Synthesis of a novel fluorescent coloured copolymer based on 4‐butylthio‐1,8‐naphthalimide

A novel fluorescent coloured copolymer based on naphthalimide was prepared. Acenaphthene was brominated and oxidised to prepare 4‐bromo‐1,8‐naphthalic anhydride and further reacted with butanethiol, 2‐aminoethanol and acryloyl chloride, in order to obtain a new polymerisable fluorescent dye. The synthesised dyes were characterised by differential scanning calorimetry, absorption spectroscopy (Fourier Transform–infrared, proton and carbon nuclear magnetic resonance, ultraviolet–visible spectroscopy) and fluorimetry. Molar extinction coefficients and wavelength maxima were obtained by examining the dye solution in ethanol. The solvatochromic effects of the prepared dyes have also been investigated. Finally, the dye was copolymerised with methyl methacrylate and an intrinsically coloured copolymer was obtained. The photophysical characteristics of the obtained copolymer have also been considered. It is assumed that 99% of the copolymerised dye is chemically bonded to polymer chains. The fluorescent characteristics of the copolymer in the solid state were determined by fluorometer and it was found that it has relatively high fluorescent intensity. The physical properties of the synthesised copolymer have been evaluated by differential scanning calorimetry and gel permeation chromatography.