volume fraction of the super‐network.
Etudes microlithographiques de résines négatives renfermant des unités tétrathiafulvalènes sensibles aux électrons
Authors: Giral Louis , Montginoul Claude , Mungroo Aumduth , Sagnes René , Schué François , Guibert Jean‐Charles
Published: April 2003

Pour résoudre le phénomène de gonflement qui limite la résolution des résines micro lithographiques classiques, nous nous sommes intéressés à de nouvelles résines avec lesquelles ce phénomène n'apparaǐt pas. Nous avons retenu pour notre étude les résines R qui renferment en mélange un polymère porteur de radicaux tétrathiafulvalénylcarbonyloxyméthyles et le dibromotétrachloroéthane. Afin de voir l'influence de la nature du radical porteur de l'unité tetrathiafulvalène dans le polymère sur les propriétés microlithographiques des résines R, nous nous sommes également intéressés aux polymères renfermant des radicaux tétrathiafulvalénoxyméthyles. Les résines R ont été testées sous irradiation électronique. Leurs sensibilités dépendent en outre de la valeur de la masse molaire du polymère. Des résolutions comprises entre 0,1 et 0,4 μm ont été obtenues. Ce type de résines possèdent un certain nomber de propriétés intéressantes telles que des sensibilités élevées et de bonnes résolutions.
Frequency dependence of the complex dielectric constant of sodium carboxymethyl cellulose
Authors: Nessim Refaat I. , Botros Maged G. , Saad Gamal R. , Shalaby Mohamed M.
Published: April 2003

The dielectric constant, ε′, and dielectric loss, ε″, were determined for three solid carboxymethyl cellulose samples having different levels of substitution and different degrees of polymerization over a frequency range of 0.1 – 10 000 kHz at temperatures from 10–60°C. In contrast to the two relaxation processes, γ and β, previously observed in native cotton cellulose, only one relaxation process within a frequency range of 0.1 – 1 kHz was identified. It was found that the dielectric properties do not only depend on the degree of substitution, but also on the weight‐average degree of polymerization and uniformity of distribution.
A redox reaction mediated by polymeric membranes containing electron carriers
Authors: Takeishi Makoto , Nakatsugawa Masahiko , Kikuchi Masayoshi
Published: April 2003

A redox reaction was mediated by polymeric membranes which contain naphthoquinone derivatives as electron and proton carriers. When such a membrane containing vitamin K1 was placed between two aqueous solutions of potassium ferricyanide and sodium dithionite, the oxidation‐reduction of them took place, but the reaction was rather slow. Although vitamin K3 was a more effective carrier and the reaction proceeded fast, the reaction rate decreased in the repeated runs. Since the reduced form of this carrier is slightly soluble in water, a part of the carrier got dissolved in the aqueous phase from the membrane during the reaction. 2‐Alkyloxy‐1,4‐naphthoquinones such as 2‐hexyloxy‐1,4‐naphthoquinone effectively transported electrons and protons through the polymeric membranes, promoting the membrane‐mediated reaction; in these cases no retardation was observed in the repeated runs.
Possibilities for the formation and characterization of solid‐state‐structures in aromatic polyoxadiazoles
Authors: Hofmann Dieter , Leibnitz Eberhard , Schmolke Rudolf , Schulz Burkhard
Published: April 2003

Depending on the coagulation conditions, poly(p‐phenylene‐1,3,4‐oxadiazole) in the solid state forms two modifications, as can be evidenced by FTIR spectroscopy and by wide‐angle X‐ray scattering curves (WAXS). In both cases each modification is detectable by characteristic peaks. Processing of fibers or films from solutions in concentrated sulfuric acid by coagulation in water results in the formation of a thermodynamically non‐equilibrium form, defined as β‐modification. Under special conditions it is possible to obtain the three‐dimensionally ordered equilibrium α‐structure that leads to processing products with markedly higher tenacities.
Ölfettsäremodifizierte wäßrige Polymethacrylatdispersionen
Authors: Müller Siegfried , Zekai Doris , Pohl Martina , Pohl Gerhard , Lorkowski Hans‐Joachim
Published: April 2003

Wäßrige Anstrichsysteme setzen sich in zunehmendem Maße durch. Als eine Entwicklungsvariante für diesbezüglich geeignete Bindemittel kommen autoxidativ vernet zende Polymethacfrylatdispersionen in Betracht. Es werden wesentliche Schritte der Synthese derartiger Dispersionen un dcharakteristische Eigenschaften auchvon Beschichtungen vorgestellt.

Die Ölfettsäurestruktureinheiten sind im Schalenbereich der disperigierten Teilchen angereichert, und sie befinden sich außerden zu etwa 30% in der wäßrigen Phase als Substituenten eines löslichen Copolymeren.
Linear polythioesters, XX. Products of interfacial polycondensation of 4,4′‐bis(mercaptomethyl)‐biphenyl with some aliphatic and isophthaloyl dichlorides
Authors: Podkoscielny Wawrzyniec , Tarasiuk Bogdan
Published: April 2003

New polythioesters were synthesized by interfacial polycondensation of 4,4'‐bis(mercaptomethyl)biphenyl with selected aliphatic and isomeric phthaloyl dichlorides.

To determine optimum polycondensation conditions, the influence of the following factors on reduced viscosity and yield were studied: type of organic phase, concentration of reagents, aqueous/organic phase ratio, type and concentration of hydrogen chloride acceptor, rate of acid chloride addition, reaction temperature and reaction time.

A thorough examination was carried out only for the polycondensation of dithiol with adipoyl and isophthaloyl dichlorides chosen as a model system. The structures of polythioesters were confirmed by elemental analysis, X‐ray analysis and infrared spectroscopy. The temperature of initial decomposition, the percentage of its mass loss, and temperature of the fastest decomposition process from curves of differential and thermogravimetric analysis were determined. Some physicochemical, mechanical and electrical properties were determined. The molecular weights were not measured because of the low solubility of the obtained polythioesters.
Permeation von Gasen in Polymermembranen aus thermoplastischer Stärke
Authors: Sala Robert , Tomka Ivan
Published: April 2003

Als Alternative zu den heutigen Massenkunststoffen wurde die Möglichkeit eines Einsatzes von thermoplastischer Stärke (TPS) als Barrierewerkstoff in Filmen und Membranen untersucht. Die Permeations‐ und Diffusionskoeffizienten wurden mitels der Induktionszeit‐Methode an Filmen aus TPS in Abhängigkeit von Temperatur und Weichmachergehalt ermitelt. Die expermentell gefundence gute Gasbarriereeigen schaft der Stärke gegenüber Sauerstoff und Stickstoff wurde durch vergleichende Messungen an Handelsprodukten ergänzt. Die TPS zeigt bei nieedrigen Wassergehalten denhandelsüblichen Barrierepolymeren vergleichbare Gaspermeationsraten. Mit steigen dem Wassergehalt verliert sie‐ wie die meisten hydrophilen Polymere ‐ ihre Gasbarrierewirkung.

Gemeinsam mit früheren Arbeiten über die Struktur und die Eigenschaften von thermoplastischer Stärke wurden die molekularen Parameter und ihr Einfluß auf die Gasdurchlässigkeit diskutiert.
Chemische Kopplung von Polystyrol und Polybutadien in Schmelzemischungen durch Verwendung eines organischen Sulfonylazids
Authors: Radusch Hans‐Joachim , Ding Jianmin , Schulz Manfred
Published: April 2003

Es wurden Untersuchungen zur chemischen Kopplung heterogener Polystyrol‐Polybutadien‐Blends bei Einsatz eines organischen Sulfonylazids während des Schmelzemischens im Laborinnenmischer angestellt. Die Wirksamkeit des Kopplungsagens wurde anhand infrarotspektroskopischer, mikroskopischer und dynamisch‐mechanischer Analysen sowie anhand des merchanischen Eigenschaftsbildes der Belends beurteilt. Die sich in der Schmelze bildenden Pfropfcopolymeren führen zu einer Erhöhung der Phasenwechselwirkungen un dami zu einer Verbesserung der Festigkeits‐ und Zähigkeits‐eigenschaften der Blends.
Zur Bestimmung des Modifikatorgehaltes von Stearinsäure‐ und Titanat‐modifizierten CaCO3‐Füllstoffen
Authors: Lühr Jens , Janowski Frank
Published: April 2003

Zur Bestimmung des Modifikatorgehaltes von Stearinsäure(STS)‐bzw. Isopropyltriisostearyltitanat(Titanat)‐modifizierten CaCO3‐Füllstoffen wurde die simultane TG/DTA‐Analyse genutzt. die Methode wurde für Modellproben sowie für verschiedene kommerzielle Füllstoffe mit einem Konzentrationsbereich von 0 – 2,7% STS bzw. 0 – 4% Titanat angewendet. Eine ausreichende Übereinstimmung der Modifikatorkonzentrationen für STS, bestimmt durch simultane TG/DTA‐Analyse sowie eine C‐Analyse, wird erreicht, wenn der Zersetzungsbereich des Modifikators berücksichtigt wird. Dieser liegt für Stearinsäurezwischen180°C und 450°C (bei STS > 1% bei 500°C) und für Isopropyltriisostearyltitanat zwischen 120 und 450°C (Titanat > 1% bei 500°C) und wird aus dem Anstieg der TG‐bzw. DTA‐Kurve erhalten. Der diesem Zersetzungsbereich zuzuordnende Masseverlust entspricht bei STS‐modifizierten Füllstoffen dem Stearinsäuregehalt. Bei Titanat‐modifizierten CaCo3‐Füllstoffen ist ein Betrag von 10% des Masseverlustes hinzuzufügen. Für die Modifikatorgehaltsbestimmung von CaCo3‐Füllstoffen, die einen höheren Feuchtigkeitsgehalt (< 0,2%) aufweisen, ist die Kenntnis dieser Größe notwendig, anderenfalls ist die STS‐Bestimmung über die Oxidationswärme zu realisieren.
Removal of methyl orange by systems of insoluble poly(glycidyl methacrylate)‐g‐tetraethylene‐pentamine and ‐g‐polyethyleneimines
Authors: Tashiro Tatsuo , Thirvenkatam P.
Published: April 2003

A study was made of the removal of methyl orange (MO) solutes in water and in a pH 7 buffer solution by the reaction products of insoluble poly(glycidyl methacrylate) (PGMA) with tetraethylenepentamine (TEP) or polyethylenimine (PEI) having molecular weight of about 600 (PEI600). An examination was made of the adaptability of the Freundlich adsorption formula and the Klotz equation to removal behaviour of these polymers, which was noted to conform better to the Klotz equation than to the Freundlich adsorption formula. The removal rate and the amount removed were greater in water than in a pH 7 buffer solution, and decreased due to coexisting salts. The amount removed does not always depend on the amount of PEI600 groups bound to PGMA.
Effect of structure and composition on physico‐mechanical properties of methyl methacrylate/alkyl (meth)acrylate copolymers
Authors: Patnaik M. , Choudhary V. , Varma I. K. , Sinha T. J. M.
Published: April 2003

The paper describes the fabrication of cast acrylic sheets by copolymerizing a prepolymer syrup of methyl methacrylate (MMA) with varying amounts (1‐20 wt.‐%) of 2‐ethylhexyl methacrylate (EHMA), n‐hexyl methacrylate (HMA), 2‐ethylhexyl acrylate (EHA) and n‐hexyl acrylate (HA). The effect of structure of copolymer on light transmittance, density and mechanical properties was evaluated. Tensile strength and storage modulus decreased with increasing comonomer content. Strain increased significantly in the case of MMA/EHA and MMA/HA copolymer sheets having 15 and 20 wt.‐% of comonomer. Softening temperature of copolymer samples was determined using dynamic mechanical thermal analysis. Heat deflection temperature under flexural load and softening temperature decreased with increasing comonomer content in copolymer.
Effect of strain rate and temperature on stress‐strain properties of EVA‐LDPE blends and the mechanism of strain hardening
Authors: Ray I. , Khastgir D. , Mukunda P. G.
Published: April 2003

Stress‐strain behaviour of different blends of poly(ethylene‐co‐vinyl acetate) (EVA) (28 wt.‐% VA content) and low density polyethylene (LDPE) is studied under various strain rates and temperatures. It is found that stress‐strain plots of such semicrystalline polymer blends consist of three parts, namely, elastic or Hookeian region, region of chain slippage and region of strain hardening. Decrease in strain rate has an increasing effect on the strain hardening region. Increase in measurement temperature adversely affects the whole stress‐strain plot. It is apparent from the study that at an elevated temperature the process of strain hardening is dependent on the crystalline melting point of the major component in the blend. The X‐ray and DSC studies reveal that the process of strain hardening is mainly due to a change in internal order of crystallites in LDPE and LDPE‐rich blends, whereas in EVA and EVA‐rich blends it is due to induced crystallization in the amorphous phase.
Improvement of ageing properties of rubber films prepared from radiation‐vulcanized natural rubber latex
Authors: Yoshii Fumio , Kulatunge Samantha , Makuuchi Keizo
Published: April 2003

Radiation‐vulcanization of natural rubber latex (NRL) with n‐butyl acrylate gives a higher tensile strength for films obtained after casting. The ageing properties of radiation‐vulcanized natural rubber in the presence of various antioxidants have been investigated. In order to find out suitable antioxidants for radiation‐vulcanized natural rubber latex (RVNRL) films, extraction of the gel fraction was carried out in xylene with 1 wt.‐% antioxidant and air bubbling. Antioxidants which give less reduction in gel fraction due to oxidative degradation during extraction are effective for ageing tests of RVNRL films. It was found that tris(nonylated phenyl) phosphite (Nonflex TNP) and 2,5‐di‐tert‐amylhydroquinone (Antage DAH), among 12 different antioxidants tested, were the most effective antioxidants for RVNRL films.
Builder performance in detergent formulations and biodegradability of partially dicarboxylated cellulose and amylose containing sugar residues in the backbone
Authors: Matsumura Shuichi , Nishioka Makoto , Shigeno Haruo , Tanaka Toshiyuki , Yoshikawa Sadao
Published: April 2003

Poly(sodium carboxylate)s containing varying amounts of unreacted sugar residues as biodegradable segments in the polymer backbone were prepared by the partial oxidation of amylose and cellulose using periodic acid/chlorite. It was found that dicarboxy polysaccharides containing sugar residues showed improved biodegradability comparing to those having no sugar blocks in the polymer chain, and their biodegradability varied according to the glucopyranose content or the degree of dicarboxylation. Dicarboxy polysaccharides containing more than 60% glucopyranose residues tended to biodegrade quickly. When compared on an equal glucopyranose content basis, the biodegradability of dicarboxy amylose (2b) was slightly superior to that of dicarboxy cellulose (2a). The builder performance in detergents was dependent on the degree of dicarboxylation, and a clear relation between the detergency and the content of carboxylate groups was observed. Dicarboxy polysaccharides with more than 40% dicarboxylation showed better builder performance than those of disodium 3‐oxapentanedioate and trisodium citrate, with some of them superior to that of sodium tripolyphosphate (STPP). The detergency of 2b was more effective than that of 2a. It was also found that the detergency was improved much by increasing the amount of polymeric builder.
Porous ion‐exchange membranes, 2. Effect of adhesion promoters
Authors: Bryjak Marek , Poźniak Gryzelda , Trochimczuk Witold
Published: April 2003

The previously described preparation of porous ion‐exchange membranes (PIEM's) from the ternary blends of polyethylene interpolymer with poly(styrene‐co‐divinylbenzene) and polypropylene and calcium carbonate filler has been supplemented with the use of stearic acid and dibutyl phthalate as adhesion promoters. It was noted that both promoters govern the huge increase of pore diameter without any significant disturbances in the other PIEM's properties. The facilitating effect of chlorosulfonic acid diffusion toward calcium carbonate grains and large amounts of carbon dioxide volatilization was concluded. This is the basic point of pore creation to be discussed in this paper.