A new hypothesis on the mechanism of nano-filled elastomers reinforcement

Abstract

Incorporation of active fillers to rubber markedly improves the strength properties and deformation characteristics of such materials. One possible explanation of this phenomenon is suggested in this work. It is based on the fact that for large deformations the binder (high-elastic, cross-linked elastomer) in the gaps between the filler particles (carbon black) is in a state close to the uniaxial extension. The greater part of polymer molecular chains are oriented along the loading axis in this situation. Therefore it can be assumed that the material in this state has a higher strength compared to other ones at the same intensity of deformation. In this paper, a new strength criterion is proposed, and a few examples are given to illustrate its possible use. It is shown that microscopic ruptures that occur during materials deformation happen not in the space between filler particles but at some distance around from it without breaking particle “interactions” through these gaps. The verification of this approach in modeling the stretching of a sample from an unfilled elastomer showed that in this case it works in full accordance with the classical strength criteria, where the presence in the material of a small defect (microscopic incision) leads to the appearance and catastrophic growth of the macrocrack.