T. Roths et al., Determination of the relaxation time spectrum from dynamic moduli using anedge preserving regularization method, RHEOL ACT, 39(2), 2000, pp. 163-173
For the numerical determination of a continuous relaxation time spectrum fr
om rheological data so-called regularization methods are necessary. The reg
ularization method based on Tikhonov regularization and commonly used in rh
eology assumes the relaxation time spectrum to be smooth. Accordingly, this
method is not able to properly resolve spectra containing edges or at leas
t large curvatures as proposed in the literature. In order to reconstruct s
uch spectra a novel edge preserving regularization (EPR) method was develop
ed which extends the properties of the commonly used method. In order to de
monstrate the efficiency of EPR it is compared with the commonly used regul
arization method by means of simulated and experimental data. This reveals
that EPR is able to prove whether or not the theoretically predicted edge c
ontaining spectra for high-molecular-weight, monodisperse polymers are comp
atible with experimental data.