Hierarchically Self-Organized Dissipative Structures of Filler Particles in Poly(styrene-ran-butadiene) Rubbers

Abstract

We elucidated the spatial distribution of filler particles in cross-linked poly­(styrene-ran-butadiene) rubbers (SBR) developed under a typical fillers/rubbers compounding process as one of dissipative structures formed under a stress field imposed on the given system. Two types of fillers and two types of SBR were used to prepare four kinds of the fillers/rubbers composites to investigate effects of specific polymer/filler interactions on the hierarchically self-organized dissipative structures under a given processing condition. The dispersion structures of the filler particles were explored by using the combined small-angle scattering (CSAS) method, which enables the exploration of the structures existing over the wide length scale ranging from ∼6 nm to ∼20 μm. The measured CSAS profiles were analyzed by using a newly developed scattering theory on fractal structures built up by the “cluster” as their lower cutoff objects. This cluster is composed of a few aggregates, defined as the fused primary filler particles, bound by the SBR chains. The scattering from the cluster having characteristic internal structures built up by the fillers and the SBR chains was theoretically formulated by generalizing the Debye–Bueche fluctuation theory for infinite space to the theory for a “confined space” relevant to the cluster size. The dispersion state of the fillers in SBR was clarified on the basis of hierarchical structures consisting of five structure levels as detailed in the text. More specifically, it has the following characteristics depending on the specific interactions: Small, compact clusters build up compact mass-fractal structures, while large, loose clusters build up open mass-fractal structures.

Decoupling the Contributions of ZnO and Silica in the Characterization of Industrially-Mixed Filled Rubbers by Combining Small Angle Neutron and X-Ray Scattering

“…Therefore, we infer that in the presence of silica, the processing conditions probably have a comparable effect on the de-agglomeration or destruction of the ZnO granulates. Besides this, the values found for the ZnO radius are comparable with the ones reported in the literature [22]. In other works, the size determination by means of other techniques for ZnO dispersed particles ranged from 300 to 500 Å as the result of the balance of fracture of aggregates and material resistance, i.e., intrinsic hardness in milling processes [32,33].…”

“…This interference impairs, therefore, a direct evaluation of the scattering response of the reinforcing fillers, which is the only component determining the performance of the rubber. The problem of the interference and also additional inhomogeneities have been discussed in the literature [5,6,14,[19][20][21][22]. Due to the difficulty in disentangling the contribution from the catalyst and the filler particles, the ZnO contribution was sometimes neglected or a simple weighted subtraction of a ZnO-containing background was applied as data correction.…”

“…Due to the difficulty in disentangling the contribution from the catalyst and the filler particles, the ZnO contribution was sometimes neglected or a simple weighted subtraction of a ZnO-containing background was applied as data correction. Recently, a more accurate correction was reported [22], based on different scattering techniques. The weighted subtraction assumed a priori an identical contribution of ZnO in filled and non-filled compounds.…”

On the Evidence of Thermodynamic Self-Organization during Fatigue: A Review

“…Some selective research works are in Refs. [ 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. Some of the applications of self-organized nanoparticles are the development of polymeric materials with improved properties in electromagnetic, catalytical, and optical fields.…”

“…Additionally, the use of rubber/nanoparticle composite in car tires having both the viscoelastic properties of soft rubbers and the hard characteristics of nanofillers particles is increasingly demanding. As an example, Hashimoto and co-workers investigated the process of self-organization and dissipative structures formation in polymer melts with different kinds of dispersed nanoparticles [ 61 , 62 , 63 , 64 ]. They used two types of fillers (silica and carbon black) and two types of cross-linked poly (styrene-ran-butadiene) rubbers (SBR) to prepare four kinds of the fillers/rubbers composites.…”