The Combined Effect of Gas Phase and Condensed Phase Mechanisms in Flame Retardancy of Polybutylene Succinate

ABSTRACT In this study, we addressed the challenge of eliminating, during combustion, the flaming dripping behavior of polybutylene succinate flame retarded with ammonium polyphosphate, a key barrier to achieving a V‐0 rating in the UL 94 flammability test without excessive additive loading levels. Different 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide‐based flame retardants were applied to combine their gas‐phase mechanism with the solid‐phase mechanisms of ammonium polyphosphate. The flame retardant efficiency was evaluated through several flammability tests, thermogravimetric analysis, thermogravimetric analysis coupled with Fourier‐transform infrared spectroscopy, and Raman spectroscopy. The results demonstrated that the combination of gas‐ and solid‐phase flame retardants can be effective in improving the flame retardancy of polybutylene succinate while minimizing the total additive content.