Figure 1

The measured tensile force resulting from five discrete continuous uniaxial stretching experiments, expressed in the form of the engineering stress ${\sigma }_{\mathrm{engr}}$, where the numbers 0.4 to $1.6{\mathrm{s}}^{-1}$ indicate the rate of extension. The coordinates of the force maximum (yield point) are designated by $t_{\max }$ and ${\sigma }_y$.Reuse & Permissions

Figure 2

The normalized “yield stress” ${\sigma }_y/G_N^0$ from such experiments as shown in Fig. 1 as a function of the “yield” strain, ${\epsilon }_y$, for all four SBR samples as well as the PIP melt, where instead of a cylindrical filament, the PIP specimen has a rectangular cross section of dimensions: $5.1\mathrm{mm}\times 1.0\mathrm{mm}$. The rates applied are SBR(100 K) 8, 6.4, 4.8, 3.2, 1.6, and $0.8{\mathrm{s}}^{-1}$; SBR(170 K) 4.8, 3.2, 1.6, 0.8, 0.4, and $0.24{\mathrm{s}}^{-1}$; SBR(250 K) 3.2, 1.6, 1.2, 0.8, 0.4, 0.24, and $0.16{\mathrm{s}}^{-1}$; SBR(500 K) 0.56, 0.48, 0.4, 0.32, 0.24, 0.16, and $0.08{\mathrm{s}}^{-1}$; PIP(550 K) 29, 19, 9.6, 4.8, 2.9, $1.9{\mathrm{s}}^{-1}$.Reuse & Permissions

Figure 3

The yield strain ${\epsilon }_y$ as a function of the applied rate of extension, revealing a master curve with a scaling exponent $1/3$ for the same five samples after normalizing the strain rate with the Rouse relaxation time ${\tau }_R$.Reuse & Permissions

Figure 4

(a) Three interrupted extension experiments involving amplitudes of 0.6, 1.0, and 1.4, respectively. The specimen remains uniform, i.e., intact for $\epsilon =0.6$. However, the higher amplitudes of step strain produce samples that are only temporarily stable. The breakup yields a sharp decline in the measured force. (b) A strain of amplitude 1.0 produced at four different rates of extension, all higher than the reciprocal Rouse time ${\tau }_R$, for SRB(250 K), shows the same breakup time. Two photos show another step extension experiment where the applied rate $\dot{\epsilon }$, the strain $\epsilon$ where the stretching was interrupted and times when pictures were taken, are all specified.Reuse & Permissions

Figure 5

A strain of $\epsilon =1.1$ performed on three different SBR samples using strain rates proportional to the reciprocal Rouse time. Taking the time to break as $t_b$, the inset plots the normalized breakup time $t_b/{\tau }_R$ as a function of a series of such interrupted stretching experiments for the three samples, revealing exponential dependence of $t_b$ on $\epsilon$: $t_b(M_w)={\tau }_R(M_w)\exp (-A\epsilon )$ where the constant $A$ is rather insensitive to the level of chain entanglement.Reuse & Permissions