Abstract
Predicting the macroscopic fracture energy of highly cross-linked glassy polymers from atomistic simulations is challenging due to the size of the process zone being large in these systems. Here, we present a scale-bridging approach that links atomistic molecular dynamics simulations to macroscopic fracture properties on the basis of a continuum fracture mechanics model for two different epoxy materials. Our approach reveals that the fracture energy of epoxy resins strongly depends on the functionality of epoxy resin and the component ratio between the curing agent (amine) and epoxide. The most intriguing part of our study is that we demonstrate that the fracture energy exhibits a maximum value within the range of conversion degrees considered (from 65% to 95%), which can be attributed to the combined effects of structural rigidity and postyield deformability. Our study provides physical insight into the molecular mechanisms that govern the fracture characteristics of epoxy resins and demonstrates the success of utilizing atomistic molecular simulations toward predicting macroscopic material properties.
Original language | English (US) |
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Pages (from-to) | 9474-9483 |
Number of pages | 10 |
Journal | Macromolecules |
Volume | 49 |
Issue number | 24 |
DOIs | |
State | Published - Dec 27 2016 |
Funding
The authors acknowledge support from the Ford Motor Company with funding from the U.S. Department of Energys Office of Energy Efficiency and Renewable Energy (EERE), under Award DE-EE0006867. W.X. gratefully acknowledges the support from the NIST-CHiMaD Postdoctoral Fellowship. M.A.B. and W.K.L. acknowledge the support by AFOSR (FA9550-14-1-0032) and by IRSES-MULTIFRAC. M.A.B. also acknowledges the support from the Portuguese National Science Foundation (SFRH/BD/85000/2012) and the Fulbright scholarship. In addition, the authors thank support from the Department of Civil and Environmental Engineering and Mechanical Engineering at Northwestern University. A supercomputing grant from Quest HPC System at Northwestern University is also acknowledged.
ASJC Scopus subject areas
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry