The Characterization of Biobased Latex Dispersions by Serum Replacement

This paper builds upon the findings of previous work on the rheological properties and dynamic water retention properties of starch latex-containing coating colours. The previous work showed that the rheological performance of starch latex and dynamic water retention of starch latex are different from conventional cooked coating starches. In this paper, the basic nature of water-swollen starch nanoparticles and their colloidal behaviour are investigated using serum replacement. Serum replacement experiments showed that starch latexes are complex systems of particles and a minor fraction of soluble polymers. Increasing the degree of crosslinking decreased the soluble fraction and lowered the dispersion viscosity. Coatings applied using a cylindrical laboratory coater showed the plasticity of SB latexes acted as a lubricant during calendering and aided to improve gloss. Crosslinked biobased latexes and hydroxyethylated starch (graft polymers) improved water retention, but the use of low crosslinked Bio-A was found to lower gloss.