Converting industrial alkali lignin to biobased functional additives for improving fire behavior and smoke suppression of polybutylene succinate

The inherent flammability of biodegradable polybutylene succinate (PBS) extremely restricts the growing applications as packaging and construction materials; meanwhile, only a minority of industrial alkali lignin has been effectively utilized until now. To address these two challenges, herein we have converted alkali lignin into one biobased additive for PBS by chemically modified lignin with phosphorus, nitrogen, and the zinc(II) ions. Cone calorimetry results show that addition of 10 wt % modified lignin (PNZn-lignin) reduces the peak heat release rate and total heat release of PBS strikingly by 50 and 67%, respectively. Moreover, the total smoke production is decreased noticeably by 50%. Observations of char residues indicate that adding PNZn-lignin leads to a compact, intact, and thick char layer that is responsible for such enhanced properties. This work offers a new strategy for reducing the flammability and smoke release of PBS, promoting high-value-added utilization of industrial lignin, and designing biobased advanced polymeric materials