Click Chemistry Reactions between Hydroxyl-Terminated or Alkynyl-Terminated Polybutadiene and Benzyl Azide

Alkynyl-terminated polybutadiene (ATPB) may be as a new type of propellant binder through click chemistry reaction between alkynyl and azide group. In this paper, The reactions between ATPB and hydroxyl-terminated polybutadiene (HTPB) with benzyl azide, respecfively, were tracked by ¹H-NMR, ¹³C-NMR, FTIR, and Elemental analysis measurements. The results show that the azide group and C=C of HTPB undergo 1,3-dipolar cycloaddition reaction to form a 1,2,3-triazoline ring without the catalyst. Both terminal C≡C and middle C=C bonds of ATPB can react with azide groups, and the reactivity of the C≡C bond is significantly higher than that of the C=C bonds. With the copper (I) catalyst, the reaction between the azide group and the C=C bonds of HTPB is significantly weakened, that is the copper (I) can not catalyze the reaction between C=C and -N₃. these results are very meaningful for the design of the ATPB and azide system as the binder of solid propellant.