bluuebunny/crossref_metadata_2025_split huggingface dataset:
Miscible blends of polycarbonate with polyurethane elastomers
Authors: Fambri Luca , Penati Amabile , Kolarik Jan 
Published: April 2003

AbstractPolyurethane elastomers based on aliphatic polycarbonate diols and/or polypropylene glycols form miscible blends with polycarbonate, thus potentially improving its resistance to microcrack initiation and growth. Up to 20 wt.‐% of synthesized polyurethane elastomers were dissolved in polycarbonate via solution casting or melt mixing. Some phase separation was detected in films cast from solutions with 10 to 20 wt.‐% of polyurethane elastomers; such blends usually turned into single‐phase systems by subsequent thermal annealing. Among the tested polyurethane elastomers, the products based on toulene diisocyanate and mixtures of polycarbonate diols with polypropylene glycols were found to be effective modifiers for polycarbonate; therefore, they were also used in the blends prepared by melt mixing and processed by injection moulding.
Modifizierung der oberfläche von polyamid‐6‐monofilamenten
Authors: Groten Robert , Höcker Hartwig 
Published: April 2003

AbstractPolyamid‐6‐Monofilamente wurden in festem Zustand mit Toluylen‐2,4‐diisocyanat (TDI) in Toluol in Gegenwart von Bis(2‐ethyl‐hexanoyloxy)‐zinn (SnOct2) behandelt und dadurch in der Oberfläche vernetzt. Gegenüber unmodifizierten Polyamid‐Monofilamenten konnten Verbesserungen der Temperaturbeständigkeit, der Höchstzugkraft, der Dehnbarkeit, der Lösungsmittel‐ und der UV‐Stabilität erreicht werden. Die Unlöslichkeit der diisocyanatmodifizierten Filament‐“Hullen” in Ameisensäure wies auf eine Vernetzung in den äußeren Bereichen der verstreckten PA‐6‐Filamente hin. Zur Charakterisierung der Vernetzungspunkte wurde aus ϵ‐Caprolactam (ϵ‐CL) und TDI die Modellsubstanz Toluylen‐2,4‐bis‐carbamoyl‐bis‐ϵ‐caprolactam (TCC) synthetisiert.
Covalent binding of an azo dye to films of vinyl chloride copolymers containing functional groups
Authors: Hensema Edwin René , Berger Joseph 
Published: April 2003

AbstractCoupling of a dye to a polymer matrix allows the preparation of intrinsically coloured products and prevents the migration of the dye out of the polymer matrix. The binding reaction of a functionalized dye to, and the simultaneous crosslinking of poly(vinylchloride) (PVC) containing hydroxy groups (PVCOH) using a triisocyanate was investigated.The binding efficiency of the azo dye 2′‐chloro‐4‐(N‐ethyl‐N‐hydroxyethylamino)‐2‐methyl‐4′‐nitroazobenzene (CHMP) to two poly(vinylchloride‐co‐vinylacetate‐co‐vinylalcohol) samples containing different concentrations of hydroxy groups using 1,1,1 ‐tris[N‐(3‐isocyanato‐4‐methylphenyl) carbamoyl‐oxymethyl]propane (TIC) was studied under various reaction conditions. The binding efficiency of the dye to the polymer matrix was investigated using Soxhlet extraction whereas the reaction between isocyanate and hydroxy groups was studied using IR. It was shown that an increasing amount of TIC results in a more efficient binding of the dye to the polymer matrix and in a higher crosslinking density of the polymer matrix. A good correlation was also found between the swelling degree of crosslinked PVCOH films and the crosslinking density due to TIC reacting with PVCOH.
Synthesis and polymerization of chiral monomers containing dimethylaminobornane moieties
Authors: Liu Jui‐Hsiang , Lin Ming‐Ter 
Published: April 2003

AbstractChiral monomers (cis, endo‐3‐dimethylamino‐2‐bornyl methacrylate (DABM) and N, N‐dimethyl[cis,endo‐2‐(2‐vinyloxyethoxy)‐3‐bornyl]amine (DVEBA)) were synthesized from (+)‐camphor. The free radical homopolymerization of both DABM and DVEBA, and the copolymerization of both chiral monomers with achiral methyl methacrylate and styrene, resp., were carried out in various organic solvents. Effects of temperature, solvents, and reaction time on the polymerizations were studied. Dependences of the specific rotation of the chiral copolymers on the feed concentration and reaction conditions were investigated. Application of the chiral polymers on the asymmetric induction were also investigated.
Lichtinduzierte polymerisation, 2. Polymerisation von methylmethacrylat mit 9,9‐disubstituierten acridanen
Authors: Braun Dietrich , Hettig‐Rupaner Claudia 
Published: April 2003

AbstractAm Beispiel von 9‐Benzyl‐9‐phenylacridan und von 9‐Benzyl‐10‐methyl‐9‐phenylacridan wird gezeigt, daß 9,9‐disubstituierte Acridane bei der Bestrahlung mit UV‐Licht auch ohne Gegenwart von Wasserstoffdonatoren unter Radikalbildung zerfallen und die Polymerisation von Methylmethacrylat ausldösen können.
Composites of surface‐treated wood fiber and recycled polypropylene
Authors: Sain M. M. , Imbert C. , Kokta B. V. 
Published: April 2003

AbstractThe effect of surface treatment of saw dust on the physico‐mechanical properties of saw dust‐filled polypropylene composites was studied. Whereas the elastomer‐pretreated saw dust decreases the strength of composites, in‐situ addition of interface modifiers, such as maleated polypropylene, m‐phenylene bismaleimideSystematic name: N‐(3‐maleimidophenyl)maleimide.
‐modified polypropylene, during kneading of polypropylene with untreated or elastomer‐pretreated saw dust improved the mechanical properties with a marginal sacrifice of impact strength. The chemical nature of interphase modifiers played an important role on the mechanical properties of the composites, e.g., maleated polypropylene was most effective among the modifiers used in this study. Halogenated elastomers and phenolic modified polypropylene improved the flame resistant properties of the composites. More over, properties varied with the particle size of wood fiber. The morphological study of the fracture surfaces of composites revealed that interfacial adhesion is improved by adding maleated polypropylene.
Photomodifizierung von Ultrafiltrationsmembranen, 2. Ultrafiltrationseigenschaften von mit Arylaziden photochemisch modifizierten Polyacrylnitril‐membranen
Authors: Ulbricht Mathias , Hicke Hans‐Georg 
Published: April 2003

AbstractNach einem neuartigen Verfahren mit Hilfe von neun, mit verschieden hydrophilen bzw. hydrophoben Substituenten synthetisierten aromatischen Aziden unterschiedlich photochemisch modifizierten Polyacrylnitril‐Ultrafiltrations‐Membranen wurden in UF‐Versuchen charakterisiert. Dabei sollte der Einfluß der so erzielten Oberflächenfunktionalisierungen (Hydrophilierung, Einführung von Ladungen oder Hydrophobierung) auf das Trennverhalten (Wasserdurchläassigkeit und Selektivitäat für Dextrane, Permeabilität während und nach der UF bzw. nach einfachem Kontakt mit Ovalbuminund mit Lysozym‐Lösungen) studiert werden. Die Modifizierung mit den Arylaziden, die hydrophile Gruppen enthalten (4‐Azidobenzoäure, Ib, (4‐Azidophenyl)‐tri‐methylammoniumiodid, If, Natrium‐4‐azidobenzolsuflfonat, Id), führt zu einer erhöhten Durchlässigkeit der Membranen für Wasser und Dextrane. Alle anderen Azide, darunter besonders stark die deutlich hydrophoben 2‐Naphthoylazid, Ih, und 2‐Naphthoylazid, IX, verringern die Wasserpermeabilität, erhöhen das Rückhaltevermögen für Dextrane und verstärken die Effekte der Wechselwirkungen mit Ovalbumin (pH = 5,0). Das wird in Flußreduzierungen verglichen mit der unmodifizierten PAN‐UF‐Membran sichtbar. Ein positiver Effekt der Photomodifizierung wird besonders deutlich bei der UF von Lyasozym (0,05%, pH = 10,5) mit der mit Id modifizierten Membran (Jv = 48,1 l/m2h) im Vergleich zur Ausgangs‐Membran (Jv = 13,1 1/m2h). Die Perspektiven und die Grenzen des Modifizierungsverfahrens werden abschließend diskutiert.
Radiation‐induced grafting of styrene onto FEP. films: Structure and thermal behaviour of copolymers
Authors: Gupta B. , Scherer G. G. 
Published: April 2003

AbstractThermal characteristics of radiation‐grafted FEP‐g‐polystyrene copolymer films were evaluated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The grafting of polystyrene onto FEP film introduced a two‐step degradation pattern where polystyrene degradation occurred in the range of 400–460°C beyond which the loss in the FEP component was observed. DSC studies showed that the heat of fusion was reduced in the grafted FEP samples. This was attributed to the dilution of inherent crystalline zones by the incorporation of amorphous polystyrene grafts into the amorphous region of the FEP matrix. The melting temperature, on the other hand, remained constant for the entire range of graft levels (0–40%). All the copolymer films exhibited two glass transition temperatures (Tg) each corresponding to the FEP and polystyrene moieties. However, the Tg in grafted films were found to be higher as compared to that in ungrafted FEP and homopolystyrene films. These results have been explained in terms of the decrease in the segmental mobility of macromolecular chains in the grafted films.
Membranen aus poly(p‐phenylen‐1,3,4‐oxadiazol)
Authors: Leibnitz E. , Eisold C. , Paul D. 
Published: April 2003

AbstractPoly(p‐phenylen‐1,3,4‐oxadiazol) (POD) ist aufgrund seiner thermischen Stabilität, pH‐ und Lösungsmittelbeständigkeit ein interessanter Werkstoff zur Herstellung von Membranen. Die Herstellung von POD‐Membranen und deren Trenneigenschaften im Prozeß der Ultrafiltration werden untersucht.
Agitation scale‐up model for the suspension polymerization of vinyl chloride
Authors: Özkaya Nesrin , Erbay Erol , Bilgiç Tülin , Savaşçi Ö. Tunç 
Published: April 2003

AbstractStudies were carried out to develop a mathematical model based on experimental results to correlate agitation and other polymerization parameters with the particle size of PVC and to specify the limits of agitation speed within the defined agitation system. Computer regression analysis of about 30 vinyl chloride polymerizations in reactors with 10 L to 27 m3 tank volume are carried out. The particle size of PVC (d50) is correlated to various polymerization parameters such as impeller diameter (D), impeller speed (N), reactor tank diameter (T), liquid height (H1) and tank volume (V) (NWe = Weber number):

d50 = 4346.8 (N)−0.905 (D)−0.901 (T)−0.514 (H1)−0.131
d50/D = 273292.1 NWe−0.51
Nmin = 3049.1 D−1.1 (T/D)−0.113

In these equations only the values 3049.1, −0.113, 4346.8 and 273 292.1 depend on the recipe. When the recipe is changed these variables must be determined by one or two bench‐scale polymerizations to adjust the correlations to the new recipe conditions so that they can be also used for scale‐up purposes with the new recipe.
Modelluntersuchungen zur topologie der härtung geordneter epoxidnetzwerke
Authors: Kirchmeyer Stephan , Müller Hanns‐Peter , Dhein Rolf , Meier Helmut‐Martin 
Published: April 2003

AbstractDie Härtung von 4‐Phenyl‐4‐(2,3‐epoxypropoxy)benzoat (I) mit den isomeren Aminophenylaminobenzoaten II bis V führt zu unterschiedlich geordneten Epoxidnetzwerken. Die Bildung verschiedener Intemediate während der Härtungsreaktion wurde anhand von Modellverbindungen studiert. Aus der Reaktion der monoamino‐substituierten Phenylbenzoate VI bis IX mit Epoxid wurden die Reaktionskostanten für die Addition an das primäre und das sekundäre Wasserstoffatom der Aminogruppen bestimmt. Die kinetischen Daten lassen sich für eine schrittweise Simulation des Härtungsverlaufs verwenden. Es wurden Argumente dafür gefunden, daß sich bei Verwendung der Amine mit 4‐Aminobenzoat‐Strukturen gut geordnete, schnell vernetzende Intermediate bilden.
Branched poly(ethylene imine) support for resins with retention properties for heavy metal ions
Authors: Rivas Bernabé L. , Maturana Hernán A. , Perić Iván M. 
Published: April 2003

AbstractA crosslinked poly(ethylene imine), using epichlorohydrin as crosslinker, was prepared and subsequently modified in order to obtain the corresponding N‐methylated, N‐carboxymethylated and N‐phosphonomethylated derivatives. The sorption characteristics of these functionalized resins were studied by a batch equilibration technique, for uptake of Cu(II), Fe(II), Fe(III) and uranyl ions from aqueous solution. Resins with tertiary amine or ammonium groups show negligible sorption for Fe(II), Fe(III) and Cu(II) at pH 1, in contrast with high sorption for U(VI), which is readily eluted with sodium carbonate.
Immobilisierbare stabilisatoren für EPDM‐kautschuk
Authors: Braun Dietrich , Rettig Rainer , Rogler Wolfgang 
Published: April 2003

AbstractAls immobilisierbare Antioxidantien für Ethylen‐Propylen‐Dien‐Terpolymere (EPDM) wuren 4‐(Mercaptoacetamido)‐diphenylaminSystematischer Name: 2‐Mercapto‐N‐[4‐phenylamino phenyl]‐acetamid.(MADA) und Dithiodiglycolsäure‐bis‐[N‐(4‐anilinophenyl‐amid]Systematischer Name: 2,2′‐Dithiobis[N‐(4‐phenylamino)phenyl]‐acetamid.(DAPA) hergestellt und charakterisert. Zur Simulation der Reaktionen bei der Umsetzung dieser Antioxidantien mit EPDM‐Kautschuken wurden Modellreaktionen mit trans‐4‐Decen, 2‐Ethylidennorbornan und 2,3‐DihydrodicyclopentadienSystematischer Name: Tricyclo[5.2.1.02,6]‐3‐decen.durchgeführt. Die Reaktionsprodukte wurden chromatorgraphisch aufgetrennt und durch IR‐Spektroskopie charakterisiert. Dabei wurde auch der Einfluß von Azoinitiatoren auf die Additionsreaktion untersucht.Die Umsetzung von EPDM mit den genannten Stabilisatoren wurde im BrabenderPlastographen bei 140 bis 180°C Massetemperatur untesucht. Der Gehalt an immobilisiertem Stabilisator wurde mit Hilfe der Thermoanalyse und UV‐spektroskopisch bestimmt. Die höchsten Gehalte an immobilisiertem Stabilisator (73%) wurden mit MADA bei 180°C Massetemperatur erzielt. DAPA ist ebenfalls bis maximal 69%immobilisierbar. Die praktische Baruchbarkeit der Immobilisierung von Mercaptostabilisatoren an EPDM‐Kautschuk wurde am Beispiel von strahlenvernetzten Kabelisoliermassen bestätigt.
Kinetic investigation of the polymerization of an epoxy resin by DSC and temperature profile determination during cure
Authors: Sbirrazzuoli Nicolas , Girault Yvonne , Elegant Lucien 
Published: April 2003

AbstractKinetic parameters of the polymerization of an epoxy resin, characterized by a high enthalpy and a low heat conductivity, are determined by DSC analysis. The mean value obtained from the peak maximum evolution methods (Kissinger, Ozawa and Lam) for the activation energy Ea was 62.71 kJ · mol−1; the Achar‐Brindley‐Sharp method, using the homogeneous law and the sample temperature, led to 68 kJ · mol−1. A comparison between theoretical computations (obtained from a modeling of the temperature profile in the DSC crucible during cure) and measurements is given. The increase of the apparent kinetic parameters with the heating rate V (expressed with a parameter e = ΔEa/ΔV) essentially results from the overestimation of the temperature, induced by the exothermicity of the phenomenon. A decrease of e from 1.725 to 0.613 is observed, with the measured temperature instead of the set calorimeter temperature.
Determination of avrami‐exponents of isotactic polypropylene by means of X‐ray methods
Authors: Wenig W. , Lemke B. 
Published: April 2003

AbstractAvrami‐exponents of polypropylene have been measured using two methods: observing the spherulitic growth in the polarization microscope, and measuring the crystallinity as a function of crystallization time using X‐ray wide angle scattering. Both methods yield the same values, showing that the determination of the Avrami‐exponent with optical microscopy is of sufficient accuracy despite the limitations of this method imposed by the restricted crystallization volume between the glass slides. Using the X‐ray method, the Avrami‐exponent of the secondary crystallization volume between the glass slides. Using the X‐ray method, the Avrami‐exponent of the secondary crystallization occurring at longer crystallization times can be measured. It is shown that this type of crystallization takes place within the already existing spherulites, whose size distribution is not changed.
Poly(phthalidylidene arylene)s: Synthesis of poly(3,3‐phthalidylidene‐4,4′‐biphenylylene) by precipitative homopolycondensation of 3‐(4‐biphenylyl)‐3‐chlorophthalide
Authors: Zolotukhin Mikhail G. , Kozlov Valerii G. , Sorokina Yulia L. , Sedova Elvira A. , Nefedjev Konstantin V. , Gileva N. G. 
Published: April 2003

AbstractThe synthesis of poly(3,3‐phthalidylidene‐4,4′ ‐biphenylylene) (PPB) by precipitative Friedel‐Crafts homopolycondensation of 3‐(4‐biphenylyl)‐3‐chlorophthalide was studied. The polymer‐catalyst complex precipitated from the initially homogeneous reaction mixture was shown to be active and providing the growth of macromolecular chains. The polymer obtained in the form of smooth, transparent glass‐like particles, depending on the reaction parameters, may have either uni‐ or bimodal molecular weight distribution. Molecular characteristics were not found to depend on the size of the polymer particles. “Precipitative” PPB shows improved properties and higher crystallinity in comparison with “solution” PPB.
The electrical conductivity of cellulose HYPHAN® and its complexes
Authors: Hanna A. A. , Kenawy I. M. M. , Mohamed A. K. , El‐Said Kh. S. 
Published: April 2003

AbstractThe electrical conductivity, σ, of cellulose HYPHAN® and its complexes with Cr3+, Mn2+, Mo5+ or Hg2+ was measured from room temperature to 510°C. The activation energy, ΔE, of the samples was calculated from log σ against 1/T curves. The results show that the electrical conductivity increases by temperature with two maximum peaks. The first peak is attributed to the moisture content, while the second one is attributed to the thermal degradation of the cellulose chain. The values of the activation energy indicate that the samples change from low semiconductor to high semiconductor property with heating.
Characterization of thermoplastic poly(ethyleneterephthalate)‐glass fibre composites, 1. Crystallization study
Authors: Gauthier Catherine , Chauchard Jacques , Chabert Bernard , Saktoun Mostafa , Boudet Alain 
Published: April 2003

AbstractThis paper presents the influence of glass fibres on crystallization kinetics and on matrix morphology for poly(ethylene terephthalate) (PET)/glass fibre composites. The following parameters are also considered: fusion‐crystallization conditions, thermal stability and the addition of nucleating agents in the matrix (talc or sodium benzoate). It clearly appears that the influence of those additives on the crystallization of PET is predominant compared to the effect of stiffening fibres. Moreover, the application of shear stresses at the PET/glass fibre interface promotes the growth of a different crystalline superstructure.
The oxidative degradation of stabilized LLDPE under accelerated and natural conditions
Authors: Tidjani Adams , Fanton Elisabeth , Arnaud René 
Published: April 2003

AbstractPhotodegradation and loss of UV stabilizer resulting from natural and accelerated exposure in stabilized linear low density polyethylene (LLDPE) are investigated by spectroscopic techniques. It is found that the processes governing the loss of UV stabilizer are quite different under the two modes of UV exposure. This result clearly demonstrates that predictions concerning polymer lifetime based on the disappearance of additives must be avoided. For a large number of stabilized samples, acceleration factors according to different criteria have been estimated. Examination of the natural photodegradation process of stabilized LLDPE through mechanical property changes establishes that stabilized LLDPE undergoes catastrophic breakdown of the elongation at break the instant the carbonyl IR band begins to develop.
Study on compatibilization‐crosslinking synergism in PVC/LDPE blends
Authors: Xu Chengwei , Fang Zhengping , Zhong Jianhua 
Published: April 2003

AbstractInfluences of nitrile rubber (NBR, acrylonitrile content 33.5 – 36.5 wt.‐%) on the structure and mechanical properties of poly(vinyl chloride) (PVC)/low density polyethylene (LDPE) blends and its synergism with crosslinking agent have been studied. The addition of NBR to the blend is accompanied by a decrease in domain size and improvements in mechanical properties of the blend. When dicumyl peroxide (DCP) is added to the blend together with NBR, good synergism is caused and mechanical properties will improve dramatically. It is concluded that NBR can promote the phase dispersion of PVC and LDPE and their interfacial adhesion. Then, the probability of DCP existing at the interface will increase and more co‐crosslinked products will form. Therefore, compatibilization and crosslinking are both exerted sufficiently.
Effect of α‐methyl styrene on curing behaviour and interfacial properties of glass fibre‐reinforced vinyl ester resins
Authors: Padma G. , Varma I. K. , Sinha T. J. M. , Patel G. H. 
Published: April 2003

AbstractThe curing behaviour of bismethacryloyl derivative of diglycidyl ether of bisphenol A (vinyl ester VE resin) containing styrene and α‐methyl styrene (MS) as reactive diluents was studied. Delayed curing was observed in samples containing increasing proportions of MS. Interfacial shear stress of untreated as well as γ‐methacryloyloxy‐propyl trimethoxy silane (MTS) treated, glass fibre‐reinforced VE resin composites were measured by single fibre technique. In comparison to untreated glass fibres, a 30 – 50% increase in interfacial shear stress was observed in composites based on MTS treated glass fibres. Addition of up to 5 wt.‐% MS to VE resin did not affect the interfacial shear strength (ILSS). This behaviour was observed by using ILSS measurement of both glass fabric‐reinforced composites as well as single fibre specimens. Further increase in MS to 15 wt.‐% resulted in an increase in ILSS and bending stiffness as well as flexural strength.
Substantial modifications of ethylene/vinyl acetate copolymers: Saponification and graft copolymerization
Authors: Liaw Der‐Jang , Su Bing‐Yaun 
Published: April 2003

AbstractModifications of ethylene/vinyl acetate copolymers (EVA) by saponification and graft polymerization with various acids were studied. The greater the degree of saponification, the higher is the melting temperature, the crystallinity and the melt viscosity of poly(ethylene‐co‐vinyl alcohol‐co‐vinylacetate). Tensile tests display that the flexibility of EVA decreases gradually as the degree of saponification increases. This effect may be caused by the interaction of hydrogen bridges after saponification. Graft copolymers of EVA with various acids were studied. The greater the portion of vinyl acetate of EVA, the greater is the graft ratio with various acids decreases in the order acrylic acid > fumaric acid > itaconic acid > maleic anhydride; this order may reflect a steric effect.Relationships between peel strength and the degree of saponification of EVA show that the adhesive strength increases initially and reaches a maximum value at a degree of saponification in the range of 20 ∼ 30%. The adhesive strength of EVA grafted with acid increases remarkably at low acid contents (less than 0.5 wt.‐%) and then remains constant even at greater acid content in the graft copolymer.