Compatibilization of Multi-Wall Carbon Nanotube/EPDM: Studies on the Properties of Nanocomposite

In order to achieve dramatic improvements in the performance of rubber materials، attempts were made to develop carbon nanotube (CNT) -reinforced rubber composites. The maleic anhydride (MAH) modification of EPDM is an interesting way of compatibilizing the EPDM rubber with CNT. Novel ternary nanocomposites were prepared based on EPDM/EPDM grafted maleic anhydride (EPDM-g-MAH) blend composition with various concentrations (0-7 phr) of multi-wall carbon nanotube (MWCNT) on a two-roll mill. The effect of EPDM-g-MAH as a compatibilizer and MWCNT concentration were investigated on cure characteristics، mechanical، morphological and rheological properties of nanocomposites. The microstructure of nanocomposites has been characterized using scanning electron microscopy (SEM). At the same time the rheological behavior has been evaluated by a rubber processing analyzer (RPA). It was found that the cure time (t90) and scorch time (t5) decreased while maximum torque (MH) and minimum torque (ML) of the compatibilized composites were increased with increasing MWCNT loading which was consistent with the swelling data. It is observed that by increasing MWCNT loading the swelling index in solvent was decreased. This can be related to good interactions between carbon nanotube and EPDM matrix in presence of EPDM-g-MAH compatibilizer. The fracture surface study indicated that compatibilizer facilitated a homogenous dispersion of MWCNTs inside the matrix. On the other hand، carbon nanotubes in matrix caused roughness of the fractured surface compared with uncompatibilized samples. The mechanical properties such as tensile strength and elongation-at-break of compatibilized EPDM/MWCNT were higher than those of uncompatibilized nanocomposites. In addition، due to increasing MWCNT content the rheological properties such as storage modulus (G'') increased with respect to angular frequency while the complex viscosity decreased.