Effects of Malienated Ethylene Propylene Diene Monomer (EPDM) Rubber on Dynamic-Mechanical and Rheological Properties of Polyamide 66 (PA 66) Composites

Reactive blends of ethylene propylene diene monomer (EPDM) and polyamide (PA) 66 were prepared in the single screw and twin screw extruder using maleic anhydride as coupling agent and dicumyl peroxide (DCP) as initiator. The optimum concentration of DCP for grafting maleic anhydride on EPDM was determined. The grafting efficiency was determined by Fourier transform infrared (FTIR) spectroscopy, and (DMTA) tests were conducted to determine the damping, loss, and storage modulus of PA 66 composites. A capillary rheometer and parallel plate rheometer were employed to characterize the rheological properties at high and low shear rates. It was seen that the glass fibers are not long and continuous, and they act as fillers, therefore reducing the damping in the composite. No significant change was observed in the glass transition temperature of the blend as compared with the individual components, especially PA 66. In malienated EPDM blends with increasing EPDM from 10 to 15%, the height of glass transition temperature peak increases. Capillary rheometer tests show that for all samples the apparent viscosity decreases with increasing shear rate, which is a characteristic of a non-Newtonian pseudo plastic fluid. The viscosity ration of malienated EPDM and PA 66 shows a considerable difference between them and only at higher shear rates do the viscosities get closer.