Abstract
This paper concerns with the error of Mn attributable to the rapidly permeating polymer species through the membrane. The polymers employed in this work are isotactic polypropylene (PP), low and high density polyethylene (LDPE and HDPE).
Well known log-normal distribution function and experimental column fractionation data enabled us to draw the correction curves of Mn for these polymers. It is considered, on the other hand, the permeation phenomena are related to the volume of the polymer in the solution, This can be evaluated experimentally from the osmotic pressure vs. time curves. The order of the permeation determined by this work was as follows: PS>PP>LDPE and HDPE.
Concerning the commercial polymers, however, it was not possible to predict the amount of error on Mn only from the above order of permeation. The error for LDPE is much greater than for HDPE and PP owing to the difference in molecular weight and its distribution.
