Structural Materials Commons^™

Structure And Properties Of Cnt Yarns And Cnt/Cnf Reinforced Pan-Based Carbon Fibers, Nitilaksha Phalaxayya Hiremath

Doctoral Dissertations

There is continuing effort to enhance the strength and modulus of carbon fibers by various combinations of materials and processing. Carbon fibers are produced from various precursors, and the strength of the CFs are directly related to the type of precursor used to make them. Carbon Nanotubes (CNTs) have received a great deal of attention due to their unique structure and properties. Major focus of this research is on the evaluation of processing, structure and properties of CNT based yarns and composite fibers.

High strength and low cost carbon fibers (CFs) are needed for today’s applicatio ns. A low cost …

Nanoscience At Interfaces And Surfaces: From Jamming To Electrode Texturing, Mengmeng Cui

Doctoral Dissertations

This dissertation focuses on the nanoparticle self-assembly on the liquid/liquid interface and the nanomaterial modification on surface. The self-assembly of nanoparticles at the liquid/liquid interface was utilized to trap non-equilibrium morphology when the nanoparticles reach jamming state. The dynamics of jammed systems were further studied by X-ray photon correlation spectroscopy. For the surface part, the nanomaterials were modified on the electrodes to improve the performance of microbial electrosynthesis. Also, a novel and simple method was developed to prepare nanomaterials including nanoparticle surfactants and carbon nanotubes (CNTs).

Creation And Evaluation Of Polymer/Multiwall Carbon Nanotube Films For Structural Vibration Control And Strain Sensing Properties, Weiwei Lin

FIU Electronic Theses and Dissertations

Multifunctional materials both with damping properties and strain sensing properties are very important. They promise to be more weight-efficient, and provide volume-efficient performance, flexibility and potentially, less maintenance than traditional multi-component brass-board systems.

The goal of this dissertation work was to design, synthesize, investigate and apply polyaniline/Multiwall carbon nanotube (PANI/MWCNT) and polyurethane (PU) /MWCNT composites films for structural vibration control and strain sensors using free layer damping methods and static and dynamic strain sensing test methods.

The PANI/MWCNT was made by in situ polymerization of PANI in the presence of MWCNT, then frit compression was used to make circular and …

Characterization Of Suspension Polymerized Polyacrylamide And Poly(Sodium Acrylate-Acrylamide) Copolymer And Their Size Influence On The Properties Of Concrete, Cole R. Davis, Kendra A. Erk, Stacey L. Kelly

The Summer Undergraduate Research Fellowship (SURF) Symposium

Shrinkage leading to cracking and mechanical instability is a major problem for concrete due to the loss of water during the curing process. However, through the addition of Superabsorbent Polymer (SAP) hydrogels, shrinkage can be prevented, increasing the strength of concrete. Characterization of suspension polymerized polyacrylamide (PAM) poly(sodium acrylate-polyacrylamide) (PANa-PAM) copolymer microsphere sizes, morphology and swelling behavior was conducted before adding them to concrete. Size was determined using microscopy paired with ImageJ analysis. Coulter Counter size characterization was also used to determine the particle size distribution. Swelling behavior was determined using the tea bag method as well as size analysis …

Development Of Eco-Friendly Composite Foam Boards For Thermal Insulation And Packaging Purposes Using Cellulose Nanofibrils (Cnf), Nadir Yildirim

Electronic Theses and Dissertations

Reducing energy consumption is a high priority in the United States and throughout the world. Energy used to heat and cool occupied constructed facilities is of particular concern, and one of the most effective strategies is insulating the building envelope. Historically, builders used whatever material was available to fill the void between interior and exterior walls, including wool fibers, paper, and even corn cobs. Today, homes are built using foam insulation that harden when applied, blown-in loose insulation, fiberglass mats or rigid foam boards usually composed of polystyrene. Rigid foam boards are used in a variety of applications despite the …

Solution Casting And Mechanical Testing Of Arabinan-Cellulose Nanocomposites, Kevin Su, Alina Lusebrink

Materials Engineering

The purpose of this work was to investigate methods to produce consistent, reliable, and testable thin films of arabinan-cellulose nanocomposites. Mechanical properties and composition of the Opuntia ficus-indica cactus spines served as motivation for this research. The high specific strength and stiffness, biodegradability, and sustainability of these spines inspired the creation of composites fabricated from the same materials found in cactus spines: arabinan and nanocrystalline cellulose (NCC). Arabinan serves as the matrix material and NCC as the reinforcement. To explore the feasibility of using a non-toxic solvent, different solution casting techniques with water as a solvent were investigated. Ultrasonication was …

Solution, Interfacial, And Interlayer Studies Of Electronically Active Polymers, Hsin-Wei Wang

Doctoral Dissertations

This thesis describes the solution behavior and interfacial properties of electronically active polymers. The performance of such polymers in devices is often determined by their chain conformation and morphology in solution and in thin films. For example, the intricate balance between polymer domain size and crystalline packing of electron donor and acceptor components, as well as the properties at the polymer-metal interface, are crucial for achieving optimal performance in devices, such as solar cells. Chapter 1 presents the current progress in polymer-based solar cells, their fundamental principles, and key factors to improve their efficiency. Literature precedents on the development of …