performance of compatibilizing processes in polystyrene/ethylene-propylene-diene terpolymer/polyamide6 (ps/epdm/pa6): in-situ grafted method versus pre-grafted compatibilizing method

In this work, the influence of compatibilizing method on the phase morphology, mechanical properties and rheological behavior of ternary blends based on polystyrene(ps) /ethylene-propylene-diene terpolymer(epdm)/ polyamide6 (pa6) was investigated. two different methods (including in-situ grafted and pre-grafted) were used to compatibilize ps/epdm/pa6 ternary blends. in the first method, all reactive materials were mixed during mixing, but in the latter, modified epdm was prepared first and then blended with other components. the chemical reactions occurred during blending followed by attenuated fourier transform spectroscopy (atr-ftir). mechanical properties investigated by impact and tensile strength measurements. the phase microstructure was observed by scanning electron spectroscopy (sem) and the rheological behavior was carried out using a parallel plate rheometer in oscillatory mode. atr-ftir results confirmed the grafting and compatibilizing reactions. the morphology size of dispersed phase particles have dramatically changed by increasing epdm-g-gma content. the pre-grafted compatibilizing method has revealed finer microstructure than the other method. the modulus of all the ternary compatibilized blends has increased compared to ps/epdm. in fact, the presence of pa6 introduces a new, more rigid phase in the blend. the pre-grafted compatibilizing method, which uses a compatibilizer content of less than 10 wt.%, is more effective than the in-situ grafted compatibilizing method. this approach results in a finer microstructure and enhanced impact strength. additionally, it creates a more rigid interface, leading to greater elasticity, which manifests as a semi-plateau in the rheological behavior. in contrast, the in-situ grafted method produces more balanced mechanical properties overall.