Mechanical characterisation of anisotropic stress softening in carbon black filled rubber

Abstract

The deformation induced stress softening strongly influences the material behaviour of the filled rubber and is a very complex issue. For the description of the anisotropic Mullins effect, there is still a lack of suitable experimental data. For this purpose, experiments with carbon black filled chloroprene rubber (CR) were carried out using multiple load steps. After repeated stretching in the same direction, a subsequent first loading in any other direction is characterised by a different stress-strain behaviour compared to the stabilised curve of the previous load. In order to emphasise the influence of the secondary loading direction on the material behaviour during that loading process, characteristic values are defined.

Anisotropic properties of elastomeric nanocomposites based on natural rubber and sp2 carbon allotropes

“…Owing to this feature, the particles may present a preferential orientation in the elastomeric matrix and, as a consequence, the composite may show anisotropic properties, that means directionally dependent properties. Anisotropic properties in elastomeric matrices may be caused by several reasons: i) orientation of the polymer chains; ii) non homogeneous filler distribution, even with ideally perfectly spherical particles; iii) stress softening caused by a repeated stretching (Mullins effect) in one direction [18][19][20][21]; iv) preferential orientation of anisotropic filler particles [22,23]. Preferential orientation and alignment of nanoparticles is sought to fully exploit their influence along specific directions, as for example in electronical applications (e.g.…”

Mechanism analysis on the increased stress softening of Mullins effect for rubber matrix composites

“…Some methodologies were also developed based on the finite element method to investigate the influence of physical interactions [9, 10]. The mechanism was further investigated by focusing on filler network interactions [11] and molecular chain disentanglement view [12]. Whereas, limited literature is currently available to find a definite reinforcement mechanism for the softened stress of Mullins effects.…”