Novel mesoporous nanosilicas for rubber reinforcement: effect of the aspect ratio

Silica nanoparticles with different aspect ratios (AR) have been tested with respect to their effectiveness as reinforcing fillers for s-SBR (solution Styrene-Buradiene rubber) based nanocomposites for "green tires". A commercial nanofiller with AR=1 (Aerosil® 200) has been compared with two nanosilica samples, with AR 2 and 4, synthesized by means of an innovative process, to ascertain if the filler shape is significant in improving the composite properties. Thermodynamic silicas surface properties were investigated by inverse gas chromatography (IGC); s-SBR/silica (unmodified or modified with bis(triethoxysilylpropyl)tetrasulfide (TESPT)) compounds were prepared and characterized using vulcanization tests, assessing their dynamic-mechanical properties and carrying out morphological observations by TEM.