Synthesis and characterization of azido-terminated hyperbranched polyester

Taking p-toluenesulfonic acid as catalyst, trimethylolpropane as core, the hydroxy-terminated hyperbranched polyester was synthesized by condensation polymerization of 2,2-dimethylol propionic acid. Then, the azido-terminated hyperbranched polyester was synthesized by sulfonation and azidotion of the terminal hydroxy group in succession. The structures of the target hyperbranched polyester were characterized and verified by infrared spectrum (IR), C-nuclear magnetic resonance spectrum (NMR), gel permeation in chromatography (GPC) and elemental analysis. The thermal properties of azido-terminated hyperbranched polyester were characterized by thermogravimetry (TG) and differential scanning calorimetry (DSC). Results show that the degree of branching of azido-terminated hyperbranched polyester is 0.45. The thermal decomposition of azido-terminated hyperbranched polyester has two stages. The first stage is the decomposition of the terminal azido (249.4°C) and the second stage is the decomposition of the main chain (350°C). The glass transition temperature of azido-terminated hyperbranched polyester is -55.2°C.