Effect of Reversible Addition-Fragmentation Transfer Emulsion Styrene Butadiene Rubber (RAFT ESBR) on the Properties of Carbon Black-Filled Compounds.

Kiwon Hwang,Hyunsung Mun,Wonho Kim

doi:10.3390/polym12040933

Kiwon Hwang, Hyunsung Mun + Show 1 more

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https://doi.org/10.3390/polym12040933

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Journal: Polymers	Publication Date: Apr 17, 2020
Citations: 6	License type: CC BY 4.0

Affiliation: Pusan National University

Abstract

Tread is an important component that directly affects the performance of passenger car radial (PCR) tires. Styrene-butadiene rubber (SBR) is mainly used for tire tread and it includes solution styrene-butadiene rubber (SSBR) and emulsion styrene-butadiene rubber (ESBR). Although SSBR is mainly used, the manufacturing process for SSBR is more challenging than ESBR, which is environmentally friendly, but has the disadvantage of a broad molecular weight distribution. To overcome this, a reversible addition-fragmentation radical transfer (RAFT) polymerization technique is used in ESBR polymerization. An environmentally friendly RAFT ESBR with a narrow dispersity can be polymerized. Here, carbon black-filled compounds were manufactured while using RAFT ESBR, and their properties were compared to ESBR. The analysis showed a low crosslink density of RAFT ESBR, due to the high polysulfide crosslink structure. We manufactured a carbon black-filled compound with the same crosslink density and structure as the ESBR carbon black-filled compound, and the effect of the dispersity of the base polymer was investigated. RAFT ESBR showed 9% better abrasion resistance and 29% better fuel efficiency than ESBR, according to the analysis of the data. The narrow dispersity can reduce energy loss and positively influence the abrasion resistance and fuel efficiency.

Highlights

Tires have a complex structure that consists of more than 10 components, such as tread, belts, carcass, sidewall, and inner liner, etc., among which treads are used to directly affect tire performance.The rubber compound must satisfy fuel efficiency, traction performance, and abrasion resistance, etc., simultaneously
The analysis showed a low crosslink density of RAFT emulsion styrene-butadiene rubber (ESBR), due to the high polysulfide crosslink structure
A carbon black-filled compound was manufactured while using RAFT ESBR and ESBR, and our experiment confirmed that RAFT ESBR had a similar abrasion performance and excellent fuel efficiency characteristics when compared to that of ESBR, despite its lower crosslink density

Summary

Introduction

The rubber compound must satisfy fuel efficiency (rolling resistance), traction performance, and abrasion resistance, etc., simultaneously. Among these properties, traction performance can be used to determine the driving safety, and tire treads directly contacting with the road surfaces have a great influence [1,2,3]. Several research studies have focused on applying styrene-butadiene rubber (SBR), which has excellent traction ability, to the tire tread rubber compound for passenger car radials (PCRs) [4,5,6]. SBR is classified into emulsion styrene-butadiene rubber (ESBR) and solution styrene-butadiene rubber (SSBR), depending on the polymerization method. The polymerization of ESBR uses water as a solvent and SSBR uses an organic solvent, and they are polymerized by different mechanisms

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