Vulcanizate Structures of SBR Compounds with Silica and Carbon Black Binary Filler Systems at Different Curing Temperatures.

Il Jin Kim,Byungkyu Ahn,Wonho Kim,Donghyuk Kim,Hak Joo Kim,Hyung Jae Lee

doi:10.3390/polym12102343

Abstract

The tire industry has shown an increasing demand for the reduction in rolling resistance. Efforts have been made to improve the viscoelastic properties of tire compounds and reduce the weight of tires through optimization of the vulcanizate structure, which has become extremely complex. In this study, vulcanizates using carbon black and silica as binary fillers were prepared at various curing temperatures. Vulcanizate structures with respect to curing temperature were classified according to the chemical crosslink density by sulfur, carbon black bound rubber (i.e., physical crosslink due to carbon black), and silica-silane–rubber network. All properties exhibited a decreasing trend under the application of high curing temperatures, and the decrease in the crosslink density per unit content of filler with an increase in curing temperature was shown to be greater in carbon black than in silica. Mechanical and viscoelastic properties were also measured to evaluate the impact that the compound variates have on tire tread performance. These results serve as a guideline for determining the content and filler type and for setting the cure condition during the design of actual compound formulations to increase the crosslink density of rubber while retaining the necessary mechanical and viscoelastic properties for practical application.

Highlights

The performance and physical properties of various rubber products are primarily determined by the type of rubber, reinforcing fillers, and the type and content of accelerators such as sulfur.In addition, the processing and curing conditions of rubber lead to changes in the performance and properties of rubber products
Vulcanizate structures at different cure temperatures were categorized into carbon black bound rubber (CBBR), silica-silane–rubber network (SSRN), and chemical crosslink density by sulfur (CCDS) and quantified
The analysis of the vulcanizate structures revealed that CBBR, SSRN, and CCDS all showed decreasing trends with increasing cure temperature, and CBBR resulted in the largest rate of decrease

Summary

Introduction

The performance and physical properties of various rubber products are primarily determined by the type of rubber, reinforcing fillers, and the type and content of accelerators such as sulfur.In addition, the processing and curing conditions of rubber lead to changes in the performance and properties of rubber products. The performance and physical properties of various rubber products are primarily determined by the type of rubber, reinforcing fillers, and the type and content of accelerators such as sulfur. Oenslager discovered the accelerated reaction of sulfur with rubber due to aniline, which shortened the cure time, and continuous development of accelerators led to the development of guanidine [1]. Research on reducing the cure time of rubber has been actively pursued for technological development in response to a greater demand for productivity and diversification of manufacturing. It is generally known that a higher cure temperature has the effect of shortening the cure time, but an increase in the cure temperature results in negative effects, such as a decrease of the mechanical properties and scorch safety, such that selecting the appropriate cure temperature is of vital importance [3,4]

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