ポリオレフィンの溶融粘性～Graessleyの理論による解析

抄録

The following is the report of the studies that were made of applicability of Graessley's theory for the Non-Newtonian viscosity to polythyelenes and polypropylenes which have very broad logarithmic-normal distributions of the molecular weight.
The relationships between the viscosity and the shear rate of the samples were measured by a cone-and-plate viscometer and a gas operated extrusion type rheometer for about four decades of shear rate, at 190°C. The functions of molecular weight distribution were determined by the column fractionation technique.
Considering a maximum molecular weight for the distribution function, the experimental relationship between the viscosity and the shear rate for polymers having a wide range of molecular weight distribution including a fruction showed on excellent agreement with the theoretical prediction of Graessley.
The molecular relaxation time of entanglement was found to be proportional to the product of the zero shear viscosity and the weight average molecular weight which justified the use of the Rouse-Bueche type relaxation time for the entanglement relaxation time, although the absolute value of the latter seemed to be about one decade smaller than the former.