Effect of a novel chitosan-based flame retardant on thermal and flammability properties of polyvinyl alcohol

A novel natural carbon agent-based flame retardant urea salt of chitosan phosphate (UPCS) has been prepared with chitosan, phosphorus pentoxide, and urea. It was characterized by C-13 NMR, P-31 NMR, Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy. Its influence on thermal properties and flammability performance of polyvinyl alcohol was investigated through thermogravimetric analysis, microscale combustion calorimetry experiment, and real time FTIR. The surface morphology of the residual char was investigated with the scanning electron microscope measurement. The results revealed that UPCS accelerated the dehydration action as well as the formation of char. Furthermore, flammability performance of polyvinyl alcohol was improved by the presence of UPCS.