During the synthesis of polyethylene using supported Ziegler–Natta catalysts, inert alkanes are crucial in improving heat and mass transfer. Employing molecular dynamics simulation, we investigate the influences of inert alkanes on in situ polymerization and crystallization of polyethylene. In the growth stage, the degree of polymerization undergoes an increase–decrease alteration with respect to the length of the inert alkanes. The coupling between nascent polyethylene and inert alkanes not only triggers this result but also impacts the subsequent process significantly. In the crystallization stage, inert alkanes with different types demonstrate a complicated role in modulating nucleation induction time, containing a novel facilitate-inhibit-facilitate mechanism. The stem length in the crystal region is elongated by inert alkanes, thereby obviously enhancing crystallinity. Furthermore, there are great differences in the effects of the types and concentrations of the inert alkanes. Our work reveals the intrinsic connection between the growth and crystallization behaviors and clarifies the regulatory function of inert alkanes.
Gong et al. (Tue,) studied this question.