Characterisation and Approval of FKM Polymers and Compounds with RPA – an Initial Experience Report

Abstract

For decades, measurement of the Mooney viscosity has been used for testing the viscosity of raw polymers and mixed stocks. The Mooney viscometer is commonly used on the shop floor alongside the rheometer. The relevance of the Mooney test for the processing of rubber compounds is limited and the use of a rubber process analyser (RPA) is a suitable alternative. The instrument is robust, easy to handle and therefore perfectly suitable for day-to-day use on the shop floor. High accuracy and repeatability of the measurement are further advantages. This article describes initial experiences with testing FKM raw polymers and compounds based on frequency and strain sweeps. Tests under high strain in particular demonstrate significant differences between polymers, which are not seen under normal test conditions (small amplitudes). In this way, rubber compounders and processors receive considerably more information about the viscoelastic properties of the raw polymers used and the compounds produced from them.