With colloidally stable hydroxymethylated nanoparticles available, our next step was to explore the possibility to hydrothermally cure the particles in dispersion state and investigate their stability in organic solvents and as a function of pH in aqeueous dispersions. To find a suitable curing temperature we subjected the hydroxymethylated lignins to thermal analysis. DSC thermograms recorded from HL60 and HL85 revealed that the degree of hydroxymethylation affects their thermal behavior. The area of the exothermic peak associated with the condensation reaction of HL between 120 to 170 °C was proportionally larger in HL85 compared to HL60 (Figure ). Successful curing of HL60 and HL85 in dry state at 150 °C was obvious also by comparing solubilities in acetone-water (3:1 w/w) solvent mixture of the original kraft lignin and the two cured samples. In contrast to their parent lignin that was fully solubilized, the hydroxymethylated lignins showed low solubility that expectedly followed the order HL60 > HL85 (Figure ).