Highly Thermostable Dynamic Structures of Polyaramid Two-Dimensional Polymers
S. Lustig, Jan Andzelm, Eric D. Wetzel
Abstract
This is the first comparative study of a chemically homologous series of linear and two-dimensional polyaramids at high temperatures. Detailed comparisons are made in the bulk and at free surface environments of the dynamical structures including ordered phases and hydrogen bonding statistics as functions of temperature. First-principles density functional theory molecular mechanics and dynamics methods agree quantitatively with the known behavior of linear poly(p-phenylene terephthalamide), more commonly known as Kevlar. The 2D polymer topology offers potential to design higher thermal resilience compared to legacy linear polymer topologies. At sufficient reticulation density, the hydrogen bonding in two-dimensional polymers significantly enhances aramid bond stability. Hydrogen-bonded 2D polymers, such as graphamid, are a unique material architecture for providing enhanced structural and thermomechanical stability. These results suggest that hydrogen-bonded 2D polymers offer significant advantages for combined light weight, high strength, and high temperature applications.