Prediction Of Viscosity Curves Of Blends Of Homologous Linear Polymers
| Title |
Prediction Of Viscosity Curves Of Blends Of Homologous Linear Polymers |
| Publication year |
2007 |
| Language |
English |
| Author |
Follestad, Arild (Norner) |
| Source |
PPS07 EA - Polymer Processing Society - Europe and Africa regional conference, Gothenburg 27. - 30. august 2007 |
| Abstract |
Blends of polyethylenes are becoming more used in the industry than nonblended polyethylenes because polymer components with extreme compositions properly combined may yield homogeneous tailormade polymer with unique combinations of properties. The viscosities of such blends are important. The proposed method, the power equation, is a simple way of estimating the complex viscosity from the viscosity of the components at the same complex modulus (shear stress). Extrapolation of the components' viscosities may be needed, in which case the method of extrapolation is important. Here is suggested a method that uses fitting of 2 parameters only for each component. Properties of this equation system are: The viscosity curve of the blend remains the same regardless of whether simultaneous or any staged mixing of components is assumed. The algorithm (except fitting the components' viscosity curves) contains no iteration nor integration. Being tested on a large amount of experimental data on linear polyethylenes of widely different nature, and with components different in viscosity by a factor of tenths of thousands, the algorithms are shown to be rather accurate. The 2-parameter curves for the components viscosities gives robustness, though perfect fit regardless of whether components are made with single site, Ziegler or Cr catalyst, as well as simple calculations. These or similar equations may be sought applied on other homologous polymers. |