Compatibility between Cellulose and Hydrophobic Polymer Provided by Microfibrillated Lignocellulose

Microfibrillated lignocellulose (MFLC) was produced from wood subjected to partial lignin extraction using an ethanol/ water mixture. After homogenization, the average fibril diameter of MFLC was in the same range as conventional microfibrillated cellulose (MFC). Although MFLC exhibited higher wettability with water compared to MFC, AFM adhesion force measurements revealed high variability in surface polarity of MFLC compared to MFC. Specifically, domains of higher polarity than in MFC but also domains of lower polarity than in MFC were observed in MFLC. This tendency towards amphiphilic behavior of MFLC was used to provide enhanced compatibility with polycaprolactone and polystyrene matrices. With both polymers, a significantly more homogeneous distribution of fibrils was achieved using MFLC compared to MFC. In line with better dispersion of the fibrils, significantly more efficient mechanical reinforcement of polymers was obtained using MFLC compared to MFC.