Production and use of microfibrillated cellulose from virgin and recycled lignin-rich sources: a comprehensive comparison

Abstract Use of microfibrillated cellulose (MFC) from recycled sources gain more and more interests in paper industry, whose prevailing direction is to increase the incorporation rate of recycled fibers without decreasing paper quality, increasing the cost or toxicity of current processes. This study proposes a better comprehension in the phenomenon involved during the fibrillation of recycled fibers. MFC were prepared from two recycled paper grades, Corrugated Cardboard (CC) and Recycled Liner (RL), and from virgin lignin-rich unbleached Kraft pulp (VKP). These materials were compared with a commercial MFC from virgin bleached pulp. Morphological analyses and AFM images evidenced highly fibrillated materials after ultra-grinding. Tensile and air permeability tests on nanopapers revealed better performance for MFC from virgin resources, even compared to recycled pulp devoid of mineral fillers. Ozonation as a pretreatment showed limited effectiveness for fibrillation. Incorporation of MFC from recycled sources (RMFC) into RL significantly enhanced mechanical properties: +39 % in Young’s modulus and +44 % in tensile strength. Despite RFMC exhibited lower intrinsic performance than MFC from VKP, its reinforcement efficiency brought to RL was similar. Sheet porosity, assessed through air permeability and roughness, further decreased with RMFC addition. Finally, RMFC proved a sustainable alternative to virgin MFC.