▎ 摘　　要

Graphene oxide (GO), p-phenylene diamine (PPD), N-hydroxysuccinimide (NHS) and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (EDC) were used as starting materials for preparation of p-phenylenediamine functionalized graphene oxide (FGO). By orthogonal design of experiments, the optimum conditions for preparation of FGO were found to be as follows: reaction temperature of 80 degrees C, reaction time of 8 h, weight ratio of graphene oxide, EDC, NHS, and PPD of 1:1:1:0.8. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed the structure of FGO. On this basis, poly(lactic acid) (PLA)/FGO nanocomposites were prepared with FGO as fillers by melt intercalation and their mechanical properties, thermal stabilities, crystallization properties, and rheological behaviors were investigated. Results showed that the impact strength, elongation-at-break, and tensile strength of PLA/FGO nanocomposites were enhanced by 58.9%, 6.12%, and 4.98%, respectively, when the amount of FGO added was 0.1 wt% in PLA. Differential scanning calorimetry and polarized optical microscopy showed that FGO improved the crystallinity of PLA. Thermal gravimetric analysis demonstrated that trace amounts of FGO improved thermal stability of PLA. Furthermore, the compatibility tests of PLA/FGO nanocomposites demonstrated that FGO had good compatibility with PLA matrix. The enzymatic hydrolysis process was simulated and described by the Michaelis-Menten equation and the depolymerization of PLA using proteinase K at different temperatures was studied to obtain the thermodynamic parameters through Arrhenius equation.