A Laplace transform method for molecular mass distribution calculation from rheometric data

Abstract

Polydisperse linear polymer melts can be microscopically described by the tube model and fractal reptation dynamics, while on the macroscopic side the generalized Maxwell model is capable of correctly displaying most of the rheological behavior. In this paper, a Laplace transform method is derived and different macroscopic starting points for molecular mass distribution calculation are compared to a classical light scattering evaluation. The underlying assumptions comprise the modern understanding on polymer dynamics in entangled systems but can be stated in a mathematically generalized way. The resulting method is very easy to use due to its mathematical structure and it is capable of calculating multimodal molecular mass distributions of linear polymer melts.

Investigation on Molecular Structures of Electron-Beam-Irradiated Low-Density Polyethylene by Rheology Measurements

“…Several representations such as vGp plots and the plots of |η* (ω) | versus |G* (ω) | of all specimens were plotted according to SAOS data for better comparison. The molecular weight distributions and the weighted relaxation spectrum were determined using the Laplace transform 46 and the edge preserving regulation method 47 by the software Rheoplus from SAOS data, respectively.…”