Melt fracture of polystyrene

Abstract The results of an experimental study of melt fracture using polystyrene samples of narrow and broad molecular weight distribution are presented. The weight average molecular weight (M̄ w ) ranged from 9.72 × 10 4 to 1.80 × 10 6 and the distribution breadth M̄ w /M̄ η from 1.06 to 9.21. The critical shear stress varies linearly with 1/M̄ w , increases slightly with temperature and is independent of the distribution of molecular weights. This type of behavior is satisfactorily explained in terms of Graessley's entanglement theory.