Study On The Properties Of Graphite Filled Rubber Materials And Preparation Of Graphite/Rubber Nanocomposites

Graphite is a layered material possessing excellent lubrication property and high aspect ratio in an exfoliated state, and it is also one of the strongest materials per unit weight with unique functional properties, e.g. good electrical and thermal conductivities. In addition, graphite is very cheap compared to carbon nanotubes. In this paper, the influence of graphite particles size on the properties of NBR was firstly investigated, graphite/rubber nanocomposites were successfully fabricated through latex compounding technology, and the properties of graphite/rubber nanocomposites were systematically studied, mainly using NBR as matrix material.Firstly, four graphite powder fillers with different form and size were mixed through melt compounding with NBR at 20, 40 and 60phr of the filler loadings, and the obtained compounds were characterized by SEM, tensile test, friction and wear test. Through the SEM observation, it was found that the expanded graphite could not be broken down to small particles uniformly when blended with rubber on the twin-roller. In the tensile test, the graphite with the smallest size possessed the best reinforcement ability as expected. The tribological properties of the rubber were improved when adding more graphite. The largest graphite particles imparted the lowest friction coefficient of the composites among four fillers, but the sub-micrometer graphite provided the best wear property to NBR.Secondly, a facile latex approach has been adopted to finely incorporate graphite nanosheets into rubber matrix and achieve high performance elastomeric nanocomposites with both excellent mechanical properties and versatile functional properties. Scanning electron microscope, transmission electron microscope and X-ray diffraction experiments show that the nanostructures of the obtained nanocomposites are higher extent of exfoliation and intercalation of graphite in the NBR matrix. Mechanical and dynamic mechanical tests demonstrate that The NBR nanocomposites possess greatly increased modulus and strength, and desirable strong interface. Moreover, The NBR nanocomposites possess greatly improved wear resistance, better gas barrier property, and good electrical/thermal conductivity. These versatile functional properties make NBR/EG nanocomposites a new class of promising advanced materials.The unexpected self-crosslinking of graphite/elastomeric nanocomposites was discovered and proved through oscillating disc rheometer and equilibrium swelling experiment. Investigated by various polymer types, X-ray photoelectron spectroscopy, electron spin resonance and Fourier transform infrared spectroscopy, a radical initiation mechanism was put forward to explain the self crosslinking reaction.In the final part, graphite/xNBR and graphite/ACM composites were prepared via LCM and their structure and the mechanical properties were studied.