The synthesis and characteristics of sodium alginate/graphene oxide composite films crosslinked with multivalent cations

Association of a method of the incorporation of graphene oxide (GO) into sodium alginate (Na‐alg) polymer matrix with a method of the use multivalent cations crosslinker was put forward to synthesize novel Na‐alg/GO nanocomposite films. The structures, morphologies, and the properties of Na‐alg/GO films were characterized by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FE‐SEM), thermogravimetric analysis (TGA), and tensile tests. The results revealed that the interlayer distance of GO sheets increased from 0.83 nm to 1.08 nm after assembling with Na‐alg, and Na‐alg inserted into GO layers crosslinking with multivalent cations increased the interlayer distance further. Ionic crosslinking significantly enhanced thermal and mechanical properties of Na‐alg/GO nanocomposite films. In particular, Fe³⁺ led to Na‐alg/GO nanocomposite films of significantly higher tensile strength and modulus than Ca²⁺ and Ba²⁺. The excellent thermal and mechanical properties of these novel Na‐alg/GO nanocomposite films may open up applications for Na‐alg films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43616.