Processing and characterization of brick-and-mortar structured bulk bio-inspired composites


Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Metalurji ve Malzeme Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2013

Öğrenci: SELEN NİMET GÜRBÜZ

Danışman: ARCAN FEHMİ DERİCİOĞLU

Özet:

The aim of this study was to fabricate inorganic-organic composites with an architecture resembling to natural nacre using a novel hybrid conventional method called Hot-Press Assisted Slip Casting (HASC). Alumina platelets, glass platelets and glass flakes with different aspect ratios were used as two-dimensional inorganic fillers to reinforce epoxy matrix. Correlation between processing parameters, inorganic content, orientation of the two-dimensional reinforcements and mechanical property enhancement of the fabricated composites was examined. In order to investigate the effect of interfacial compatibility and adhesion on the mechanical properties of the fabricated composites, reinforcement surfaces were modified with silane coupling agents. As received and functionalized reinforcement surfaces were studied by x-ray photoelectron spectroscopy to confirm the adsorption of silane molecules. Fabricated bio-inspired bulk lamellar composite materials were characterized in terms of their microstructural architecture and mechanical properties. The results obtained indicated that HASC processing is an easy, fast and effective pathway to fabricate bulk inorganic-organic composites exhibiting nacre-like brick-and-mortar architecture. HASC processed composites reinforced by either alumina platelets or glass flakes exhibited enhanced mechanical performance as compared to neat epoxy and composites fabricated by simple mixing, as a result of their nacre-like architecture with well aligned reinforcements. Functionalization of the reinforcement surfaces by silane coupling agents improved the compatibility and adhesion between the reinforcements and the matrix resulting in further enhancement of mechanical properties of bulk lamellar composites fabricated by HASC process. Experimental investigations also revealed the fact that high aspect ratio reinforcements are more effective in reinforcing the epoxy matrix.