A multiscale model applied to ionic polymer stiffness prediction

Abstract

A multiscale modeling approach applied to the stiffness prediction of polymers with high cross-link density is discussed. The material of focus in this work is the ionic polymer Nafion®. The approach applies rotational isomeric state theory in combination with a Monte Carlo methodology to develop a simulation model for polymer chain conformation. From this a large number of end-to-end chain lengths between cross links are generated; the probability density function of these lengths is estimated with the most appropriate Johnson family method. This estimation is used in a Boltzmann statistical thermodynamics approach to the multiscale prediction of stiffness. This work addresses the importance of the simulated polymer chain length in the generation of stable predictions. The multiscale prediction is found to be physically reasonable; the approach has the potential of serving as a first-order prediction tool for properties that are experimentally difficult or impossible to measure.