Abstract
We report control of mechanical properties via morphological control through blending of elastomeric polystyrene-block-polybutadiene-block-polystyrene (SBS) triblock copolymers. For this purpose, we controlled overall composition by blending two SBS triblock copolymers having different compositions and surveyed variation of the mechanical properties with structural change. The microdomain structure was analyzed by the small-angle X-ray scattering (SAXS) technique and the mechanical properties were examined by the tensile stress-strain test. The blending enabled us to change morphology from polystyrene cylinders to alternating lamellae. In between them, a double-gyroid (DG) microdomain structure was also formed. The DG structure is a well-ordered bicontinuous structure, which is formed in a narrow range of composition between cylinder and lamella regions. As a result, the tensile modulus increased tremendously in the narrow range of composition where the DG structure was formed.
