Synthesis and Properties of Nitrogen Heterocycle-Functionalized Core-Shell Hyperbranched Polyester

Core-shell hyperbranched polyesters (HBPE) of third generation prepared from 2,2'-bis (hydroxymethyl) propionic acid (Bis-MPA) as an AB(x) monomer and N-heterocyclic (indole, piperidine and piperazine) phosphoryl dichloride as a core molecule by melt condensation process. These polymers were characterized by FT-IR, H-1 NMR, C-13 NMR, P-31 NMR, elemental analysis, and MALDI spectroscopy. The thermal behavior of the polymers has been investigated by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). There is no weight loss observed until 250 degrees C under nitrogen atmosphere. DSC showed that the glass transition temperatures was about -14 and -30 degrees C for the prepared core-shell HBPE. The dielectric properties such as dielectric constant and loss factor for these polyesters were also studied with respect to change of frequency (50 Hz to 5 MHz).