Figure 3.

Predictions for the variable link tension coefficient, $\epsilon /{\epsilon }_0=S_2^2$ in planar elongational flow as a function of dimensionless elongation rate $\mathrm{Wi}$ for $N=100$ ($Z\approx 33$ entanglements) and various values of ${\epsilon }_0^{\prime }$. The thick lines give the analytical predictions of Equation (23) when ${\epsilon }_0^{\prime }=0$ (dark blue) and 0.9 (dark yellow). The dependency of ${\mathsf{\Gamma }}_1$ on ${\epsilon }_0^{\prime }$ determines their offsets and is relatively weak for any N. For $N>2$ the coefficient ${\mathsf{\Gamma }}_1$ decreases monotonically with increasing ${\epsilon }^{\prime }$, starting from ${\mathsf{\Gamma }}_1=0.125$ at ${\epsilon }^{\prime }=0$. For any $N\ge 20$ one has ${\mathsf{\Gamma }}_1\approx 0.081$ at ${\epsilon }^{\prime }=0.9$ (and ${\mathsf{\Gamma }}_1\approx 0.078$ at ${\epsilon }^{\prime }=1$).