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

Alexander Konstantinovich Sokolov,Alexander L’Vovich Svistkov,Oleg Konstantinovich Garishin

doi:10.1186/s40759-018-0040-x

Alexander Konstantinovich Sokolov, Alexander L’Vovich Svistkov + Show 1 more

Open Access

https://doi.org/10.1186/s40759-018-0040-x

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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.

Highlights

Elastomeric nanocomposites contains a highly elastic rubber matrix, where rigid grain nanoparticles or aggregates of nanoparticles are dispersed
Many researchers associate an increase in the strength of the material with either specific processes occurring near the filler particles or with the features of the movement of the macro-fracture in the filled elastomeric material
We drew attention to the fact that the increase in the strength of elastomers can be even in the case when the filler particles have micron dimensions. This phenomenon cannot be explained with the help of hypotheses about the important role of the layers with special properties near the filler particles and specific processes in the polymer network near the surface of the filler particles

Summary

Introduction

Elastomeric nanocomposites contains a highly elastic rubber matrix, where rigid grain nanoparticles or aggregates of nanoparticles are dispersed. The reasons for such improvement of their mechanical characteristics are still the subject of discussions among materials experts. Since the beginning of the 20-th century, it has been well established that the reinforcement of rubbers with carbon black (20–30% by volume) significantly improves their operational characteristics. Such materials possess enhanced rigidity; their tensile strength and ultimate strains increase by 5–15 times and 2–4 times, respectively. Intensive study of the mechanical properties of elastomeric nanocomposites in relation to the type of

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