Inhomogeneity of hydrolytic polyamide 6 with respect to the average molecular mass

The point of view was advanced that in spinning fibres from polymer melts, the molecular inhomogeneity of the melts is not due to the polydispersity of the polymer but to important differences in the average molecular mass of the individual granules. Using the example of three industrial samples of hydrolytic PA 6, it was shown that the standard deviation of the average molecular mass of the polymer with respect to the individual granules from its mean statistical values is at the level of 10–11% for a practically significant (for up to several percent of granules) deviation of 30–50%. The use of samples of PA 6 with the mass provided by GOST 18245–72, OST 6-06-S9-76, and GOST 11034-82 in determining the viscosity a solution of the polymer in H2SO4 allows correctly estimating its average molecular mass but makes it impossible to obtain reliable information relative to the real degree of inhomogeneity of the granulate based on this index.