TY - JOUR
T1 - The effect of alkyl chain length on mechanical properties of fatty-acid-functionalized amidoamine-epoxy systems
AU - Srikanth, Arun
AU - Kinaci, Emre
AU - Vergara, John
AU - Palmese, Giuseppe
AU - Abrams, Cameron F.
N1 - Funding Information:
Funding from the U.S. Army Research Laboratory ( W911NF-13-2-0046 and W911NF-12-2-0022 ) is gratefully acknowledged. Simulations were performed in part on equipment in the Drexel University Research Computing Facility and in part thanks to the US DoD high-performance computing modernization program (HPCMP).
Publisher Copyright:
© 2018
PY - 2018/7
Y1 - 2018/7
N2 - The effects of pendant alkyl chain length n ranging from n=0 to n=10 in amidoamine crosslinkers on mechanical properties of epoxy thermosets are explored in this work. The glassy-state Young's modulus was estimated using non-equilibrium molecular dynamics (MD) simulations and compared with experiments. Both simulations and experiments showed that Young's modulus decreases with increase in n. Stress partitioning based on molecular interaction types showed that both Lennard-Jones and covalent bond interactions were responsible for this sensitivity, with Coulombic interactions playing no significant role. The dependence of Young's modulus on n was strain-rate dependent in the simulations, with moderate to high strain rates showing no sensitivity. A strong correlation was observed between Young's modulus from non-equilibrium MD and volume fraction of methylenes estimated from equilibrium MD. Poisson's ratios of all systems predicted from the simulations were insensitive to n, indicating a lack of anisotropy. The information revealed here on the roles of various intermolecular interactions on the mechanical properties of these thermosets could be useful for design of crosslinkers.
AB - The effects of pendant alkyl chain length n ranging from n=0 to n=10 in amidoamine crosslinkers on mechanical properties of epoxy thermosets are explored in this work. The glassy-state Young's modulus was estimated using non-equilibrium molecular dynamics (MD) simulations and compared with experiments. Both simulations and experiments showed that Young's modulus decreases with increase in n. Stress partitioning based on molecular interaction types showed that both Lennard-Jones and covalent bond interactions were responsible for this sensitivity, with Coulombic interactions playing no significant role. The dependence of Young's modulus on n was strain-rate dependent in the simulations, with moderate to high strain rates showing no sensitivity. A strong correlation was observed between Young's modulus from non-equilibrium MD and volume fraction of methylenes estimated from equilibrium MD. Poisson's ratios of all systems predicted from the simulations were insensitive to n, indicating a lack of anisotropy. The information revealed here on the roles of various intermolecular interactions on the mechanical properties of these thermosets could be useful for design of crosslinkers.
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U2 - 10.1016/j.commatsci.2018.03.073
DO - 10.1016/j.commatsci.2018.03.073
M3 - Article
AN - SCOPUS:85044577035
SN - 0927-0256
VL - 150
SP - 70
EP - 76
JO - Computational Materials Science
JF - Computational Materials Science
ER -