Prediction of dielectric constant and loss for some polypropylene - additive compounds

Résumé

In order to influence properties of polymers, several different type of additives can be used. Often, time consuming experimental work is needed to assess performance and suitable concentrations for the chosen polymer-additive system. Therefore, it is preferable to be able to estimate the properties by means of theoretical work. In the present work, dielectric constant and loss for polypropylene-meso-erythritol compounds were studied. The experimental results were compared to the theoretically assessed properties.
The compounds were prepared in three different concentrations. The obtained samples were pressed to plates which were characterized by dielectric response
measurements. The dielectric constants were also assessed using Maxwell-Garnett estimation and molecular dynamics simulations. For the later, both
atomistic model and a more coarse multiscale model were used. The Maxwell-Garnett equation gave a good estimation of the dielectric constant level whereas with the molecular dynamics simulations the obtained dielectric constant were in exact accordance to the measured values. With the molecular dynamics simulation, also the loss could be estimated. As expected, the atomistic model gave better correlation to the measured loss levels than the multi-scale model.