The filler–rubber interface in styrene butadiene nanocomposites with anisotropic silica particles: morphology and dynamic properties. Issue 20 (22nd April 2015)

• Record Type: Journal Article
• Authors: Tadiello, L.; D'Arienzo, M.; Di Credico, B.; Hanel, T.; Matejka, L.; Mauri, M.; Morazzoni, F.; Simonutti, R.; Spirkova, M.; Scotti, R.
• Is Part Of: Soft matter. Volume 11:Issue 20(2015)
• Page Start: 4022
• Page End: 4033
• Publication Date: 2015-04-22
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c5sm00536a
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : In SBR–silica nanocomposites the amount of immobilized rubber is higher with rod-like filler particles which self-align compared to spherical ones, improving rubber reinforcement. Abstract : Silica–styrene butadiene rubber (SBR) nanocomposites were prepared by using shape-controlled spherical and rod-like silica nanoparticles (NPs) with different aspect ratios (AR = 1–5), obtained by a sol–gel route assisted by a structure directing agent. The nanocomposites were used as models to study the influence of the particle shape on the formation of nanoscale immobilized rubber at the silica-rubber interface and its effect on the dynamic-mechanical behavior. TEM and AFM tapping mode analyses of nanocomposites demonstrated that the silica particles are surrounded by a rubber layer immobilized at the particle surface. The spherical filler showed small contact zones between neighboring particles in contact with thin rubber layers, while anisotropic particles (AR > 2) formed domains of rods preferentially aligned along the main axis. A detailed analysis of the polymer chain mobility by different time domain nuclear magnetic resonance (TD-NMR) techniques evidenced a population of rigid rubber chains surrounding particles, whose amount increases with the particle anisotropy, even in the absence of significant differences in terms of chemical crosslinking. Dynamic measurements demonstrate that rod-like particles induce stronger reinforcement of rubber, increasing with the AR. This was related to the self-alignment of the anisotropic silica particles in domains able to immobilize rubber.