Evaluation of the influence of the polymer-filler interaction on compounds based on epoxidized elastomeric matrix and precipitated silica

Tatiana L A C Rocha,Robert H Schuster,Marly M Jacobi,Dimitrios Samios

doi:10.1590/s0104-14282006000200010

Abstract

The introduction of epoxy groups into the main chain of elastomers has emerged as a promising alternative, considering the monitoring of polymer-filler interaction leading to changes in the properties of vulcanizates. The epoxidation reaction (in situ) was chosen to modify elastomers, such as polybutadiene (BR) and copolymer of styrene- butadiene-rubber (SBR), because it is a simple, easily controlled reaction, even considering the small epoxidation degree. The modification degree of the polymeric chain was studied with FT-IR and 1 H-NMR. The shift of the Tg to high temperatures with the increase of the epoxy group in the polymer chain was monitored through differential scanning calorimetry (DSC). An analysis of the dynamic modulus of the material in relation to its dependence on the amplitude and temperature was carried out. The interaction between epoxidized elastomeric matrix and silica as filler was extremely improved, even in the presence of very low content of epoxy groups into the polymer chain.

Highlights

The higher reactivity of the butadiene -1,4-cis and –1,4trans units allows that the epoxidation reaction initiates first a modification into the main chain of the rubber and do not reacting with the vynil units
A statistical distribution of the epoxy groups results in a linear increase of the Tg as the epoxidation degree becomes higher. This result can be understanding by the reduction of the free energy translacional and rotational of the modified units, which is caused by the increase in the inter- and intramolecular interaction of the epoxy groups
Taking into account the vulcanized SBR-2(ep7), the in situ silanization of the precipitated silica leads to a small increase in the Gvalues, indicating that the polymer-filler interaction is masked by the modification of the silica surface activity

Summary

Introduction

The interaction between epoxidized elastomeric matrix and silica as filler was extremely improved, even in the presence of very low content of epoxy groups into the polymer chain. The non-linear dependency of G’ as a cation degree can improve the compatibility of specific function of deformation amplitued (Payne effect) can be polymers, and due to the strong polymer-filler explained due to the breakdown of the filler network interaction, leads to changes in the dynamical-mechanical considering a continuous increase in the periodic properties improving the wet-skid resistance[6].

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Conclusion