THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Monday, April 24, 2017

2:00 - 4:00 PM
in LOVE 210

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Alexander Lohse

"Toward Sustainable Composites: Atomistic simulation of composites, covalent adaptable networks, and cellulose/PAN fibers"

Committee Members:

Prof. Karl Jacob, Co-Advisor, MSE

Prof. Edmond Chow, Co-Advisor, CSE

Prof. Surya Kalidindi, MSE

Prof. Jerry Qi, ME

Prof. Donggang Yao, MSE

Abstract:

Epoxy materials are some of the most widely used polymers in the aviation and automotive industries because of their environmental degradation resistance and strength at high temperatures. Carbon fiber reinforced plastic with an epoxy matrix has been used in the defense industry since the 1960's and its use is becoming more prevalent due to the high specific strength and specific modulus. The development of nanomaterials in the past two decades has led to the use of nanofillers, such as silica nanoparticles or carbon nanotubes, in composites to improve the modulus and inplane and out-of-plane strength. The number of filler types, functionalities, and orientations lead to a complicated and lengthy trial and error experimental approach. Computational researchers have been trying to find a new approach to narrow down promising combinations of fillers and matrix materials using their known chemical and mechanical attributes. This work is directed toward developing a fundamental understanding of the behavior of certain classes of nanocomposite materials.

This research will use molecular dynamics simulation to analyze the (1) interfacial atomistic structure of a traditional epoxy/graphene system with different surface functionalities, (2) dissolution (recycling) mechanism of covalent adaptable networks (CAN), and (3) carbonization mechanism of a cellulose/polyacrylonitrile (PAN) composite system. A new method for characterizing interfacial atomistic structure will be presented for the traditional epoxy/graphene system that could be applied to other polymer matrix nanocomposite systems as well. Simulations of CAN polymers further the mechanistic understanding of recyclability and recoverability in these matrix materials. Reactive forcefield carbonization simulations will demonstrate viability and a potential new path for fiber production that would reduce cost and improve sustainability through the use of nanocellulose.