EFFECT OF FUNCTIONAL SUBSTITUENTS ON THE ISOMERIZATION POLYMERIZATIONOF CYCLIC PSEUDOUREAS

Six cyclic pseudoureas having functional substituents were newly prepa red, and their ring-opening isomerization polymerization initiated wit h methyl trifluoromethanesulfonate and double isomerization polymeriza tion (DIP) initiated and catalyzed by methyl iodide were investigated. The monomers have a common base-structure of 2-(4-substituted piperad in-1-yl)-2-oxazoline (1b similar to e) or 2-(4-substituted piperidin-1 -yl)-2-oxazoline (1f, g). The substituent on the imino ring strongly i nfluenced the polymerization behavior of the monomers in DIP because o f their neighboring group participation with the propagating alkyl hal ide end. The introduction of an aliphatic amide group enhanced the sta bility of the propagating end, particularly when the substituent was v aleroyl (Ic), while degradative chain transfer was induced when the su bstituent was ethoxycarbonyl (le). The introduction of an ester (If) o r hydroxyl (Ig) group caused significant chain transfer in both modes of polymerization.