Crystallization, rheology behavior, and antibacterial application of graphene oxide-graft-poly (L-lactide)/poly (L-lactide) nanocomposites

Poly L-lactide nanocomposites with graphene oxide (GO) were prepared via solution casting in this work. With the aim of improving the interface compatibility, the GO grafted with poly L-lactide (GO-g-PLLA) was synthesized by the ring-opening polymerization of L-lactide on the surface of lyophilized GO. The chemical structure, morphology and thermal properties of GO and GO-g-PLLA were compared by X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and thermal gravimetric analysis (TGA), respectively. Based on the isothermal and non-isothermal crystallization of PLLA/GO-g-PLLA blends, the added GO-g-PLLA acted as nucleating agents to enhance the crystallization rate of PLLA, with its special surface grafted with the PLLA matrix. The introduced GO-g-PLLA sheets also improved the viscosities of PLLA as rheological enhancers, which is favorable for the processibility of PLLA. The added GO-g-PLLA also endow PLLA nanocomposites with significantly improved electrical conductivity. More interesting, this work presented the antibacterial activity of PLLA/GO and PLLA/GO-g-PLLA nanocomposites electrospinning membrane for Escherichia coli and Staphylococcus aureus, which further widen the biomedical application of PLA.