高分子濃厚溶液の非ニュートン流 : I. ポリビニルアルコール水溶液 : 高分子レオロジー

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The apparent viscosity η_a of concentrated solutions of polyvinyl alcohol (PVA) samples having different molecular weigher have been measured within the ranges of rates of shear from 0・5 to 1000 and the temperature range from 20° to 55℃. The instrument employed here is a capillary viscometer with continuously varying pressure head as described by Maron, Krieger and Sisko. Some data have been supplemented for polyvinyl acetate obtained by acetylation of PVA. The important results are summerized as follows : 1) The apparent-viscosity data can been superposed as satisfactorily as dynamic-viscosity data according to the method of reduced variables. Shift factors obtained agree well with those obtained from the dynamic data. 2) Log-log plot of the zero shear viscosity against concentration consists of two straight lines that intersect at one point (critical concentration c_c). The slopes of the lines are about 6 above c_c and 4・4 below c_c, respectively. Critical concentration in volume fraction of polymer in soluton, υ_<2c>, multiplied with the chain length Z increase with increasing chain length and ranges from 130 to 280. The product υ_<2c>Z^<1/2> is almost constant and independent of the chain length. 3) the reductions of viscosity curves referring to concentration as reported by Ferry and DeWitt et al. are not applicable to our data. But when log-log plot of the apparent viscosity against the rate of shear are shifted along a straight line having slope -1 or higher, they can be superposed fairly well in the concentration region above c_c. By such a reduction, rheological properties of pure polymer can be expected, but they are quite different from those measured actually with PVA films.
社団法人日本材料学会の論文
1960-04-15

高分子濃厚溶液の非ニュートン流 : I. ポリビニルアルコール水溶液 : 高分子レオロジー

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