Molecular Simulations Of Strain-induced Crystallization In Binary Mixtures Of Short-chain And Long-chain Polymers

We performed dynamic Monte Carlo simulations of strain-induced isothermal crystallization in the homogeneous binary mixtures of short-chain and long-chain polymers of the same species. We separated our work into two parts.In the first part, both long-chain and short-chain polymers were restricted at their corresponding plates. We observed that crystal nucleation is enhanced by the short-chain component at a high temperature and a high strain rate, corresponding to the situation of strain-hardening of rubbers. In addition, both components join into the nucleation process. We attributed its microscopic mechanism to the sporadic distributions of highly stretched short segments, which are rich in the short-chain component and appear as responsible for the initiation of crystal nucleation.In the second part, only long-chain polymers were restricted at their corresponding plates, and the short-chain polymers were relaxed upon stretching. Although the highly stretched segments on the long chains induce the intermolecular crystal nucleation, the relaxed short chains still join together in the crystal nucleation process. The observation facilitates our better understanding on the microscopic mechanism of flow-induced crystal nucleation in the polydisperse polymer systems.