Rapid Payne effect test - A novel method for study of strain-softening behavior of rubbers filled with various carbon blacks

Abstract

In the presented article, the strain-softening process in rubber compounds filled with carbon black is investigated. First people to observe this process were Fletcher and Gent in 1954. Later, Payne did an extensive investigation of the process thus the test is generally known as Payne effect test. Based on the measured data, so-called Payne softening can be calculated. The Payne softening is broadly considered as the measure of the strain-softening. In order to investigate strain-softening behavior of a filled rubber compound several strain amplitudes are imposed during a Payne effect test. In this article, a two-point (rapid) version of the test containing only two strain amplitudes is introduced and verified statistically. This test has shown that for the investigation of the filler network disintegration in filled rubbers primarily the large deformations are important, notwithstanding the strain history of a sample. Moreover, the softening characteristic is observed in 30% of the time of the original test. The new method is exemplified for a study of three different rubbers filled with various carbon blacks.