Avi Natan
Advisor: Prof. Satish Kumar

will propose a doctoral thesis entitled,

Solution-Processed Boron Nitride Materials for High-Temperature Composites

On

Tuesday, May 27th at 2 p.m.
MRDC 3515
and
Virtually via MS Teams
Link

Committee
           Prof. Satish Kumar – School of MSE (advisor)
           Prof. Natalie Stingelin – School of MSE
           Prof. Scott Danielsen – School of MSE
           Prof. Satish Kumar – School of ME
           Dr. Cheol Park – Senior Researcher, NASA Langley

Abstract
               Composite materials have garnered significant interest given the desire to increase the limits for materials’ capabilities. Carbon fiber reinforced composites have a higher specific strength than the aluminum they replace in aerospace devices, providing energy savings for these vehicles. With the discovery of new nanomaterials, the research has significantly broadened to a variety of new applications. However, processing and choice of nanomaterials can have a major impact on the resulting composite properties. For example, boron nitride (BN) materials have been explored for their unique properties of high thermal conductivity, electrical insulation, low dielectric constant, and more. For hexagonal-BN (h-BN), the exfoliation and dispersion can play a critical role in how it improves composite materials. 
           This work focuses on improving BN-based composites through solution-processing. First, a novel, economical method for producing h-BN/BNNT hybrid fiber via a solution-spun polymer/BO/BNNT precursor fiber was developed. The conversion of BO to BN was studied and then mechanical properties were improved by incorporating BNNTs into the fiber. Through further development, the solution-spun polymer/BO/BNNT fibers offer an opportunity to produce h-BN/BNNT fibers at a commercial scale, which would be beneficial for aerospace and high-power computing applications. From there, BN-based fillers are studied in comparison to carbon-based fillers in fluoroelastomer (FKM) using a solution-processing method. Solution-processing elastomer composites offers greater control over the filler processing and dispersion compared to mechanical or melt mixing. The main purpose of this study will be to understand how these different fillers impact the high temperature stability of the FKM. Additionally, mechanical properties, crosslink density, thermal conductivity, and dispersion quality are studied for the different fillers to understand the structure property relationships between the different filler chemistries and geometries. From there, fillers will be combined to produce hybrid FKM composites. In doing so, the composite properties can be further improved when compared to the single-filler composites. By improving the high temperature stability of FKM, seals for applications such as aerospace and automotive will last longer reducing the frequency at which these parts need to be changed and increasing the possible operating temperature in these vehicles.  This work will develop an understanding for solution-processing BN composites and assist in their development and understanding for polymer and ceramic matrix composites.