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Morphology and Morphology Formation of Injection Molded PP-based Nanocomposites

  • The mechanical properties of semi-crystalline polymers depend extremely on their morphology, which is dependent on the crystallization during processing. The aim of this research is to determine the effect of various nanoparticles on morphology formation and tensile mechanical properties of polypropylene under conditions relevant in polymer processing and to contribute ultimately to the understanding of this influence. Based on the thermal analyses of samples during fast cooling, it is found that the presence of nanoparticle enhances the overall crystallization process of PP. The results suggest that an increase of the nucleation density/rate is a dominant process that controls the crystallization process of PP in this work, which can help to reduce the cycle time in the injection process. Moreover, the analysis of melting behaviors obtained after each undercooling reveals that crystal perfection increases significantly with the incorporation of TiO2 nanoparticles, while it is not influenced by the SiO2 nanoparticles. This work also comprises an analysis of the influence of nanoparticles on the microstructure of injection-molded parts. The results clearly show multi-layers along the wall thickness. The spherulite size and the degree of crystallinity continuously decrease from the center to the edge. Generally both the spherulite size and the degree of crystallinity decrease with higher the SiO2 loading. In contrast, an increase in the degree of crystallinity with an increasing TiO2 nanoparticle loading was detected. The tensile properties exhibit a tendency to increase in the tensile strength as the core is reached. The tensile strength decreases with the addition of nanoparticles, while the elongation at break of nanoparticle-filled PP decreases from the skin to the core. With increasing TiO2 loading, the elongation at break decreases.

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Metadaten
Verfasserangaben:Buncha Suksut
URN (Permalink):urn:nbn:de:hbz:386-kluedo-44332
Betreuer:Alois K. Schlarb
Dokumentart:Dissertation
Sprache der Veröffentlichung:Englisch
Veröffentlichungsdatum (online):25.08.2016
Jahr der Veröffentlichung:2016
Veröffentlichende Institution:Technische Universität Kaiserslautern
Titel verleihende Institution:Technische Universität Kaiserslautern
Datum der Annahme der Abschlussarbeit:24.06.2016
Datum der Publikation (Server):25.08.2016
Freies Schlagwort / Tag:injection molding; polymer morphology; polymer nanocomposites; thermal analysis
GND-Schlagwort:Morphology; Polymer; crystallization; nanocomposites; thermal analysis
Seitenzahl:X, 134
Fachbereiche / Organisatorische Einheiten:Fachbereich Maschinenbau und Verfahrenstechnik
DDC-Sachgruppen:6 Technik, Medizin, angewandte Wissenschaften / 620 Ingenieurwissenschaften und Maschinenbau
Lizenz (Deutsch):Standard gemäß KLUEDO-Leitlinien vom 30.07.2015