Preparation, characterization, and reaction kinetics of poly (lactic acid)/amidated graphene oxide nanocomposites based on reactive extrusion process

Abstract

The poly (lactic acid) (PLA)/amidated graphene oxide (AGO) nanocomposites were prepared by reactive extrusion process with L-lactide as raw material, zinc lactate as catalyst, hexamethylene diisocyanate as chain extender, and AGO as nano-nucleating agent prepared by amidation. The molecular weight of PLA and PLA/AGO were 29,424 g/mol and 32,516 g/mol, respectively, under the optimum conditions, which were obtained through orthogonal experiments. The structure and performance of PLA and PLA/AGO nanocomposites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), mechanical properties, differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), and capillary rheology. The results showed that the AGO could uniformly dispersed in PLA matrix, which significantly improved the mechanical properties, crystallinity, and thermal stability of PLA. Kinetics studies showed that the polymerization reaction model presented the second-order reaction, and the apparent rate constant of PLA/AGO nanocomposites was 7.612 × 10³ g·mol ⁻¹ ·min ⁻¹.

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