Chinedu Okoro

Dissertation Topic:  Bio-elastomer Toughened Conductive Carbon Fiber Composites

Major Professor:  Dr. Vijaya Rangari, Associate Professor of Material Science and Engineering

M.S.:  Mechanical Engineering, Tuskegee University

B.S.: Mechanical Engineering, Tuskegee University

Dissertation Abstract:

The use of composites to supplement heavier and dense structural materials with conductive properties has steadily inclined over the past decade. Epoxy resins are being widely used in a multitude of applications that range from common adhesives to the polymer matrix of high performance composite materials. However, a major limitation in these thermoset systems is that they produce highly brittle materials when nanoparticles are used as fillers.  For this reason toughening mechanisms have been studied extensively throughout the past decades.  In addition, these resin systems are typically insulators and do not possess conductive capabilities. A vegetable oil based product (Linseed oil) is used as a plasticizer and additive to commercial polymers to improve their toughness, tensile strength and biodegradability. Subsequently, technologies that enable conductivity and electromagnetic shielding (EMI) solutions are of major interest within defense initiatives, particularly aerospace.   Therefore, a conductive composite material with EMI capabilities toughened with biodegradable components was fabricated.  Microwave (CEM) synthesis was used to fabricate conductive carbon based-Ag nanoparticles.  Chemical vapour deposition (CVD) was then performed to grow conductive carbon based particles onto the surface of commercially available carbon fiber.  A multiscale composite was then fabricated using the bio-modified epoxy system.  Quantitative thermal, electrical and mechanical tests were conducted to characterize and assess material properties.