화학공학소재연구정보센터
Polymer Engineering and Science, Vol.36, No.10, 1414-1424, 1996
Orientation of Triblock Copolymers in Planar Extension
Three commercial styrenic triblock copolymers were subjected to planar extension in a lubricated channel die, as a model for the orientation that may occur during processing operations. Materials that contain cylinders of polystyrene show a pronounced orientation of the cylinder axis in the flow direction as revealed by small-angle X-ray scattering in the three orthogonal directions. This anisotropy produces small-strain tensile moduli that differ by a factor of 10 or more in tile two in-plane directions. A material that contains lamellae of polystyrene shows pronounced orientation of the lamellae in tile plane of the sample-in particular, lamellar normals are strongly forbidden from pointing along the flow direction. For similar strains, planar extension is much more effective in orienting these materials than simple shear.