Abstract
The viscosity of the Yamagata-clay sol is measured with the capillary method and with the falling-body method as well; and some anormalisms of it, the relation of viscosity-temperature and that of viscosity-concentration, the specific hydrodynamical volume of colloidal particle have been studied, a model of particle formation being finally inferred. The following is the brief summary of the present investigation.
1. The dense sol of the clay shows some anormalous viscosities. The structural viscosity of the sol is a indication of any gel structure. The structure is easily broken with a small shearing stress exerted by the flow head of capillary, causing the serious apparent viscosity drop. Yet the broken structure of the sol shows a self-curing ability and recovers slowly but almost completely the original structure, that is the so-called thixotropism. Moreover, there is a very singular anormalism, i.e., when the falling-body method is applied, the apparant viscosity of the sol gradually increases with increasing path of the falling-body.
2. There is the following relation between the relative viscosity, of the thiner sol and the concentration, c, in grams per 100cc of sol:
logηr=αc+βc2
where α and β are the empirical constants. But in case the sol increases in concentration, the estimated value of ηr becomes larger than is shown in the above equation.
3. When sol is thin, the temperature effect to viscosity is denoted by the following equation, that is the same as that given by Poiseuille for pure water:
ηt=ηo/1+pt+qt2
where ηt and ηo are viscosities at t and 0°C respectively, p and q being the empirical constants.
4. The specific hydrodynamical volnme, φ, of the clay in sol is calculated with the following viscosity formula, which was presented by I. Sakurada recently for celullose sol:
ηr=ηc/ηo=1+aφc/100-φc
Here ηc and η0 are the viscosity coefficients of sol and simple medium, accordingly the ratio of them, ηr, the relative viscosity; c, the concentration in grams per 100cc of sol, and a is a constant called ‘Form und Ladungsfactor’ by Sakurada. The average value of φ for Yamagata-clay is 32.5cc per 100cc of sol, which contains lg of dried mass, covering the temperature range 10-35°C. This figure of φ shows that the swelling ratio of the clay is roughly 80. The value of φ has a slightly decreasing tendency with increasing temperature.
5. The particle suspending in dilute sol must be a fragment of the gel structure. It seems to does some visco-elestic but not plastic deformation by any stress, and moreover to be a complex grouping of some flexible chain-like aluminosilicic molecules. Besides, every heavy molecule or unit micelle must have dense and less-mobile liquid layer or ionic swarm on and near the surface, only that mobility quickly increases outwardly
