Designing of energetic miktoarm A2B2 star‐shaped polymer by means of click chemistry and ROP techniques

Novel A2B2‐type energetic miktoarm star‐shaped copolymers composed of two PGN arms and two PCL arms was synthesized by the combination of ring‐opening polymerization (ROP) and “click” chemistry. Initially, diazido end‐functionalized two‐arm PGN, (PGN)2‐(N3)2, was synthesized by ROP of glycidyl nitrate monomers. Subsequently, (PGN)2‐(PCL)2 was obtained from the click reaction between diazido end‐functionalized (PGN)2‐(N3)2 polymers and propargyl‐terminated poly(ε‐caprolactone) (PTPCL). This star copolymer solves problems of PCL (lake of energy) and PGN (low Tg). The Fourier‐transform infrared (FT‐IR), 1H nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC) studies revealed that (PGN)2‐(PCL)2 was successfully obtained. The thermal behavior of star polymer was investigated by thermogravimetric analysis (TGA) and derivative thermogravimetry. The results show that (PGN)2‐(PCL)2 decomposed at two stages. The first stage is seen at 212.6°C which related to degradation of –ONO2 group and second stage attributed to degradation of PCL group which is seen at 346.1°C.