Preparation of Covalently‐colored Polymer Latex via Batch Emulsion Polymerization

Abstract

Covalently-colored polymer latex was synthesized via batch emulsion copolymerization of styrene, butyl acrylate and methacrylic acid in the presence of red polymerizable dye monomer consisting of anthraquinone chromophore, alkyl spacer and acryloyl group, and the influences of the initiator, surfactant and polymerizable dye on the polymerization and the latex properties were investigated. Results showed that the initiator amount was a determinative factor for the monomer conversion, and a high conversion of the polymerizable dye could be achieved when the ammonium persulfate amount was equal to or more than 1 wt% to the total monomers. Most of the chromophores were covalently bonded to the polymer chains if the polymerizable dye was used in the range of 0-1.5 wt%. The light fastness of the resulting latex film was much better than that of the noncovalently-colored polymer film.

Preparation and properties of covalently colored polymer latex based on a new anthraquinone monomer

“…For instance, Winnik et al synthesized several kinds of fluorescent monomers and prepared fluorescent latex particles by traditional emulsion polymerization and miniemulsion polymerization 18, 19. In our previous work, the polymerizable azo and anthraquinone dyes were synthesized and utilized to prepare the red and yellow covalently colored latexes by different emulsion polymerization processes, and the storage stability of the latexes and the light fastness of the latex films were proved to be much better than that of the noncovalently colored latex 20–22. For the further application, a kind of blue covalently colored latex with higher color strength was expected to complete the color species.…”

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

“…It is notable that for the system without using dye, the monomer conversion was higher than that system containing dye in the first 60 min because of the inhibition effect of the AQ structure of the dyes according to the literature. [18,20] However, all of the final conversions were almost 100%, regardless dye used or not. Thus, the miniemulsion polymerization time was controlled at 2 h in the following study.…”

“…The sharp increase of the polymerization rate at high monomer conversion ascribed to a pronounced gel effect. Because of the inhibition of AHAQ and PHAQ, [18,20] the free radical concentration in the dyecontaining polymerization systems was lower than that in the system without dye, and as a consequence, the overall polymerization rate was lower as shown in Figure 4. Along with the polymerization in the presence of AHAQ, AHAQ was gradually incorporated into the polymer; thus, the mobility of the AQ groups decreased compared with the polymerization system with PHAQ.…”

“…However, when the dye amount was 1.0 wt% in a semi-continuous emulsion polymerization process, the dye conversion was only 82% according to literature. [18] This is an advantage of miniemulsion polymerization against conventional emulsion polymerization in the preparation of covalently colored latexes. Because AHAQ is water insoluble, it is difficult for AHAQ molecules to transfer from monomer droplets to the latex particles in conventional emulsion polymerization process.…”

“…[18][19][20] However, because the synthesized dyes were barely dissolved in water, it is difficult for these dye molecules to transfer from the monomer droplets to the latex particles through water phase to carry out copolymerization in the conversional emulsion polymerization process, and as a result, the dye conversion was only 82.0% when the dye amount was 1.0% to the total monomers. [18] To improve the incorporation efficiency of the polymerizable dye, a more hydrophilic polymerizable dye was synthesized via six-step organic reaction, and a stable colored polymer latex was prepared with 97.3% conversion of the polymerizable dye through semi-continuous emulsion polymerization. [21] In this work, in order to simplify the synthesis process, miniemulsion polymerization was explored to prepare covalently colored polymer latex.…”