Figures 9 and 10 show the corresponding profiles for number-and weight-average molecular weights, respectively.
Figure 23 shows profiles for number- and weight-average molecular weights at [TEMPO]/[BPO] = 0.
D] should be used to rank their fracture toughness, which suggests that the dominant factor for toughness is the molecular weight, most likely the weight-average molecular weight, followed by the short-branch concentration.
For polyethylene of similar concentration in short branches, their study shows that the increase of the weight-average molecular weight from 176,600 to 232,900 causes a significant increase of [K.
To illustrate this effect, elongation at break for all process settings over the weight-average molecular weight
3, it can be seen that the weight-average molecular weight
of the polymers increases quickly to a constant in the start-up process of the polymerization, and the plant data are lower than the simulated data.
On the basis of the temperature and the weight-average molecular weight
in the ith iterative step, the zero shear viscosity in the (i + 1)th iterative step is calculated via Eqs.
A power-law constitutive equation is used to model the polymer viscosity, with temperature and weight-average molecular weight
dependent parameters, and a viscosity plateau at low strain rates:
For weight-average molecular weights
of 54,000, 77,000 and 120,000 g/mol, the ductile-brittle transition is observed at crystallinities of about 65%, 72% and 76%, respectively (23).