Journal article
Mechanical behavior of highly cross-linked polymer networks and its links to microscopic structure
Physical review. E, Statistical, nonlinear, and soft matter physics, v 79(6 Pt 1), pp 061802-061802
Jun 2009
PMID: 19658517
Abstract
Highly cross-linked polymer (HCP) networks are becoming increasingly important as high-performance adhesives and multifunctional composite materials. Because of their cross-linked molecular architectures, HCPs can be strong but brittle. One key goal in improving the performance of an HCP is to increase toughness without sacrificing strength. Using large scale molecular-dynamics simulation, we compare and characterize the mechanical behavior of two model HCPs under tensile deformation. In the first case, bond angles among any three connected monomers are unconstrained and in the second case we impose harmonic tetrahedral bond angle constraints. We perform a detailed microstructural analysis that establishes a unique correlation between macroscopic mechanical behavior and the microscopic structure of an HCP. While, in the unconstrained system, strain-hardening behavior is observed that is attributed to the formation of microvoids, the void growth is completely arrested in the constrained system and no strain hardening is observed. Moreover, after the initial strain-hardening phase, the unconstrained system displays the same stress-strain behavior as that of a constrained network. Strain hardening makes the unconstrained system ductile while it retains the same tensile strength as the constrained system. We suggest that bond angle flexibility of cross-linkers might be a possible means to control ductility in an HCP network at a constant cross-linker density. We have also studied the effect of temperature, strain rate, and intermonomer nonbonded interaction strength on the stress-strain behavior. Interestingly at a strong intermonomer nonbonded interaction strength, no strain hardening is observed even in the unconstrained system and fracture sets in at around 1% strain, similar to what is observed in an experimental system such as epoxy and vinyl-ester based thermosets. This indicates that strong nonbonded interactions play a key role in making an HCP strong but brittle.
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Details
- Title
- Mechanical behavior of highly cross-linked polymer networks and its links to microscopic structure
- Creators
- Debashish Mukherji - Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA. debashish.mukherji@drexel.eduCameron F Abrams
- Publication Details
- Physical review. E, Statistical, nonlinear, and soft matter physics, v 79(6 Pt 1), pp 061802-061802
- Publisher
- Cold Spring Harbor Press; United States
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Chemical and Biological Engineering
- Web of Science ID
- WOS:000267698700065
- Scopus ID
- 2-s2.0-67650928401
- Other Identifier
- 991014877983104721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Physics, Fluids & Plasmas
- Physics, Mathematical