PLATEAU MODULUS IN THE LATERAL MOTION MODEL FOR MELT POLYMER DYNAMICS- A COMPUTER-SIMULATION

A numerical simulation model is considered to study the relaxation of polymer melts within the context of the lateral motion model. This mod el assumes that the chain motion is primarily lateral motion along the backbones of neighboring chains. It is unclear whether a plateau woul d be observed in the relaxation modulus, if this is the mechanism of t he chain dynamics. The simulation model considers the relaxation of a many-chain system. The beads of a given chain are paired with the bead s of other chains. The two beads in a pair are constrained to move in unison. The chains are also allowed to slide along the backbones of th e chains with which they have contacts through moves that interchange adjacent bead pairing. These moves mimic the types of motions present in the simplest form of the lateral motion model. The relaxing energy of this multichain system is found to display a pronounced plateau, de monstrating that models which are not based on a tube hypothesis can p roduce a plateau in the relaxation modulus.