Fabrication of radiation crosslinked and MWCNT reinforced ethylene acrylic elastomer nanocomposites: Evaluation of mechanical, dynamic mechanical, thermal and dielectric properties

Abstract

Abstract The electron beam (EB) crosslinked and MWCNT reinforced ethylene acrylic elastomer (AEM) nanocomposites have been developed with varying the EB dose (50–250 kGy) and MWCNT loading level (0–8 parts per hundred gram of rubber (phr)) for various applications. The crosslink density and gel fraction significantly increase with increase in EB dose and MWCNT loading which ensures the radiation sensitizing effects of MWCNT. The chain scission to crosslink density has been check by using Flory–Rehner relationship at room temperature and the decrease in slope of the plots again confirms the predominance of crosslinking over chain scission at higher EB dose. The dispersion patterns of the MWCNT phase in bulk AEM matrix have been analyzed by using FESEM technique. Uniformly dispersed MWCNT with closely spaced network structures has been found in the FESEM photomicrographs at 4 phr loading level. The tensile strength and tensile modulus are extensively increased with increasing EB dose and up to 6 phr of MWCNT loading which ensures the reinforcing nature of MWCNT. Increase in tensile modulus (M100) and storage modulus (E ') with increase in EB dose and MWCNT indicates the absorption of applied load due to decrease in free volume of the systems. Increase in decomposition temperature with MWCNT loading of the nanocomposites has been confirmed from the thermal analysis. The significant increase in dielectric permittivity (eʹ) on increasing the MWCNT loading is mostly due to the increase accumulation of charge particles at the interface as well as increase in polarizable dipoles. The improvement in AC conductivity (σac) of these nanocomposites is mostly due to the easy electron tunnelling and hopping transport processes executed through the constructed networks by MWCNT in the bulk as well as interface.