Effect of short polyethylene terephthalate fibers on properties of ethylene-propylene diene rubber composites

The alteration in some properties of electron beam (EB) cured ethylene-propylene diene rubber (EPDM) reinforced by polyethylene terephthalate (PET) fiber was investigated in this study. Bonding system Resorcinol/Hexamethylenetetramine/Silica (RHS) was used to enhance the fiber/EPDM adhesion and to maintain optimum composite strength properties. Mechanical properties of composites namely; tensile strength, hardness and modulus at 100 % elongation have been enhanced by adding PET fibers and increasing irradiation dose. Moreover, the effect of fiber loading and irradiation dose on the soluble fraction behavior of the composite in benzene was also investigated. The soluble fraction of the composites decreased with increasing the fiber loading and irradiation dose. The extent of fiber alignment and strength of fiber-rubber interface adhesion were analyzed from the anisotropic swelling measurements. In addition, thermal stability of the composites was increased. Besides, the mechanical properties like tensile strength and stiffness were improved by thermal ageing. Scanning electron microscopy (SEM) for the fractured surfaces and Wide- angle X- ray diffraction (WAXD) of the investigated samples confirmed that the adhesion occurred between fibers and EPDM.