Plasticity Mechanism for Glassy Polymers: Computer Simulation Picture

Reduced Plastic Dilatancy in Polymer Glasses

“…Argon et al, found that plastic relaxation was induced by repeatable nucleation of shear transformations that leads to dilatancy in polypropylene [18] while the opposite behavior was observed in polycarbonate. [19] Although there have been extensive studies on mechanical behaviors of glassy polymers under plastic deformation via molecular dynamics simulations, [20][21][22][23][24][25] and a few reviews, [7,26,27] the quantitative relationships between deformation dilatancy and plastic relaxation events are yet to be fully understood.…”

“…The method of molecular simulations is well established and it is an indispensable tool for various investigations in nowadays. [7,20,[30][31][32] For the present study, we deal with seven distinct alkane glasses as listed in Table 1. The molecular structures were created using a method proposed by Müller et al [33] It essentially consists of a heuristic search algorithm in the space of torsion angle that automatically delivers correct conformational statistics of the chains and maintain rotational-isomericstate probabilities.…”

“…Our results agree with previously reported dilatancy of deformed glassy polymers. [7,20,35] Take C5 as an example. The density decreases continuously between the individual relaxation events, followed by a sudden increase during the relaxation event.…”

“…Among these materials, the plastic deformation of alkane glasses draws our special interests because it is of great importance in solving problems related to fracture mechanics and plasticity. [5][6][7]…”

“…In a typical stress–strain response of a glassy material, stress initially increases, drops after yielding, and increases again due to strain hardening. [ 7 ] The discontinuities usually suggest plastic relaxation events. Highly localized plastic shear zones have been widely reported.…”