抄録
Intrinsic viscosities of various cellulose acetate samples having about the same basic degree of polymerization but differing in the acetyl contents were determined in several types of solvents.
In the range of the acetyl contents tested, intrinsic viscosities were in all cases highest in acetic acid and lowest in pyridine and the mixture of methylene chloride and ethanol, while acetone and dioxane gave the intermediate values.
A tentative interpretation, based on the configuration on the cellulose chain involving the intramolecular hydrogen bonding, were presented to account for these variations of intrinsic viscosities with the solvent type, such as acidic, basic and neutral.
In order to examine the influence of the acetyl contents on the intrinsic viscosities in various solvents, the ratio of intrinsic viscosity in these solvents corrected to the triacetate and that of the same sample determined in cuoxam was taken and the changes of these ratio with the acetyl contents were tested.
It was shown that intrinsic viscositces in general with the increase of the acetyl contents, but these tendencies are strongest in the acidic solvents and weakest in the basic solvents. Neutral solvents lay between these two types.
But with the increase of the acetyl contents near to the triacetate, intrinsic viscosities in pyridine and the mixture of methylene chloride and ethanol show the tendency to increase with the acetyl contents.
These variations of intrinsic viscosities with the acetyl contents are also tentatively discussed relating to the chain configuration as the results of the interaction between free hydroxyl, acetyl groups and the solvents.
