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

Abstract

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 1 H-NMR, 13 C-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 termi-nal 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 -N 3 . these results are very meaningful for the design of the ATPB and azide system as the binder of solid propellant.

Facile synthesis of three diazido compounds and their application in polyether polytriazido elastomers as solid propellant binders

“…2,3 The polyurethane binder could exhibit outstanding comprehensive performance, 4 especially for hydroxyl terminated polybutadiene (HTPB) propellant which has already been widely applied due to its low glass transition temperature, great mechanical properties, ease of processing and highly resistant to oxidation. 5,6 However, this requires a complete reaction of all hydroxyl groups since it is vulnerable to the moisture and oxidizer, 7 otherwise the side reaction will much likely take place during and after cross-linking reaction. Therefore, it is mandatory to strictly control the water content of the raw materials and the environmental humidity, which asked for a high requirement for the production condition.…”