The flow-induced structure of immiscible polyolefin blends under steady shear flow was studied by small angle neutron scattering. The sample used was a 3:7 blend (by weight) of i-polypropylene and ethylene-octene random copolymer. At low shear rates, anisotropic scattering was observed on a two-dimensional detector in through-view measurements (incident beam perpendicular to the flow). The intensity was stronger in the direction perpendicular to the flow direction. In edge-view measurements (incident beam parallel to the flow), no anisotropy was observed. At higher shear rates ( > 50 sec -1 ) , the anisotropy became very weak but the intensity itself became rather strong. A simple explanation of these observations can be given by assuming the existence of string-like domains at low shear rates and their splitting at high shear rates. This idea can be supported by the low interfacial tension between two polyolefins.
All Science Journal Classification (ASJC) codes
- Chemical Engineering (miscellaneous)
- Materials Science (miscellaneous)
- Environmental Science(all)
- Polymers and Plastics