Open Access. Powered by Scholars. Published by Universities.®

Materials Science and Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Polymer and Organic Materials

Doctoral Dissertations

Theses/Dissertations

Composite

Articles 1 - 4 of 4

Full-Text Articles in Materials Science and Engineering

3d Printing Of Hybrid Architectures Via Core-Shell Material Extrusion Additive Manufacturing, Robert Cody Pack May 2021

3d Printing Of Hybrid Architectures Via Core-Shell Material Extrusion Additive Manufacturing, Robert Cody Pack

Doctoral Dissertations

Biological materials often employ hybrid architectures, such as the core-shell motif present in porcupine quills and plant stems, to achieve unique properties and performance. Drawing inspiration from these natural materials, a new method to fabricate lightweight and stiff core-shell architected filaments is reported. Specifically, a core-shell printhead conducive to printing highly loaded fiber-filled inks, as well as a new low-density syntactic foam ink, are utilized to 3D-print core-shell architectures consisting of a syntactic epoxy foam core surrounded by a stiff carbon fiber-reinforced epoxy composite shell. Effective printing of test specimens and structures with controlled geometry, composition, and architecture is demonstrated …


Stretching The Applications Of Biomass: Development Of Lignin Based Thermoplastic Elastomers And Composite Materials, Anthony Stephen Bova May 2021

Stretching The Applications Of Biomass: Development Of Lignin Based Thermoplastic Elastomers And Composite Materials, Anthony Stephen Bova

Doctoral Dissertations

Bio-based plastics and composites have seen increased industry adoption in recent years due to growing demand for materials with a low carbon footprint. The use of lignin as a feedstock for polymers has seen growing interest as the concept of an integrated cellulosic biorefinery gains traction and advances the need to use all components of separated biomass for value-added applications. Historically, use of lignin in thermoplastic and elastomeric copolymers and blends has been bottlenecked by the inability to introduce lignin content above 30 weight percent due to difficulties with interfacial adhesion of lignin with other soft segments. Efforts to overcome …


Controlling The Assembly Of Nanoparticles In Polymer Blends, Kyle C. Bryson Mar 2016

Controlling The Assembly Of Nanoparticles In Polymer Blends, Kyle C. Bryson

Doctoral Dissertations

While many novel methods have been devised for directing the assembly of nanoparticles in block copolymers, the topic has not reached the same level of sophistication for polymer blends. The assembly of particles at the interface between phase-separated domains can serve as a means to compatibilize polymer blends, reducing domain sizes and enhancing interdomain adhesion by impeding coalescence and decreasing interfacial tension. Compatibilization optimizes the performance of blended materials in applications where the properties of both components must be expressed synergistically, such as in plastics requiring both high strength and high toughness and in photovoltaic films. Thus, approaches to robustly …


Synthesis, Characterization And Surface Modification Of Polydimethylsiloxane And Its Composites, Yan Wang Mar 2015

Synthesis, Characterization And Surface Modification Of Polydimethylsiloxane And Its Composites, Yan Wang

Doctoral Dissertations

Silicone elastomers are widely employed in composite, coatings, biomedical, sealant and electronics applications. This dissertation highlights new methodologies and formulation approaches to improve the performance of siloxane polymers, including the mechanical properties, surface properties, optical properties and transport properties. It also provides an in-depth understanding about dip-coating deposition on chemically patterned surfaces. The first chapter presents the process of transforming sand into siloxane polymers of excellent mechanical strength. History, properties and applications of siloxane polymers are systematically discussed. Another focus of this chapter is wetting, including the concepts of contact angles and capillary bridge ruptures. Five interconnected projects are discussed …