Spontaneous Breakup of Extended Monodisperse Polymer Melts

Catastrophic failure of polymer melts during extension

“…Wang and Wang [20] and Bach et al [11] measured at about the same λ max ·ǫ values, and the 95 kg/mole SBR melt has almost identical flow behavior as a 390 kg/mole PS [6], of course relative to λ max . Bach et al [11] extended a short cylindrical sample.…”

“…In figure 3 the strain of break is shown as a function of the elongational rate multiplied by the maximal relaxation time. The corresponding computations of ǫ c with the material parameters obtained by Rasmussen and Yu [6] and Lyhne et al [40] (table 1) are shown in figure 3 as well. I apply the same initial deviations from an ideal cylinder (H/R = 0.015, 0.05 and W/R = 0.2) as in Rasmussen and Yu [6], where they explained the spontaneous rupture in polymer melts.…”

“…The corresponding computations of ǫ c with the material parameters obtained by Rasmussen and Yu [6] and Lyhne et al [40] (table 1) are shown in figure 3 as well. I apply the same initial deviations from an ideal cylinder (H/R = 0.015, 0.05 and W/R = 0.2) as in Rasmussen and Yu [6], where they explained the spontaneous rupture in polymer melts. As in Rasmussen and Yu [6] only the sample height has been changed, as the computations are considerably less sensitive to changes in the width.…”

“…This approach accurately predicts the startup and steady shear [22] as well as extensional flow [14], potentially followed by stress relaxation [23,6], of monodisperse polymer melts. This has currently been documented up to about 160 entanglements in shear [22] and at least 30 in extensional flow [14].…”

“…I apply the same initial deviations from an ideal cylinder (H/R = 0.015, 0.05 and W/R = 0.2) as in Rasmussen and Yu [6], where they explained the spontaneous rupture in polymer melts. As in Rasmussen and Yu [6] only the sample height has been changed, as the computations are considerably less sensitive to changes in the width. In experiments, imperfections on the samples will not be exactly the same, although the break is not very sensitive to the size of the disturbance.…”