The Effect of Cross-Linking Type on EPDM Elastomer Dynamics and Mechanical Properties: A Molecular Dynamics...

Area of Science:

• Polymer Science
• Materials Science
• Computational Chemistry

Background:

• Ethylene-propylene-diene monomer (EPDM) cross-linking is crucial for its properties.
• Various cross-linking types exist, including main chain, monomer, and ether crosslinks.
• Understanding the impact of specific cross-linking structures on EPDM performance is essential.

Purpose of the Study:

• To investigate the contribution of different cross-linked structures to EPDM dynamics and mechanical properties.
• To compare the effects of eight distinct cross-linking types with uncross-linked EPDM.
• To elucidate the microscopic mechanisms governing EPDM performance based on cross-linking.

Main Methods:

• Molecular dynamic simulations were employed to model and analyze cross-linked EPDM.
• Eight types of cross-linked EPDMs were created by mixing with EPDM free chains in a 1:1 ratio.
• Simulations analyzed density, radius of gyration, free volume, mean square displacement, and stress-strain curves.

Main Results:

• Cross-linking generally improved mechanical characteristics, but relaxation inhibition varied.
• Diene monomer cross-linking at C9 increased free volume and diffusion ability.
• Ether cross-linking enhanced stiffness and hindered diffusion, while main chain cross-linking had opposing effects.

Conclusions:

• The study provides a detailed understanding of how specific cross-linking structures influence EPDM properties.
• Molecular dynamics simulations are effective in predicting material behavior based on structural variations.
• Tailoring cross-linking strategies can optimize EPDM for specific applications.