Molecular formula :
nature : polymer extrusion destabilizing flow of critical shear stress value to τ c said. When the shear rate over τ c, with the shear rate increase, from the appearance of extrusion appear rough and undulating, spiral twist or melt flow instability breakdown phenomenon, and therefore, forming the shear stress must τ c below.
Notice:Each item can have many explanations from different angels. If you want grasp the item comprehensively,please see below "more details data".