Experimental study on preparation and properties of carbon nanotubes-, graphene -natural rubber composites

Carbon nanotubes (CNTs-), graphene (GNs)-natural rubber (NR) composites were prepared by wet mixing process and dry mixing process, respectively. Thermal conductivity, 300% tensile stress, tear strength and elongation at break of the samples were measured experimentally. The effects of mixing process, carbon materials content and type on thermal properties and mechanical properties of composites were studied. The experimental results show that, the thermal conductivity of the mixed rubber, the 300% tensile stress and the tear strength of the vulcanizate all increase first and then decrease slightly with the increase of the carbon material content, regardless of the mixing process. However, the elongation at break of vulcanizate showed an opposite trend. When the carbon material content is 2.0% (w.t.%), thermal conductivity, 300% tensile stress and tear strength all reach their maximum, while elongation at break obtains minimum. Under the same amount of addition, GNs is more conducive to improving the thermal conductivity and elongation at break of composites, while CNTs are more conducive to improving the tensile strength and tear strength of composites. For CNTs-, GNs-NR composites, the wet mixing process can greatly improve the thermal conductivity, tensile strength and tear strength of composites, while the dry mixing process can greatly improve the elongation at break of composites. Therefore, when preparing CNTs-, GNs-NR composites, it is necessary to select a suitable mixing process according to the performance requirements of the final product.