Development of biodegradable vinyl acetate and acrylic acid grafted gelatin copolymer for dye adsorption

A novel biodegradable copolymer and nanocomposite with nickel-doped zinc oxide were developed using grafting acrylic acid and vinyl acetate as gelatin backbone in the presence of ammonium persulfate as an initiator. The copolymer and its nanocomposite were formed through free radical polymerization. The prepared copolymer and its nanocomposite were characterized using Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). The intense bands at 1750 cm(-1), 1375 cm(-1), 1250 cm(-1), and 1050 cm(-1)in the FTIR spectrum of polymers confirm the grafting of monomers of the gelatin backbone. The TGA analysis indicates that the copolymers were not wholly exhausted up to 500 degrees C, and adding nanoparticles enhanced the thermal stability. The degradation study revealed a 25.29% and 15.01% weight loss over two months for copolymer and nanocomposite, respectively. Results showed that the initial weight of the copolymer and its nanocomposite increased due to water adsorption and then decreased, as identified by the soil burial method. The copolymer is biodegradable, and the addition of nanoparticles (nanocomposite) increased its shelf life and resistance to soil microbes. The synthesized nanocomposite was evaluated as an adsorbent for methylene blue dye from an aqueous solution. The adsorbent copolymer gelatin-g-poly(vinyl-acetate-co-acrylic acid) with Ni-doped ZnO NPs may prove to be a new route toward pollution control for the removal of methylene blue, having a removal capacity of 521.26 mg/g.