Synthesis and Characterization of Covalently Linked Graphene/Chitosan Composites

Abstract

Chitosan, a naturally derived polysaccharide, was covalently linked to chemically converted graphene (CCG) and the properties of the resulting composites were investigated. The composites were prepared using a stable dispersion of CCG in aqueous solvent. The CCG sheets are stabilised in solution by a small number of peripheral charged groups that can be used to form amide linkages with the polymer matrix. Apart from processability and swellability, the synthesized composites exhibited improved mechanical properties and conductivity by the addition of graphene. Graphene incorporation also introduced a control over the extent of swelling in the composites. The synthesized graphene/composites are promising materials for a variety of applications, for example as conducting substrates for the electrically stimulated growth of cells. Chitosan, a naturally derived polysaccharide, was covalently linked to chemically converted graphene (CCG) and the properties of the resulting composites were investigated. The composites were prepared using a stable dispersion of CCG in aqueous solvent. The CCG sheets are stabilised in solution by a small number of peripheral charged groups that can be used to form amide linkages with the polymer matrix. Apart from processability and swellability, the synthesized composites exhibited improved mechanical properties and conductivity by the addition of graphene. Graphene incorporation also introduced a control over the extent of swelling in the composites. The synthesized graphene/composites are promising materials for a variety of applications, for example as conducting substrates for the electrically stimulated growth of cells.

In vitro investigation of electrophoretically deposited bioactive hydroxyapatite/chitosan coatings reinforced by graphene

“…Graphene is known as an excellent material for the modification of biopolymers, because it acts as a reinforcing filler in polymer-based composites [20,31,34,35]. Diffraction peaks corresponding to the (0 0 2), (211), ( 112), and (3 0 0) crystal planes of HAP are shifted to lower angles in HAP/CS/Gr composites than in pure HAP (Table 1), which means that the corresponding d-spacings increased (Table 2).…”

“…Additionally, incorpo-ration of HAP in the composite structure increases the osteocon-ductivity of the material, improving its bioactivity and bone-bonding ability [18,19]. Some properties of chitosan, including its mechanical proper-ties and conductivity, can be modified by the incorporation of 61 graphene, which controls the swelling rate of the polymer [20]. Graphene is composed of a single layer of sp2-hybridized carbon atoms arranged in a twodimensional honeycomb lattice.…”

“…It is well known that electrophoretic deposition (EPD) of composite coating on the metal substrate is very suitable method for obtaining potential hard tissue implants [6][7][8]30]. Great number of papers are available dealing with different systems based on graphene oxide, hydroxyapatite and/or chitosan composites with the aim to be applicable as biomaterials [9,20,24,31]. It has been postulated that graphene-based materials cause physical damage on bacterial membranes upon direct contact, resulting in the release of intracellular contents.…”

Wet‐spinning and carbonization of graphene/PAN‐based fibers: Toward improving the properties of carbon fibers

“…Graphene is a planar monolayer of carbon material arranged in an hexagonal honeycomb structure . The extraordinary properties of graphene have been used to great effect in composites . With graphene being scalable and facile synthesis processes are available, making it an ideal filler for the composites.…”

Partially reduced graphene oxide and chitosan nanohybrid membranes for selective retention of divalent cations

“…14,15 CS and GO based membranes were reported to have denser structures than the bare CS membrane and showed an improved performance in ethanol-water separation, proton conductivity and mechanical strength. 16,17 Until now, only a few GO-CS desalination membranes have been reported, which focused on the removal of anions and sodium ions. Gao and coworkers reported a negatively charged composite membrane of O-(carboxymethyl)-CS and GO with a nanoporous structure and high rejection of a divalent anion (Na 2 SO 4 , 92.9%), but a moderate rejection of a monovalent anion (NaCl, 62.0%).…”