Biobased flame retardants for improving flame retardancy and smoke suppression of polyvinyl alcohol

In the research of flame‐retardant materials, flame retardants containing 9,10‐dihydro‐9‐oxo‐10‐phosphaphenanthrene‐10‐oxide have become a hot topic in domestic and international research due to their highly reactive P‐H bonds and the characteristic of not releasing harmful gases during the combustion process. Resveratrol cross‐linked with tannic acid and 9,10‐dihydro‐9‐oxo‐10‐phosphaphenanthrene‐10‐oxide in polyvinyl alcohol were prepared. The UL‐94 grade of the polyvinyl alcohol compounds reached the V‐0 grade. The synergistic effect of resveratrol cross‐linking tannic acid and 9,10‐dihydro‐9‐oxo‐10‐phosphaphenanthrene‐10‐oxide can significantly enhance the effect of smoke suppression on polyvinyl alcohol. The total smoke production of resveratrol/tannic acid/9,10‐dihydro‐9‐oxo‐10‐phosphaphenanthrene‐10‐oxide/polyvinyl alcohol‐3 is 9.3 m 2 , which is 59.1 % less than that of polyvinyl alcohol. The dense expanded char layer formed during combustion and the presence of gas pores on the test specimen surface prove that resveratrol/tannic acid/9,10‐dihydro‐9‐oxo‐10‐phosphaphenanthrene‐10‐oxide plays an active role as a flame retardant both in the condensed phase and gas phase.