Highly anisotropic properties of thermoplastic elastomer composites with aligned hierarchical structures

This paper describes the preparation, characterization and properties of a highly anisotropic thermoplastic elastomer composite. The composite was prepared by melt-blending of cylinder forming poly(styrene-b-butadiene-co-butylene-b-styrene) (SBBS) and a liquid crystal polymer (LCP), followed by injection molding of the blend. The composites have an oriented hierarchical structure in which LCP forms oriented fibers in SBBS matrix and the micro-phase-separated polystyrene (PS) phase in the matrix is also aligned along the injection direction. The property measurements demonstrated that the prepared composite showed extremely high anisotropic properties. The modulus in the direction parallel to the melt injection direction is about 47 times higher than that in the transverse direction, while the elongation at break is about 56 times smaller. The novel anisotropic properties reveal that the composite is a typical plastic in the melt injection direction, but an elastomer when the stress is applied along the transverse direction.