高分子-溶媒系の粘度に及ぼす圧力の影響

抄録

In connection with the studies that have been made on the viscoelastic behaviour of polymeric liquids under high pressure, the concentration dependence of the change of viscosity, η_p/η_o, and the critical concentration, C_c, under static pressures up to 900kg/cm² for polydimethyl siloxane-toluene system are discussed in this paper. The measurement was made over a wide range of polymer concentration from 0.10 to 1.00 at 40 and 80°C.
In this system, C_c is found at about 0.30 and seems to be independent of pressure and temperature within the experimental error. As observed in various polymeric liquids previously studied, log(η_p/η_o) is proportional to Pⁿ at each concentration. Below C_c, log(η_p/η_o) takes an approximately constant value independent of concentration, and in the range of concentration from C_c to about 0.60, double logarithmic plot η_p/η_o against C is represented by a straight line having a positive slope under each pressure. This result is consistent with that obtained of polystyrene solution in toluene where the concentration was lower than 0.50. Over the range of higher concentration near 1.00, this plot is concave, that is, the effect of pressure on viscosity becomes larger with the increase of concentration.