Preparation of covalently colored polymer latex through miniemulsion polymerization based on a polymerizable dye

A polymerizable red dye 1-(6-acrylamidohexylamino) anthraquinone (AHAQ) was synthesized and used to prepare colored polymer latexes using styrene and butyl acrylate as main monomers. Influences of the initiator and surfactant amounts, oil/aqueous phase ratio, and AHAQ content on the polymerization process, the particle size, and surface tension of the resulted latex were investigated, and the migration resistance and light fastness of the red latex films were determined. Results showed that the polymerization was carried out smoothly, and the miniemulsion polymerization mechanism was confirmed by monitoring the dimensions of oil phase before and after polymerization. The latex particle size can be adjusted by varying the surfactant amount, and when AHAQ content was 0.2-1 wt% of total monomers, the encapsulation efficiency and dye conversion could be achieved to 98.7 and 96.3%, respectively. The UV-vis spectra of AHAQ and its corresponding covalently colored polymer indicated that the maximum absorption peak was the same, meaning that the chemical structure of chromophore in AHAQ maintains unchanged after undergoing polymerization. The migration resistance and light fastness of the covalently colored latex films were much better than that of the correspondingly non-covalently colored ones.