1970 年 19 巻 205 号 p. 919-925
The viscosity measurements of polyvinyl acetate (PVAc) in the bulk and in the concentrated solutions were carried out in diethyl phthalate and in cetyl alcohol with capillary and pippet type viscometers in the molecular weight range from 1.34×106 to 7.95×103, the concentration range from 1.0 to 0.106 in weight fraction and the temperature range from 35 to 157°C.
In a wide range of the variables covered in this study, the interrelationship of the viscosity of the bulk and solutions of PVAc, η, the chain length Zw, the concentration (Volume fraction v, of polymer) and the temperature T can be represented by the following formulas:
The dependence of critical chain length Zc on concentration is represented as;
The relationship between the viscosity and the chain length was examined further by correcting the effect of free volume. The viscosity date were reduced to the values corresponding to the free volume state for the reference molecular weight by employing the theories and literature values of Ninomiya et al., Fujita et al., and Pezzin. The reduced viscosities were proportional to Zw in the short chain length range where Zw≤Zc. The further reduction based on the concentration dependence of free volume made it possible to superpose the reduced viscosity logarithmically plotted against Zw for different concentrations by shifting them parallel to the horizontal axis. The shift factors were examined by the theory proposed by Onogi et al.
The magnitude of the slippage factor in Bueche's theory was estimated with the data in this study. It was considered that the effect of solvent on the slippage factor was relatively small.