Dispersion Enhancement of Multi-Walled Carbon Nanotube (MWCNT) in Nitrile Rubber (NBR)

Abstract

Attempts to enhance dispersion degree of multi-walled carbon nanotubes (CNT) in nitrile rubber (NBR) matrix, and to improve the NBR-CNT interaction were carried out by different approaches, namely, sonication and chemical treatments of CNTs with nitric acid (HNO 3 ), nitric-sulfuric acid mixture (HNO 3 /H 2 SO 4 ) and potassium permanganate (KMnO 4 ). Rheological behavior of NBR/CNT composites was monitored as an indication of filler dispersion degree using the Rubber Process Analyzer (RPA2000) via the alteration in Payne effect. Results gained reveal the magnitude of Payne effect in the following order: untreated system> sonicated system> HNO 3 system> HNO 3 /H 2 SO 4 KMnO 4 system, implying a significant improvement in the state-of-mix of NBR/CNT composites by sonication and/or chemical treatment of CNT prior to being mixed with NBR. The SEM results demonstrate the highest magnitude of CNT dispersion in the system with HNO 3 followed by the sonicated system untreated system, HNO 3 /H 2 SO 4 KMnO 4 . The SEM results suggest that the surface treatment of CNT with HNO 3 yields highest magnitude of improvement in CNT dispersion. Poor CNT dispersion after treatment with HNO 3 /H 2 SO 4 or KMnO 4 is due probably to the re-agglomeration of CNT during the drying stage after the chemical treatment process.