Synthesis of polymers having 1,3-cyclobutanedione unit in the main chain by cycloaddition polymerization of bisketene

Summary A novel polymer having 1,3-cyclobutanedione unit in the main chain was prepared by cycloaddition polymerization of the bisketene derived from 1,4-cyclohexanedicarbonyl chloride. The polymer was soluble in MeOH, acetone, and CHCl₃. The structure of the polymer was confirmed by IR, ¹H-, and ¹³C-NMR spectroscopies compared with those of the model compounds. The polymer was found to contain anhydride bond as well as 1,3-cyclobutanedione unit in the main chain. The anhydride bond in the polymer was cleaved by MeOH under reflux condition in benzene. Received: 8 February 1999/Accepted: 16 March 1999