Bound ("Glassy") Rubber as a Free Radical Cross-linked Rubber Layer on a Carbon Black.

Alexey Kondyurin,Anastasia Eliseeva,Alexander Svistkov

doi:10.3390/ma11101992

Abstract

A model of rubber with a cross-linked rubber layer on a carbon black filler has been proposed. The cross-links are the result of free radical reactions generated by carbon atoms with unpaired electrons at the edge of graphitic sheets in a carbon black filler. The experimental study of the cross-linking reactions in polyisoprene was done on a flat carbonized surface after ion beam implantation. The cross-linking process in the polyisoprene macromolecules between two particles was simulated. The model with a cross-linked rubber layer on a carbon filler as a “glassy layer” explains the mechanical properties of the rubber materials.

Highlights

Rubber materials are widely used in modern industrial processes, devices, and machines: from tires for Formula 1 racing cars and thermoprotecting coating in solid rocket engines up to agriculture irrigation systems and elements of clothes [1,2,3,4,5,6]
The same strength of the rubber with the carbon black was observed for artificial elastomers such as polybutadiene, polyisoprene, butyl rubber, styrene–butadiene rubber (SBR), ethylene–propylene rubber (EPR) and ethylene–propylene–diene rubber (EPDM)
The carbon black that was used in rubbers contains a mixture of carbon phases of sp2 and sp3 hybridizations with different sizes

Summary

Introduction

Rubber materials are widely used in modern industrial processes, devices, and machines: from tires for Formula 1 racing cars and thermoprotecting coating in solid rocket engines up to agriculture irrigation systems and elements of clothes [1,2,3,4,5,6]. The mechanical properties of the rubber materials are not well understood [7]. A rubber is a heterogenic material with high mechanical strength and deformability. The rubber contains an elastic matrix with embedded solid nanoparticles. The interaction between the elastic matrix and the particles play a key role in the mechanical properties of the rubber. From the beginning of the 20th century, the natural gum is filled with carbon black particles, which increased the tensile strength by 5–15 times and deformation when broken two to four times. The same strength of the rubber with the carbon black was observed for artificial elastomers such as polybutadiene, polyisoprene, butyl rubber, styrene–butadiene rubber (SBR), ethylene–propylene rubber (EPR) and ethylene–propylene–diene rubber (EPDM)

Methods

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Discussion

Conclusion