Intrinsic viscosity‐number average molecular weight relationship for poly (n‐Octadecyl acrylate) and poly (N‐n‐octadecylacrylamide)

Intrinsic viscosity‐number average molecular weight relationships have been measured, at 30C in benzene, for poly (n‐octadecyl acrylate) as [॑]=2.72ȕ10 蜢4 Mn 0.638 and for poly (N‐n‐octadecylacrylamide) as [॑]=0.82ȕ10 蜢4 Mn 0.676 . Whole polymers of various molecular weights were prepared in benzene solution at 65C with dodecyl mercaptan as primary regulator. By the use of these parameters, the molecular weight of such polymers and their homologs may now be measured by simple solution‐viscosity determinations. In the expression { } (relating degrees of polymerization { } to the mercaptan/monomer ratio), intercept { } and apparent transfer constant C s for n‐octadecyl acrylate were 6.28ȕ10 蜢3 and 0.68; for N‐n‐octadecylacrylamide 1.10ȕ10 蜢3 and 0.62 respectively. These parameters permit preparation of homopolymers of chosen molecular weight.