Magadiite/styrene‐butadiene rubber composites for tire tread applications: Effects of varying layer spacing and alternate inorganic fillers

ABSTRACT Magadiite (MGD), a synthetic layered silicate (Na2Si14O29·9H2O) with surface chemistry similar to precipitated silica, was cation‐exchanged with three different organic cations to explore the effect of varying MGD layer spacing on the mechanical properties of MGD‐based styrene‐butadiene rubber (SBR) composites. This work also compares the mechanical properties of MGD/SBR composites with those formulated with montmorillonite (MMT) and precipitated silica. Dodecylpyridinium (DP+) produces greater expansion of MGD layers than cetyltrimethylammonium (CTA+); the resulting DP‐MGD/SBR composites have greater yield strain, toughness, and rubbery storage modulus than comparable CTA‐MGD/SBR composites. MGD treated with hexadecylammonium (HDA+) has the greatest layer spacing, but the HDA‐MGD layers collapse upon melt‐blending with SBR. CTA‐treated MMT (CMMT) exfoliates in aqueous suspension, but the platelets re‐stack upon drying and during melt‐blending with SBR. The presence of exfoliated and/or disordered platelet stacks in CMMT/SBR probably accounts for its higher tensile and dynamic moduli compared to MGD‐ and silica‐based SBR composites. Dynamic mechanical properties are used to predict tire tread performance metrics for these composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44764.