Properties of poly (l-lactic acid) reinforced by l-lactic acid grafted nanocellulose crystal

In this research, nanocellulose crystal (NCC) grafted with lactic acid (LA) oligomer was synthesized by one-pot method and used to reinforce the poly( l -lactic acid) (PLLA) matrix. FT-IR, XRD, and 13C NMR were used to analyze the structure of modified nanocellulose crystal (g-NCC). The results of GPC suggested that the degree of polymerization of the grafted segments was 23, and the degree of hydroxyl substitution of g-NCC was 2.4%. For the g-NCC/PLLA composite, its crystallization rate increases significantly compared with pure PLLA, indicating that g-NCC acted as a nucleating agent to promote the crystallization. Moreover, tensile strength of the composite materials was significantly improved from 41.9 MPa to 53.9 MPa due to the enhanced compatibility. This study provides a fast and effective modification method for g-NCC/PLLA biodegradable composites. According to the above-mentioned experimental results, the g-NCC/PLLA composites can be considered as a potential material in the packaging field, mainly due to its proper biological and physicochemical properties.