Preparation and Characterization of Nanocellulose/Polylactide Fully Green Nanocomposites

A novel approach for mass production of filamentous nanocellulose(NC) with a transverse size of 20-40 nm and a length of 400-2000 nm was developed. The NC was modified with acetic anhydride, and obtained hydrophobic acetylated nanocellulose(ANC). NC and ANC were respectively blended with polylactide(PLA) to prepare nanocomposites by a solution-casting process. The effect of filler content, chemical modification and blending methods on the mechanical and crystallization properties of nanocomposites were investigated. The results showed that ANC displayed better dispersibility than NC in PLA matrix. However, the improvement for mechanical properties of nanocomposites was not obvious. Moreover, differential scanning calorimetry(DSC) isothermal crystallization test showed that ANC increased crystallization rate and crystallinity degree of PLA simultaneously. The NC/PLA nanocomposites prepared by melt compounding not only maintained high modulus, high yield strength, but also exhibited better thermal stability and remarkably improved toughness. For instance, when the addition of NC was 3.5%(mass fraction), the elongation at break of the nanocomposites increased by 12.1 folds in comparison with that of neat PLA matrix.