Effect of polyacrylonitrile (PAN) short fiber on the mechanical properties of PAN/EPDM thermal insulating composites

Polyacrylonitrile short fibers/ethylene–propylene–diene terpolymer rubber (PAN/EPDM) composites are prepared for the first time by mechanical mixing and subsequent vulcanization at 150 °C for 50 min to substitute for composites reinforced with aramid short fibers, as thermal insulating materials. The relationships between fiber content and the mechanical performances of the two kinds of composites are investigated. To PAN/EPDM composites and aramid/EPDM composites, as the fiber content increases, the tensile modulus, the tear strength and tensile strength increase, the break elongation decreases, and the fracture mode of the two composites changes from yielding prior to breaking to simultaneous yielding and breaking. PAN/EPDM composites have higher elongation than aramid fiber/EPDM composites, but as their mechanical properties such as tensile modulus, tear strength and tensile strength are comparable, the former is expected to replace the later as a low density thermal insulator.