Synthesis of zinc hydroxystannate/reduced graphene oxide composites using chitosan to improve poly(vinyl chloride) performance

Chitosan-modified zinc hydroxystannate (ZHS-CS) was synthesized using the cations of the biomaterial chitosan (CS) and ion replacement strategy. A ZHS-CS and reduced graphene oxide (rGO) hybrid flame retardant (ZHS-CS/rGO) was synthesized for use in flexible poly (vinyl chloride) (PVC). Scanning electron microscopy images indicated that ZHS-CS and rGO were evenly dispersed in ZHS-CS/rGO without agglomeration. Fourier transform infrared spectroscopy results showed that rGO was fully reduced. The flame-retardant and mechanical properties of PVC composites were investigated using the limiting oxygen index (LOI), a cone calorimeter, and mechanical equipment. By replacing one-fifth of the zinc ions in ZHS by chitosan cations to obtain Sn-4Zn-1CS/rGO, the ZHS-CS/rGO was found to improve PVC composite performance. The total heat release and total smoke release of PVC/Sn-4Zn-1CS/rGO were reduced by 24.2 and 40.0 %, respectively, from those of pure PVC.