Common Origin of Filler Network Related Contributions to Reinforcement and Dissipation in Rubber Composites

Abstract

A comparative study focusing on the visco–elastic properties of two series of carbon black filled composites with natural rubber (NR) and its blends with butadiene rubber (NR-BR) as matrices is reported. Strain sweeps at different temperatures are performed. Filler network-related contributions to reinforcement (ΔG′) are quantified by the classical Kraus equation while a modified Kraus equation is used to quantify different contributions to dissipation (ΔGD″, ΔGF″). Results indicate that the filler network is visco-elastic in nature and that it is causing a major part of the composite dissipation at small and intermediate strain amplitudes. The temperature dependence of filler network-related reinforcement and dissipation contributions is found to depend significantly on the rubber matrix composition. We propose that this is due to differences in the chemical composition of the glassy rubber bridges connecting filler particles since the filler network topology is seemingly not significantly influenced by the rubber matrix for a given filler content. The underlying physical picture explains effects in both dissipation and reinforcement. It predicts that these glassy rubber bridges will soften sequentially at temperatures much higher than the bulk Tg of the corresponding rubber. This is hypothetically due to rubber–filler interactions at interfaces resulting in an increased packing density in the glassy rubber related to the reduction of free volume. From a general perspective, this study provides deeper insights towards the molecular origin of reinforcement and dissipation in rubber composites.

The Anisotropic Self-Assembly Effect of Silica Hairy Nanoparticles: toward Sustainable Rubber Nanocomposites for Tyre Application

“…In fact, the V-SiO 2 -ST/SBR reference material shows a relatively at curve, with the lowest G' and Δ(G′(0.4%)-G′(10%)), as reported in Table 1. This indicates that bare SiO 2 -ST NPs are too aggregated to result in effective percolation of the ller network [13,42]. After silica functionalization with APTES, a strong increase of Payne effect occurs in V-SiO 2 -APTES/SBR NCs, while the reinforcement is still very low.…”

Towards the Development of a Strategy to Characterize and Model the Rheological Behavior of Filled, Uncured Rubber Compounds

“…Considerable research has been performed to characterize the dynamic mechanical properties of filled rubber compounds [17][18][19][20][21][22][23][24]. Addition of fillers leads to two contributions to the dynamic modulus of the material; a strain-dependent contribution and a strainindependent one.…”

Influence of the Polarity of the Plasticizer on the Mechanical Stability of the Filler Network by Simultaneous Mechanical and Dielectric Analysis

“…The internal space between the polymer chains is thus larger, and the free volume that allows the polymer chains to flow above their glass transition temperature increases [ 11 , 12 , 13 , 14 , 15 ]. This new conformation of the polymer chains, in turn, increases their mobility and enhances the filler distribution in the rubber mixture [ 16 , 17 , 18 , 19 , 20 , 21 ]. Above a certain percolation threshold, a filler network is formed that reinforces the rubber compounds and provides the necessary mechanical stability [ 16 , 17 ].…”

“…Above a certain percolation threshold, a filler network is formed that reinforces the rubber compounds and provides the necessary mechanical stability [ 16 , 17 ]. This applies to both the carbon-based fillers such as carbon black and silica [ 18 , 19 , 20 , 21 ]. Indeed, the plasticizer type strongly affects the mechanical properties of rubber products due to a shift in the glass transition temperature.…”