The Effect of Network Structure on Compressive Fatigue Behavior of Unfilled Styrene-Butadiene Rubber

Liu Yang,Kaikai Liu,Aihua Du

doi:10.1155/2020/6729754

Abstract

The effect of network structure on dynamic compressive fatigue behavior and static compressive mechanical properties of styrene-butadiene rubber (SBR) were investigated. A series of SBR compounds with different amounts of sulfur and dicumyl peroxide (DCP) were prepared, and their crosslinking densities were calculated using the Flory–Rehner equation. Compressive fatigue resistance and creep behavior of the vulcanizates were performed on a mechanical testing and simulation (MTS) machine. The fatigue damage surface of SBR vulcanizates before and after a dynamic compressive fatigue test was observed with a scanning electron microscopy (SEM). The results suggested that the surface of the samples was badly damaged as the number of compressive cycles increased. By comparison, compressive fatigue caused less surface damage to sulfur-cured SBR than to peroxide-cured SBR. The peroxide-cured SBR samples showed higher energy dissipation than sulfur-cured SBR during cyclic compression. The peroxide-cured SBR showed lower creep strain and compression set than the sulfur-cured SBR. The -Sx- linkages provided by the sulfur curing system allow dynamic compressive deformation but suffer from poor static compressive resistance. However, the carbon-carbon linkages from DCP are irreversible and provide higher resistance to static compressive stress, but they do not show obvious dynamic compressive fatigue resistance.

Highlights

Rubber materials are widely used in industrial fields because of their high elasticity and excellent damping properties [1, 2]
Our work focuses on styrene-butadiene rubber (SBR) composites cured by peroxide-cured systems and sulfur systems to investigate the effect of network structure on the compressive fatigue behavior of unfilled styrene-butadiene rubber. e compressive fatigue behavior of unfilled styrenebutadiene rubber (SBR) in the dynamic conditions was correlated with the polymer crosslink network structure. e dynamic and static compressive fatigue behavior was investigated by characterizing their hysteresis loops, dissipated energy, S-N curves, damage surface morphology, compression set, and creep behavior
Concentric circles of different colors were drawn on the surface of the samples before the cyclic compression test. e experimental results indicate that the compressive fatigue behavior is significantly affected by the type of linkage. e surface damage of the two samples is more serious as the number of compressive cycles increases

Summary

Introduction

Rubber materials are widely used in industrial fields because of their high elasticity and excellent damping properties [1, 2]. Fatigue failures that are common in rubber components remain a key issue Rubber components, such as seals, tires, and automotive mounts, are usually subjected to static or dynamic compressive loading environments in service life. Only several studies study the fatigue behaviors of SBR under compression loading conditions with different crosslink network structures [16,17,18]. Fu et al [23] investigated the influence of the network structure on the mechanical properties and fatigue life of natural rubber. Our work focuses on styrene-butadiene rubber (SBR) composites cured by peroxide-cured systems and sulfur systems to investigate the effect of network structure on the compressive fatigue behavior of unfilled styrene-butadiene rubber. E compressive fatigue behavior of unfilled SBR in the dynamic conditions was correlated with the polymer crosslink network structure. We attempted to obtain a better understanding of the influence of network structure on the compressive fatigue behavior of unfilled SBR vulcanizates

Experimental

Results and Discussion

Conclusions