Styrene-Based Elastomer Composites with Functionalized Graphene Oxide and Silica Nanofiber Fillers: Mechanical and Thermal Conductivity Properties.

Jaehyeung Park,Jaswinder Sharma,David L Wood,David A Cullen,Jong K Keum,Georgios Polizos,Kyle W Monaghan,Andres M Rossy,Harry M Meyer

doi:10.3390/nano10091682

Abstract

The mechanical and thermal conductivity properties of two composite elastomers were studied. Styrene–butadiene rubber (SBR) filled with functionalized graphene oxide (GO) and silica nanofibers, and styrene–butadiene–styrene (SBS) block copolymers filled with graphene oxide. For the SBR composites, GO fillers with two different surface functionalities were synthesized (cysteamine and dodecylamine) and dispersed in the SBR using mechanical and liquid mixing techniques. The hydrophilic cysteamine-based GO fillers were dispersed in the SBR by mechanical mixing, whereas the hydrophobic dodecylamine-based GO fillers were dispersed in the SBR by liquid mixing. Silica nanofibers (SnFs) were fabricated by electrospinning a sol–gel precursor solution. The surface chemistry of the functionalized fillers was studied in detail. The properties of the composites and the synergistic improvements between the GO and SnFs are presented. For the SBS composites, GO fillers were dispersed in the SBS elastomer at several weight percent loadings using liquid mixing. Characterization of the filler material and the composite elastomers was performed using x-ray photoelectron spectroscopy, x-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, dynamic mechanical analysis, tensile testing, nanoindentation, thermal conductivity and abrasion testing.

Highlights

Composite elastomers are a very significant category of polymeric materials with numerous applications such as tire manufacturing, high-performance elastomers, gas barrier materials and advanced binders for energy storage devices [1,2,3,4,5,6,7]
Graphene oxide (GO) is one of the most promising filler materials that can potentially replace the carbon black and silica nanoparticles that are commonly been used in the fabrication of rubber composites [14,15]
The mechanical properties of the graphene oxide (GO) and Silica nanofibers (SnFs) composites were compared to an Styrene–butadiene rubber (SBR) composite that was filled with 9 wt.% non-functionalized silica nanoparticles (SBR/SnP)

Summary

Introduction

Composite elastomers are a very significant category of polymeric materials with numerous applications such as tire manufacturing, high-performance elastomers, gas barrier materials and advanced binders for energy storage devices [1,2,3,4,5,6,7]. Graphene oxide (GO) is one of the most promising filler materials that can potentially replace the carbon black and silica nanoparticles that are commonly been used in the fabrication of rubber composites [14,15]. Their planar structure, high surface area when exfoliated, and the possibility to tailor the surface functionality makes them unique fillers. The intrinsic hydrophilicity of the GO due to the high oxygen content and the hydrophilic nature of the sulfur groups make the exfoliation and dispersion of the GO in the hydrophobic SBR matrix more difficult. It is less robust than the crosslinked SBR, the addition of GO can provide additional benefits that are associated with the significant increase in the thermal conductivity

Experimental

SBR Composites

SBS Composites