Cellulose nanofiber-reinforced polylactic acid

The reinforcement of polylactic acid (PLA) using microfibrillated cellulose (MFC, mechanically fibrillated pulp, mostly consisting of nanofibers) is reported, with the goal of making sustainable ‘green-composites’. The production procedure to attain uniform dispersion of MFC in a PLA compound was assessed, and then mechanical and thermo-mechanical properties of the sheets after hot-pressing of the compounds were studied. Needle-leaf Bleached Kraft Pulp (NBKP) and refiner-treated NBKP were also used to study the effects of filler morphology. When MFC was premixed with PLA using organic solvent and the mixture was kneaded after the removal of the solvent, the MFC was uniformly dispersed in the PLA. The MFC increased Young’s modulus and tensile strength of PLA by 40% and 25%, respectively, without a reduction of yield strain at a fiber content of 10 wt%. On the other hand, NBKP reduced the yield strain by 30% and reduced the strength by 15% at a fiber content of 5 wt%.