Title: Atomistic Scale Analysis of the Carbonization Process for C/H/O/N-Based Polymers with the ReaxFF Reactive Force Field

Abstract

During the carbonization process of raw polymer precursors, graphitic structures can evolve. The presence of these graphitic structures affects mechanical properties of the carbonized carbon fibers. To gain a better understanding of the chemistry behind the evolution of these structures, we performed atomistic-scale simulations using the ReaxFF reactive force field. Three different polymers were considered as a precursor: idealized ladder PAN (polyacrylonitrile), a proposed oxidized PAN, and poly(p-phenylene- 2,6-benzobisoxazole). We determined the underlying molecular details of polymer conversion into a carbon fiber structure. Because these are C/H/O/ N-based polymers, we first developed an improved force field for C/H/O/N chemistry based on the density functional theory data with a particular focus on N2 formation kinetics and its interactions with polymer-associated radicals formed during the carbonization process. Then, using this improved force field, we performed atomistic-scale simulations of the initial stage of the carbonization process for the considered polymers. On the basis of our simulation data, the molecular pathways for the formation of low-molecular-weight gas species and all-carbon ring formation were determined. We also examined the possible alignment of the developed all-carbon 6-membered ring clusters, which is crucial for the further graphitic structure evolution.

Authors:

Kowalik, Malgorzata ^[1]; Ashraf, Chowdhury  ^[1];

• Search DOE PAGES for author "Ashraf, Chowdhury"
• Search DOE PAGES for ORCID "0000-0002-7375-2540"

Damirchi, Behzad ^[1]; Akbarian, Dooman ^[1]; Rajabpour, Siavash ^[1]; van Duin, Adri C. T.  ^[1]

• Search DOE PAGES for author "van Duin, Adri C. T."
• Search DOE PAGES for ORCID "0000-0002-3478-4945"

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+ Show Author Affiliations

1. Pennsylvania State Univ., University Park, PA (United States)

Publication Date:

Thu May 30 00:00:00 EDT 2019

Research Org.:

Univ. of Virginia, Charlottesville, VA (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:

1542911

Grant/Contract Number:  

EE0008195

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

Additional Journal Information:

Journal Volume: 123; Journal Issue: 25; Journal ID: ISSN 1520-6106

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY