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  • Wiley-Blackwell  (1,151)
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  • 1
    Electronic Resource
    Electronic Resource
    Berichte über Tagungen und Messen (1972)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 3 (1972), S. 98-103 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19720030212
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  • 2
    Electronic Resource
    Electronic Resource
    Cascade reactions with chiral michael acceptors; synthesis of enantiomerically pure tricyclo[3.2.1.02,7]- and bicyclo[3.2.1]octanesDedicated to Professor Dr. Wolfgang Lüttke, Georg-August-Universität Göttingen, on the occasion of his 75th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 2165-2169 
    Details
    ISSN: 0947-3440
    Keywords: Peterson olefination ; Horner Emmons olefination ; Diastereoselective aprotic Michael cascade reaction ; Tricyclo[3.2.1.02,7]octanes ; Bicyclo[3.2.1]octanes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting from the easily accesible chiral aldehyde 2, we obtained enantiomerically pure (Z)- and (E)-α,-chloro-α,β-unsaturated esters 4c in good yields by olefination reactions. (Z)-and (E)-4c were allowed to react with the kinetically controlled generated lithium dienolate Li-7 to give the enantiomerically pure tricyclo[3.2.1.02,7]octanes 8 and 9, respectively. The „push-pull“ substituted cyclopropane moiety of 8 was opened to give solely bicyclo[3.2.1]octane 10.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1995199512302
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  • 3
    Electronic Resource
    Electronic Resource
    Heterogeneous grafting of maleic anhydride and α-methylstyrene from atactic polypropylene (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 251 (1997), S. 37-48 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ataktisches Polypropylen (PP) ist ein amorphes, kurzkettiges Nebenprodukt des isotaktischen Polypropylens (iPP). Wegen seiner erhöhten Löslichkeit ist PP ein günstiges Modellpolymeres für Studien der Kinetik von iPP-Schmelzereaktionen. Untersucht wurde die Maleinierung von PP durch radikalische Pfropfung in der Schmelze. Da Maleinsäureanhydrid (MAA) verfärbende Oligomere bildet, wurde PP mit einer Mischung aus MAA und α-Methylstyrol (MS) gepfropft. Von Vorteil ist, daß MS bei hohen Temperaturen nicht homopolymerisieren kann und daß MAA und MS praktisch alternierende, farblose Copolymere liefern. Die Kinetik des Pfropfprozesses kompliziert sich durch eine Phasenseparation von PP und [MAA+MS], die bei höheren Monomerkonzentrationen auftritt und von speziellen Wechselwirkungen zwischen den beiden Monomeren ausgelöst wird. Deswegen werden zwei gepfropfte PP-Produkte gebildet, ein wenig gepfropftes Hauptprodukt und ein hochgepfropftes Nebenprodukt. Dieses entsteht vermutlich in den Phasengrenzflächen. Es trägt pro PP-Kette einen MAAMS-Ast, der ungefähr aus drei MAA- und fünf MS-Bausteinen besteht.
    Notes: Atactic polypropylene (PP) is an amorphous short-chained by-product of isotactic polypropylene (iPP). Due to its enhanced solubility, PP is a suited model polymer for kinetic studies of iPP melt reactions. The maleination of PP via radical grafting at high temperatures was investigated. Since maleic anhydride (MAA) produces discoloring oligomers, PP was grafted with a mixture of MAA and α-methylstyrene (MS). Advantageous is that MS cannot homopolymerize at high temperatures and that MAA and MS tend to copolymerize alternatingly (to colorless products). The kinetics of the grafting process is complicated by a phase separation of PP and [MAA+MS] that is caused by the special attractions between the two monomers. As a result, two grafted PP products are obtained, of which the major is only slightly but the minor is heavily grafted. The latter graft copolymer, which is probably created in the interfaces between phase domains, carries one MAAMS graft per PP back bone chain, approximately with three MAA and five MS units.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1997.052510104
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  • 4
    Electronic Resource
    Electronic Resource
    Gemeinsame kondensation von bisphenol A, melamin und formaldehyd (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 163 (1988), S. 169-193 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The condensation reaction of bisphenol A, melamine, and formaldehyde was investigated by gel permeation chromatography, 13C-NMR-spectroscopy, IR-spectroscopy and elemental analysis. Because of the high reaction rates the condensation could be investigated only in the range of pH 6-10. At pH 6 and 7 the reaction of melamine with formaldehyde is dominating.With increasing pH-value the condensation of bisphenol A with formaldehyde is observed preferably. At pH 10 the condensation results in high molecular products. Cocondensation of melamine and bisphenol A through methylene bridges does not take place. But as a separation of the bisphenol A-formaldehyde condensates from the other condensation products was not possible, the three components may be connected through methylene-ether groups and/or intermolecular hydrogen bridges.
    Notes: Die gemeinsame Kondensation von Bisphenol A, Melamin und Formaldehyd wurde mit Hilfe der Gelpermeationschromatographie, der 13C-NMR-Spektroskopie, IR-Spektroskopie und Elementaranalyse untersucht. Wegen der hohen Kondensationsgeschwindigkeit verläuft die Reaktion in Gegenwart der drei Komponenten nur im Bereich von pH 6-10 kontrollierbar. Bei pH 6 und 7 überwigt die Kondensation zwischen Melamin und Formaldehyd. Mit steigendem pH-Wert tritt die Reaktion von Bisphenol A mit Formaldehyd in den Vordergrund und führt bei pH 10 zu hochmolekularen Kondensationsprodukten.Auf direkte Cokondensation hinweisende Methylenverknüpfungen zwischen der phenolischen Komponente und Melamin konnten nicht nachgewiesen werden. Die Kondensationsprodukte des Melamins bzw. des Bisphenol A mit Formaldehyd lassen sich aber nicht mehr vollständig aus den Reaktionsgemischen der Vorkondensation abtrennen, was dafür spricht, daß die Komponenten über Methylenetherbrücken und/oder intermolekularen Wasserstoffbrücken miteinander verknüpft sind.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1988.051630115
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  • 5
    Electronic Resource
    Electronic Resource
    Ozoninduzierter Abbau von Polyoxymethylen (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 156 (1988), S. 123-137 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Samples of polyoxymethylene (unstabilized and stabilized with the antiozonants N-isopropyl-N′-phenyl-p-phenylenediamin (IPPD) and bis-(1,2,3,6-tetrahydrobenzaldehyd)pentaerithritylacetal (Vulkazon AFS)) were ozonized under mechanical load in a special climate chamber. Surface damages were determined by IR-spectroscopy and scanning electron microscopy. During the ozonolysis a damaged layer is formed, the thickness of which increases with increasing time of ozonization. During this damaging reaction acetal groups are attacked and oligomers are formed.
    Notes: Proben von unstabilisiertem und mit den Antiozonantien N-Isopropyl-N′-phenyl-p-phenylendiamin (IPPD) und Bis-(1,2,3,6-tetrahydrobenzaldehyd)-pentaerithrityl-acetal (Vulkazon AFS) stabilisiertem Polyoxymethylen wurden unter mechanischer Belastung in einer Klimakammer ozonisiert. Die Schädigungen auf der Oberfläche wurden IR-spektroskopisch und rasterelektronenmikroskopisch untersucht. Während der Ozonisierung von POM bildet sich eine geschädigte Schicht, deren Dicke mit zunehmender Ozonisierungszeit wächst. Hierbei wird das Polymere an den Acetalbindungen angegriffen, wodurch Ketten gespalten werden und Oligomere entstehen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1988.051560111
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  • 6
    Electronic Resource
    Electronic Resource
    Strain-induced crystallisation and miscibility behaviour of hydrogenated nitrile rubbersPaper presented at the meeting of the GDCh-Fachgruppe “Makromolekulare Chemie” on “Kautschukelastische Polymersysteme” in Bad Nauheim (Germany), March 30-31, 1992. (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 202 (1992), S. 143-158 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: HNBR rubbers, which are made by selective hydrogenation of the olefinic bonds of NBR rubbers, have been developed, because they show improved resistance towards heat and chemicals. In this study, two other properties are discussed that arise from the fact that HNBR rubbers are fairly alternating copolymers of unpolar butylene and polar acrylonitrile units: At intermediate compostions, HNBR rubbers form homogeneous blends with PVC, and near the symmetric composition they exhibit strain-induced crystallisation. The thermal transitions of the HNBR rubbers and their miscibility with PVC were analyzed, as well as the crystallisation and the stress-strain behaviour of a HNBR of symmetric composition.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.052020109
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  • 7
    Electronic Resource
    Electronic Resource
    Modification of melamine-formaldehyde moulding compounds with ethylene/vinyl acetate copolymers (1994)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 222 (1994), S. 61-87 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Melamin-Formaldehyd-Harz-Formmassen (MF) wurden durch mechanisches Mischen mit Ethylen-Vinylacetat-Copolymeren (EVA) und teilverseiftem EVA modifiziert, wobei Etherbindungen zwischen dem hydrolysierten EVA und dem MF-Harz nachgewiesen werden konnten, die die mechanischen Eigenschaften von spritzgepreßten Formteilen im Vergleich zur Modifizierung mit EVA verbessern. Der Zusatz solcher Modifikatoren erhöht die Duktilität und verringert im Falle von EVA die Nachschwindung der überaus steifen MF-Matrix, solange der Modifikatoranteil gering bleibt. Dagegen werden die Steifigkeit und die Wärmeformbeständigkeit verschlechtert. Die durch solche unvernetzten Polymeren erreichbare Steigerung der Schlagzähigkeit bleibt allerdings unzureichend.
    Notes: Melamine-formaldehyde moulding compounds (MF) were modified by mechanical mixing with ethylene/vinyl acetate copolymers (EVA) and with partially hydrolysed EVA. Ether linkages between the hydrolysed material and the MF resin improve the mechanical properties of the transfer moulded parts containing the hydrolysed material compared to those made with EVA. The use of both modifying polymers improves the ductility and, in case of the partially hydrolysed material, the postshrinkage of the extremely rigid MF matrix, as long as the modification polymer content is kept low. On the contrary, Young's modulus and the heat deflection temperature are deteriorated. The improvement in impact strength by use of those uncrosslinked polymers is still insufficient.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1994.052220106
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  • 8
    Electronic Resource
    Electronic Resource
    Alkane als initiatoren zur radikalischen polymerizationHerrn Professor Dr. rer. nat. Dr.-Ing. E.h. Hansjörg Sinn mit den besten Wünschen zum 65. Geburtstag gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 223 (1994), S. 69-79 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Alkanes with highly substituted carbon-carbon bonds can be cleaved in free radicals by homolytic dissociation under the influence of thermal energy. The energy of dissociation is mainly determined by the type and size of the respective substituents. For tetraarylbutane dinitriles the temperatures of decomposition are in the range of other technically used initiators. But nevertheless, these compounds are up to now rather seldom used to initiate free radical polymerizations. This is connected with the special mechanism of initiation: the formed highly substituted alkyl radicals are relatively stable and show only a rather low reactivity against the usually used monomers. Therefore, in the beginning of the polymerization the radical concentration is rather high which leads not only to addition to monomers but also to a pronounced primary radical termination. In some cases this termination process is reversible which results in an unusual polymerization kinetics. Depending on the type of monomer and the degree of reversibility of the primary radical termination, either a period of “dead-end” polymerization follows or the cleavage of the oligomers at the chain end results in a re-initiation process with a “normal” polymerization with increased rate. The reaction mechanism, kinetics and some possible applications of such initiating alkanes are reported.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1994.052230106
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  • 9
    Electronic Resource
    Electronic Resource
    Modification of melamine-formaldehyde moulding compounds with epoxy resins (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 237 (1996), S. 1-44 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zur Verbesserung der Maßhaltigkeit und der Zähigkeit von gehärteten Melamin-Formaldehyd-Harz-Formmassen (MF) wurden teilverträgliche, methylolgruppenhaltige Epoxidharze (EP) auf Bisphenol A-Basis hergestellt und charakterisiert. Die Vernetzung solcher Epoxyresolharze durch 2-Ethyl-4-methylimidazol in Gegenwart von MF-Harz wurde untersucht. Spritzgepreßte Probekörper zeigen eine Zweiphasenstruktur; die EP-Phase kann als Wirt für carboxy-funktionalisierte, oligomere NBR-Kautschuke (CTBNX) dienen, die für sich allein in MF-Harzen nicht wirksam sind. Unter der Voraussetzung von kovalenten Bindungen in der Phasengrenzfläche kann durch den Zusatz von 0,5 bis 4 Gew.-% CTBNX zur MF-Formmasse bei EP-Anteilen bis 20 Gew.-% eine 50 bis 100proz. Steigerung von Bruchdehnung und Schlagzähigkeit erreicht werden, ohne daß Steifigkeit und Wärmeformbeständigkeit wesentlich abfallen. Bei moderaten EP/CTBNX-Gehalten wird zusätzlich die Nachschwindung von MF-Formteilen vermindert.
    Notes: In order to improve dimension stability and toughness of melamine formaldehyde moulding materials (MF), compatible bisphenol A epoxy resins (EP) with additional methylol groups were synthesized and characterized. Crosslinking of those epoxyresol resins with 2-ethyl-4-methylimidazole in the presence of MF resin was investigated. Transfer-moulded specimens revealed a two-phase morphology in which the EP phase is used as a host for modification with carboxylic functionalized oligomeric NBR rubber (CTBNX), which is not effective in MF moulding materials alone. The addition of 0.5 - 4 wt.-% CTBNX to the MF moulding materials at an epoxy content of maximum 20 wt.-% results in 50-100 % increase of elasticity and toughness without serious decrease in stiffness and heat deflection temperature, provided that covalent interfacial bonds exist. In addition, the post-shrinkage of MF parts decreases if a moderate EP/CTBNX content is introduced.
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1996.052370101
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  • 10
    Electronic Resource
    Electronic Resource
    The program FANTOM for energy refinement of polypeptides and proteins using a Newton - Raphson minimizer in torsion angle space (1990)
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 679-694 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The program FANTOM (fast Newton-Raphson torsion angle energy minimizer) performs minimizations of the ECEPP/2 energy function for proteins with the Newton-Raphson method. It is implemented for use with conventional computer hardware. The torsion angles are chosen as independent variables. The first and second derivatives are calculated with a previously described rapid algorithm. For the matrix inversion a modified Cholesky factorization is used. A line search adjusts the step length and nonbonded interactions can be calculated with a cutoff. The following tests of the program are described: All local minima of the ECEPP/2 energy function for the amino acids glycine and alanine were determined. An exhaustive search by more than 16,000 independent energy minimizations was used to identify low-energy structures of Met-enkephalin, which were then compared with previously published structures of this pentapeptide. To investigate the use of FANTOM with disulfide bonds, it was applied with conotoxin. As an illustration of the intended primary use of the program, an energy refinement of the structure of the basic pancreatic trypsin inhibitor determined by nmr spectroscopy in solution is described.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360290403
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