Localized Instability Propagation Behavior of Polymer under Shearing -Formation and Growth of Surface Microstructure in Polycarbonate
Yoshio KOUTA, Taiji ADACHI and Yoshihiro TOMITA
Abstract:Polymeric materials under large deformation exhibit localized instability propagation, such as neck propagation under tension and shear band propagation under shearing. In this study, formation and growth of micro-shear bands in a glassy polymeric material, polycarbonate (PC) deformed under simple shear, were observed using an Atomic Force Microscope (AFM). In the early stage of shear deformation, the first micro-shear bands along the shearing direction was formed, and they merged together with increase in its density, and then, resulted in the formation of the macro-shear band. In this process, crossing orthogonally to the first micro-shear band, the secondary micro-shear bands were formed. After the applied force reached its maximum, the macro-shear band propagation started in the perpendicular direction to the shearing direction. As the macro-shear band propagated, the rotation of the secondary micro-shear band was observed. In addition, hierarchical structure of the secondary micro-shear band was revealed in region right after the macro-shear band propagation. Key Words:Polymers, Polycarbonate, Shear deformation, Instability propagation, Shear band, Atomic Force Microscope