Simulation study on molecular relaxation in ionomer melts

Relaxation behavior of ionomer molecule in melt state was investigated by B rownian simulation where motion of a bead-rod chain representing a linear i onomer molecule was calculated in two-dimension. Entanglement between the o ther molecules was assumed by a repulsive interaction between the chain and randomly located entanglement points. Effect of ion aggregates was also in troduced by an attractive interaction between the chain and attractive site s randomly dispersed in the simulation box. Relaxation spectra of end-to-en d motion and local bond orientation were obtained in equilibrium calculatio n for various chain lengths. The effect of the attractive site was discusse d on the spectrum. It was found that on the end-to-end motion, the longer t he chain was, the more discrepant the spectrum was, while on the bond orien tation, the shorter it was, the more discrepant the spectrum was. On the ba sis of these results, a picture to describe the experimental phenomena was proposed. (C) 2001 Elsevier Science Ltd. All rights reserved.