Synthesis and Properties Study of PESF-b-PBIT White Fluorescent Copolyesters

In order to prepare white fluorescent emitting materials, poly(ethylene glycol succinate- co -2,5-furandicarboxylic acid ethylene glycol ester) (PESF) blue fluorescent copolyester was prepared by melt polycondensation, and an orange fluorescent copolyester was prepared by introducing 1,6,7,12-tetrachloro-3,4,9,10-perylene tetracarboxylic acid dianhydride, as one of the fluorescent units, into the molecular chain of poly(butylene glycol isophthalate- co -butylene glycol terephthalate)(PBIT). 4,4-dicyclohexylmethane diisocyanate (HMDI) was used as a chain extender for linking PESF and PBIT to obtain the white fluorescent copolyester. The results showed that introducing 2,5-furandicarboxylic acid (FDCA) into the molecular chain of aliphatic polyesters can significantly enhance the blue fluorescence intensity of the PESF copolyesters, and white-light emission with CIE coordinates of (0.31, 0.35) and (0.30, 0.34) was achieved for the copolyester by varying the content of in the PESF and the copolymerization ratio of PESF and PBIT. In addition, by adjusting the magnitude of the excitation wavelength, it is possible to achieve the fine-tuning of the light color of the white copolyester in a certain region, e.g., the CIE coordinates at 350 nm excitation are (0.32, 0.35). The white copolyester displayed high thermal decomposition temperature about 350  o C, remarkably increased elongation at break above 300%, relatively high tensile strength up to 33.2 MPa; therefore, these performance advantages make enhance their potential for applications.