高せん断速度領域におけるポリジメチルシロキサンの分子量と粘度の関係

概要

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The upper (or second) Newtonian viscosities (η_∞) of different molecular weights determined with a capillary viscometer driven by means of N_2 gas pressure. In order to diminish an experimental error, the reservoir of the viscometer was planned so as to have its much greater radius than that of the capillaries used. By the introduction of such a combination of capillaries and a reservoir, the upper limit of measurable rate was increased to 4.3×10^6sec^<-1>. These polymers η_∞ can be sorted into three groups according to their molecular weights, those below M'_c, those above M'_c or up to M_c, and those above M_c. (M'_c is the critical molecular weight at which the increases in the density and in the activation energy of flow with increasing molecular weight saturate, and M_c is the critical molecular weight at which the entanglement between cular weight saturate, and M_c is the critical molecular weight at which the entanglement between the polymers begins.) The polymer below M'_c has a Newtonian behaviour throughout the whole shear rate range. The polymer above M'_c up to M_c is non-Newtonian fluid, and its upper Newtonian viscosity depends on the molecular weight. In the case of its being above M_c, the flow curves of the polymers join in the upper Newtonian region, and η_∞ is almost independent of the molecular weight.
社団法人日本材料学会の論文
1972-05-15