Uniaxial Tensile Creep Behavior of Epoxy-Based Polymer Using Molecular Simulation

Area of Science:

• Materials Science
• Polymer Science
• Computational Chemistry

Background:

• Understanding polymer creep is crucial for material design and performance prediction.
• Epoxy resins are widely used in various engineering applications, necessitating detailed characterization of their mechanical behavior.
• Molecular dynamics simulations offer a powerful tool to investigate material properties at an atomic level.

Purpose of the Study:

• To investigate the tensile creep behavior of epoxy-based polymers using all-atomic molecular dynamics simulations.
• To characterize the influence of temperature and stress levels on creep at a molecular level.
• To elucidate the evolution of free volume during the creep process and its relation to material failure.

Main Methods:

• All-atomic molecular dynamics simulations were employed to model epoxy-based polymers.
• The model's accuracy was validated by comparing simulation results with existing experimental and simulation data for properties like glass transition temperature and yield strength.
• Tensile creep tests were simulated at various temperatures and stress levels.

Main Results:

• The simulations accurately predicted the three classical stages of creep: primary, secondary, and tertiary.
• Creep rate was found to increase with rising temperature and stress levels.
• An increase in free volume proportion was observed during creep under high stress, correlating with weakened interatomic interactions and eventual failure.

Conclusions:

• Molecular dynamics simulations provide a reliable method for studying polymer creep behavior.
• Temperature and stress are critical factors governing the creep rate and failure mechanisms in epoxy resins.
• The evolution of free volume is a key indicator of structural changes and impending creep failure in polymers.