A combined experimental and molecular dynamics simulation study on the miscibility of Eucommia ulmoides gum with butadiene rubber

Abstract

The miscibility of Eucommia ulmoides gum (EUG) blended with butadiene rubber (BR) was investigated by atomistic molecular dynamics (MD), mesoscopic dynamics (MesoDyn) simulations and melt-mixing in an open two-roll mill at 80°C and 50 rpm. Seven EUG/BR blends (with weight ratios of 80/20, 70/30, 50/50, 30/70, and 20/80), as well as pure EUG and BR, were examined. Flory Huggins parameters, phase diagrams, the radial distribution function, free energy, and order parameters were computed for different blends using atomistic simulations to predict blend miscibility. The simulation results showed that all the EUG/BR blends have good miscibility. However, the mechanical properties of the vulcanized EUG/BR blends improved with the addition of EUG into BR matrix, and scanning electron microscopy (SEM) micrographs of the fractured surface had also revealed that the phase separation was not found, but which indicated EUG/BR had good miscibility. All the simulation results are qualitatively consistent with the experimental results, which demonstrates that the modeling strategies in this study may provide a powerful tool for predicting the miscibility and mesoscopic morphology of polymer blends.

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