On the Evolution of Entanglements in Initially Unentangled Polymer Melts

The entanglement process in initially unentangled polymer chains with molecular weight greater than the entanglement molecular weight was examined using a modified bond fluctuation model. The relative roles of Rouse-like and reptation-like dynamics in the entanglement process were assessed. A scheme for fitting the time evolution of entanglement density was proposed and applied successfully to experimental data. The entanglement mechanism was elucidated by showing that at early times, the polymer chains preferentially develop entanglements away from their centers.