Block chemistry for accurate modeling of epoxy resins

Livraghi, Mattia; Pahi, Sampanna; Nowakowski, Piotr; Smith, David M.; Wick, Christian Rainer; Smith, Ana-Sunčana (2023) Block chemistry for accurate modeling of epoxy resins. The Journal of Physical Chemistry B, 127 (35). pp. 7648-7662. ISSN 1520-6106

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Abstract

Accurate molecular modeling of the physical and chemical behavior of highly cross-linked epoxy resins at the atomistic scale is important for the design of new property-optimized materials. However, a systematic approach to parametrizing and characterizing these systems in molecular dynamics is missing. We therefore present a unified scheme to derive atomic charges for amine-based epoxy resins, in agreement with the AMBER force field, based on defining reactive fragments─blocks─building the network. The approach is applicable to all stages of curing from pure liquid to gelation to fully cured glass. We utilize this approach to study DGEBA/DDS epoxy systems, incorporating dynamic topology changes into atomistic molecular dynamics simulations of the curing reaction with 127,000 atoms. We study size effects in our simulations and predict the gel point utilizing a rigorous percolation theory to recover accurately the experimental data. Furthermore, we observe excellent agreement between the estimated and the experimentally determined glass transition temperatures as a function of curing rate. Finally, we demonstrate the quality of our model by the prediction of the elastic modulus based on uniaxial tensile tests. The presented scheme paves the way for a broadly consistent approach for modeling and characterizing all amine-based epoxy resins.

Item Type:	Article
Uncontrolled Keywords:	epoxy resins
Subjects:	NATURAL SCIENCES > Chemistry > Physical Chemistry
Divisions:	Division of Physical Chemistry
Depositing User:	Piotr Nowakowski
Date Deposited:	01 Mar 2024 13:57
URI:	http://fulir.irb.hr/id/eprint/8699
DOI:	10.1021/acs.jpcb.3c04724

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