The effect of tannic acid functional multi‐walled carbon nanotubes on the properties of nitrile rubber/ethylene propylene diene monomer composites

Abstract Multi‐walled carbon nanotubes (MWCNT) were first non‐covalently functioned by tannic acid (TA), then blended with nitrile rubber (NBR) and ethylene propylene diene monomer (EPDM) with NBR:EPDM:TA‐MWCNT = 70:30:5. TA‐MWCNT and the composites had been characterized by various techniques, including Fourier transform infrared spectroscopy (FT‐IR), Raman analysis, transmission electron microscopy (TEM), mechanical properties testing, thermal‐oxidative aging testing, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). Results indicated that TA molecules were successfully absorbed to the surface of MWCNT. And compared with NBR/EPDM/MWCNT composites, the compatibility between NBR and EPDM had been significantly improved. The NBR/EPDM/TA‐MWCNT exhibited excellent mechanical properties and thermal‐oxidative aging properties due to the phenolic hydroxyl groups on the surface of TA‐MWCNT, which had high chemical reactivity and physical adhesion. These phenolic hydroxyl groups gave TA‐MWCNT better dispersion in the rubber matrixes and can participate in the vulcanization process, creating the firm interface between the rubber matrixes and the surface of MWCNT.