Molecular Dynamics Simulations on Crystallization of Polyethylene Copolymer with Precisely Controlled Branching

Molecular dynamics simulations of three kinds of linear low-density polyethylene (LLDPE) single-chain models with precisely controlled branching are performed. It is shown that the crystallinity of copolymers with branches shorter than C 10 H 21 decreases with increasing branch length, whereas for copolymers having branches longer than C 10 H 21, the crystallinity increases as the branch length increases. From the simulations of ethylene/vinyl chloride copolymer model, it is found that the crystallization process and driving force of LLDPE chain with polar comonomer are similar to those having a nonpolar comonomer, and the MD simulations of the models with branches of different flexibilities show that as branch flexibility decreases, the side-chain co-crystallization becomes more difficult, and the corresponding lamella is packed more loosely.