Studies on polymerization and depolymerization of ϵ‐caprolactam polymer IV.. Molecular weight distribution of the water‐soluble chain molecules in poly‐ϵ‐capramide

The molecular weight distributions of the water‐soluble chain molecules in poly‐ϵ‐capramide HO[CO(CH2)5NH]nH at equilibrium have been investigated in order to ascertain whether they coincide with the FLORY‐SCHULZ distribution or not. Each of the chain molecules has been isolated by paperchromatography and its quantity has been determined and compared with the value calculated from the FLORY‐SCHULZ distribution. Comparing the equilibrium constants for the condensation reactions between chain molecules, it was resulted that they are affected by the chain length. Therefore, the FLORY‐SCHULZ's assumption that the reactivity of the functional group is independent of the chain length, can not be applied to the water‐soluble chain molecules in poly‐ϵ‐capramide. Moreover the reactivity of the functional end‐group in poly‐ϵ‐capramide molecules becomes greater as the chain length becomes longer.