Preparation and characterization of trans-1,4-polybutadiene nanocomposites containing in situ generated silica

trans-1,4-Polybutadiene (tPBD) networks crosslinked free radically with dicumyl peroxide (DCP) were reinforced by in situ silica formed in a two-step sol-gel technique. Changing the degree of crosslinking by changing the amount of DCP, or changing the amounts of the sol-gel components [tetraethoxysilane (TEOS) and dibutyltin diacetate (DBTDA)], changed the silica generated with regard to the amount precipitated, particle size, and degree of dispersion. Stress-strain measurements in continuous extension indicated good reinforcement, even at relatively low amounts of silica. Differential scanning calorimetry (DSC) indicated decreases in heat of crystallization with increases in the amounts of silica, but thermogravimetric analysis showed initial decomposition temperatures (IDT) remained relatively constant. Suggestions are made regarding interpretation of these properties in terms of the composite morphologies.