| 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 (M?w) ranged from 9.72 × 104 to 1.80 × 106 and the distribution breadth M?w/M?η from 1.06 to 9.21. The critical shear stress varies linearly with 1/M?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. |
