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Advanced Manufacturing of Lightweight Porous Carbide Shapes Using Renewable Resources
Başlık:
Advanced Manufacturing of Lightweight Porous Carbide Shapes Using Renewable Resources
Yazar:
Islam, Monsur, author.
ISBN:
9780438054103
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (195 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Rodrigo Martinez-Duarte Committee members: Suyi Li; Garrett Pataky; Xiangchun Xuan.
Özet:
This dissertation presents an origami-inspired manufacturing and an additive manufacturing platform for the fabrication of 3D shapes of porous carbide material using renewable biopolymers as the carbon source. Porous carbide materials possess interesting properties including low density, high surface area, high chemical inertness, high oxidation resistance, adjustable electrical conductivity, and high mechanical properties. Due to such properties, they are used in different applications such as high temperature filters, catalytic support, thermal insulators and structural materials. The state-of-the-art to manufacture porous carbide materials includes direct foaming and templating methods. However, shaping of porous materials with these techniques relies on the use of molds, which restricts the shape complexity of the fabricated parts. Furthermore, most of the carbon precursors used in the current fabrication methods are polymers synthesized from non-renewable petroleum, which leads to a non-environment-friendly synthesis process of carbide materials. Different biopolymers including gelatin, chitosan and glucose have been demonstrated for a sustainable approach for the synthesis of carbide materials by previous authors. However, these synthesis approaches were limited only to the production of carbide nanoparticles. No method was reported so far for the fabrication of 3D shapes of porous carbide materials using the biopolymeric approaches. Hence, in this dissertation, I intend to develop manufacturing platforms which allow for the fabrication of 3D complex shapes of carbide materials using renewable biopolymers to achieve an environment-friendly process.
The scientific contributions of this dissertation are (i) use of the biopolymers for fabrication of 3D parts of porous carbide materials, (ii) development of an origami-inspired manufacturing platform to fabricate lightweight 3D complex shapes of carbonaceous materials which includes carbon and carbide, (iii) additive manufacturing of porous carbide material using extrusion-based 3D printing of a gel composite. Both the manufacturing processes are based on the basic process of mixing the biopolymers with a metal precursor, shape such composite using the mentioned techniques and heat treat such shapes to synthesize a metal carbide. During heat treatment, the biopolymers carbonize, reduce a metal from the precursor and finally carbon and metal react to originate a carbide. The renewable biopolymers that are used here as carbon precursors are carrageenan from seaweed, chitin from shrimp shells and cellulose from plants. The dissertation is organized in 3 parts: a) characterization of carbide synthesis from different renewable precursors, b) folding of a functionalized cellulose paper using origami techniques, and c) additive manufacturing of porous carbide using a biopolymer gel composite. Here, I focus on the development of tungsten carbide. In the first part I explored different biopolymers for the synthesis of WC. The parameters of interest were the proportion of the biopolymer to the tungsten precursor, the synthesis temperature, dwell time and heating rate. Synthesis temperature was proved to be the most influential parameter on the synthesis of WC followed by the ratio of the precursors. The biopolymers yield a porous WC with a purity > 96% at a synthesis temperature of 1300 °C, when compared to a temperature > 1400 °C used in the industrial synthesis methods. Furthermore, the grain size of the WC obtained from these biopolymers ranges from 20 nm--60 nm, which is advantageous when compared to a grain size >100 nm obtained in the industrial synthesis processes. In the second part I present origami-inspired manufacturing by using the cellulosic precursor utilizing its ability to fold into different origami structures. Along with the origami inspired manufacturing of porous WC, I explored the fabrication of carbonized paper as well to understand the effect of carbonization on the folded carbon precursor itself. Significant shrinkage occurred during the heat treatment process, which was attributed to the material release during the heat treatment and the structural mechanics of the origami structure. The carbonaceous origami structures featured low density and considerable mechanical properties, which compares advantageously to most of the lightweight cellular materials. In the third part, additive manufacturing of a gel composite featuring iota-carrageenan, chitin and tungsten oxide nanoparticles is presented. Heat treatment of such 3D printed gel composites yielded to 3D complex shapes of porous WC. Shrinkage of the 3D printed parts was characterized at each step of the fabrication. The 3D printed WC parts featured a density less than 3% of the bulk WC material. The parameter explored in this study was the layer thickness, as it is shown to be the most influential parameter in mechanical properties of 3D printed parts. The elastic modulus and compressive strength exhibited an increasing trend with the increase in the layer thickness. However, use of water as the solvent resulted in limitations in the 3D printing process, which includes inability to fabricate overhang or suspended structures. (Abstract shortened by ProQuest.).
Notlar:
School code: 0050
Tüzel Kişi Ek Girişi:
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(680144.1) | 680144-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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