Synthesis, characterization and biodegradation of biodegradable-cum-photoactive liquid-crystalline copolyesters derived from ferulic acid

Novel biodegradable-cum-photoactive liquid-crystalline copolyester was prepared by melt polycondensation of ferulic acid (FA), 4-hydroxybenzoic acid (HBA) and d,l-lactic acid (LA) in the presence of acetic anhydride and a transesterification catalyst. The chemical structures and properties of the synthesized copolyesters were characterized by means of viscosity measurements, Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), thermogravimetry (TGA), polarizing light microscopy (PLM) and ultraviolet spectroscopy (UV). It was found that modestly increasing LA content and adjusting feed ratios could enhance the solubility and biodegradability of the copolyesters, still retaining the liquid crystallinity. The obtained copolyester could degrade in phosphate buffer solution (pH 7.2) with enzyme proteinase K, and could crosslink by UV-irradiation at ambient temperature.