Facile synthesis and characterisation of covalently coloured polyurethane latex
In a recent work, a new method for facile synthesis of covalently colored polyurethane latex was developed. A series of blue dye monomers were synthesised via one-step reaction of a reactive dye and amino compounds, and then employed as chain extenders to react with polyurethane prepolymer in the emulsification process to prepare the covalently coloured polyurethane latexes.
The chemical structures and the properties of dye monomers and the corresponding polymers were investigated, and the UV–Vis spectra of covalently colored polyurethane featured fairly consistent with dye monomers with maximum absorption wavelength at 620 nm and 580 nm, since the chemical structure of chromophore maintained unchanged.
Light fastness of the covalently colored latex film was greatly promoted
The conversion of dye monomer reached more than 92% with 1.0 wt% dye content, whereas the conversion decreased with the increase of the dye amount and the adding time. Compared with the noncovalently latex film, the light fastness of the covalently colored latex film was greatly promoted due to the chemical bonding of chromophores with polymer matrix.
The complete study can be found in Progress in Organic Coatings, Volume 129, April 2019.