VIDEO-CLIP- LECTURES #53 from the New School Polymer Physics Influence of the Entanglement State on Crystallization (PET): b-grain glassification vs crystal nucleation in the melt by JP Ibar - ABSTRACT (see below) - INTRODUCTION (audio-12 min): Introduction - part 1 of VCL#53 https://docs.google.com/file/d/0B1EGViD3w4U0ZUhIUHZQa0QtSFk/edit?usp=sharing - part 2 of VCL#53: https://docs.google.com/file/d/0B1EGViD3w4U0QktncmtvdGhaYnM/edit?usp=sharing - part 3 of VCL#53: https://docs.google.com/file/d/0B1EGViD3w4U0bHpRMV92TXBvZkE/edit?usp=sharing Abstract: "Rheo-Fluidification processing" is a new processing method which has been shown to create new entanglement states for polymeric melts, modifying the fluidity of the melt, its elasticity and its stability [1,2,3]. The classical concept of entanglement in polymer melt is seriously challenged when melt deformation takes place in the non-linear visco-elastic range, which is the working range for Rheo-Fluidification processing. In particular, we have discovered that “sustained-orientation” can occur, for which the melt retains its deformed state at temperatures well above its Tg, in apparent contradiction with the concept of reptation time which no longer represents the longest relaxation time. The stability of sustained-deformed melts can extend to 100,000 times the reptation time, thus questioning the current understanding of entanglements for such systems. It is anticipated that crystallization occurring under processing conditions which force the melt to be out of equilibrium, such as in Rheo-fluidification, may bring useful