硝化纤维素溶液冰冻过程中的粘度行为

用乌式毛细管粘度计对硝化纤维素稀溶液的粘度行为进行了研究,测定了原溶液、冰冻后溶液、冰冻后经过加热的溶液以及加热后继续冰冻溶液相对粘度的变化规律。结果表明：冰冻过程中硝化纤维素溶液粘度的降低是由于分子链内发生链内凝聚（缠结）造成的。并且发现,不同浓度的高分子溶液冰冻过程中相对粘度变化的规律不相同,浓度较高的硝化纤维素溶液在冰冻过程的初期可能同时伴随有链内凝聚和链间凝聚。文中还讨论了一种快速形成链内凝聚的方法,并对冰冻过程中硝化纤维素分子形成链内交联点的倍数进行了估计。

The Viscosity Behaviour of Nitrocellulose Chain in Freezing Procedure

Having been frozen, polymer solution will have lower viscosity. For a long time, this phenomenon has been considered as a result of the fracture of polymer chain (degradation). In this paper, the viscosity behaviour of the dilute solution of nitrocellulose is studied and ,by means of Ubbelodhe capillary viscometer, the changing regularities in relative viscosity of the original solution, the frozen solution, the frozen heated solution and the frozen heated frozen solution are measured. The results show that the viscosity decrease of nitrocellulose solution in freezing procedure is not due to the fracture of nitrocellulose chains (degradation) but the condensation (tangle) within the nitrocellulose chain, that the nitrocellulose solution with different concentration has different changing regularity in relative viscosity in freezing procedure, and that at the initial freezing stage the nitrocellulose with higher concentration may see its condensation happening within chain and among chains simultaneously.