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Structure-Property Relationships in Rubber/Layered Silicate Nanocomposites

  • The scientific and industrial interest devoted to polymer/layered silicate nanocomposites due to their outstanding properties and novel applications resulted in numerous studies in the last decade. They cover mostly thermoplastic- and thermoset-based systems. Recently, studies in rubber/layered silicate nanocomposites were started, as well. It was presented how complex maybe the nanocomposite formation for the related systems. Therefore the rules governing their structure-property relationships have to be clarified. In this Thesis, the related aspects were addressed. For the investigations several ethylene propylene diene rubbers (EPDM) of polar and non-polar origin were selected, as well as, the more polar hydrogenated acrylonitrile butadiene rubber (HNBR). The polarity was found to be beneficial on the nanocomposite formation as it assisted to the intercalation of the polymer chains within the clay galleries. This favored the development of exfoliated structures. Finding an appropriate processing procedure, i.e. compounding in a kneader instead of on an open mill, the mechanical performance of the nanocomposites was significantly improved. The complexity of the nanocomposite formation in rubber/organoclay system was demonstrated. The deintercalation of the organoclay observed, was traced to the vulcanization system used. It was evidenced by an indirect way that during sulfur curing, the primary amine clay intercalant leaves the silicate surface and migrates in the rubber matrix. This was explained by its participation in the sulfur-rich Zn-complexes created. Thus, by using quaternary amine clay intercalants (as it was presented for EPDM or HNBR compounds) the deintercalation was eliminated. The organoclay intercalation/deintercalation detected for the primary amine clay intercalants, were controlled by means of peroxide curing (as it was presented for HNBR compounds), where the vulcanization mechanism differs from that of the sulfur curing. The current analysis showed that by selecting the appropriate organoclay type the properties of the nanocomposites can be tailored. This occurs via generating different nanostructures (i.e. exfoliated, intercalated or deintercalated). In all cases, the rubber/organoclay nanocomposites exhibited better performance than vulcanizates with traditional fillers, like silica or unmodified (pristine) layered silicates.The mechanical and gas permeation behavior of the respective nanocomposites were modelled. It was shown that models (e.g. Guth’s or Nielsen’s equations) developed for “traditional” vulcanizates can be used when specific aspects are taken into consideration. These involve characteristics related to the platy structure of the silicates, i.e. their aspect ratio after compounding (appearance of platelet stacks), or their orientation in the rubber matrix (order parameter).

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Metadaten
Verfasserangaben:Konstantinos, G. Gatos
URN (Permalink):urn:nbn:de:hbz:386-kluedo-52484
ISBN:3-934930-55-7
Schriftenreihe (Bandnummer):IVW-Schriftenreihe (59)
Verlag:Institut für Verbundwerkstoffe GmbH
Verlagsort:Kaiserslautern
Betreuer:Jôzsef Karger-Kocsis
Dokumentart:Dissertation
Sprache der Veröffentlichung:Englisch
Veröffentlichungsdatum (online):24.05.2018
Datum der Erstveröffentlichung:28.10.2005
Veröffentlichende Institution:Technische Universität Kaiserslautern
Titel verleihende Institution:Technische Universität Kaiserslautern
Datum der Annahme der Abschlussarbeit:28.10.2005
Datum der Publikation (Server):24.05.2018
Freies Schlagwort / Tag:Nanocomposites
Seitenzahl:XV, 121
Quelle:Konstantinos G. Gatos, Structure property relationships in rubber layered silicate nanocomposites. Gedruckte Ausgabe
Fachbereiche / Organisatorische Einheiten:Fachbereich Maschinenbau und Verfahrenstechnik
DDC-Sachgruppen:6 Technik, Medizin, angewandte Wissenschaften / 600 Technik
Lizenz (Deutsch):Zweitveröffentlichung