Structural and optical study of chitosan–graphene oxide composite through hydrothermal route

Abstract

Chitosan (CS), a semi-crystalline biomolecule, has gained widespread attention due to its great synthesis flexibility and biological compatibility. In this study, chitosan was synthesized from chitin, a homopolymer of N-acetyl-D-glucosamine linked by β–(1→4) bonds extracted from shrimp shell. Crystallinity of chitosan was always an issue while applying it in various applications. Graphene Oxide (GO) can be a very capable substitute for enhancing the crystallinity of chitosan due to its mechanical, thermal, optical, biomedical, and electronic properties. In this study, a chitosan–graphene oxide composite was synthesized by following the hydrothermal method. The characterization of chitosan–graphene oxide composite performed by different processes: x-ray diffraction revealed that the produced chitosan–graphene oxide composite has improved crystalline characteristics, with a smaller crystallite size of 6.2 nm when compared to GO and CS. Fourier transform infrared spectroscopy confirmed the presence of functional groups in GO, CS, and GO–CS. The Raman spectrum predicted the increased disorders originated from sp2 carbon hexagonal networks with strong covalent bonds. The relative quality and successful preparation of the GO–CS composite were evaluated and confirmed by ultraviolet spectroscopy. The scanning electron microscopy (SEM) analysis pictured the morphology of the GO-CS composite. The novel aspect of this study was the incorporation of graphene oxide in order to boost the crystal structure of chitosan derived from raw shrimp shells.