デキストラン水溶液に対する熱処理効果の光散乱による研究

抄録

Since the effect of dextran, as a plasma expander, differs wide1y according to its molecular weight, the dextran solutions of various molecular weight has been studied by light scattering and viscosity methods. According to the Zimm plot method, the weightaverage molecular weight, M_w, radius of gyration, R_g, and second virial coefficient, A₂, were obtained for (1) solutions dissolved at 25°, (2) the solutions heated at 80° for 2 hr and (3) mixed solutions of two polymers dissolved at 25°. The relation of A₂=4.90×10_^<-2>M^-0.426 between A₂ and M_w is obtained in common for (1) to (3). R_g for the case (1), on the other hand, decreased at first with increase of M_w and reached a minimum at M_w=110000 and then increased at M_w=2500000. For the case (2), the value of R_g increased by heating. For the case (3), R_g was larger than the values expected from those of both components. The data for cases (2) and (3) are expressed by the equation R_g=1.67×10^-7M_w^0.187. The relation [η]=6.95×10^-4M_w^0.493 was also obtained for the intrinsic viscosity [η] of these solutions. It is concluded that the dextran molecules are dissolved in more extended state in aqueous solution when the solutions are heated or when the sample is a mixture of dextrans of different molecular weight.