Preferential Orientation of Lamellar Microdomains Induced by Uniaxial Stretching of Cross-Linked Polystyrene-block-polybutadiene-block-polystyrene Triblock Copolymer

Abstract

We report an experimental result for a lamellar orientation in cross-linked polystyreneblock-polybutadiene-block-polystyrene (SBS) triblock copolymer that was uniaxially drawn at 130 °C (above the glass transition temperature of polystyrene; T g(PS)). The lamellar orientation was examined using two-dimensional small-angle X-ray scattering (2d-SAXS) experiments. It was revealed that the lamellar normal preferentially oriented perpendicular to the stretching direction such that the microdomain interface between polystyrene and polybutadiene lamellae is more or less parallel to the stretching direction, where the lamellar normal denotes the direction normal to the lamellar interface. On the other hand, a herringbone structure was induced by the uniaxial stretching for a sample drawn at room temperature (below T g(PS)) without the lamellar orientation. Therefore, it is concluded that the straininduced orientation of lamellae can be only attained above Tg(PS) and that the uniaxial stretching above Tg(PS) was found to be an effective way to induce the preferential orientation of lamellae. The lamellar orientation was found to be improved by the thermal annealing at a stretched state and more by increasing the extent of the stretching, as well as cross-linking density.

Spontaneous Enhancement of Packing Regularity of Spherical Microdomains in the Body-Centered Cubic Lattice upon Uniaxial Stretching of Elastomeric Triblock Copolymers

“…We prepared a film of this sample by compression molding at 230 °C (as-mold sample). The SAXS measurements were performed at SAXS beamlines BL-10C and BL-15A in the Photon Factory of the High Energy Accelerator Research Organization, Tsukuba, Japan [11,12], and at SAXS beamline BL45XU of SPring-8 in the Japan Synchrotron Radiation Research Institute [13]. The wavelength of the X-rays was tuned to  = 0.149 nm for BL-10C,  = 0.150 nm for BL-15A, and  = 0.099 nm for BL45XU.…”

Block Copolymer Nanocomposites Based on Multiwall Carbon Nanotubes: Effect of the Functionalization of Multiwall Carbon Nanotubes on the Morphology of the Block Copolymer

“…The orientation of the morphology of polystyrene-block-polybutadiene has been well described by experiments performed on films with pre-oriented and randomly oriented lamellar microphases. [5,7] Representative 2D-SAXS images as a function of the strain can be appreciated in Figure 2. When AS-SB 26 film is stretched, the deformation of the lamellar domains can be described by the evolution of the 2D-SAXS patterns: starting from a film consisting of randomly oriented lamellar grains, as evidenced in transmission electron micrographs and by concentric rings in the scattering patterns, the stretch of the film promotes the deformation of the ring to an ellipsoidal shape with a compressed meridian axis and an expanded equatorial axis.…”

“…[2,3] Particularly, it is known that the deformation behavior of the SBS strongly depends on the microstructure of the polybutadiene and on the microdomain orientation of the copolymer. [3][4][5][6][7] Although the tuning of the properties of the (co)polymers broadens the range of applications of these materials, there are still requirements that are beyond their possibilities. In those cases, (co)polymers have been combined with fillers that seek to improve the properties of the final material.…”

Structural arrangement of crystalline/amorphous phases of polyethylene‐block‐polystyrene copolymer as induced by orientation techniques

“…For preparation of such bulk morphology composed by the homogenous arrangement of the separated phases, various external fields, including force, [11][12][13][14][15][16][17][18][19][20][21] magnetic, and electric fields 9,[22][23][24][25] have been applied.…”

“…Therefore, it is difficult to obtain the highly oriented morphology of this copolymer. In order to fix the morphological orientation induced by the tensile force, Sakurai et al 11 introduce the cross-linking into the copolymer chains after tensile deformation.…”