Meaning
Rheological framework used to describe the non-linear flow of entangled polymer chains. The rolie-poly model accounts for convective constraint release and chain stretch during high-rate deformation. Calculations stop being accurate at the point of molecular fracture or extreme chain scission.
Chain Entanglement
Interaction between long polymer molecules creates a temporary network that resists movement. The rolie-poly model describes how these entanglements are removed and reformed as the material flows through a die or into a mould. Understanding this process is necessary for predicting the pressure drop and the final orientation of the chains.
Shear Flow
Behavior of the melt at high speeds determines the quality of the surface and the occurrence of melt fracture. The rolie-poly model predicts the onset of instabilities like sharkskin that can ruin the appearance of an extruded part. Moulders use these predictions to select the best processing temperature and injection speed for a given resin.
Melt Elasticity
Recovery of the polymer after the stress is removed depends on the stored energy within the entangled network. The rolie-poly model quantifies this elasticity, which is responsible for phenomena like die swell and part shrinkage. Accurate modeling of these effects allows for more precise tool design and better dimensional control.
The framework remains a primary tool for simulating complex flows in industrial polymer processing.
