Relation between Intrinsic Viscosity and Degree of Polymerization
IT is generally agreed that the relation between intrinsic viscosity and degree of polymerization (D.P.), for the majority of polymer systems, is of the form [η] = K (D.P.)a; but there appears to be no slackening in the controversy as to the numerical values of K and α for a particular system. Most of the values have been obtained from measurements of the intrinsic viscosity and osmotically determined degree of polymerization on nearly homogeneous fractions. Apart from experimental error, there is a number of ways in which discrepancies can arise. High intrinsic viscosities may not be free from the influence of the non-Newtonian behaviour of the solutions from which they are derived; fractions may not be sufficiently homogeneous; and membranes may not be strictly semi-permeable1.
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