Mechanical behavior and modification of poly-ether-ether-ketone using a molecular dynamics method

Abstract

The molecular dynamics method was employed to predict the tensile mechanical properties of polyether-ether-ketone (PEEK). Non-equilibrium tensile simulation with anisotropic pressure control was employed to obtain the stress-strain curve of PEEK, and to calculate the elastic modulus, yield strength and other mechanical properties. The influences of the strain rate and temperature on the mechanical properties, free volume, mean square radius of gyration (Rg), and energy for PEEK were investigated to explain the relationship between PEEK chain characteristics and macro mechanical properties. The results indicate that the elastic modulus and yield strength of PEEK significantly increase with the increase of strain rate, and significantly decrease with the increase of temperature. In the elastic and yield stage, free volume linearly increases, and Rg of PEEK chains remains steady, and the non-bonded energy results in the amount of the total potential energy increase. The interchain non-bonded interactions play a dominant role in the elastic and yield performance. Therefore, the amino modification strategy is investigated to improve the mechanical property of PEEK. It is found that the elastic modulus and yield strength of PEEK modified by amino are increased by 21% and 34% respectively than that of PEEK.

Keywords

• poly-ether-ether-ketone
• molecular dynamics
• mechanical property
• non-bonded interaction
• amino functionalization