Study of the alkali lignin stabilization thanks to plasma process

The influence of plasma treatment on lignin chemical and physical properties was studied. The screening of the different process parameters (gas chemical nature, flow, pressure and discharge power) shows changes in the glass transition temperature (Tg) of different lignins. Chemical nature of plasma phase has the highest influence. These changes are related to the modulation of the molecular weight of lignin chains (crosslinking or degradation) and were evidenced by differential scanning calorimetry and by dielectric spectroscopy. Treated lignin powder showed better processability by extrusion (lower viscosity) than the pristine one.