Synthesis, characterization and degradation of a novel class of fluorescent poly[1,3-bis(p-carboxyphenoxy) propane: p-(carboxyethylformamido)benzoic anhydride] (P(CPP:CEFB))

One class of fluorescent copolyanhydrides were synthesized by melt copolycondensation of the fluorophoric diacid, p-(carboxyethylformamido)benzoic acid (CEFB), with 1,3-bis(p-carboxyphenoxy) propane (CPP). ¹H NMR spectra of the copolymers confirm their chemical structures. All the copolymers can give off fluorescence with the excitation of both UV (356 nm) and visible light (470 nm). The fluorescence intensity increases with an increase in CEFB fraction. The degradation rate of the copolyanhydrides can be modulated by the polymer components, increasing with a decrease in CPP content. In addition, CEFB segments in the copolymers degraded rapider than CPP segments, resulting in an increase in CPP fraction in the degraded copolyanhydrides. Morphology change of the copolyanhydrides during degradation was also examined by SEM. It was found that the outer layers of the degraded samples erode faster than the inner layers. Fluorescence intensity of the degraded copolyanhydrides diminished with time.