Synthesis and characterization of the PTMG aliphatic hyperbranched polyurethane

The isocyanate-terminated polyurethane prepolymer (PPU) was synthesized by step-growth polymerization using polytetramethylene ether glycol (PTMG, Mn=2000) with isophorone disocyanate (IPDI) as the monomers, dibutyltin dilaurate (DBTDL) as the catalyst. The appropriate reaction conditions were optimized by single factor experiments as follows. The reaction temperature was 75°C, the reaction time was 1.5 h and the quantity of catalyst was equal to 0.007% of feedstocks. And then the hyperbranched polyurethane (HBPU) was synthesized by graft copolymerization using isocyanate-terminated polyurethane prepolymer (PPU) and hyperbranched poly (amide-ester) polyol (HPAE) as the raw materials. The appropriate reaction conditions were optimized by single factor experiments as follows. The reaction temperature was 75°C, the reaction time was 4.5 h. The molecular structure of the monomers of PPU and HBPU were characterized by FT-IR. The thermal stability of PPU and HBPU were characterized by thermogravimetry.