Biodegradation of Composites of Polylactic Acid and Microfibrillated Lignocellulose

We present a study of the controlled biodegradation of polylactic acid (PLA) reinforced with high lignin containing microfibrillated cellulose (MFLC) isolated from chemi-thermomechanical pulp. The surface of MFLC was modified using an acetylation method to decrease its polarity. Biocomposites with different MFLC and acetylated MFLC (Ac-MFLC) contents were fabricated via a solvent casting method. The biodegradation of biocomposites was performed by burying in soil and holding at 45 ° C for 30 days. After soil burial, MFLC/biocomposites exhibited higher weight loss (5.4 %) compared to neat PLA (4.2 %) and Ac-MFLC/biocomposites (4.6 %). Morphological analysis results showed surface erosion of the PLA to change with the addition MFLC and Ac-MFLC, resulting in porous formations on the surface of biocomposites. These formations led to the loosening of microfibril-PLA interface in the internal structure, resulting in a significant decrease in the storage modulus of biocomposites. The biocomposites exhibited no antimicrobial properties, confirming their biotic degradability. Graphical Abstract