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  • Chemistry  (16)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 170 (1989), S. 137-143 
    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: Die vorliegende Arbeit untersucht das linear-elastische Bruchverhalten von (PMMA) mit Poly(ethylen-co-vinylacetat) (EVA) oder EVA  -  g-Bernsteinsäureanhydrid (EVA-g-SA) mittels Kerbschlagzähigkeitsmessungen nach Charpy. Rasterelektronenmikroskopaufnahmen zeigen, daß in Blends, die durch „in situ“-Polymerisation des acrylischen Monomeren in Gegenwart des Elastomeren hergestellt wurden, eine IPN-Morphologie vorliegt, während ein Blend, das durch Mischung der Polymerkomponenten im Schmelzezustand gebildet wurde, die typische zweiphasige Struktur von dispergierten Elastomerdomänen in einer glasartigen Matrix zeigt.Die Ergebnisse der mechanischen Messungen stimmen gut mit den beobachteten Morphologien überein.
    Notes: In the present work blends between poly(methylmethacrylate) (PMMA) and poly(ethylene-co-vinylacetate) (EVA) or its derivative EVA-g-succinic anhydride (EVA-g-SA) have been investigated by linear elastic fracture mechanics (LEFM) with Charpy impact tests and by scanning electron microscopy (SEM). Blends prepared by “insitu” radical polymerization of the acrylic monomer in the presence of the rubbers have an IPN morphology, while a blend prepared by melt-mixing the polymer components shows the typical biphasic structure of rubbery domains dispersed in a glassy matrix.Furthermore, a different behaviour is found when using EVA-g-SA instead of EVA. A fair agreement is found between the response of the LEFM analysis applied to the results of Charpy impact tests and the observed morphologies.
    Additional Material: 4 Ill.
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  • 2
    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: Die thermischen und dynamisch-mechanischen Eigenschaften einiger linearer kautschukelastischer Polyurethane mit chemisch unterschiedlichen starren Segmenten wurden untersucht und zur chemischen Zusammensetzung in Beziehung gesetzt. Interessante Zusammenhänge wurden zwischen der Kristallinität der elastischen Polyurethanharnstoffe und der aromatischen oder cycloaliphatischen Natur der Diisocyanat-Komponenten gefunden. Darüber hinaus scheinen die Ergebnisse bei einem bestimmten Verhältnis zwischen starren und flexiblen Segmenten und bei gegebener Zusammensetzung der flexiblen Gruppen auf eine bessere Phasenseparation bei den Polyurethanharnstoffen mit cycloaliphatischen starren Segmenten als bei solchen mit aromatischen, starren Einheiten hinzuweisen.
    Notes: Experimental batches of linear rubber-like polyurethanes characterized by the presence of chemically different hard segments are studied and their thermal and dynamic-mechanical properties are related to the differences in chemical compositions. Interesting correlations are found between the development of crystallinity in such elastomeric poly(urethaneurea)s and the aromatic or alicyclic nature of the diisocyanate. Moreover, for a fixed ratio between hard and soft segments, and for a given composition of the soft segment, the results seem to indicate a better degree of phase separation in cycloaliphatic-based hard segment poly(urethaneurea)s than in aromatic-based hard segment poly(urethaneurea)s.
    Additional Material: 7 Ill.
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  • 3
    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: Poly(L-milchsäure) ist ein biokompatibler, semikristalliner, thermoplastischer Polyester mit ungünstigen mechanischen Eigenschaften. Daher wurde in einem “reactive blending”-Prozeß ein Acrylkautschuk, n-Butylacrylat, mittels einer Suspensionspolymerisation in Wasser auf in einem organischen Lösungsmittel gelöste Poly(L-milchsäure) gepfropft. Die gebildeten Copolymeren konnten isoliert und durch NMR-Spektroskopie und DSC-Messungen charakterisiert werden. Die Untersuchung der mechanischen Eigenschaften ergab keine befriedigenden Ergebnisse, weil die Kautschukphase wahrscheinlich aus viskosen linearen Makromolekülen besteht und daher keine elastischen Eigenschaften besitzt. In weiteren Arbeiten soll der Syntheseweg so modifiziert werden, daß durch den Einbau von Diacrylaten eine zumindest partielle Vernetzung der Kautschukphase erreicht wird.
    Notes: Poly(L-lactic acid) is a biocompatible polyester, semicrystalline, thermoplastic, with low versatility in mechanical properties. To overcome this problem, a reactive blending procedure was performed by grafting an acrylic rubber, n-butyl acrylate, via water suspension polymerization onto poly(L-lactic acid) dissolved in an organic solvent. It was possible to isolate the copolymeric phase formed from the two polymers and characterize it by using NMR and DSC techniques. Mechanical tests on blends gave no satisfactory response, probably because the rubbery phase is composed essentially of viscous linear macromolecules, not able to perform elastic properties. Work is in progress to modify the synthetic pathway to incorporate diacrylates in order to realize a rubbery phase at least partially cross-linked.
    Additional Material: 7 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 210 (1993), S. 129-141 
    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: Blends aus Poly-ε-caprolacton (PCL) und Poly(β-hydroxybyurat-co-β-hydroxyvalerat) (PHBV) mit 4 mol-% Hydroxyvalerat-Anteil wurden durch Mischen der Polymeren sowohl ohne Initaiator als auch in Gegenwart von Dicumylperoxid (DCPO) bei 160°C oder Dibenzoylperoxid (DBPO) bei 100°C hergestellt. Es wurden PCL/PHBV-Blends mit dez Zusammensetzungen 30/70 und 70/30 Gew.-% hergestellt. Zum vergleich wurden diereinen Polymeren ebenfallsmit DCPO bei 160°C umgesetzt. Die Produkte wurden thermisch (DSC) und Mechanisch (Zugversuche) sowie mittels Rasterrelektronenmikroskipie (SEM) untersucht. SIgnifikateUnterschiedein den chemisch-physialischen Eigenschaften der Beldns Konnten auf den Einfluß sowohl des Initiators als auch der Temperatur zurückegeführt werden.
    Notes: Blends of poly-ε-caprolactone (PCL) and poly(β-hydroxybutyrate-co-β-hydroxy-valerate) (PHBV) containing 4 mol-% of hydroxyvalerate were prepared by mixing the two polymers in the presence of either dicumylperoxide (DCPO) at 160°C or dibenzoylperoxide (DBPO) at 100°C. Similarly, blends were obtained by mixing the two polymers without any peroxide added. The blends were prepared in to complementary compositions, namely 70 wt.-% PCL/30 wt.-% PH BV and 30 wt.-% PCL/70 wt.-% PHBV, respectively. Also pure polymers were reacted with DCPO at 160°C in the same way as the blends.Thermal (DSC), mechanical (tensile tests) and SEM analyses were performed on the blends and on the pure polymers.Significant differences were found in the chemical-physical characteristics of blends with and with out peroxides as well as in blends prepared at low and high temperatures.
    Additional Material: 5 Ill.
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  • 5
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 13 (1992), S. 231-235 
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 12 (1991), S. 563-570 
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 6 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 39 (1996), S. 191-204 
    ISSN: 0959-8103
    Keywords: Biopol ; polybutylacrylate ; polycaprolactone ; reactive blending ; melt-mixing ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Multicomponent polymeric systems containing Biopol as one of the phases are described as obtained according to two different procedures: radical polymerization of an acrylic polymer in the presence of Biopol, and melt-mixing of Biopol with polycaprolactone in the presence of peroxide. The decomposition of peroxide causes, in both cases, the formation of intergrafted species responsible for interfacial activity and compatibilization. The results of chemical, chemical-physical, morphological and mechanical tests, confirming the occurrence of such interactions, are reported.
    Additional Material: 14 Ill.
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  • 9
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Thermal and mechanical properties of various functionalized ethylene-propylene rubbers (EPR) were evaluated. The samples studied varied both in the type of functional groups and in the grafting degree. Grafted molecules included succinic anhydride, 2-(dimethylamino)ethylsuccinimide and 2-(dimethylamino)ethyl methacrylate. The insertion of these groups was found to influence deeply the elastic response of rubbers, leading to the formation of network whose properties were dependent upon the density of polar crosslinks introduced. On the other hand, the thermal properties were less influenced, i.e. the glass transition temperature Tg increased only slightly with increasing content of functional groups.
    Additional Material: 8 Ill.
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  • 10
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Influences of type and content of functional groups on the mechanical response of various functionalized (grafted) ethylene-propene rubbers (EPRs) are reported. Grafted molecules include succinic anhydride (SA), monomethyl succinate (MMS) and 2-(dimethylamino)ethylsuccinimide (DAESI). A semiquantitative correlation between the decrease of the mechanical properties at high grafting degree and degradation of the polyolefinic backbone is given. Also a study of the dynamic-mechanical properties of the functionalized rubbers is reported. A rubbery plateau is found, the strength and temperature dependence of which is a function of the type and content of the grafted molecules.
    Additional Material: 11 Ill.
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