Cellulose nanocrystals modified with a triazine derivative and their reinforcement of poly(lactic acid)-based bionanocomposites

In order to improve the thermal stability of cellulose nanocrystals (CNCs) and to weaken their hydrophilicity, extensive research has been conducted to graft hydrophobic molecular chains on CNC surfaces to cover and/or replace hydroxyl and sulfate ester groups. According to our previous research, it was proposed that triazine derivative is an ideal candidate to modify CNCs. In this study, triazine derivative-grafted CNCs were synthesized and incorporated into poly(lactic acid) (PLA) nanocomposites as a reinforcing filler. The synthesis of triazine derivative was confirmed by FT-IR and the characterization of modified CNCs was determined by TEM, FT-IR,C-13 NMR, EDX, TGA and contact angle measurements. It was found that the triazine derivative was successfully grafted onto the CNC surfaces. The thermal stability of the modified CNCs was improved, and hydrophobic CNCs were obtained. Moreover, the properties of CNC/PLA composites were investigated by SEM, UV-Vis spectrophotometer and DSC, and the mechanical properties of composites were measured. The compatability of the modified CNCs with the PLA matrix was improved, and the mechanical properties of PLA composites were improved without serious destruction of their transmittance.