Abstract:
This research aims to prepare the rubber blend nanocomposites of carboxylated styrene butadiene rubber (XSBR) and natural rubber (NR) filled with polystyrene (PS)- encapsulated nanosilica. The XSBR and NR were blended at XSBR/NR dry weight ratios of 70/30, 50/50 and 30/70, before mixing with PS-encapsulated nanosilica at 3 parts per hundred rubber by latex compounding method. The nanolatex of PS-encapsulated nanosilica was first synthesized via in situ differential microemulsion polymerization of styrene monomer in the presence of nanosized silica pretreated with 3-methacryloxypropyltrimethoxy silane coupling agent. The resulting hybrid nanoparticles showed core-shell structure with an average diameter of 34 nm. The blended latices of XSBR, NR and PS-encapsulated nanosilica were cast into sheets on a glass mold, air dried and then cured in an oven at 80°C for 3 h. After that, the specimens were examined for their mechanical properties (tensile properties, tear strength and hardness), dynamicmechanical properties, thermal behaviors and morphology using a universal testing machine, Shore A hardness tester, dynamic mechanical analyzer, thermal gravimetric analyzer and scanning electron microscope. The results showed that the tensile and dynamic mechanical properties of the obtained rubber blend nanocomposites could be improved by the addition of the PS-encapsulated nanosilica. Whereas the PS-encapsulated nanosilica provided insignificant effects on the tear strength, hardness and thermal stability of the rubber blend nanocomposites.