Evaluation of modified graphene and nanocomposites based on poly(lactic acid)

Full text: Graphene has recently attracted attention in polymer nanocomposites. Chemical modifications have been studied to improve the interfacial interaction between polymer and nanoparticle. The poly(lactic acid) - PLA - is a biodegradable, compostable and biocompatible polymer; a polyester obtained of renewable resources such as corn and sugar beet and is considered one of the most promising biopolymers for industrial applications. The aim of this study consisted in chemical modification of graphene with octadecylamine (ODA) and preparation of nanocomposites via casting based on PLA and modified graphene (GODA). Polymer nanocomposites were prepared via casting on chloroform and the nanoparticle was dispersed through ultrason bath. The GODA were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) and thus the modification was proved [1,2]. The dynamic molecular of nanocomposites were evaluated by low field NMR (23MHz) and both relaxation times (T₁^H1, T₁^H2) increased when the GODA was incorporated (0,01% GODA) and a higher relaxation time to the more concentrated film (0,1% GODA). The increase of relaxation times denote a raise of stiffness of the material, which also is associated to elevation of crystallinity. And this bigger stiffness can be connected with the increase of the interaction between PLA and GODA. This study showed that the chemical modification of graphene with octadecylamine promoted better interactions with PLA and increase of stiffness on nanocomposites. References: 1. ZHANG, S. P.; SONG, H. O. New J. Chem., 2012, 36, 1733-1738. 2. KIM, I. H.; JEONG, Y. G. J. Polym. Sci. B Polym. Phys., 2010, 48, 850-858. (author)