All samples were measured using IR spectroscopy to gain insight into possible chemical changes within the macromolecules. The spectra of the test series: lignin without additives, lignin with NaOH, lignin only with SPC can be found in the supporting information (Fig. ). Figure shows the baseline corrected and normalised spectra of the time-dependent test series, which were milled with SPC and NaOH. The spectra were normalised against the vibration of the aromatic framework at 1591 cm -1 . Figure shows the overview spectrum and Figure B the 'region of interest' in the spectral range of 2000-700 cm -1 .