Molecular dynamics and dissipative particle dynamics simulations for prediction of miscibility in polyethylene terephthalate/polylactide blends

Abstract

The miscibility of polyethylene terephthalate (PET)/polylactide (PLA) blends is studied through atomistic molecular dynamics (MD) and mesoscale dissipative particle dynamics (DPD) simulation. Five PET/PLA blends (with the weight ratio at 90/10, 70/30, 50/50, 30/70 and 10/90) as well as pure PET and PLA are examined. The solubility parameter values obtained by using the MD simulation are in good agreement with the reference data. The Flory–Huggins parameters, χ, which are computed for different blends and determined from the cohesive energy densities, with the radial distribution functions g(r) of the inter-molecular atoms, suggest that PET is completely miscible with PLA over the entire composition range. This is further proved by the mesoscopic morphologies of PET/PLA blends. All the simulation results are qualitatively consistent with the experimental results, and demonstrate that the modelling strategies in this study may serve as a powerful tool for predicting miscibility and mesoscopic morphology of polymer blends.

Keywords:

• blend
• miscibility
• molecular simulation
• PET
• PLA

Acknowledgements

The authors are very grateful for the financial support from the National “973” Project, Shanxi Province Science Foundation for Youths, China (Grant No. 2010021023-5), and excellent Innovation Programme for graduate students of Shanxi Province and Youth Science Foundation of North University of China.