Abstract
Clay/polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene triblock copolymer (SEBS) intercalated composites were prepared by melt-blending. The clays were a pristine montmorillonite (Mt) and three organically modified montmorillonites (organo-Mts) with different amounts of distearyldimethylammonium (D18) cation. The amounts of D18 were 50, 70 and 100% of the cation exchange capacity (denoted as D18Mt(50), D18Mt(70) and D18Mt(100), respectively). The clay/SEBS composites were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD). The dynamic mechanical analysis (DMA) and the tensile properties were also examined.
The size of agglomerated clay particles decreased with the increasing amount of D18. The FE-SEM image of D18Mt(100)/SEBS revealed that the clay particles were dispersed at the sub-μm level (100–500 nm). The XRD patterns suggested that the SEBS chains were inserted into the interlayers of the organo-Mts. The DMA curves indicated that the addition of the organo-Mts produced an increase in the storage modulus in the rubbery plateau region, but a slight decrease in the glass transition temperature of the polystyrene domains. The tensile properties of the organo-Mt/SEBS composites were higher than those of the unmodified Mt/SEBS. D18Mt(100)/SEBS displayed an improved tensile modulus, tear strength and hardness compared to pure SEBS, without sacrificing the tensile strength and elongation at break.
