Crosslinking through the reaction between the COOH of polyester and epoxy group of TGIC. (a) Schematic mechanism for the crosslinking reaction between the polyester and TGIC; FT-IR spectra of the polyester/nano-TiO2 composites with 2.0 wt.% nano-TiO2 from 130°C to 205°C. (b) The nano-TiO2 was not modified. (c) The nano-TiO2 was modified with aluminate coupling agent. (d) The absorbance at 908 cm-1 as a function of temperature for the two systems.