Molecular dynamics simulation of the effects of intermolecular interactions on the diffusion mechanism of 1,2,3-benzotriazole in low density polyethylene

It is of great significance to understand the diffusion rate of the volatile corrosion inhibitor (VCI) in the VCI films for corrosion inhibition. The diffusion behavior of 1,2,3-Benzotriazole (BTA) in pure low density polyethylene (LDPE) and VCIs/LDPE blends was investigated using molecular dynamics (MD) simulation at 310, 328 and 353 K temperatures. The temperature dependence and diffusion property of BTA in LDPE were revealed. Subsequently, the accuracy of the MD simulations was confirmed by comparing the diffusion coefficients obtained from the MD simulations with those obtained from the experiments. The fractional free volume, interaction energy between BTA and VCIs/LDPE, activation energy of BTA and the self-diffusion behavior of LDPE on the diffusion of BTA were explored, which illustrated the microscopic diffusion mechanism of BTA in LDPE. Results showed that the diffusion coefficients of BTA increased with increasing temperature, increasing free volume and the more flexible chain of LDPE, while the increase in the interaction energy between BTA and VCIs/LDPE slowed down the diffusion of BTA. It can be concluded that the increase in the interaction energy between BTA and the system, the activation energy of BTA and the formation of H-bonds due to the addition of other VCIs led to the decrease in the diffusion coefficients of BTA. The strong molecular interactions between BTA and VCIs were the main reason for the decrease in the BTA diffusion coefficients. Adjusting the formulation of the VCI films can provide new ideas for regulating the BTA diffusion rate, which is beneficial for extending the corrosion inhibition time of BTA.