A study on dispersions of CB and CNT in PP/EPDM composites and their mechanical reinforcement

Carbon material (carbon black (CB) and carbon nanotube (CNT)-reinforced composites are being studied widely. The content of the reinforcing materials is known as the main influencing factor. However, the dispersion of the reinforcing materials is often neglected or, where it is investigated, not thoroughly evaluated. In this article, the dispersion states of carbon materials in the composite materials were quantitatively analyzed using an image processing method. Meanwhile, the reliability of the image analysis was verified through the testing results of the mechanical and rheological properties of the composites. Both CB and CNTs improved the mechanical properties of maleic anhydride-grafted polypropylene (PP)/ethylene propylene diene monomer composites, wherein their dispersion was the dominant factor instead of their content. The dispersion of the easily agglomerated CNT was significantly poorer than that of CB. Therefore, CB was better in inducing the crystallization of PP.