Experimental investigation of crack initiation and propagation for electrical conductive nanocomposite elastomer materials with dic method

Many factors can influence the crack initiation and propagation resistance of the natural rubber. One of the most glaring factors is reinforcing filler of the rubber. Recently, graphene nanoplatelets (GNPs) and multi-walled carbon nanotubes (MWCNTs) have attracted considerable attention due to their excellent reinforcing efficiency. When the nanofillers used even at very low loading as phr, could not only improve the mechanical properties of rubbers but also improvmed service life, supplied electrical conductivity, and developed wear resistance. In this study, two groups of conductive nanocomposites were prepared by mixing a rubber mixture (SVR, SBR, and CBR) with different nanofillers by a two-stage mechanical mixing method. The first group was reinforced by GNPs, whereas the second group was reinforced by MWCNTs. The quasi-static loading was implemented using single-edge notched specimens which were adopted to estimate the crack propagation and the electrical resistance relation. Digital Image Correlation (DIC) technique was used to investigate the local strains distribution in the area near the crack tip. The results evaluated to clarify the relationship between crack length, graphene filler ratio, and electrical conductivity properties. GNPs affected negatively on the compound's fracture resistance, whereas the MWCNTs had positive effect observed by increasing the fracture resistance of the compound. The fracture properties of the nanocomposite had a very close relationship with The local performance of the area near the crack tip. The electrical conductivity of both of nanocomposites was improved because of the conductive network, which was formed by nanofillers and reduced the electrical resistance.