Comparison on the properties of the wheat straw/rubber composites by adding graphite/carbon fiber

The conductive wheat straw/rubber composites (WSRCs) were prepared with wheat straw fiber (WSF), rubber compound and graphite powder (GP), or carbon fiber (CF). WSRCs with different loading of conductive fillers were prepared. The curing properties, mechanical properties, dynamic mechanical properties, morphology structure and conductive properties of the composites were investigated with reference to the conductive filler loading. Sodium hydroxide combined with bis‐[γ‐(triethoxysily)‐propyl] tetrasulfide (NaOH‐Si69‐treated WSF) had a better bonding with the rubber matrix. The incorporation of GP and CF could restrict the mobility of matrix macromolecular chains and increase the viscosity of GP/CF‐filled WSRCs, resulting in the increases in torque, stiffness and storage modulus and the slight reduction in scorch time and tensile strength as well as the damping behavior. Moreover, the conductivity of the WSRCs was increased significantly as the increase in filler loading. It was also found that the conductivity of GP‐filled WSRCs were higher than that of the CF‐filled ones. POLYM. COMPOS., 40:E983–E992, 2019. © 2018 Society of Plastics Engineers