Thermal behaviors of ferrocenyl-terminated hyperbranched polyester

The first to the fourth generation (G1-G4) of ferrocenyl-terminated hyperbranched polyesters (HBPE-CP-Fe) were successfully synthesized by esterification between ferrocene carboxylic and hyperbranched polyester(HBPE). The molecular structures of HBPE-CP-Fe were characterized by FTIR, ¹H NMR and ¹³C NMR techniques. The thermal properties and the structure of thermal decomposition segments were investigated by thermal gravimetry (TG)-derivative thermal gravimetry (DTG), differential scanning calorimetry (DSC), FTIR and element analysis techniques. G1-G4 HBPE-CP-Fe are more thermally stable than G1-G4 HBPE and the incorporation of ferrocene could efficiently improve the thermal stability of HBPE. The thermal degradation of HBPE-CP-Fe is multi-stage process between 240 and 500 °C and the mass loss of the HBPE-CP-Fe seems to stop further at the temprerature above 500 °C with the final weight losing rate of 78. 6%. The left residua is carbon and iron elements. A possible thermolysis mechanism is proposed as that the thermal decomposition might contain some complicated subsequent reactions including the scission of weak links of ester bands, the formation of intermediate composites and the degradation of the ferrocene.