Analysis of structures of rubber-filler systems with combined scattering methods

Abstract

This review presents an analysis of the hierarchical structures formed in rubber-filler systems by using combined scattering methods. The combined scattering methods utilize various scattering methods and are powerful tools for the quantitative characterization of hierarchical structures over a wide range of length scales, ranging from nanometers to micrometers. Scattering theories for the analysis of the experimental scattering functions and their applications are described. Polymer Journal (2013) 45, 10-19; doi:10.1038/pj.2012.187; published online 21 November 2012Keywords: combined scattering methods; hierarchical structure; rubber-filler systems INTRODUCTION Rubber-filler systems have been widely used in industrial applications, such as for tires and belts so on. 1-6 The use of fillers in rubber compounds reinforces the rubber material and improves the barrier properties. There are several important factors for controlling the efficiency of rubber reinforcement by fillers. The dispersion of filler particles in the rubber matrix is one of the most important factors in this process. Typically, following the use of conventional compounding processes, the fillers are not dispersed homogeneously and form hierarchical structures within the rubber matrices. For example, in rubber-carbon black (CB) systems, the CB primary particles are not distributed independently but coalesce into aggregates, which are indestructible units of CB, during conventional compounding processes. 2 The aggregates of CB, which are called aggregates or agglomerates, can also lead to the formation of hierarchical structures, which consist of higher levels of ordered structure. 2 It is believed that the hierarchical structures affect the efficiency of filler reinforcement. Other rubber-filler systems also form hierarchical structures; furthermore, the characteristic lengths and morphologies of each level of ordered structure, such as agglomerates, vary with the specific combination of rubber and filler used in the system in addition to the compounding processes. To analyze the hierarchical structure, scattering techniques are one of useful techniques. In scattering experiments, we investigated the angular dependence of the scattered intensities induced by the incident beam hitting samples. Although the interpretation of the scattering intensities is complicated, nonetheless, scattering techniques are suitable for obtaining the statistical features of rubber-filler systems. However, the length scales of the hierarchical structures can extend from nanometers to micrometers, which prevents the characterization

Nanoparticle self-assembly: from interactions in suspension to polymer nanocomposites

“…(4) to polymer nanocomposites of industrial relevance. In its unified form proposed by Beaucage,36,165 it can be applied to multi-level structures, of different fractal dimension, and a finite size can be attributed via a Guinier expression to each level, see for instance 166,167 . Recently, a pseudo-thermodynamic analysis has been proposed by Jin et al, 168 based on the second virial coefficient expressing particle or aggregate interactions, see also 130 for the 'real' thermodynamic analysis.…”

Recent developments in polymer applications of synchrotron small‐angle X‐ray scattering

“… USAXS is required to reveal the hierarchical structure in the wide q ‐range . Also, combined scattering measurements of SAXS with small‐angle neutron scattering (SANS) have been shown to be powerful tools for characterizing the hierarchical structure more precisely . SAXS and SANS complementary studies have also been applied for structure analyses of cured phenolic resins …”

Epoxy Resin Nanocomposites: The Influence of Interface Modification on the Dispersion Structure—A Small-Angle-X-ray-Scattering Study

“…A difficulty of SAXS is, however, that numerical fitting of SAXS intensities with model functions is required. Different approaches are frequently used, such as the polydispersity index, if global scattering functions are used [31], or the Percus-Yevick approximation, which was extended for polydisperse particles by the decoupling or the local monodisperse approximation, see [32,33] for an overview. In the presented study, for a weakly aggregated system, the simple Percus-Yevick approximation was sufficient (as described in chapter 2).…”