Physical Properties And Oil Resistance Of Epoxidized Natural Rubber/Carbon Nanotube Nanocomposites Prepared Via In Situ Epoxidation
In this study, epoxidized natural rubber (ENR) was prepared via in situ epoxidation of NR in the latex state using
different molar ratios of hydrogen peroxide (H2O2):formic acid to isoprene unit at 50°C for 4, 6 and 8 h to gain different
epoxide levels. ENR with 30 mole% epoxidation referred to as ENR30 was obtained using a molar ratio of H2O2:formic acid
of 0.75:0.75 at 50°C for 4 h. Consequently, ENR30/carbon nanotube (CNT) nanocomposites were also prepared using a
latex-based process by incorporating five loadings of CNTs (0.5, 1, 1.5, 2 and 2.5 phr) in NR latex and was then followed by
in situ epoxidation of NR. The cure time (t90), tensile properties (tensile strength, elongation at break and modulus at 300%
strain (M300)), glass transition temperature (Tg), thermal stability and oil resistance of the nanocomposites were investigated
and compared with NR and ENR30. The results showed that the t90 of ENR30/CNT nanocomposites was the longest
followed by NR and ENR30. The incorporation of CNTs could increase the tensile strength, M300, Tg, thermal stability and
oil resistance but decrease the elongation at break of the nanocomposites. Among them, the nanocomposite containing 2 phr
CNTs exhibited the highest tensile strength, M300, Tg, thermal stability and oil resistance compared to the NR and ENR30.
However, the elongation at break of ENR30 (673.8%) and the ENR30/CNT nanocomposites (591.2–695.3%) was still rather
high when compared to that of NR (726.6%). Thus, the CNTs reinforced ENR30 vulcanizates were soft nanocomposites.
Keywords- Epoxidized Natural Rubber, Carbon Nanotubes, In situ Epoxidation, Oil Resistance, Nanocomposites.